TK-FGDSCE-010314 Rev 1 of 110113 · Lamella clarifier, and finally filtration. The PWP discharge treatment system consists of filtration only. Typical operation of the CPRP is to

Revision: 1 – 1/3/14 Turk Pond Treatment System Description Page 1 of 64



Figure 1 - Pond Treatment System Basic Flow Reference Diagram


Turk Pond Water Treatment System Description

NOTE: Figure 1 can be referenced to provide an elementary flow path for the Pond Water

Treatment System. Additionally the following flow diagrams can be referenced for specific

information:

Flow Diagram Description

1-51WW001 COAL PILE RUNOFF POND

1-51WW002 PROCESS WATER POND

1-51PW004 POTABLE WATER

1-51SW011 SERVICE WATER

1-51QW010 LAMELLA SETTLERS

1-51QW011 THICKENER, FILTER PRESS

1-51QW012 EFFLUENT TANK, PUMPS

1-51QW013 BACKWASH, RINSE WATER TANK

1-51QW014 BACKWASH AND RINSE PIPING

1-51QW015 MULTI MEDIA FILTERS



1-51QW019 FLOCCULENT PUMPS

1. Introduction

1.1. Purpose

The coal pile run-off pond (CPRP) and process water pond (PWP) discharge water treatment

system is intended to reduce total suspended solids (TSS) to the levels required for discharging

to internal outfalls 201 and 101 respectively. This is accomplished through supplemental

treatment to achieve the required TSS reductions and simultaneously manage water inventory.

The CPRP discharge treatment system consists of coagulation, flocculation, settling through a

Lamella clarifier, and finally filtration. The PWP discharge treatment system consists of

filtration only.

Typical operation of the CPRP is to provide storage (surge) capacity during rain events, such that

the treatment system is not overburdened. Routine management of CPRP water levels are to

ensure that free storage volume is readily available to hold run-off water from major rain events.

Thus CPRP levels must be maintained at as low a level as possible (ideally empty) at all times

(when practical) by discharging to the PWP, or when necessary to outfall 201. Therefore

utilization of the treatment system at the start of all significant / measurable rain events,

providing the required TSS reduction, must be implemented to ensure that the CPRP provides


ample retention for subsequent major rain events and prevents the need for any potential

discharge to outfall 002 or exceedences of outfall 201’s TSS limits.

Typical operation of the PWP is to supply and store water to and from plant process water users /

contributors as needed. The PWP also provides surge capacity, though it is intended to operate

as a net consumer of water, without the need for surplus discharge to control pond levels.

However should excess PWP influent(s) ultimately require discharge to outfall 101 to manage

pond levels; this flow is treated with multi-media filtration (MMF) for TSS removal to prevent

exceedences of outfall 101’s TSS limits.

The treatment system for both internal outfalls (101 and 201) is combined and share common

multi-media filtration equipment that can only be used for treatment of one pond waters at a

time. The options to manage CPRP and/or PWP discharge within the treatment system are

determined / selected based on several operational factors and provide the functionality to

support the three following scenarios:

1) Treatment of CPRP discharge only

2) Treatment of PWP discharge only

3) Simultaneous treatment of both CPRP and PWP discharge

Additionally, within these three treatment scenarios, subsequent options exist for the treated

effluent location of the pond(s) discharge and/or processing steps. These include the following:

Treatment of CPRP discharge only

A) For routine management of CPRP levels, CPRP discharge is sent through the Lamella

clarifiers followed by multi-media filtration, with the final treated effluent directed into the

PWP. This provides a high quality effluent for supplemental PWP make-up while managing

CPRP levels. This option is available provided the PWP levels are low enough to accept this

effluent. Based upon the overall system design (subsequently described) this treatment

option is suggested for CPRP discharge flow rates ranging from 100 to 400 gpm.

B) For CPRP discharge treatment rates greater than 400 gpm that are used to supply

supplemental make-up water to the PWP; the option available is to send the Lamella effluent

directly to the PWP. This is accomplished by a controlled overflow of the Lamella effluent

storage tank, which is directed into the PWP. This also provides a relatively high quality

make-up water to the PWP, though it may be slightly higher in TSS than a filtered effluent.

C) If the level in the PWP becomes/is too high to accept treated CPRP discharge or if a decision

is made to select this effluent destination, the treated water can be directed into the make-up

water pond (MWP) through outfall 201 to control CPRP levels. With this option the CPRP

discharge is treated through the Lamella clarifiers, then the following options are available to

send the Lamella effluent to the MWP:

a. Further treatment with multi-media filtration, provided the filters are not treating

PWP discharge and are available, sending the filtered effluent to outfall 201. This is

the recommended treatment for flow rates up to 550 gpm.

b. Directing the Lamella effluent storage tank into outfall 201. This option is available

if the multi-media filters are unavailable and/or when flow rates exceed 550 gpm.


c. Any flow rate combinations of the two previously described options (a. and/or b.),

depending on equipment availability (filters) and/or the total CPRP discharge flow

rates required to manage CPRP levels. The two treated effluents are combined prior

to the 201 outfall and sent to the MWP.

Treatment of PWP discharge only

Treatment of surplus PWP discharge is accomplished by multi-media filtration only. A portion

of the PWP sump pump discharge is directed through the multi-media filters at a nominal

designed flow rate of 300 gpm. Filtered effluent is combined with cooling tower blowdown

through outfall 101 and ultimately sent into the waste water pond (WWP).

Simultaneous treatment of both CPRP and PWP discharge

With simultaneous treatment of both pond discharges; the multi-media filters can only treat

discharge from the PWP. Therefore, PWP treatment proceeds as previously summarized,

through the multi-media filters into internal outfall 101. Discharge from the CPRP is treated

thought the Lamella clarifiers and is pumped from the Lamella effluent storage tank to the MWP

through internal outfall 201.

The pond treatment system is sized based on historic rain event data to provide an adequate

treatment rate, storage volume for routine rain events, and historically frequent major rain

events. However, atypical high frequency major rain events may exceed the design flow of the

treatment system. These rare instances are outside of the design basis and in order to quickly

regain the surge capacity of the CPRP and prevent a discharge to external outfall 002, the CPRP

is pumped directly to the MWP, thought internal outfall 201, via the (treatment system) bypass

line. If bypassing the CPRP discharge treatment system is necessary, the TSS could be in excess

of outfall 201’s permit limits, though a discharge to outfall 002 would be avoided.

2. Design Basis

2.1. CPRP Design Basis and Operation

The CPRP is sized to provide storage of rain water run-off from a 25 year rain event,

approximately 9 million gallons of water. In order to maintain and restore the pond’s storage

capacity from routine rain events, two sets of pumps are employed. Normal operation is with

two 100% low-flow pumps each rated at approximately 200 gpm, pumping to the treatment

system and into the PWP. For management of extreme rain events or emergency circumstances,

two 50% high-flow pumps each rated at 3,350 gpm discharges into the plant’s MWP via a

dedicated 20-inch line. To protect the integrity of the pond walls, the pond also employs an

overflow weir that discharges to Bridge Creek (waters of the State), through external outfall

002.

NOTE: Any operation of the high flow pumps, bypassing the treatment system and discharging

to the MWP, and/or weir overflows to outfall 002 are only employed to manage extreme and/or

emergency situations. These are not anticipated to occur and are not considered standard

operation.


2.2. TSS Management – PWP and CPRP

The objective of the pond treatment system is to reduce the TSS levels in the CPRP and PWP

discharge water to less than 30 mg/L. This level of TSS ensures that the permit limit for both

internal outfalls, which is 30 mg/L monthly average, and 50 mg/L daily maximum, are met.

Empirical testing has demonstrated that the required TSS reduction of the CPRP discharge is

achieved by a combination Lamella clarifier followed by a multi-media filter (MMF) system.

Similarly, multi-media filtration alone has demonstrated the required TSS reduction for

treatment of PWP discharge.

2.3. Water Treatment System Capacity

Evaluations of historical rainfall data for the region assessed the likely outcomes of varying

capacities of CPRP discharge treatment systems. The analysis assumed that at the onset of a

significant / measureable / typical rainfall event, defined as a rain event with rainfall totals

below the 25 year rain event, plant personnel would initiate operation of the CPRP water

treatment system, discharging to the PWP or when necessary to outfall 201. This is to ensure

adequate pond inventory for storage of major rain event(s) run-off water, defined as a rain

event with rainfall totals up to the 25 year rain event. Continuing/continuous and/or increasing

rainfall in excess of the 25 year rain event and/or with events occurring at un-historically high

frequencies, the design basis of the CPRP discharge treatment system’s pond inventory

management capacity would be exceeded. In these instances where the CPRP level would

reach six inches below the overflow weir to outfall 002, the existing high flow pumps would be

placed in service thus bypassing the water treatment system. This condition is termed a

“Bypass Event”, and under such a situation the 6,700 gpm high-flow pumping system,

discharging to the MWP, would keep the pond from overflowing into outfall 002. This

prevents a CPRP discharge to an external outfall. However the TSS levels in the bypass line

exceeding the plant’s discharge permit limits, established for internal outfall 201, would be a

highly probable outcome. Additionally, despite the designed capacity of the high-flow pumps

to prevent weir overflows, extreme rainfall events, beyond what can be anticipated based on

the available historical rainfall data analyzed, may not preclude a weir overflow (discharge to

002). Given the pond’s poor settling characteristics, in such an extreme situation, external

outfall 002 would most certainly experience a permit TSS exceedence.

Based on this prefaced design philosophy and historical rain fall data analysis, a nominal 800

gpm Lamella clarification system, which is the main component for suspended solids removal

in the CPRP discharge, was selected. This design treatment rate, based on the historical data

analysis, would prevent CPRP weir overflow events; provided extreme rainfall events are not

encountered. Two 50% capacity Lamella clarifiers (each rated at a nominal flow of 400 gpm)

provide treatment of CPRP discharge to meet the nominal 800 gpm design criteria.

The MMF is provided based upon the filtration capacity needs for the PWP as part of a prior

engineering study. As such, the MMF is a 3 x 50% triplex system, designed to treat a nominal

300 gpm (each filter is rated at a 150 gpm nominal capacity) with a maximum of 550 gpm.

The triplex filtration system allows for one filter vessel to be backwashed online while

maintaining a nominal flow of 300 gpm through the other two vessels.

When the MMF is configured for CPRP treatment where it provides final polishing of the

Lamella effluent, the total effluent flow from the Lamella can/will be in excess of the designed

nominal filter capacity. Under these conditions, the excess Lamella effluent flow is combined


with the filtered water. The TSS of the combined waters is anticipated to be below the 201

outfall limit, though it will be tested to confirm this prior to discharging to the 201 outfall.

Additional capacity may be available within the MMF system that may allow the treatment

system to operate without a direct flow of Lamella effluent to the 201 outfall; however it will

depend on the effluent quality of the Lamella as well as further onsite testing to confirm higher

flow rates through the MMF will be acceptable. In either case when the MMF is utilized for

CPRP treatment the designed filtration system redundancy is compromised.

3. Equipment Descriptions

3.1. Coal Pile Runoff Pond Pumping and Piping to Lamella Influent Mix Tanks / Clarifiers

3.1.1. The CPRP low flow pumps (1PP-WW0210/WW0220) are each rated at 200 gpm at 130’

TDH with a maximum flow capability of 395 gpm at 85’ TDH. This allows for

approximately 790 gpm of total influent flow to the Lamella clarifiers.

3.1.2. The low flow pumps are direct drive utilizing a nominal 20 HP motor.

3.1.3. The low flow pump discharge feeds are re-directed to the 20-inch high flow pump (1PP-

WW0110/WW0120) discharge line which is branched off via an 8-inch line to the inlet of

the Lamella influent mix tanks. The low flow pump discharge also feeds an alternate line

for coal yard water users (a future installation/usage based on plant assessment).

3.1.4. At the take-off location of the 8-inch feed line to the Lamella influent mix tanks a 20-inch

isolation valve (1HV-WW4403) is placed just downstream to prevent untreated flow

from going to the MWP (201 outfall). The associated 8-inch return line (treated water)

from the CPRP treatment system is tied back into the same 20-inch line just downstream

of the 20-inch isolation valve. The official 201 outfall TSS sample location (1HV-

WW4603) is on the 8-inch return line, inside the pond treatment building, downstream of

the 8-inch MMF common outlet line and Lamella effluent feed tie point.

3.1.5. A pressure transmitter (1PIT-WW9400) is located on the CPRP low flow pump common

discharge header.

3.1.6. Two vee-ball style control valves (1RV-QW0112/1RV-QW0122) controls the flow

independently to each Lamella clarifier trains. This allows for independent Lamella

clarifier train operation.

3.1.7. The CPRP low flow pumps are operated as follows.

3.1.7.1. One pump is in service with the second pump in automatic standby.

3.1.7.2. The flow control valves to each Lamella clarifier train are automatically adjusted

to maintain a flow rate set point based on feedback from each trains inlet flow

transmitter (1FIT-QW0112/1FIT-QW0122). Each flow control valve controlling flow

to the Lamella train fail/trip in the closed position.

3.1.7.3. The flow transmitters’ signal to the Lamella trains also controls the speed of the

coagulant and flocculent chemical injection pumps to maintain respective dosage set

points.


3.1.7.4. Due to high velocities expected when the low flow pump is operated at the end of

its curve, mitigation of this potential is accomplished by starting the standby pump

when the total Lamella clarifier influent flow rate set point is above 300 gpm or when

header pressure drops below 40 psig.

3.1.7.5. Provision are incorporated in the plant DCS logic to allow the use of one high flow

pump (1PP-WW0110/1PP-WW0120) in place of the low flow pumps at total Lamella

clarifier influent flow rates greater than 550 gpm.

3.1.8. Coagulant Feed (1SK-QW4100)

A coagulant feed, common to both Lamella trains, is injected upstream of two inline static

mixers in the common 8-inch influent line prior to branching off to each individual influent

mix tank. The total flow signal from both Lamella train flow transmitters is added to provide

the total inlet flow signal that is used to pace the coagulant feed for the CPRP treatment

system. There are 2 x 100% coagulant injection pumps, one duty and one standby. Estimated

(average) dosage is approximately 50 ppm of an aluminum based coagulant.

PLC values used for flow pacing of the coagulant feed are:

User input values at PLC HMI Reference Variable

Coagulant dose (ppm) C_D

Coagulant specific gravity (no units) C_SG

Coagulant percent solution (%) C_P

Dosing pump output at 100% speed (ml/min) C_MX

PLC Values From Instrumentation

Lamella Train 1 Influent Flow (gpm) LT1_Q

Lamella Train 2 Influent Flow (gpm) LT2_Q

Dosing Equation [C_Q], (% speed):

(LT1_Q�LT2_Q�C_D�0.377

C_SG�C_P�C_MX� 100%

3.1.9. Sample points with manual isolation valves are located upstream of the coagulant

injection point (1HV-QW0100) and downstream of the static mixers on each Lamella

train influent line (1HV-QW0510/1HV-QW0520).

3.2. Lamella Influent Mix Tanks (1TK-QW3010/1TK-QW3020).

3.2.1. The Lamella influent mix tanks are each a 108-inch diameter by 120-inch high open top

baffled mixing tank. The tanks are equipped with a 1.5 HP, 100 rpm constant speed,


variable drive, top mounted mixer used for dispersion and mixing of the flocculent with

the influent water.

Flocculent is added into each individual Lamella influent mix tank influent line at

approximately 1.5 ppm as product. The flocculent is activated in a solution tank through

a mix chamber with dilution water provided from the potable water header. Each

flocculent feed system consists of 1 neat flocculent feed pump, 1 mixing chamber, 1

prepared solution day tank, and 1 solution (prepared flocculent) feed pump.

Each Lamella inlet flow transmitter provides the signal to an individual flocculent

solution feed pump to pace the flocculent feed to each Lamella train independently.

There are 2 x 100% flocculent solution feed systems, one dedicated to each Lamella train

and one common 1 x 100% “cold” standby, that is a shared standby system with the

thickener/filter press flocculent feed skid.

PLC values used for flow pacing of the Lamella flocculent feed are:

User input values at PLC HMI Reference Variable

Flocculent dose (ppm) F*_D

Flocculent percent solution (%) F*_P

Dosing pump output at 100% speed (ml/min) F*_MX

PLC Values From Instrumentation

Lamella Train 1 Influent Flow (1FIT-QW0112,

gpm)

LT1_Q

Lamella Train 2 Influent Flow (1FIT-QW0122,

gpm)

LT2_Q

(*) = 1 or 2 depending on Lamella train

Dosing Equation [F*_Q], (% speed – example for Lamella train 1):

LT1_Q�F1_D�0.377

F1_P�F1_MX� 100%

3.3. Lamella Clarifiers (1TK-QW3110/1TK-QW3120)

3.3.1. The Lamella clarification process is utilized for the removal of the suspended material

(TSS) in the CPRP discharge water. Clarification in general is designed to bind the

smaller particles (i.e. coal fines) in the raw (CPRP) water together to produce larger


particles through coagulation and flocculation. This is accomplished by charge

neutralization of the suspended particles through the reaction between the coagulant and

the influent water and subsequent agglomeration of these particles together with the

addition/aid of a flocculent. With proper contact time and mixing, the influent (smaller)

particles will combine in this physical-chemical process to form larger particles with a

mass high enough that it will drop out in the clarifier’s settling basin by gravity.

The clarified water (“clear” overflow) should have a significant portion of the influent

TSS removed in this process and the suspended material drops out in the settling basin

(“sludge” underflow) for disposal.

The Lamella clarification process also utilizes inclined plates within the settling basin to

provide a significant increase in surface area compared to traditional clarifiers to enhance

settling. The inclined plates decreases the particulate settling distance that needs to occur

in the settling basin, allowing for a Lamella clarifier to operate at higher rise rates

(velocities) and with a consequential footprint reduction than traditional clarifiers.

3.3.2. The Lamella clarifiers have a nominal minimum flow capacity of 100 gpm and a

maximum total flow capacity of 800 gpm (400 gpm per train). Individual Lamella

clarifier operating values are:

Nominal Flow (gpm) 400

Maximum Influent TSS (mg/L) 1000

Nominal Effluent TSS (mg/L) 30 – 50

Nominal Underflow Solids (%) 0.2 – 1.0

Surface Rise Rate (gpm/ft2) 1.7

Plate Area (ft2) 1884

Plate Area Rise Rate (gpm/ft2) 0.21

Settling Basin Length (ft) 19.50

Settling Basin Width (ft) 11.75

Nominal Sludge Removal (gpm) 50

Maximum Sludge Removal (gpm) 100

3.3.2.1. The Lamella clarifier treatment system is supplied as a 2 x 50% (2 x 400 gpm)

train configuration and consists of 2 inlet flow control valves, 2 inlet flow

meters/transmitters, 2 influent (flocculent) mixing tanks, 2 effluent turbidity meters, 2

inclined FRP plate Lamella clarifiers, eight (8) ¾-inch settling basin sludge sample

valves, and 4 underflow sludge transfer pumps (each train has a 2 x 100% (2 x 50

gpm) pump configuration).

3.3.3. Effluent discharge from the Lamella clarifier will gravity feed to the Lamella effluent

storage tank or the backwash / rinse water storage tank.

3.3.3.1. An automatic control option for the Lamella effluent destination can be done

utilizing the online turbidity meter analysis. A high-high turbidity alarm would

provide an option for the PLC to automatically shut the block valve feeding the

effluent storage tank and open the block valve in the line feeding the backwash / rinse

water storage tank.


3.3.4. The Lamella sludge transfer pumps (sludge underflow) (1PP-QW3111/3112/3121/3122)

are each rated at 50 gpm. Each Lamella train has 2 x 100% capacity pumps (total sludge

pumping capacity per Lamella train is 100 gpm, system total is 200 gpm). Sludge

transfer from the Lamella to the thickener will be done on a timed duration and frequency

basis (time the pump is on and time the pump is off) with all parameters adjustable

through the PLC HMI. Sludge transfer will depend on the influent solids loading to the

Lamella trains and will require operator interaction to optimize and manage this

inventory.

3.3.5. A single biocide chemical addition skid (1 x 100% pump) is used for manual,

intermittent treatment with biocide (initially sodium hypochlorite) to the flocculent mix

tanks to prevent microbiological growth within the system. Treatment with biocide may

be done online or offline as necessary.

3.4. Lamella Effluent Storage Tank (1TK-QW3400) and Pump Skid (1PP-QW3410/1PP-QW3420)

3.4.1. The primary function of the Lamella effluent storage tank is to provide storage for MMF

backwash influent and rinse water to prevent cross-contamination of PWP water into

CPRP water when the MMFs are used for treating Lamella effluent.

3.4.2. Tank capacity is a nominal 30,000 gallons, which supplies the required volume to

backwash and rinse one MMF vessel (anticipated backwash volume of 20,250 gallons)

without any influent flow to the tank.

3.4.3. Tank level transmitter (1LIT-QW1102) provides the signal for:

3.4.3.1. Permissive to start MMF backwash sequence (set point level above grade, default

of 9-feet).

3.4.3.1.1. When discharge from this tank is directed to the MMFs, the tank level is

automatically maintained at 9-feet above grade to ensure adequate volume for

MMF backwashing.

3.4.3.2. Permissive for Lamella effluent transfer pump operation (minimum set point level

above grade).

3.4.3.3. Provide a bias for the Lamella influent flow control valves to prevent a tank

overflow by reducing flow rates should tank levels exceed 9-feet above grade.

3.4.4. Discharge pumping consists of 2 x 100% pumps, each rated at 1365 gpm.

3.4.4.1. Pumps are capable of supplying 900 gpm backwash and concurrent influent flow

to two MMFs at 400 gpm (one MMF backwashing, two MMFs online processing 400

gpm).

3.4.4.2. Pump minimum flow protection is accomplished using an orifice plate providing

sufficient flow, approximately 65 gpm, to prevent the pump(s) from overheating.

3.4.5. There is a turbidity monitor (1AIT-QW1302) on the pump discharge upstream of the

recirculation tap-off point.


3.4.5.1. Turbidity values can be used to direct flow to the backwash / rinse water storage

tank on a high-high turbidity alarm.

3.4.6. Direct discharge into the PWP is accomplished through the 10-inch tank overflow line

(1QW160).

3.4.7. Discharge into the MMFs is controlled by the MMF outlet flow control valve (1RV-

QW0105).

3.4.8. Direct discharge to outfall 201 from the Lamella effluent transfer pumps (through 1RV-

QW1802), is only possible provided the TSS sample analysis obtained from sample valve

(1HV-QW4600) indicate this is acceptable.

3.4.9. Discharge to the backwash / rinse water storage tank or to the coal pile run-off pond can

be done during Lamella startups, to control Lamella effluent storage tank level, or to

purge the Lamella effluent storage tank if contaminated.

3.5. Multi Media Filters (MMFs) (1SK-QW3500)

3.5.1. Three (3) 84-inch diameter, 225 psi ASME code stamped MMF vessels provide solids

removal for PWP discharge or Lamella clarifier effluent from the CPRP. The MMF

system design basis is to treat a nominal 300 gpm of PWP water prior to discharging into

the 101 outfall. However due to the anticipated infrequent usage of these filters for this

service, they are also set up to provide supplemental TSS removal for the Lamella

effluent; providing downstream filtration during periods of un-steady state / transitional

conditions, which has been found to be necessary to consistently meet discharge TSS

levels for the 201 outfall.

The MMF vessels contain filter media to remove the suspended solids. The media depths

in each vessel are 18-inches of anthracite, 12-inches of filter sand, and 6-inches of garnet.

MMFs provide deep bed filtration of the suspended solids allowing for staged filtration as

each of the media layers provide finer particle filtration as flow moves vertically down

the bed. As such, the design of the MMF allows for relatively high filtration rates with

less pressure decay than typical single or dual media filtration systems. Solids that

accumulate within the media produce head loss (pressure drop/decay from the filter inlet

line to the filter outlet line) across the filter bed. Once the head loss through the media is

high enough, the filter must be backwashed (reverse flow) at a relatively high rate to

remove the accumulated solids and restore the media.

3.5.2. Normal operation, when treating PWP discharge - influent comes from the PWP sump

pumps discharge, MMF outlet (filtered discharge) is sent to outfall 101, backwash and

rinse water influent is supplied by the PWP sump pumps discharge, and backwash waste

and rinse water outlet is sent back to the PWP. A MMF skid outlet turbidity meter is

used for indication of outlet quality and should these levels trigger a high-high turbidity

alarm during operation, the MMF discharge is automatically directed back to the PWP.

3.5.3. Normal operation, when treating Lamella clarifier effluent - influent comes from the

Lamella effluent storage tank transfer pumps, MMF outlet (filtered discharge) is sent to

the PWP or when necessary (typically during high PWP levels) discharged to outfall 201,

backwash and rinse water influent is supplied from the Lamella effluent storage tank

transfer pumps, and backwash waste and rinse water outlet is sent to the backwash / rinse


water storage tank. A MMF skid outlet turbidity meter is used for indication of outlet

quality and should these levels trigger a high-high turbidity alarm when discharging to

outfall 201, the MMF discharge is automatically directed to the backwash / rinse water

storage tank.

3.5.4. System design uses manual double block and bleed isolation philosophy of the MMF

outlet water to maintain isolation of PWP water from CPRP water discharge to outfalls

101 or 201 respectively.

3.5.5. Valve position indication provides permissives for each mode of operation and

transitional usage of the MMF system.

3.5.6. Chemical Feed Systems

3.5.6.1. A ½- inch female NPT tap is installed in the filter inlet line for provisions to

accommodate a future chemical feed (filter aid) inlet/injection point should it be

necessary.

3.5.7. Disinfection

3.5.7.1. Periodic disinfection with a sodium hypochlorite soak and backwashing can be

performed if needed. A ¾-inch female NPT connection on the backwash inlet line to

each filter vessel is provided to accommodate a periodic injection of sodium

hypochlorite. Should disinfection be necessary, the Lamella sodium hypochlorite

dosing skid can feed to the injection point. The dosing skid will feed to the injection

point by portable hose connections. Once chemicals have been added the vessel can

be air mixed, soaked (as/if needed), and backwashed. This is all a manual operation

controlled by the User.

3.6. Backwash / Rinse Water Storage Tank (1TK-QW3600) and Pump Skid (1PP-QW3610/1PP-

QW3620)

3.6.1. The purpose of the backwash / rinse water storage tank is primarily to temporarily hold

the MMF backwash and rinse water when filtering Lamella effluent to prevent solids

accumulation in the PWP; the initially designed location for backwash waste. The tank

also provides temporary storage for Lamella effluent during upset conditions. This tank

provides the normal means of returning waste / upset waters back to the CPRP.

3.6.2. Tank capacity is a nominal 40,000 gallons providing volume to hold 2 MMF vessel

backwashes / rinse cycles without effluent flow from the tank. Normal operation with

300 gpm effluent from the tank provides storage capacity for typical MMF backwashing

as needed.

3.6.3. Tank level transmitter will provide signal for:

3.6.3.1. Permissive to MMF skid for backwash sequencing of one vessel (set point level

above grade, default value of 1-foot 8-inches).

3.6.3.2. Permissive for discharge pump operation (1-foot 6-inches above grade pump trip,

1-foot 8-inches above grade reset).


3.6.3.3. Level control in the tank is accomplished by a defined set point in the PLC HMI to

start and stop the discharge pumps to ensure a maximum free inventory in the tank at

all times as practical. Discharge pumps will start at the defined level set point,

initially 2-feet 6-inches and will continue to run until the low level set point,

initially1-foot 8-inches is achieved. Pumps will remain in automatic standby when

discharge flow is not required and will start when the set point value is achieved. PLC

automatically will define the Lead/Lag pump operation or can be designated by the

User.

3.6.3.4. Auto start and stop of the Lag pump will occur at tank levels of 7-feet 6-inches and

4-feet respectively.

3.6.3.5. Provide an override to close the Lamella influent flow control valves to stop

influent flow should the high level alarm be active for a specified amount of time

when the system is running in “1st Stage Startup”.

3.6.3.6. Provide a bias for the Lamella Effluent Tank to Backwash Tank flow control valve

(1RV-QW1902) to prevent a tank overflow by reducing flow rates should tank levels

exceed the high level set point for a specified amount of time.

3.6.4. When the tank is receiving MMF backwash outlet flow (up to 900 gpm) the Lead pump

will start when the level in the tank reaches 1-foot 6-inches (low level trip point)

3.6.5. Discharge pumping consists of 2 x 100% pumps each rated at 315 gpm.

3.6.5.1. Minimum flow protection is achieved by a manual recirculation with an orifice

plate.

3.7. Lamella Sludge Thickener (1TK-QW3200)

3.7.1. Partially thickened sludge from the Lamella underflow is sent to the sludge thickener for

holding and the continuing thickening necessary prior to feeding the sludge filter press

for ultimate disposal / re-application to the coal pile. The sludge thickener is essentially a

traditional clarifier without upstream coagulation of the influent. The low rise rates

(settling velocities) and high detention time provided in the sludge thickener vessel allow

for settling and further thickening of the Lamella sludge to acceptable concentrations for

filter press operation. If gravity settling alone does not provide acceptable settling,

provisions for a flocculent feed are provided and can be implemented when/if necessary.

The solids that settle to the bottom of the thickener vessel are collected in the center,

ultimately through a sludge scraper mechanism, and are pumped to the sludge filter press.

Overflow from the thickener is sent to the online Lamella influent mix tank(s) or if

overflow solids concentrations are excessive to the PWP.

3.7.2. The sludge thickener vessel is a 30-foot diameter, nominal 84,964 gallon steel tank with a

2 x 12 sloped bottom floor used to collect and thicken the settled sludge from the Lamella

clarifiers.

3.7.3. FUTURE – Sludge scraper mechanism

3.7.4. 2 x 100% (2 x 50 gpm) air operated diaphragm sludge transfer pumps send settled sludge

from each Lamella train underflow to the sludge thickener (4 total pumps, maximum


sludge pumping capacity is 200 gpm). Sludge concentrations entering the thickener are

assumed to be approximately 0.2 – 1.0% solids. Overflow from the sludge thickener is

assumed to be less than 50 mg/L TSS. Underflow from the thickener vessels is assumed

to be 2 – 5% solids.

3.7.5. The air operated diaphragm pumps are controlled by User adjustable PLC HMI set points

defining the pumping duration (minutes pump is on) and dwell/deadband time (minutes

pump is off).

3.7.5.1. During normal Lamella clarifier operation, the air operated diaphragm pumps are

staged such that only one (total) pump is in operation at a time. Should solids

management in the Lamella clarifier settling basin become inadequate with this

restriction, an option on the PLC HMI is available to override this and put the Lamella

in “high solids” mode, allowing up to 100 gpm of sludge flow out of each Lamella.

3.7.6. Four sample locations are provided on the bottom side shell of the thickener vessel to

assess sludge concentrations and bed level.

3.7.7. Sludge level indication instrumentation (1LIT-QW0702) is provided to estimate sludge

volume in the thickener vessel.

3.7.8. Flocculent addition is provided if needed to enhance settling. The flocculent is activated

in a solution tank through a mix chamber with dilution water provided from the potable

water header. Each flocculent feed system consists of 1 neat flocculent feed pump, 1

mixing chamber, 1 prepared solution day tank, and 1 solution (prepared flocculent) feed

pump.

Operational feedback from the Lamella sludge transfer pumps (number of pumps in

operation and Lamella train pumping to the thickener) provides the signal to the

flocculent solution feed pump to pace the flocculent feed to the thickener and opens the

appropriate feed inlet valve. The flocculent feed is provided by a 1 x 100% flocculent

solution feed system and one common 1 x 100% “cold” standby that is a shared standby

system with the Lamella trains’ flocculent feeds. The flocculent system feed piping

branches off to the outlet line from each Lamella train sludge transfer pump discharge.

The feed line also has a second branch off to provide flocculent for a potential future use

to the filter press inlet.

PLC values used for flow pacing of the thickener flocculent feed are:

PLC user input values at the HMI Reference Variable

Flocculent dose (ppm) FT_D

Flocculent percent solution (%) FT_P

Dosing pump output at 100% speed (ml/min) FT_MX

PLC Values


Lamella Train 1, Transfer Pumps in Operation LT1_STP_ON

Lamella Train 2, Transfer Pumps in Operation LT2_STP_ON

Sludge flow per pump (gpm) S_Q (50 – Normal)

(100 – High Solids Mode)

Dosing Equation [FT_Q], (% speed – example for Lamella train 1):

(LT1_STP_ON�S_Q�FT_D�0.377

FT_P�FT_MX� 100%

3.8. Sludge Filter Press (1FL-QW3000)

3.8.1. A sludge filter press is utilized to de-water the pre-thickened sludge from the thickener

for ultimate disposal / re-application on the coal pile. The filter press will provide the

means to transform the sludge slurry into a friable solid suitable for transport. The filter

cake produced from the filter press is discharged to a roll-off dumpster and filtrate

(overflow water) is sent to the effluent storage tank or the PWP. Operation of the filter

press is largely accomplished through relays provided in the Siemens control cabinet

located on the filter press mezzanine. The User will determine when a filter press run is

necessary and will initiate the press sequencing through the PLC HMI. Detailed

operating and system descriptions for the filter press are found in the Siemens vendor

manuals.

3.8.2. The filter press has a 95 cubic foot capacity and produces approximately 3,200 pounds of

a 20% moisture filter cake per run.

3.8.3. Filter press feed pump skid has 2 x 100 % air operated diaphragm pumps each rated from

25 to 175 gpm depending on discharge head pumping thickened sludge (underflow) from

the thickener to the press. The PLC controls the operation of these pumps when the press

is in operation.

3.8.3.1. Until the sludge scraper mechanism is installed in the thickener, the interim

operation of the filter press feed pumps will be automated to continuously recycle

sludge within the thickener tank to prevent solids accumulation at potential “dead”

zones in the tank when sludge is not being transferred from the thickener to the filter

press.

3.8.4. Filtrate water will typically be sent to the Lamella effluent storage tank, though a manual

option is available to route filtrate to the PWP.

3.8.5. A pressure transmitter (1PIT-QW0302) on the filter press inlet line provides a signal to

pace a future flocculent feed (if found necessary) and provide operation information to

the User to evaluate filter press operation.

3.8.6. A locally mounted high pressure washer is available to clean filter press as needed.

3.8.7. Dumping of filter cake is into a roll-off dumpster.


3.8.8. Center core blow back is sent to the roll-off dumpster.

3.8.9. A provision for a future flocculent addition is provided to improve sludge press

operation, should the sludge characteristics change and/or other future operational issues

reveal that this may be necessary.

The proposed automated flocculent addition would only feed when the filter press

sequence is in “stage 1”. Should an additional flocculent feed be necessary past the

“stage 1” sequence, operations would need to set up the flocculent system for a manual

addition.

The flocculent is activated in a solution tank through a mix chamber with dilution water

provided from the potable water header. Each flocculent feed system consists of 1 neat

flocculent feed pump, 1 mixing chamber, 1 prepared solution day tank, and 1 solution

(prepared flocculent) feed pump.

Operational feedback from the filter press feed pumps (discharge pressure) provides the

signal to the flocculent solution feed pump to pace the flocculent feed to filter press. The

flocculent feed is provided by a 1 x 100% flocculent solution feed system, that is shared

with the thickener flocculent feed application, and one common 1 x 100% “cold” standby

that is a shared standby system with the Lamella trains’ flocculent feeds

PLC values needed for flow pacing of the flocculent are:

PLC user input values at HMI Reference Variable

Flocculent dose (ppm) FT_D

Flocculent percent solution (%) FT_P

Dosing pump output at 100% speed (ml/min) FT_MX

PLC Values

Discharge Pressure (1PIT-QW0302, psig) PR_FPF

(Proposed) Dosing Equation [FT_Q], (% speed):

(-PR_FPF�0.38�92.2�FT_D�0.377

FT_P�FT_MX� 100%


4. Operation

NOTE: In this section User refers to either plant laboratory or operations personnel

4.1. When flow is anticipated and/or required to discharge from the CPRP and/or PWP to control

pond levels, the User begins the process of bringing the treatment system online through the PLC

control system interface (HMI)

4.2. User checks the PLC HMI for alarms and/or other issues that would prevent a startup of the

system. User clears alarms and/or addresses issues and then begins the process of starting up the

system.

4.2.1. Alarms and/or issues that cannot be resolved are communicated to the plant laboratory

staff and/or plant management as appropriate and the process to address these items is

initiated.

4.3. User designates the treatment mode on PLC HMI “Main Page” from the following options.

4.3.1. CPRP treatment

4.3.2. PWP treatment

4.3.3. Dual treatment (treatment of both CPRP and PWP waters)

4.4. Once a treatment system mode is designated the User then has the option to select the treatment

scheme for each mode. The options available are:

4.4.1. CPRP Treatment

4.4.1.1. MMF treatment discharging to the PWP

4.4.1.2. MMF treatment discharging to outfall 201

4.4.1.3. MMF treatment and Lamella effluent combined discharge to outfall 201

4.4.1.4. Lamella effluent direct discharge to PWP

4.4.2. PWP Treatment

4.4.2.1. Discharge to outfall 101

4.4.2.1.1. This is the only option for this treatment mode and is automatically selected

when this mode of operation is designated by the User

4.4.3. Dual treatment

4.4.3.1. CPRP discharging to outfall 201, PWP discharging to outfall 101

4.4.3.2. CPRP discharging to PWP, PWP discharging to outfall 101

4.5. CPRP Treatment


4.5.1. Selecting this option puts the system into CPRP treatment mode.

4.5.2. The PLC HMI displays selections buttons for the User to select one of the following on

the “Main Page” to designate the treatment system option:

(1) MMF treatment discharging to the PWP

(2) MMF treatment discharging to outfall 201

(3) MMF treatment and Lamella effluent combined discharge to outfall 201

(4) Lamella effluent direct discharge to PWP

NOTE: For discharge of the Lamella effluent tank directly to outfall 201 the User can

select the third option and input a MMF maximum outlet flow rate set point (on the HMI

“Set Points” screen) to 0 gpm.

NOTE: Prior to a direct discharge of the Lamella effluent tank to outfall 201 a TSS

sample analysis is required from the effluent transfer pump discharge sample valve

(1HV-QW4600) indicating that the TSS levels are acceptable to discharge to outfall 201.

These results must be logged prior to a 201 outfall discharge

Once a treatment option has been designated by the User, the startup process for the

Lamella clarifiers can be initiated.

4.5.3. Initial Startup

4.5.3.1. User checks PLC HMI “Main Page” once a treatment option is selected. If the

system displays “Ready” this allows User to walk down the system and line-up /

confirm any valves, equipment, etc. necessary to bring flow into the treatment system

as appropriate for the option selected. System valve line-up for the options presented

in section 4.4.1 is provided in section 5.1.

The following process permissives are necessary to display the “Ready” status on the

PLC HMI for initial startup in CPRP treatment mode:

Description Tag Number Position/Status

CPRP High Flow Bypass Block Valve 1HV-QW4403 Closed

CPRP Supply to Treatment System

Block Valve 1HV-WW4303 Open

Treatment System Return to Outfall

201 Header Block Valve 1HV-QW4503 Open

Coagulant Feed System 1SK-QW4100 Ready

Flocculent Feed System 1SK-QW4000 Ready

PWP Sump Discharge to MMF

Double Block A 1HV-QW8000 Closed




Double Block B 1HV-QW8200 Closed

MMF Outlet to 101 Outfall Double

Block A 1HV-QW7400 Closed

MMF Outlet to 101 Outfall Double

Block B 1HV-QW7600 Closed

4.5.3.2. Once the correct flow path (valving) and equipment status is confirmed and logged

by the User, the chemical feed systems are checked and the appropriate set points and

dosages for coagulant and flocculent are input into the PLC HMI in the “Chemical

Feed” page.

4.5.3.3. The User can input a total Lamella clarifier influent flow rate set point or specify

individual Lamella train influent set points, in “gpm” into the PLC HMI in the

“Lamella” page.

4.5.3.3.1. Inputting a total Lamella clarifier influent flow rate set point, the number of

Lamella trains in service is controlled by the PLC under the following ranges:

“Initial” Operation

Flow

Range

(gpm)

Required # of

Lamella Trains

in Service Train-1 Train-2

100 – 200 1 Lead Standby

200 – 800 2 Lead Lag

The PLC will cycle Lamella trains lead-lag-standby designation following each

shutdown or they can be designated at the discretion of the User.

4.5.3.3.2. Inputting individual Lamella train influent flow rate set points, each Lamella

can operate independently at the flow rates designated by the User.

4.5.3.4. Once the User inputs a Lamella influent flow rate set point greater than 100 gpm,

the PLC then moves the system from “Ready” to “1st Stage Startup”. When the

system is in “1st Stage Startup”:

4.5.3.4.1. Lamella clarifier effluent water is automatically routed to the backwash / rinse

water storage tank.

4.5.3.4.2. Discharge from the backwash / rinse water storage tank is directed to the CPRP.

PREREQUISITE: System turbidity meter online, cleaned,

calibrated, and ready for service


4.5.3.4.3. The PLC HMI will display an option to “Move Into 2nd

Stage Startup”

4.5.3.5. Once the User determines that the Lamella clarifier(s) effluent turbidity values (or

TSS sample results) observed/obtained from the 8-inch Lamella train overflow lines

(Lamella train 1 and 2 turbidity meters and sample point locations 1AIT-QW0512 and

1HV-QW1610, 1AIT-QW0522 and 1HV-QW1620 respectively) indicate it is

acceptable to send water to the Lamella effluent storage tank, the User will select

“Move Into 2nd

Stage Startup”. Initially the User will monitor this process and

determine when acceptable turbidity values are achieved and makes the decision to

direct flow to the Lamella effluent storage tank. An option for automatic routing of

Lamella effluent based on turbidity values is available on the PLC HMI, but should

not be implemented until sufficient operation experience with the system is obtained

to confirm the turbidity values are acceptable to support this operation.

4.5.3.5.1. If unacceptable Lamella clarifier(s) effluent turbidity continues to where

backwash / rinse water storage tank levels continue to increase up to the high

level alarm point, this information needs to be communicated to the plant

laboratory supervisor and/or plant management as appropriate. If acceptable

effluent turbidity values cannot be obtained within a reasonable period of time

(such that CPRP levels are at risk of not providing sufficient run-off water

volume storage), these individual(s) must then make a decision to continue with

treatment or bypass the TSS removal system to manage CPRP levels.

4.5.3.6. Once the system has moved into “2nd

Stage Startup”:

4.5.3.6.1. Effluent/overflow water from the Lamella clarifier(s) is sent to the Lamella

effluent storage tank.

4.5.3.6.2. Discharge from Lamella effluent storage tank is routed to the backwash / rinse

water storage tank or directly to the CPRP depending on the level in the

backwash / rinse water storage tank or at the discretion of the User.

4.5.3.6.2.1. Since flow is not monitored from the Lamella effluent transfer pumps

when discharging through the 8-inch line to the backwash / rinse water

storage tank, control of these pumps will be based on level control in the

Lamella effluent storage tank. The pump will start at a specified tank level

and stop at a specified tank level.

4.5.3.6.3. The PLC HMI “Main Page” will display the selection button “Startup Complete

– Proceed with Discharge Treatment Option *”

(*) = One of the options presented in section 4.5.2.

4.5.4. To be able to select “Startup Complete – Proceed with Discharge Treatment Option *”

the following must be determined and/or confirmed by the User depending on the

treatment option selected:

4.5.4.1. For CPRP discharge treatment options (1), (2), or (4) presented in section 4.5.2:

User determines that stable operations and turbidity readings observed from the

effluent transfer pump discharge turbidity meter (1AIT-QW1302) and/or bench top


turbidity analysis have been achieved and are acceptable to complete the startup

process. The User logs the operational values (turbidity, flow, etc.) as appropriate and

proceeds with one of these operational options.

4.5.4.2. For CPRP discharge treatment option (3) presented in section 4.5.2:

A TSS sample must be obtained and analyzed from the effluent transfer pump

discharge sample valve (1HV-QW4600). The results of the TSS analysis must show

acceptable levels for continuous discharge into outfall 201; as the MMF system will

startup in “Alternate Outlet to PWP/Recirculation” mode such that a combination of

MMF outlet flow with the Lamella effluent will not be possible until the MMF system

moves from “Alternate Outlet to PWP/Recirculation” to “Discharge” mode. These

results are logged and communicated with the plant laboratory supervisor and/or plant

management. Once this communication has taken place, the authoritative plant

personnel can determine that the system can continue with this treatment option or if

alterative operation is needed. If a decision to proceed with alternate operation is

made, the User logs this communication and alternate operation is determined by the

plant staff as appropriate.

4.5.5. MMF treatment discharging to the PWP:

4.5.5.1. MMF treatment to the PWP is to be the default treatment method utilized for

routine CPRP level management. This mode of operation however is constrained by

what flow rate the system can continuously manage as the Lamella clarifiers treatment

rate could potentially exceed the MMFs treatment capacity, and that pond and tank

level management is limited based on the discharge flow rate (return to the CPRP) of

the backwash / rinse water transfer pumps. As such, this mode of operation is

suggested when routine CRPP level management can be successfully obtained with

discharge flow rates (total Lamella influent flow) of less than 400 gpm. Therefore if

higher flow rates are necessary to where high pond or tank levels or unacceptable

MMF performance is observed at the flow rates necessary for CPRP level

management, an alternate treatment mode must be selected. This option can also be

used if the Lamella effluent turbidity levels are too high for direct continues discharge

to the PWP where accumulation of solids and/or unacceptable water quality would

ultimately be detrimental to PWP operation.

4.5.5.2. In this mode of operation:

The Lamella effluent transfer pumps discharge is directed to the MMFs to supply

MMF inlet, backwash inlet, and rinse water. Pump discharge is also directed to the

backwash / rinse water storage tank when necessary to maintain the flow path through

the Lamella clarifier(s) should the MMF outlet flow rate required to maintain the PWP

level set point (automatically reduced MMF outlet flow rate) result in high Lamella

effluent storage tank levels.

MMF outlet water is directed into the PWP.

MMF backwash outlet and rinse water is directed to the backwash / rinse water

storage tank.

The backwash / rinse water storage tank effluent is directed back to the CPRP to


maintain tank level.

The Lamella influent flow rate is controlled by a User defined flow rate set point,

which initially should be less than 400 gpm. Higher flow rates may be possible once

additional operation of the system is achieved and it is found that the system can

successfully handle the higher flows.

4.5.5.3. The MMF outlet flow control valve (1RV-QW7605) modulates based on two

cascading parameters:

(1) Lamella effluent storage tank level (1LIT-QW1102) – the PLC is designed to

maintain a minimum level of 9-feet in the Lamella effluent storage tank at all times

when treating CPRP discharge to provide adequate volume for MMF backwashing.

Therefore if the MMF outlet flow rate exceeds the influent(s) to the tank (Lamella

effluent flow) the PLC will automatically reduce the MMF outlet flow to maintain the

tank level. Should the Lamella effluent storage tank influent(s) exceed the MMF

outlet flow rate resulting in increasing tank levels the excess flow is sent to the

backwash / rinse water storage tank to maintain the level.

NOTE: In this mode of operation it is highly unlikely that low (below 9-feet) Lamella

effluent storage tank levels will occur as MMF outlet flow rates should be less than or

equal to the total Lamella influent flow. However should the MMF maximum outlet

flow rate set point exceed the Lamella influent flow rate (this could be a possibility),

the PLC will alarm/alert the User that this is the case.

(2) PWP level (1LT-WW0400A/B) – increasing PWP levels decreases the MMF

outlet flow rate to maintain a level set point down to a minimum flow rate of 100

gpm. Should a high level alarm occur in the PWP in this mode of operation the MMF

outlet flow control valve will close and will not re-open until a PWP level permissive

is activated. Correspondingly falling PWP levels will increase the MMF outlet flow

rate up to the maximum MMF outlet flow rate set point, provided Lamella effluent

storage tank levels are being maintained accordingly.

4.5.5.4. Once the MMF system is put into operation to treat Lamella effluent water, the

MMF system moves into “Alternate Outlet to PWP/Recirculation” mode and remains

in this mode when operating within this treatment option.

4.5.5.5. Since the MMF system cannot handle an excessive amount of influent solids

without producing terminal headloss rapidly, the MMF inlet turbidity is monitored by

a turbidity meter (1AE-QW0305, displayed on / transmitted by 1AIT-QW0305) on the

common 6-inch MMF inlet line. If inlet turbidity levels are not acceptable when in

service the PLC will issue high and high-high MMF inlet turbidity alarms. A high-

high turbidity alarm closes the MMF outlet flow control valve (1RV-QW0105) and

requires the User to acknowledge the alarm before the MMFs can be placed back into

service. Until the alarm is acknowledged all Lamella effluent flow is sent to the

backwash / rinse water storage tank.

4.5.5.6. The Lamella effluent storage tank level is maintained by the MMF outlet flow

control valve and the Lamella effluent storage tank to backwash / rinse tank inlet

control valve (1RV-QW1902). The PWP level will dictate the MMF outlet flow rate

but will be reduced as needed to maintain the Lamella effluent storage tank level.


Additionally excess influent water (Lamella influent flow minus MMF outlet flow)

will be sent to the backwash / rinse water storage tank as needed to maintain level.

4.5.5.7. The backwash / rinse water storage tank level is maintained by pumping back to

the CPRP through the backwash / rinse water transfer pumps. The level in the

backwash / rinse water storage tank is to be maintained to provide adequate storage

for MMF backwash and rinse water. The limitations of these pumps at approximately

300 gpm should not result in accumulation within the tank and maintaining level

should not be an issue with Lamella influent flows less than 400 gpm. However

should levels in the backwash / rinse water storage tank not permit a MMF backwash

sequence when one is called for, the Lamella influent flow rate is automatically

decreased until a backwash level permissive in the backwash / rinse water storage tank

is achieved. The Lamella influent flow rate set point is resumed once the backwash

sequence is complete. Additionally should a high level alarm in the backwash / rinse

water storage tank be active for greater than 30-minutes a common alarm is sent to the

DCS and informs operations of a flow imbalance issue that will need to be resolved.

4.5.5.8. The PWP level provides the permissive to receive outlet flow from the MMF. A

high level (stop MMF outlet flow) in the PWP closes the MMF outlet flow control

valve and all Lamella effluent flow is sent to the backwash / rinse water storage tank.

If no action is taken by the user on a high PWP level alarm discharge to the PWP

thought the MMFs will automatically resume once a level permissive in the PWP

(start MMF outlet flow) is met and operation continues as described in section 4.5.5.2.

Therefore selecting this mode of operation automatically maintains PWP and CPRP

levels.

4.5.6. MMF treatment discharging to outfall 201:

4.5.6.1. MMF treatment to outfall 201 is to be utilized when PWP levels are considered too

high to accept continuous CPRP discharge and the discharge rate of CPRP water

required to maintain CPRP levels is less than the MMF maximum outlet flow rate.



MMF inlet, backwash inlet, and rinse water. Pump discharge is also directed to the

backwash / rinse water storage tank when necessary to maintain the flow path through

the Lamella clarifier(s) should the MMF outlet flow result in high Lamella effluent

storage tank levels.

MMF outlet water is directed into the 201 outfall.


storage tank.


maintain tank levels as necessary.

The Lamella influent flow rate is controlled by a User defined flow rate set point,

which needs to be less than the MMF maximum outlet flow rate set point. The PLC


will alarm/alert the User if the Lamella influent flow rate set point is greater than the

MMF maximum outlet flow rate set point in this mode of operation.






Therefore if the MMF outlet flow rate exceeds the influent(s) to the tank (Lamella

effluent flow) the PLC will automatically reduce the MMF outlet flow to maintain the

tank level. Should the Lamella effluent storage tank influent(s) exceed the MMF

outlet flow rate resulting in increasing tank levels the excess flow is sent to the

backwash and rinse water storage tank to maintain the level.


effluent storage tank levels will occur as MMF outlet flow rates should be less than or

equal to the total Lamella influent flow. Should this occur it could be an indication of

process control issues and needs to be investigated.

(2) Lamella influent flow rate set point – initial value for the MMF outlet flow rate set

point will be equal to this set point value, up to the MMF maximum outlet flow rate

set point; provided Lamella effluent storage tank levels are being maintained

accordingly.


MMF system moves into “Alternate Outlet to PWP/Recirculation” mode and the

startup process is initiated. The User navigates to the “MMF” screen on the PLC HMI

to complete the startup process.






high turbidity alarm closes the MMF outlet flow control valve (1RV-QW0105) and


service.

4.5.6.6. Once the MMF system is in “Alternate Outlet to PWP/Recirculation” mode for

approximately 1 – 2 retention times or until outlet turbidity values read from the

turbidity instrument on the common 6-inch filter outlet line (1AE-QW2005, displayed

on / transmitted by 1AIT-QW0305) stabilize the inlet pH values are noted and a

sample off of the 6-inch common MMF outlet line sample valve (1HV-QW3105) is

obtained. The sample is sent to the plant lab for a TSS analysis and the pH value is

reported to the plant lab staff. The plant lab will report the result of the TSS analysis

to the User. A pH level between 6 and 9 and TSS analysis result less than 30 mg/L is

considered acceptable. A pH level greater than 9 or less than 6 is considered

unacceptable. A TSS level greater than 30 mg/L is also considered unacceptable, but

provisions may allow for TSS levels up to 50 mg/L to be considered acceptable

pending plant lab supervisor or management approval and/or review. Any TSS


analysis results greater than 50 mg/L is considered unacceptable. The results of the

analysis are logged by the User.

NOTE: pH control is not part of the CPRP discharge treatment system, however pH

limits for the 201 outfall must be in range prior to discharging to the outfall. It is not

anticipated that pH will be outside of these limits when treating CPRP discharge,

though should this occur, an analysis of the treatment system would need to be

performed to evaluate options to control pH appropriately.

4.5.6.7. Acceptable MMF outlet water analysis results allow a User with appropriate PLC

security access to place the filter into “Discharge” mode. In “Discharge” mode the

MMF outlet water is sent to the 201 outfall and the PLC controls MMF operation per

the operational modes described in section 4.9 and the respective PLC set points.


control valve and the Lamella effluent storage tank to backwash / rinse tank inlet

valve (1RV-QW1902). The Lamella influent flow rate set point will dictate the MMF

outlet flow rate but will be reduced as needed to maintain the Lamella effluent storage

tank level. Additionally excess influent water (Lamella influent flow minus MMF

outlet flow) will be sent to the backwash / rinse water storage tank as needed to

maintain level.

NOTE: While unlikely to occur, the functionality to automatically send water from the

Lamella effluent storage tank to the backwash / rinse water storage tank remains as a

backup to prevent tank overflows, though as stated it primarily would indicate process

and /or control issues that need to be investigated.


the CPRP from the backwash / rinse water transfer pumps. The level in the backwash

/ rinse water storage tank is to be maintained to provide adequate storage for MMF

backwash and rinse water. Should levels in the backwash / rinse water storage tank

not permit a MMF backwash sequence when one is called for, the filter vessel in the

backwash queue is placed on hold until a permissive level in the backwash / rinse

water storage tank is achieved. If a backwash / rinse water storage tank backwash

level permissive is not obtained within 60-minutes, a common alarm is sent to the

DCS and informs operations of the issue.


4.5.7. MMF treatment and Lamella effluent combined discharge to outfall 201:

4.5.7.1. MMF treatment and Lamella effluent combined discharge to outfall 201 is to be

utilized when PWP levels are considered too high to accept continuous CPRP

discharge and the discharge rate of CPRP water required to maintain CPRP levels is

greater than the MMF maximum outlet flow rate. Selecting this option requires that a

combination of MMF outlet and Lamella effluent water meets the TSS discharge level

requirements for the 201 outfall. The combined effluent is sampled at the official 201

outfall sample point (1HV-WW4603).



MMF inlet, backwash inlet, and rinse water, to outfall 201 through the Lamella

effluent transfer pump direct discharge line to outfall 201 (1QW155), and when

necessary to the backwash / rinse water storage tank to maintain the flow path through

the Lamella clarifier(s) should the total flow to outfall 201 result in high Lamella

effluent storage tank levels.



storage tank.


maintain tank levels as necessary.

The Lamella influent flow rate is controlled by a User defined flow rate set point.

BLEND_TSS!(LETD_TSS�LETD_Q*�(MMF_OUT_TSS�MMF_OUT_Q

LETD_Q*�MMF_OUT_Q

PREREQUISITE: The TSS of an anticipated combination of MMF outlet water and

Lamella effluent must be calculated and the results logged and communicated with

the plant laboratory staff and/or plant management as appropriate. The equation to

calculate the anticipated combination is as follows and requires TSS analysis from the

MMF common outlet sample valve (1HV-QW3105) and the Lamella effluent transfer

pump discharge sample valve (1HV-QW4600) and/or individual Lamella train

effluent samples.

LETD_TSS sample obtained per section 4.5.4.2

Where:

LETD_TSS = Lamella effluent transfer pump discharge TSS, mg/L

LETD_Q* = Anticipated Lamella effluent flow to outfall 201, gpm

MMF_OUT_TSS = MMF outlet TSS, mg/L

MMF_OUT_Q = MMF outlet flow rate, gpm







Therefore if the outlet flow rate exceeds the influent(s) to the tank (Lamella effluent

flow) the PLC will automatically reduce the MMF outlet flow to maintain the tank

level. Should the Lamella effluent storage tank influent(s) exceed the MMF outlet

flow rate resulting in increasing tank levels the excess flow is sent to directly to outfall

201. Additionally should the Lamella effluent storage tank levels continue to increase

with maximum flow being sent to the MMFs and through the Lamella effluent storage

tank direct discharge to outfall 201 the inlet valve the backwash / rinse water storage

tank inlet valve (1RV-QW1902) is opened to provide supplemental flow out of the

Lamella effluent storage tank to maintain the level.


effluent storage tank levels will occur as total outlet flow rates should be less than or

equal to the total Lamella influent flow. Should this occur it could be an indication of

process control issues and needs to be investigated.

(2) Lamella influent flow rate set point – the value for the MMF outlet flow rate set

point will be equal to this set point value up to the MMF maximum outlet flow rate set

point, provided Lamella effluent storage tank levels are being maintained accordingly.

A Lamella influent flow rate set point greater than the MMF maximum outlet flow

rate set point will direct the excess flow to outfall 201 and the MMF outlet flow rate

will be set to the MMF maximum outlet flow rate set point. Lamella effluent tank

level will continue to be maintained as previously described.


MMF system moves into “Alternate Outlet to PWP/Recirculation” mode and the

startup process is initiated. The User navigates to the “MMF” screen on the PLC HMI

to complete the startup process.






high turbidity alarm closes the MMF inlet flow control valve (1RV-QW0105) and


service.

4.5.7.6. Once the MMF system is in “Alternate Outlet to PWP/Recirculation” mode for

approximately 1 – 2 retention times or until outlet turbidity values read from the

turbidity instrument on the common 6-inch filter outlet line (1AE-QW2005, displayed

on / transmitted by 1AIT-QW0305) stabilize the inlet pH values are noted and a

sample off of the 6-inch common MMF outlet line sample valve (1HV-QW3105) is

obtained. The sample is sent to the plant lab for a TSS analysis and the pH value is

reported to the plant lab staff. The plant lab will report the result of the TSS analysis

to the User. A pH level between 6 and 9 and TSS analysis result less than 30 mg/L is


considered acceptable. A pH level greater than 9 or less than 6 is considered

unacceptable. A TSS level greater than 30 mg/L is also considered unacceptable, but

provisions may allow for TSS levels up to 50 mg/L to be considered acceptable

pending plant lab supervisor or management approval and/or review. Any TSS

analysis results greater than 50 mg/L is considered unacceptable. The results of the

analysis are logged by the User.

NOTE: pH control is not part of the CPRP discharge treatment system, however pH

limits for the 201 outfall must be in range prior to discharging to the outfall. It is not

anticipated that pH will be outside of these limits when treating CPRP discharge,

though should this occur, an analysis of the treatment system would need to be

performed to evaluate options to control pH appropriately.

4.5.7.7. Acceptable MMF outlet water analysis results allow a User with appropriate PLC

security access to place the filter into “Discharge” mode. In “Discharge” mode the

MMF outlet water is sent to the 201 outfall and the PLC controls MMF operation per

the operational modes described in section 4.9 and the respective PLC set points.


control valve, the Lamella effluent transfer pump discharge to outfall 201 flow control

valve, and the Lamella effluent storage tank to backwash / rinse tank inlet valve

(1RV-QW1902). The Lamella influent flow rate set point will dictate the MMF outlet

flow rate as described in section 4.5.7.3 (2), but will be reduced if needed to maintain

the Lamella effluent storage tank level. Additionally excess influent water (Lamella

influent flow minus MMF outlet flow) will be sent to outfall 201, and if necessary to

the backwash / rinse water storage tank to maintain level. Since flow to the backwash

/ rinse water storage tank is considered an atypical operation, and could be indicative

of more fundamental operational issues, the PLC will track how long the backwash /

rinse water storage tank inlet valve is open and send a common alarm to the DCS to

alert operations of this issue once a User defined time has elapsed

NOTE: While unlikely to occur, the functionality to automatically send water from the

Lamella effluent storage tank to the backwash / rinse water storage tank remains as a

backup to prevent tank overflows, though as stated it primarily would indicate process

and /or control issues that need to be investigated.


the CPRP from the backwash / rinse water transfer pumps. The level in the backwash

/ rinse water storage tank is to be maintained to provide adequate storage for MMF

backwash and rinse water. Should levels in the backwash / rinse water storage tank

not permit a MMF backwash sequence when one is called for, the filter vessel in the

backwash queue is placed on hold until a permissive level in the backwash / rinse

water storage tank is achieved. If a backwash / rinse water storage tank backwash

level permissive is not obtained within 60-minutes, a common alarm is sent to the

DCS and informs operations of the issue.

4.5.8. Lamella effluent direct discharge to PWP:

4.5.8.1. Lamella effluent discharge to the PWP is to be utilized when CPRP discharge

treatment does not require filtration to remove additional TSS and Lamella effluent

TSS levels are consistently low enough not to impact PWP operation. In this mode of


operation the Lamella effluent storage tank high and high-high level alarms are

temporarily set to 100% and the Lamella effluent transfer pumps run at minimum flow

at 100% recirculation (all discharge valves are closed and water is recirculated

through 1QW174). These pumps run in this mode to allow for a continuous turbidity

reading on the Lamella effluent transfer pump discharge to monitor effluent quality.

In this mode of operation the Lamella effluent storage tank overflows through the 10-

inch overflow line (1QW160) into the PWP.

4.5.8.2. The PWP level provides the permissive for this mode of operation. A high level in

the PWP opens the inlet valve to the backwash / rinse water storage tank. Discharge

to the PWP will automatically resume once a level permissive in the PWP is met and

operation continues as described in section 4.5.8.1. Therefore selecting this mode of

operation automatically maintains PWP and CPRP levels.

4.5.9. Once CPRP discharge flow is established to the PWP, the MMFs, or into outfall 201, the

User checks the sludge transfer pump set points on the PLC HMI and makes appropriate

adjustments to these values as needed to initially manage solids inventory within the

Lamella.

4.5.10. The PLC controls the Lamella influent flow control valves, the number of Lamella trains

in service, chemical feed systems, and sludge transfer pump operation to automatically

maintain their respective set points.

4.6. PWP Treatment

4.6.1. Selecting this option puts the system into PWP treatment mode.

4.6.1.1. Discharge to outfall 101 is automatically selected as the operational option.

4.6.2. In this mode of operation:

A portion of the PWP sump pumps discharge is directed to the MMFs to supply MMF

inlet, backwash inlet, and rinse water.


MMF backwash outlet and rinse water is directed back to the PWP.

MMF outlet flow rate is controlled by a User defined flow rate set point

4.6.3. User checks PLC HMI “Main Page”. If system displays “Ready” this allows User to

walk down the system and line-up any valves necessary to bring flow into the treatment

system as appropriate for the mode of operation required. System valve line-up is

provided in section 5.2.

The following process permissives are necessary to display the “Ready” status on the

PLC HMI for initial startup in PWP treatment mode:



MMF Outlet to 201 Block Valve-A

Position 1HV-QW7700 Closed

MMF Outlet to 201 Block Valve-B



Position 1HV-QW7400 Open



PWP Sump Discharge to MMF Block

Valve-A 1HV-QW8000 Open


Valve-B 1HV-QW8200 Open

MMF Backwash Outlet to BWP Block

Valve 1HV-QW5000 Open

MMF Backwash Outlet to Backwash /

Rinse Water Storage Tank Block

Valve-A

1HV-QW5100 Closed



Valve-A

1HV-QW5100 Closed

4.6.4. Once the correct valving is confirmed and logged by the User, the User will define the

discharge flow rates from the PWP necessary to manage PWP levels and begin the

process of bringing the treatment system (MMFs) online.

4.6.5. User navigates to the “MMF” screen on the PLC HMI and inputs an appropriate MMF

outlet flow rate set point, in “gpm”, necessary to manage PWP levels. Flow is directed to

the MMF from the PWP sump discharge header.

4.6.6. The MMF moves into “Alternate Outlet to PWP/Recirculation” mode and the startup

process is initiated.

4.6.7. Since the MMF system cannot handle an excessive amount of influent solids without

producing terminal headloss rapidly, the MMF inlet turbidity is monitored by a turbidity

meter (1AE-QW0305, displayed on / transmitted by 1AIT-QW0305) on the common 6-

inch MMF inlet line. If inlet turbidity levels are not acceptable when in service the PLC

will issue high and high-high MMF inlet turbidity alarms. A high-high turbidity alarm

closes the MMF inlet flow control valve (1RV-QW0105) and requires the User to

acknowledge the alarm before the MMFs can be placed back into service.

4.6.8. Once the MMF system is in “Alternate Outlet to PWP/Recirculation” for approximately 1

– 2 retention times or until outlet turbidity values read from the turbidity instrument on

PREREQUISITE: Turbidity and pH meter online, cleaned,



the common 6-inch filter outlet line (1AE-QW2005, displayed on / transmitted by 1AIT-

QW0305) stabilize the inlet pH values are noted and a sample off of the 6-inch common

MMF outlet line sample valve (1HV-QW3105) is obtained. The sample is sent to the

plant lab for a TSS analysis and the pH value is reported to the plant lab staff and logged.

The plant lab will report the result of the TSS analysis to the User (as appropriate). A pH

level between 6 and 9 and TSS analysis result less than 30 mg/L is considered acceptable.

A pH level greater than 9 or less than 6 is considered unacceptable. A TSS level greater

than 30 mg/L is also considered unacceptable, but provisions may allow for TSS levels

up to 50 mg/L to be considered acceptable pending plant lab supervisor or management

approval and/or review. Any TSS analysis results greater than 50 mg/L is considered

unacceptable. The results of the analysis are logged by the User.

NOTE: pH control for the PWP is described in the PWP acid feed system description.

4.6.8.1. If the TSS and/or pH analysis is not acceptable, the User will continue to monitor

the outlet turbidity and inlet pH levels with the filter in “Alternate Outlet to

PWP/Recirculation” mode and after 30-minutes sampling is repeated. If the second

set of TSS sample analysis and/or pH values indicate an unacceptable outlet water

quality these results are communicated by the plant lab to the laboratory supervisor

and/or plant management as appropriate. These individual(s) must then make a

decision to continue to recirculate the filter system or find alternate ways to manage

PWP levels.

4.6.9. Acceptable outlet water analysis results allow a User with appropriate PLC security

access to place the filter into “Discharge” mode. In “Discharge” mode the MMF outlet

water is sent to the 101 outfall and the PLC controls MMF operation per the operational

modes described in section 4.9 and the respective PLC set points.

4.6.10. When discharge flow rates to the 101 outfall are anticipated to significantly decrease

and/or are no longer necessary the filter can be placed into “recirculation”, “standby”, or

“offline” modes as needed.

4.7. Dual treatment (treatment of PWP and CPRP discharge)

4.7.1. Selecting this option puts the system into Dual treatment mode.

4.7.2. The PLC HMI displays selections buttons for the User to select one of the following

options on the “Main Page”:

(1) CPRP discharging to outfall 201, PWP discharging to outfall 101

(2) CPRP discharging to PWP, PWP discharging to outfall 101

NOTE: Individual treatment of either CPRP or PWP waters can be accomplished under

this mode by inputting flow rate set points to 0 gpm for the respective pond treatment

system that is chosen to not be in service.

4.7.3. User checks PLC HMI “Main Page”. If system displays “Ready” this allows User to

walk down the system and line-up any valves necessary to bring flow into the treatment

system as appropriate for the mode of operation required. System valve line-up is

provided in section 5.3.


The following permissives are necessary to display the “Ready” status on the PLC HMI

for Dual treatment mode:


CPRP High Flow Bypass Block Valve

Position

1HV-QW4403

Closed

CPRP Supply to Treatment System

Block Valve Position 1HV-WW4303 Open

Treatment System Return to Outfall

201 Header Block Valve Position 1HV-QW4503 Open

Coagulant Feed System 1SK-QW4100 Ready

Flocculent Feed System 1SK-QW4000 Ready

Lamella Effluent Tank Discharge to

MMF Block Valve-A Position 1HV-QW4800 Closed

Lamella Effluent Tank Discharge to

MMF Block Valve-B Position 1HV-QW4900 Closed










Valve-A 1HV-QW8000 Open


Valve-B 1HV-QW8200 Open

MMF Backwash Outlet to PWP Block




Valve-A

1HV-QW5100 Closed



Valve-B

1HV-QW5300 Closed

4.7.4. Once the correct valving is confirmed and logged by the User, the User will define the

discharge flow rates from the PWP and CPRP necessary and begin the process(es) of

bringing the treatment system(s) online to treat these flows.


4.7.5. CPRP discharging to outfall 201, PWP discharging to outfall 101

4.7.5.1. This mode of operation is to be utilized when both CPRP and PWP levels are high

enough that discharge to their respective internal outfalls is necessary to reduce pond

levels. This mode of operation would likely be implemented following a major rain

event that occurred during a time when PWP usage was minimal (plant outages, etc.).


The Lamella effluent transfer pumps discharge is directed to outfall 201 through the

Lamella effluent transfer pump direct discharge line to outfall 201 (1QW155).

The Lamella influent flow rate is controlled by a User defined flow rate set point.

A portion of the PWP sump pumps discharge is directed to the MMFs to supply MMF

inlet, backwash inlet, and rinse water.


MMF backwash outlet and rinse water is directed back to the PWP.

MMF outlet flow rate is controlled by a User defined flow rate set point.

4.7.5.3. CPRP treatment – in Dual treatment mode

4.7.5.3.1. User completes the Lamella initial startup procedure as described in sections

4.5.3.3 through 4.5.3.6.

4.7.5.3.2. Once the system has moved into “2nd

Stage Startup” per section 4.5.3.6, the

PLC HMI “Main Page” will display the selection button “Lamella Startup

Complete – Proceed with Discharge to Outfall 201”

4.7.5.3.3. For a User with appropriate PLC security access to be able to select “Lamella

Startup Complete – Proceed with Discharge to Outfall 201”, a TSS sample must

be obtained and analyzed from the effluent transfer pump discharge sample

valve (1HV-QW4600). The results of the TSS analysis must show acceptable

levels for continuous discharge into outfall 201. These results are logged and

communicated with the plant laboratory supervisor and/or plant management.

Once this communication has taken place, the authoritative plant personnel can

determine that the system can continue with this treatment option or if alterative

operation is needed. If a decision to proceed with alternate operation is made,

the User logs this communication and alternate operation is determined by the

plant staff as appropriate.

4.7.5.4. PWP treatment – in Dual treatment mode

4.7.5.4.1. PWP discharge treatment proceeds per the procedure presented in sections 4.6.5

– 4.6.10.

PREREQUISITE: Turbidity and pH meter online, cleaned,



4.7.5.5. Since the Lamella effluent and backwash / rinse water storage tanks are not

necessary for MMF backwashing, control of their respective transfer pumps will be

based on tank levels. The pump will start and stop at specified tank levels.

4.7.6. CPRP discharging to PWP, PWP discharging to outfall 101

4.7.6.1. CPRP discharging to the PWP when in dual treatment mode is provided for added

flexibility in the system. However this option should be very seldom used and

primarily is only included if there were issues with the performance (high TSS) of the

Lamella that prevented discharge into outfall 201 and discharge from the CPRP was

necessary to maintain pond levels.

4.7.6.2. PWP treatment would proceed as described in section 4.7.5.4.

4.7.6.3. In this mode of operation the Lamella effluent storage tank high and high-high

level alarms are temporarily set to 100% and the Lamella effluent transfer pumps run

at minimum flow at 100% recirculation (all discharge valves are closed and water is

recirculated through 1QW174). These pumps run in this mode to allow for a

continuous turbidity reading on the Lamella effluent transfer pump discharge to

monitor effluent quality.

4.7.6.4. The PWP level provides the permissive for this mode of operation. A high level in

the PWP sends a common alarm to the DCS and opens the inlet valve to the backwash

/ rinse water storage tank.

4.8. MMF Operation When Switching Between CPRP and PWP Treatment Modes

Presently a discharge of PWP water into CPRP water is not allowed due to the design of the

plant pond system outfalls and permit limitations. To prevent this from occurring when

transitioning the MMFs from CPRP treatment (Lamella effluent water) to and from PWP

treatment the following procedural summary must be followed.

4.8.1. Initial and/or transitional use of the MMFs from PWP filtration to CPRP treatment:

4.8.1.1. All MMF vessels are to be backwashed with backwash inlet supplied by the

Lamella effluent transfer pumps.

4.8.1.2. Backwash outlet is directed to the PWP.

4.8.1.3. Rinse water is supplied by the Lamella effluent transfer pumps.

4.8.1.4. Rinse water outlet is directed to the PWP.

4.8.1.5. Following the completion of the backwash sequencing of all of the MMF vessels,

MMF inlet is supplied by the Lamella effluent transfer pumps.

4.8.1.6. Filter outlet is directed to the PWP for a minimum of 2 vessel retention times.

4.8.1.7. Once 2 vessel retention times are met, filter outlet can be directed to the 201 outfall

if necessary.


4.8.1.8. Continuing MMF operation is summarized as:

4.8.1.8.1. MMF inlet is supplied by the Lamella effluent transfer pumps.

4.8.1.8.2. MMF backwash inlet is supplied by the Lamella effluent transfer pumps.

4.8.1.8.3. MMF backwash outlet is directed to the backwash / rinse water storage tank.

4.8.1.8.4. MMF rinse water is supplied by the Lamella effluent transfer pumps.

4.8.1.8.5. MMF rinse water outlet is directed to the backwash / rinse water storage tank.

4.8.2. Initial and/or transitional use of the MMFs from CPRP treatment to PWP filtration:

4.8.2.1. No special procedure is necessary as CPRP discharge to the PWP is allowed.

Operation is standard as follows:

4.8.2.1.1. MMF inlet is supplied by the PWP sump pumps

4.8.2.1.2. MMF outlet is directed to the PWP/101 outfall (recirculation/discharge)

4.8.2.1.3. MMF backwash inlet is supplied by the PWP sump pumps.

4.8.2.1.4. MMF backwash outlet is directed to PWP.

4.8.2.1.5. MMF rinse water is supplied by the PWP sump pumps.

4.8.2.1.6. MMF rinse water outlet is directed to the PWP.

4.9. MMF Operational Modes Summary

4.9.1. “Discharge”

4.9.1.1. MMF outlet is discharged to the 101 or 201 outfall as specified by the User

depending on the mode of operation (“PWP” or “CPRP” treatment modes

respectively).

4.9.1.2. MMF outlet flow rates when treating Lamella effluent water vary depending on the

operational option selected but are firstly based on maintaining a level in the Lamella

effluent storage tank to provide adequate volume for backwashing. MMF outlet flow

rates when treating PWP discharge are controlled by a User input set point in “gpm”

into the PLC HMI. The filter outlet flow control valve (1RV-QW0105) located on the

common MMF inlet line modulates based on feedback from the MMF outlet flow

meter (1FE-QW2105) on the common MMF outlet line to maintain the MMF outlet

flow rate set point.

PREREQUISITE: MMF system outlet TSS sample has been analyzed by the lab and it is

less than 30 mg/L and inlet pH levels are between 6 to 9. An outlet TSS sample result up to

50 mg/L may allow the filters to be placed into “discharge” mode however it requires

approval from plant laboratory supervisor and/or management.


4.9.1.3. The number of filter vessels in service is controlled by the PLC under the

following ranges:

“Initial” Vessel Operation

Flow

Range

(gpm)

Required #

of Filters in

Service 1 2 3

100 – 175 1 Lead Standby-A Standby-B

175 – 300 2 Lead Lag-A Standby-A

300 – 550 3 Lead Lag-A Lag-B

The PLC will cycle filter vessels in service following backwashing and/or based on a

User input time to ensure filters do not stagnate and/or have excessive service time.

Individual vessel flow rates are determined by a division of the total flow indicated on the

outlet flow meter by the number of vessels in service.

4.9.1.4. Backwashing is controlled by the PLC and can be automatically initiated based one

of the following:

1) Outlet turbidity set point

2) Single filter vessel influent to effluent differential pressure set point

3) Single vessel throughput

4) Time based

5) Manually initiated by the User

4.9.1.4.1. Automatic initiation of backwashing can be disabled by the User on the PLC

HMI “MMF” screen. If automatic initiation of backwashing is disabled the

backwash conditions described in section 4.9.1.4 remain active and will “lock”

the filter out of service rather than initiating a backwash sequence. The User

will need to manually initiate a backwash sequence in order to put the vessel

back into service.

4.9.2. “Alternate Outlet to PWP/Recirculation”

4.9.2.1. MMF outlet is directed to the PWP through the branch line off of the MMF outlet

header to the trench drain.

4.9.2.2. MMF alternate outlet/recirculation flow rates when treating Lamella effluent water

vary depending on the operational option selected but are firstly based on maintaining

a level in the Lamella effluent storage tank to provide adequate volume for

backwashing. MMF alternate outlet/recirculation flow rates when treating PWP

discharge are controlled by a User input set point in “gpm” into the PLC HMI. The

filter outlet flow control valve (1RV-QW0105) located on the common MMF inlet

line modulates based on feedback from the MMF outlet flow meter (1FE-QW2105)

on the common MMF outlet line to maintain the MMF outlet flow rate set point.

4.9.2.3. The number of filter vessels in service is controlled by the PLC under the

following ranges:


“Initial” Vessel Operation

Flow

Range

(gpm)

Required #

of Filters in

Service 1 2 3

100 – 175 1 Lead Standby-A Standby-B

175 – 300 2 Lead Lag-A Standby-A

300 – 550 3 Lead Lag-A Lag-B

PLC will cycle filters vessels in service following backwashing and/or based on a User

input time to ensure filters do not stagnate and/or have excessive service time.

Individual vessel flow rates are determined by a division of the total flow indicated on the

outlet flow meter by the number of vessels in service.

4.9.2.4. Backwashing is controlled by the PLC and can be automatically initiated based one

of the following:

1) Outlet turbidity set point

2) Single filter vessel influent to effluent differential pressure set point

3) Single vessel throughput

4) Time based

5) Manually initiated by the User

4.9.2.4.1. Automatic initiation of backwashing can be disabled by the User on the PLC

HMI “MMF” screen. If automatic initiation of backwashing is disabled the

backwash conditions described in section 4.9.2.4 remain active and will “lock”

the filter out of service rather than initiating a backwash sequence. The User

will need to manually initiate a backwash sequence in order to put the vessel

back into service.

4.9.3. “Standby”

4.9.3.1. Filters are not receiving or discharging flow

4.9.3.2. PLC is active and filters are backwashed automatically with PWP water based on a

User input time. Backwash discharge is directed back to the PWP. The PLC will

cycle filter vessel backwashing to ensure filters do not stagnate and/or have excessive

idle time.

4.9.4. “Offline”

4.9.4.1. Filters are not receiving or discharging flow

4.9.4.2. PLC is active and filters are backwashed manually with PWP water by the User.

Backwash discharge is directed back to the PWP. The PLC will not cycle filter vessel

backwashing. User will need to manage filter out-of-service time and backwash

appropriately to ensure filters do not stagnate and/or have excessive idle time. PLC

will continue to be utilized to perform the backwash sequencing.

4.9.5. Backwashing


4.9.5.1. Backwashing of the MMF is necessary to remove the solids that have accumulated

within the filter bed over the service run. Excessive solids accumulation on the filter

media results in headloss across the vessel(s) and/or poor filter outlet quality.

Backwashing involves primarily an air scour, backwash to achieve a 30 – 50% media

bed expansion, and a rinse down step. Only one filter vessel is allowed to backwash

at a time and a filter cannot be backwashed when the MMFs are in “Alternate outlet to

PWP/Recirculation” mode. If the MMF system is running in “Alternate outlet to

PWP/Recirculation” and a backwash of one of the vessels is necessary, backwashing

will take priority and MMF outlet flow is temporarily suspended during the backwash

sequence when backwash outlet flow is discharged from the vessel. If more than one

filter requires a backwash per one/multiple triggers of the presented options/trip

points, it will be queued and is backwash based on its place in the queue. Queue

priorities are: Lead, Lag-A, Lag-B, Standby-A, Standby-B.

NOTE: All backwash “trigger” set points for the items listed in sections 4.9.1.4 and

4.9.2.4 will have initial values but primarily will be determined upon commissioning

and/or adjusted over time as needed.

NOTE: All backwash “sequencing”, timing, and other applicable set points will have

initial values but primarily will be determined upon commissioning and/or adjusted

over time as needed.

4.9.6. Backwash permissives

4.9.6.1. CPRP treatment mode:


Lamella Effluent Storage Tank Level 1LIT-QW0102 9-ft or set point

value

Backwash / Rinse Water Storage Tank

Level 1LIT-QW0202

1-ft 8-in or set

point value

4.9.6.2. PWP or Dual treatment mode(s):


PWP Level 1LT-

WW0400A/B

Greater than set

point value

MMF Backwash Outlet to BWP Block




Valve-A

1HV-QW5100 Closed



Valve-B

1HV-QW5300 Closed


4.9.7. Backwash sequencing

NOTE: Time ranges are estimates; initial values will be determined following

commissioning.

Step Process Time Purpose

1 Drain Down TBD Provide void space for air scour in the top of the vessel

2 Air scour 5 – 15 min. Agitate media and loosen sediment in media layers

3 Settle 3 – 10 min. Allow media to settle back in filter vessel

4 Refill TBD Prevents air surge / hammer prior to backwashing

5 Backwash 10 – 30 min. Remove sediment from filter media

6 Settle 3 – 10 min. Allow media to re-classify

7 Rinse TBD Allow filter effluent quality to stabilize

Backwash steps can also be held or adjusted at any time during the backwash

sequence by the User through the PLC HMI should it seem that additional time is

needed for a particular step. The backwash sequence can also be stopped at any time

and restarted or reset as appropriate.

A low backwash flow alarm set point is active during the backwash step (step 5)

(initially < 400 gpm) that stops the backwash sequence and restarts step 5 after a 10-

minutes. If (3) restarts are encountered during a single vessel backwash sequence

this filter vessel is “locked” out of service until a complete backwash sequence can

be performed. A common trouble alarm is sent to the DCS.

4.9.8. Backwash steps

4.9.8.1. Backwash air scour

4.9.8.1.1. Air flow for the air scour step is required at approximately 200 cfm at 7 – 8 psi.

Air flow is supplied from the 2-inch air scour inlet line. Air flow is introduced

for approximately 5 – 15 minutes and is User adjustable on the PLC HMI. Air

flow through the MMF vessel during the air scour is vented to atmosphere.

4.9.8.2. Backwash flow

4.9.8.2.1. Backwash water is introduced through the common MMF backwash inlet line

at 400 – 900 gpm to achieve a 30 – 50% media bed expansion. Media

expansion during backwashing can be observed through the upper sight glass on

the side of the filter vessel. If proper media expansion is not observed during

backwashing the backwash inlet flow can be increased by changing the set point

on the PLC HMI as needed. If proper media expansion is not observed up to the

maximum flow rate of 900 gpm the filter may be experiencing mechanical

issues.

Backwash water is fed to the MMF system through the 8-inch discharge line off

of the Lamella effluent transfer pumps or the branch off of the PWP sump

pumps discharge line depending on the system’s operational mode. Backwash

inlet flow rates are controlled by a User input set point in “gpm” into the PLC


HMI. The backwash inlet flow control valve (1RV-QW1405) modulates based

on feedback from the backwash inlet flow meter (1FIT-QW1605) on the

common backwash inlet line to maintain the backwash inlet flow rate set point.

Backwash effluent water (outlet) from the vessel is sent to the backwash and

rinse water tank or to the PWP depending on the operational mode, tank level

permissives, or can be manually directed to the PWP by the User if necessary.

The required backwash flow rates to accomplish the required media expansion

is, to a certain extent, dependent on the water temperature. As such, an option

for temperature compensated/biased backwash flow rate adjustment is available

in the PLC. Initially backwash flow rates will be set manually to observe bed

expansion and can be adjusted as additional operational experience is obtained.

Backwash duration should be approximately 10 – 30 minutes.

The following are recommended flow rates for determining proper backwash

flow rates based on water temperature ranges.

Temperature

(°F)

Flux Rate

(gpm/ft2)

Flow

(gpm)

40 – 50 11.8 454

50 – 60 14.2 547

60 – 70 16 616

70 – 80 18.5 712

80 – 90 20.7 797

90 – 100 22.9 882

4.9.8.3. Rinse / Filter-to-waste

4.9.8.3.1. Following backwashing the filter vessel is rinsed down to remove any

excessive solids in the bed and/or lines and allow the filtered outlet water to

stabilize to a certain degree to prevent inadvertent filtered outlet turbidity spikes.

Filtered water (outlet) from the vessel that was just backwashed during the rinse

step is sent the backwash / rinse water tank or to the PWP depending on the

operational mode, tank level permissives, or can be manually directed to the

PWP by the User if necessary. Rinse flow rates are controlled by a User input

set point in “gpm” into the PLC HMI. The backwash inlet flow control valve

modulates based on feedback from the backwash inlet flow meter on the

common backwash inlet line to maintain the rinse flow rate set point.

4.9.9. Out of Service

4.9.9.1. When no flow is required to be processed through the MMF and they are

anticipated to be offline for 3 – 7 days or longer, the MMF system will need to be

protected from excessive biological growth within the filter media. This is to prevent

excessive maintenance, unavailability, or accelerated / irreversible media fouling of

the system. Ideally the filter vessels should be kept full of water and backwashed on a

weekly or greater basis when out of service. However depending on plant

operation(s) and length of time the filters are/will be out of service, extended media

layup procedures may need to be developed.


NOTE: Prevention of biological growth within the filter media when not in service

can be difficult to predict and numerous factors (water temperature, organism growth

rates, nutrient levels, etc.) affect this process. Therefore biological growth can occur

within periods of less than 3 days or greater than 7 days and likley operational

experience will need to factor into the biological control plan. Additionally since it

can be difficult to completely “dry” out the media during an extended out of service

period, periodic disinfection and/or alternate biological control may need to be

considered. Should a “drained and dry” extended layup procedure be implemented it

will likely be necessary to fully backwash and/or disinfect the media prior to returning

it to service.

Typically routine backwashing can prevent biological growth within the media. To

accomplish this two modes of “automatic” filter operation can be selected, “standby”

or “offline”. In “standby” mode the filters are out of service and are automatically

backwashed periodically to prevent biological growth. In “offline” mode the filters

are backwashed manually by the User to prevent biological growth.

Should routine backwashing become ineffective and/or it becomes necessary to

supplement the biological control within the media, periodic disinfection can be

accomplished with the addition of sodium hypochlorite. This can be fed from the

Lamella clarifier’s biocide injection skid into each individual filter vessel’s backwash

inlet line. These will be temporary hose connections from the biocide dosing skid to

the injection point. The filters will need to be out of service and filled with water.

They can then be dosed with the appropriate level of hypochlorite to manage any

potential biological activity. The best way to accomplish this is to dose the

hypochlorite into the vessel and allow it to soak for approximately 0.5 – 4 hours

depending on the anticipated growth. Then perform a standard backwash to remove

the chemicals, this can be followed by a second backwash to reclassify the media as/if

necessary.

4.9.10. Common MMF system valve position summary

O = Fully Open

X = Fully Closed

M = Modulating

S = Standby (only used during backwashing)

NA = Not Applicable

BW = Backwash

Operation

Description Valve ID Discharge Recirculation Standby Offline Backwash Fail/Trip

Common inlet block 1HV-QW0105 O O O O O

Inlet control valve

isolation block-A 1HV-QW0205 O O O O O

Inlet control valve

isolation block-B 1HV-QW0305 O O O O O


Operation

Description Valve ID Discharge Recirculation Standby Offline Backwash Fail/Trip

Inlet control valve bypass

block 1HV-QW0405 X X X X X

Common backwash inlet

block 1HV-QW1905 O O O O O

Backwash control valve

isolation block-A 1HV-QW2005 O O O O O


isolation block-B 1HV-QW2105 O O O O O


bypass block 1HV-QW2205 X X X X X

Filter inlet flow control 1RV-QW0105 M M X X NA X

Backwash inlet flow

control 1RV-QW1405 S S S S M X

Filter outlet 1BV-QW2205 O X X X NA X

Recirculation outlet 1BV-QW2305 X O O O NA O

Backwash outlet 1BV-QW2405 S S S S O X

4.9.11. Filter vessel valve position summary

Note: All actuated valves on the filter vessels in this section’s table are equipped with

limit switches to indicate valve position and operate as air to open, spring to close.

Operation

Valve Valve ID Service

BW

Step 1

Drain

BW

Step 2

Air

scour

BW

Step

3

Settle

BW

Step

4

Refill

BW Step

5

Backwash

BW

Step

6

Settle

BW

Step

7

Rinse Standby

Vessel 1 (1TK-QW3510)

Vessel Inlet 1BV-QW0415 O X X X X X X X X

BW Outlet 1BV-QW0515 X X X X X O X X X

Rinse Inlet 1BV-QW0615 X X X X X X X O X

BW/Refill

Inlet 1BV-QW0815 X X X X O O X X X

Rinse Outlet 1BV-QW0715 X X X X X X X O X

Vessel Outlet 1BV-QW0915 O X X X X X X X X

Air Inlet 1BV-QW1015 X X O X X X X X X

Drain Down 1BV-QW1715 X O X X X X X X X

Vent 1BV-QW1915 X O O O O X X X X

Vessel Inlet 1HV-QW0815 O O O O O O O O O

BW Inlet 1HV-QW2515 O O O O O O O O O

BW/Rinse

Outlet 1HV-QW1215 O O O O O O O O O

Air Inlet 1HV-QW1715 O O O O O O O O O

Drain Down 1HV-QW2615 O O O O O O O O O

Vessel Outlet 1HV-QW1615 O O O O O O O O O

Vent 1HV-QW2715 O O O O O O O O O


Operation

Valve Valve ID Service

BW

Step 1

Drain

BW

Step 2

Air

scour

BW

Step

3

Settle

BW

Step

4

Refill

BW Step

5

Backwash

BW

Step

6

Settle

BW

Step

7

Rinse Standby

Drain 1HV-QW1815 X X X X X X X X X





BW/Refill

Inlet

1BV-QW0825

X X X X O O X X X








BW/Rinse

Outlet

1HV-QW1225

O O O O O O O O O










BW/Refill

Inlet

1BV-QW0835

X X X X O O X X X








BW/Rinse

Outlet

1HV-QW1235

O O O O O O O O O







4.10. Abnormal Operations

4.10.1. Contaminated Lamella effluent storage tank

During/Following a significant process (Lamella clarifier) upset, should analysis or

instrumentation indicate that the TSS (and/or turbidity) in the entire volume of the

Lamella effluent storage tank is too high for treatment within the MMF or to discharge

into outfall 201; the contents of the tank must be purged to the CPRP. To accomplish

this, the User can select the “Contaminated Lamella Effluent Storage Tank” selection

button on the PLC HMI “Lamella” screen, and the contents of the Lamella effluent

storage tank are discharged directly to the CPRP.

Selecting this option closes the Lamella train outlet to effluent storage tank valves (1BV-

QW0312/0322) and opens the Lamella train outlet to backwash / rinse water storage tank

valves (1BV-QW0412/0422), sending all Lamella effluent directly to the backwash /

rinse water storage tank. The MMF outlet flow control valve (if operating in CPRP

treatment mode) (1RV-QW0105) and the Lamella effluent to outfall 201 flow control

(1RV-QW1802) valves close. The User must manually close the Lamella effluent tank to

backwash tank inlet block valve (1HV-QW5800*) and open the Lamella effluent tank to

CPRP block valve (1HV-QW5700*), allowing for a direct flow path from the Lamella

effluent transfer pumps to the CPRP.

(*) = Permissive position for the User to be able to select the “Contaminated Lamella

Effluent Storage Tank” option. Selecting this option without these permissives met, the

PLC HMI will display “Permissives not met” and will not proceed with the purge.

4.11. Lamella Sludge Processing (temporary operation)

4.11.1. TSS that has been removed from the CPRP discharge during the clarification process and

the residual treatment chemicals (coagulant and flocculent) are ultimately disposed of

through re-application to the coal pile. This occurs through a three step process

(Lamella) clarification (initial TSS removal from the CPRP discharge), thickening

(concentrating settled solids from the Lamella), and pressing (dewatering concentrated

solids).

Lamella clarification was covered in previous sections. Thickening occurs in the Lamella

sludge thickener tank (1TK-QW3200), described in section 3.7 and pressing occurs in the

filter press (1FL-QW3000), described in section 3.8.

4.11.2. Initially the Lamella sludge thickener will not be equipped with a scraper mechanism to

collect solids that have settled within the vessel. During the interim when operating the

vessel without a scraper, to mitigate potential “dead” zones in the bottom of the vessel

that may accumulate settled sludge, the filter press feed pumps will remain in operation

when the system is processing water from the CPRP and recycle sludge through the tank.

The filter press feed pumps will cycle water from the bottom of the Lamella sludge

thickener vessel to the top continuously when the filter press is not in service, in an effort

to keep the sludge moving and prevent un-even settling and/or “dead” zones within the

vessel that may go anaerobic. When the filter press is in service the recycle valve (1BV-

QW2002) closes and all of the filter press feed pump discharge is sent to the filter press.

A 3-way solenoid valve regulates the pressure (flow) for the filter press feed pumps to


accommodate both modes of operation in the interim (recirculation, high flow/low

pressure and filter press feed, variable flow/variable (high) pressure).

4.11.3. To manage sludge inventor in the Lamella clarifiers, the User will need to adjust the

sludge transfer pump operation as needed. This is largely dependent on the Lamella

influent solids loadings (influent TSS and chemical feed(s)) and operational experience.

Sludge transferred from the Lamella underflow is sent to the Lamella sludge thickener

from the sludge transfer pumps through an (temporary) open ended tee connection

discharging approximately 4 to 5-feet below the top of the thickener vessel.

4.11.4. Overflow from the thickener vessel is directed to the Lamella influent mix tanks,

depending upon which Lamella train(s) are in operation.

4.11.5. Should TSS levels in the thickener overflow seem excessive and/or sludge settling seem

unacceptable, a flocculent can be fed into the individual sludge transfer pump feed lines

as needed. These set points are adjustable in the PLC HMI “Chemical Feed” page.

4.11.6. Once sufficient solids have collected / concentrated in the sludge thickener the User has

several options available to determine if it is acceptable to begin a filter press run.

(1) Analyze a TSS sample from one of the 4 bottom/side sample ports (ideal sample port

sample location may require some trial-and-error / operational experience to evaluate the

optimal or best representative sample location). A TSS sample in the 1 – 5% range will

typically indicate acceptable solids concentrations to begin a filter press run.

(2) Analyze a settled solids density sample (V/V) from one of the 4 bottom/side sample

ports (ideal sample port sample location and V/V settled sludge results analysis may

require some trial-and-error / operational experience to evaluate the optimal or best

representative sample location and analysis results for an acceptable filter press run).

(3) Sludge level indication provided by the vessel level instrumentation (1LIT-QW0702)

(ideal sludge bed levels observed to determine an acceptable filter press run may require

some trial-and-error / operational experience).

(4) Treatment system operating flow rates / operating conditions / operational experience

/ etc. that necessitate filer press operation to manage solids inventories and maintain pond

levels.

4.11.7. Once the User determines that a filter press run can begin, the User will navigate to the

“Filter Press” page on the PLC HMI. If the status on the PLC HMI “Filter Press” screen

indicates “Ready” the User can select the option “Begin Filter Press Run”. Signal/Status

from the filter press skid will largely provide the permissives for the “Ready” status on

the PLC HMI, though one operational permissive that the User must

check/verify/complete is the status of the filter press feed valve (1HV-QW2700), which

must be open. Once the User selects this option the filter press run is started and the

sludge recirculation valve closes and the filter press skid steps through it sequencing until

the filter press run is complete.

4.11.8. Status from the filter press skid is sent to the PLC and indications of the press sequencing

and completion will be displayed on / transmitted by the PLC HMI “Filter Press” screen.

Once a filter press run is complete the PLC HMI will display “Press Complete”. The


User will then need to begin the process of separating the filter press plates, dumping the

dewatered sludge into a roll-off dumpster.

4.12. Filter Press Operation

4.12.1. Detailed filter press operation is covered in the Siemens O&M manual


5. Operation valve line up (standard operation)

NOTE: Valve positions for the MMF system and vessels provided in sections 4.9.10 and 4.9.11

5.1. CPRP Treatment

O = Fully Open

X = Fully Closed

M = Modulating

Z = Varies Depending on Operation

* = Permissive Status

Treatment Option

Description Valve ID Ready

1st Stage

Startup

2nd

Stage

Startup 1 2 3 4

Fail/Trip

Position

CPRP High Flow Bypass Block 1HV-WW4403 X* X* X* X* X* X* X*

CPRP Supply to Treatment

System Block 1HV-WW4303 O* O* O* O* O* O* O*

Treatment System Return to

Outfall 201 Header Block 1HV-WW4503 O* O* O* O* O* O* O*

CPRP Low Flow Pump to

Treatment Header Block 1HV-WW4103 O O O O O O O

CPRP Low Flow Pump to Future

User Block 1HV-WW4203 X X X X X X X

Lamella Train 1 Inlet Block 1HV-QW0310 O O O O O O O

Lamella Train 1 Inlet Flow

Control 1RV-QW0112 X M M M M M M X

Lamella Train 2 Inlet Block 1HV-QW0320 O O O O O O O

Lamella Train 2 Inlet Flow

Control 1RV-QW0122 X M M M M M M X

Coagulant Inlet Block 1HV-QW0200 O O O O O O O

Treatment Options

1. MMF treatment discharging to the PWP

2. MMF treatment discharging to outfall 201

3. MMF treatment and Lamella effluent combined discharge to outfall 201

4. Lamella effluent direct discharge to PWP


Treatment Option


1st Stage

Startup

2nd

Stage

Startup 1 2 3 4

Fail/Trip

Position

Lamella Train 1 Flocculent Inlet

Block 1HV-QW0610 O O O O O O O

Lamella Train 2 Flocculent Inlet


Lamella Train 1 Thickener

Overflow Inlet Block 1BV-QW1012 Z Z Z Z Z Z Z

Lamella Train 2 Thickener

Overflow Inlet Block 1BV-QW1022 Z Z Z Z Z Z Z

Lamella Train 1 Sludge Transfer

Pump A Suction 1HV-QW0911 O O O O O O O


Pump B Suction 1HV-QW0912 O O O O O O O


Pump A Suction 1HV-QW0921 O O O O O O O


Pump B Suction 1HV-QW0922 O O O O O O O


Pump A Discharge 1HV-QW1511 O O O O O O O


Pump B Discharge 1HV-QW1512 O O O O O O O


Pump A Discharge 1HV-QW1521 O O O O O O O


Pump B Discharge 1HV-QW1522 O O O O O O O

Lamella Train 1 Outlet to Effluent

Storage Tank 1BV-QW0312 X X* O* O O O O X

Lamella Train 1 Outlet to

Backwash / Rinse Water Storage

Tank 1BV-QW0412 O O* X* X X X X O

Lamella Train 2 Outlet to Effluent

Storage Tank 1BV-QW0322 X X* O* O O O O X


Treatment Option


1st Stage

Startup

2nd

Stage

Startup 1 2 3 4

Fail/Trip

Position

Lamella Train 2 Outlet to


Tank 1BV-QW0422 O O* X* X X X X O

Lamella Effluent Storage Tank

Outlet Block 1HV-QW3800 O O O O O O O

Lamella Effluent Transfer Pump

A Suction Block 1HV-QW3910 O O O O O O O


B Suction Block 1HV-QW3920 O O O O O O O


A Discharge Block 1HV-QW4110 O O O O O O O


B Discharge Block 1HV-QW4120 O O O O O O O

Lamella Effluent to 201 Block 1HV-QW4700 O O O X X O X

Lamella Effluent to 201 Flow

Control 1RV-QW1802 X X X X* X* M X* X

MMF Lamella Inlet Double Block

A 1HV-QW4800 O O O O O O X*


B 1HV-QW4900 O O O O O O X*


Bleed 1HV-QW7000 X X X X X X O

Lamella Sludge Thickener Tank

Underflow Block 1HV-QW1900 O O O O O O O

Filter Press Feed Pump A Suction


Filter Press Feed Pump B Suction


Filter Press Feed Pump A

Discharge Block 1HV-QW2510 O O O O O O O

Filter Press Feed Pump B

Discharge Block 1HV-QW2520 O O O O O O O


Treatment Option


1st Stage

Startup

2nd

Stage

Startup 1 2 3 4

Fail/Trip

Position

Lamella Sludge Thickener

Recycle Block 1BV-QW2002 Z Z Z Z Z Z Z

Filter Press Feed Block 1HV-QW2700 Z Z Z Z Z Z Z

Filter Press Filtrate to Lamella

Effluent Storage Tank Block 1HV-QW3500 Z Z Z Z Z Z Z

Filter Press Filtrate to Trench

Block 1HV-QW3400 Z Z Z Z Z Z Z


Double Block A 1HV-QW8000 X* X X X* X* X* X


Double Block B 1HV-QW8200 X* X X X* X* X* X


Double Block Bleed 1HV-QW8100 O O O O O O O

MMF Outlet to 201 Double Block

A 1HV-QW7700 O O O X* O* O* X*


B 1HV-QW7900 O O O X* O* O* X*


Bleed 1HV-QW7800 X X X X X X X


A 1HV-QW7400 X* X X X* X* X* X


B 1HV-QW7600 X* X X X* X* X* X


Bleed 1HV-QW7500 O O O O O O O

MMF Backwash Outlet to PWP

Block 1HV-QW5000 X X X X* X* X* X

MMF Backwash Outlet to


Tank Double Block A 1HV-QW5100 O O O O* O* O* O


Treatment Option


1st Stage

Startup

2nd

Stage

Startup 1 2 3 4

Fail/Trip

Position



Tank Double Block B 1HV-QW5300 O* O O O O* O* O*



Tank Double Block Bleed 1HV-QW5200 X X X X X X X

Lamella Effluent Tank to

Backwash Tank / CPRP Double

Block A 1HV-QW5400 O O O O O O O



Block B 1HV-QW5600 O O O O O O O



Block Bleed 1HV-QW5500 X X X X X X X


Backwash Tank / CPRP Control

Valve 1RV-QW1902 X X O M M M M O


Backwash Tank Inlet Block 1HV-QW5800 O O Z O* O* O* O

Lamella Effluent Tank to CPRP

Block 1HV-QW5700 X X Z X X X X

Backwash / Rinse Effluent

Storage Tank Outlet Block 1HV-QW6200 O O O O O O O


Transfer Pump A Suction Block 1HV-QW6310 O O O O O O O


Transfer Pump B Suction Block 1HV-QW6320 O O O O O O O


Transfer Pump A Discharge Block 1HV-QW6510 O O O O O O O


Transfer Pump B Discharge Block 1HV-QW6520 O O O O O O O


5.2. PWP Treatment

O = Fully Open

X = Fully Closed

M = Modulating


* = “Ready” Permissive


Discharge

to 101

Fail/Trip

Position

MMF Lamella Inlet Double Block A 1HV-QW4800 X* X*

MMF Lamella Inlet Double Block B 1HV-QW4900 X* X*

MMF Lamella Inlet Double Block Bleed 1HV-QW7000 O O

PWP Sump Discharge to MMF Double

Block A 1HV-QW8000 O* O*


Block B 1HV-QW8200 O* O*


Block Bleed 1HV-QW8100 X X

MMF Outlet to 201 Double Block A 1HV-QW7700 X* X*

MMF Outlet to 201 Double Block B 1HV-QW7900 X* X*

MMF Outlet to 201 Double Block Bleed 1HV-QW7800 O O

MMF Outlet to 101 Double Block A 1HV-QW7400 O* O*

MMF Outlet to 101 Double Block B 1HV-QW7600 O* O*

MMF Outlet to 101 Double Block Bleed 1HV-QW7500 X X

MMF Backwash Outlet to PWP Block 1HV-QW5000 O* O*

MMF Backwash Outlet to Backwash / Rinse

Water Storage Tank Double Block A 1HV-QW5100 X* X*


Water Storage Tank Double Block B 1HV-QW5300 X* X*


Water Storage Tank Double Block Bleed 1HV-QW5200 O O


5.3. Dual Treatment

O = Fully Open

X = Fully Closed

M = Modulating


* = “Ready” Permissive

Treatment Option


1st

Stage

Startup

2nd

Stage

Startup 1 2

Fail/Trip

Position

CPRP High Flow Bypass Block 1HV-WW4403 X* X X X X

CPRP Supply to Treatment System Block 1HV-WW4303 O* O O O O

Treatment System Return to Outfall 201

Header Block 1HV-WW4503 O* O O O O

CPRP Low Flow Pump to Treatment Header

Block 1HV-WW4103 O O O O O

CPRP Low Flow Pump to Future User Block 1HV-WW4203 X X X X X

Lamella Train 1 Inlet Block 1HV-QW0310 O O O O O

Lamella Train 1 Inlet Flow Control 1RV-QW0112 X M M M M X

Lamella Train 2 Inlet Block 1HV-QW0320 O O O O O

Lamella Train 2 Inlet Flow Control 1RV-QW0122 X M M M M X

Coagulant Inlet Block 1HV-QW0200 O O O O O

Lamella Train 1 Flocculent Inlet Block 1HV-QW0610 O O O O O

Lamella Train 2 Flocculent Inlet Block 1HV-QW0620 O O O O O

Lamella Train 1 Thickener Overflow Inlet

Block 1BV-QW1012 Z Z Z Z Z

Treatment Options

1. CPRP discharging to outfall 201, PWP discharging to outfall 101

2. CPRP discharging to PWP, PWP discharging to outfall 101


Treatment Option


1st

Stage

Startup

2nd

Stage

Startup 1 2

Fail/Trip

Position

Lamella Train 2 Thickener Overflow Inlet

Block 1BV-QW1022 Z Z Z Z Z

Lamella Train 1 Sludge Transfer Pump A

Suction 1HV-QW0911 O O O O O

Lamella Train 1 Sludge Transfer Pump B







Discharge 1HV-QW1511 O O O O O







Lamella Train 1 Outlet to Effluent Storage

Tank 1BV-QW0312 X X* O* O O X

Lamella Train 1 Outlet to Backwash / Rinse

Water Storage Tank 1BV-QW0412 O O* X* X X O

Lamella Train 2 Outlet to Effluent Storage

Tank 1BV-QW0322 X X* O* O O X

Lamella Train 2 Outlet to Backwash / Rinse

Water Storage Tank 1BV-QW0422 O O* X* X X O

Lamella Effluent Storage Tank Outlet Block 1HV-QW3800 O O O O O

Lamella Effluent Transfer Pump A Suction

Block 1HV-QW3910 O O O O O


Treatment Option


1st

Stage

Startup

2nd

Stage

Startup 1 2

Fail/Trip

Position

Lamella Effluent Transfer Pump B Suction


Lamella Effluent Transfer Pump A Discharge


Lamella Effluent Transfer Pump B Discharge


Lamella Effluent to 201 Block 1HV-QW4700 O O O O X

Lamella Effluent to 201 Flow Control 1RV-QW1802 X X X M X* X

MMF Lamella Inlet Double Block A 1HV-QW4800 X* X* X* X* X*

MMF Lamella Inlet Double Block B 1HV-QW4900 X* X* X* X* X*

MMF Lamella Inlet Double Block Bleed 1HV-QW7000 O O O O O

Lamella Sludge Thickener Tank Underflow


Filter Press Feed Pump A Suction Block 1HV-QW2010 O O O O O

Filter Press Feed Pump B Suction Block 1HV-QW2020 O O O O O

Filter Press Feed Pump A Discharge Block 1HV-QW2510 O O O O O

Filter Press Feed Pump B Discharge Block 1HV-QW2520 O O O O O

Lamella Sludge Thickener Recycle Block 1BV-QW2002 Z Z Z Z Z

Filter Press Feed Block 1HV-QW2700 Z Z Z Z Z

Filter Press Filtrate to Lamella Effluent

Storage Tank Block 1HV-QW3500 Z Z Z Z Z

Filter Press Filtrate to Trench Block 1HV-QW3400 Z Z Z Z Z

PWP Sump Discharge to MMF Double Block

A 1HV-QW8000 O O O O O


B 1HV-QW8200 O O O O O


Bleed 1HV-QW8100 X X X X X


Treatment Option


1st

Stage

Startup

2nd

Stage

Startup 1 2

Fail/Trip

Position

MMF Outlet to 201 Double Block A 1HV-QW7700 X* X* X* X* X*

MMF Outlet to 201 Double Block B 1HV-QW7900 X* X* X* X* X*

MMF Outlet to 201 Double Block Bleed 1HV-QW7800 O O O O O

MMF Outlet to 101 Double Block A 1HV-QW7400 O* O O O* O*

MMF Outlet to 101 Double Block B 1HV-QW7600 O* O O O* O*

MMF Outlet to 101 Double Block Bleed 1HV-QW7500 X X X X X

MMF Backwash Outlet to PWP Block 1HV-QW5000 O O O O* O*


Water Storage Tank Double Block A 1HV-QW5100 X* X* X* X* X*


Water Storage Tank Double Block B 1HV-QW5300 X* X* X* X* X*


Water Storage Tank Double Block Bleed 1HV-QW5200 O O O O O

Lamella Effluent Tank to Backwash Tank /

CPRP Double Block A 1HV-QW5400 O O O O O


CPRP Double Block B 1HV-QW5600 O O O O O


CPRP Double Block Bleed 1HV-QW5500 X X X X X


CPRP Control Valve 1RV-QW1902 X X O Z Z O

Lamella Effluent Tank to Backwash Tank

Inlet Block 1HV-QW5800 O* O Z O O

Lamella Effluent Tank to CPRP Block 1HV-QW5700 X* X Z X X

Backwash / Rinse Effluent Storage Tank

Outlet Block 1HV-QW6200 O O O O O

Backwash / Rinse Effluent Transfer Pump A

Suction Block 1HV-QW6310 O O O O O

Backwash / Rinse Effluent Transfer Pump B

Suction Block 1HV-QW6320 O O O O O


Treatment Option


1st

Stage

Startup

2nd

Stage

Startup 1 2

Fail/Trip

Position

Backwash / Rinse Effluent Transfer Pump A

Discharge Block 1HV-QW6510 O O O O O

Backwash / Rinse Effluent Transfer Pump B

Discharge Block 1HV-QW6520 O O O O O


5.4. Valve Status and Response

Action on

Description Valve ID

Fail/Trip

Status Fail to open Fail to close

Lamella Train 1

Inlet Flow Control 1RV-QW0112 X Local Alarm Common Alarm

Lamella Train 2

Inlet Flow Control 1RV-QW0122 X Local Alarm Common Alarm

Lamella Train 1

Thickener

Overflow Inlet

Block

1BV-QW1012 X Local Alarm Local Alarm

Lamella Train 2

Thickener

Overflow Inlet

Block


Lamella Train 1

Outlet to Effluent

Storage Tank

1BV-QW0312 X Local Alarm

Common Alarm – Closes

Lamella influent control valve

(1RV-QW0112)

Lamella Train 1

Outlet to Backwash

/ Rinse Water

Storage Tank

1BV-QW0412 O Local Alarm Common Alarm

Lamella Train 2

Outlet to Effluent

Storage Tank

1BV-QW0322 X Local Alarm

Common Alarm – Closes

Lamella influent control valve

(1RV-QW02)

Lamella Train 2

Outlet to Backwash

/ Rinse Water

Storage Tank

1BV-QW0422 O Local Alarm Common Alarm

Lamella Effluent to

201 1RV-QW1802 X Local Alarm

Common Alarm – Trips

Lamella effluent transfer

pumps

Filter inlet flow

control 1RV-QW0105 X Common Alarm

Common Alarm and PLC

moves into “recirculation”

mode if flow is > 0 gpm on

outlet flow meter

Backwash inlet

flow control 1RV-QW1405 X


“locks” out vessel that was

queued for backwash, one

failed backwash sequence is

logged


“locks” out vessel that was

backwashed if flow on the

backwash inlet flow meter is >

0 gpm, further PLC action

based on operating mode

Filter outlet 1BV-QW2205 X


moves into “recirculation”

mode

Common Alarm and PLC trips

1RV-QW0105

Recirculation outlet 1BV-QW2305 O


1RV-QW0105 if flow on outlet

flow meter is > 0 gpm

Common Alarm


6. Alarms / Set points

6.1. Alarms

Common Alarm – Signal sent from PLC to plant DCS

Local Alarm – Alarm condition displayed on / transmitted by PLC HMI only

Backwash outlet 1BV-QW2405 X

Common Alarm and PLC logs

one failed backwash sequence,

PLC closes 1RV-QW1405 if

backwash inlet flow is > 0 gpm


1RV-QW1405 if backwash

inlet flow is > 0 gpm

Lamella Effluent

Tank to Backwash

Tank / CPRP

Control Valve

1RV-QW1902 O Common Alarm Local Alarm

Thickener

Underflow

Recirculation


Alarm Levels and Actions

Parameter Unit

Low-

Low Action Low Action High Action

High-

High Action

Lamella Inf.

Flow gpm 80

Common Alarm –

Stand by pump

started if off 100

Local

Alarm 850

Local

Alarm NA

Lamella

Mixer Run Trip Local Alarm

Lamella

Train Eff.

Turbidity NTU NA NA NA NA 25

Local

Alarm 50

Common

Alarm –

Further action

based on

option(s)

selected

Lamella Eff.

Tank Level ft

Removes MMF

backwash

sequence

permissive

Local

Alarm

Local

Alarm

Common

Alarm

Lamella Eff.

Tank Turb. NTU NA NA NA NA 25

Local

Alarm 50

Common

Alarm – Directs

flow to

Backwash

Storage Tank

Lamella Eff.

Tank

Discharge

Pressure psig

Local Alarm –

Trips duty pump

and starts standby

Local

Alarm

Local

Alarm Local Alarm

BW Tank

Level ft

Local

Alarm

Common

Alarm –

Removes MMF

backwash

sequence

permissive


BW. Tank

Flow gpm Local Alarm

Local

Alarm

BW Tank

Discharge

Pressure psig

Local Alarm –

Trips duty pump

and starts standby

Local

Alarm

Local

Alarm Local Alarm

Thickener

Level ft

Local Alarm –

Stops transfer

pump(s)

Local

Alarm

Local

Alarm

Common

Alarm

Filter Press

Feed

Pressure psi

Local Alarm –

Trips duty pump

and starts standby

Local

Alarm

Local

Alarm Local Alarm

MMF Inlet


Local

Alarm 250

Common

Alarm

MMF Outlet


Common

Alarm 50

Common

Alarm and PLC

moves into

“recirculation”

mode

Inlet pH 6.3

Common Alarm

and PLC moves

into

“recirculation”

mode 6.8

Common

Alarm 8.2

Common

Alarm 8.7

Common

Alarm and PLC

moves into

“recirculation”

mode

MMF Vessel

Outlet Flow gpm 75 Common Alarm 100

Local

Alarm 175

Local

Alarm 200

Common

Alarm

MMF

Backwash

Flow gpm 400

Common Alarm

and PLC restarts

backwash step 5,

one failed

backwash

sequence is

logged 450

Common

Alarm 900

Common

Alarm 1000

Common

Alarm and PLC

suspends

backwash, one

failed

backwash

sequence is

logged

MMF Vessel

Differential

Pressure psid NA NA NA NA 15

PLC

places

vessel

into

backwas

h queue 25

Local Alarm

and PLC places

vessel into

backwash

queue

MMF Vessel

Backwash

Sequence

Failures NA NA NA NA NA NA 3

Common

Alarm and PLC

“locks” vessel

out of service


7. PLC control set points

Parameter Unit Minimum Maximum Initial

PWP

Stop MMF inlet flow ft

Start MMF inlet flow ft

MMF treatment level ft

Lamella

System Influent Flow gpm 100 800

Train 1 Influent Flow gpm 100 400

Train 2 Influent Flow gpm 100 400

Coagulant Dose ppm 0 200

Coagulant Specific Gravity NA NA

Coagulant Dosing Pump Max ml/min

Flocculent Dose ppm 0 10

Flocculent Solution %

Flocculent Dosing Pump Max ml/min

Train 1 Sludge Pump On minutes

Train 1 Sludge Pump Off minutes

Train 2 Sludge Pump On minutes

Train 2 Sludge Pump Off minutes

Lamella Effluent Tank

Backwash Permissive Level ft

Backwash / Rinse Water Storage Tank

Backwash Permissive Level ft

Maximum High Level Time minutes

Multi-Media Filter (MMF)

Total Outlet Flow gpm 100 800 550

Vessel Idle Time hours 12 600 72

Vessel Standby / Backwash

Timer hours 0 720 72

Vessel Maximum Throughput gallons NA 100,000 4,200

MMF Backwashing

Flow gpm 400 900 575

Drain Down Time minutes TBD TBD TBD

Air Scour Time minutes 0 60 5

Settle Time minutes 0 60 TBD

Refill Time minutes TBD 60 TBD

Backwash Time minutes 5 60 10

Settle Time minutes 0 60 TBD

Rinse Time minutes 0 240 10

Rinse Flow gpm 100 300 230

Sludge Thickener


Parameter Unit Minimum Maximum Initial

Sludge Level ft

Rake Torque ft-lbs

Filter Press

TBD

8. Reserved for future use

9. Reserved for future use

Documents

TK-FGDSCE-010314 Rev 1 of 110113 · Lamella clarifier, and finally filtration. The PWP discharge treatment system consists of filtration only. Typical operation of the CPRP is to