Process Monitoring for Biological and Chemical Nutrient RemovalOWEA 2016 PLANT OPERATIONS & LABORATORY WORKSHOP

October 27, 2016

Agenda

Why Consider Nutrient Removal?

Nitrogen Monitoring & Removal

Phosphorus Monitoring & Removal

2

Why Nutrient Removal?

Required by Discharge Permit

Improve Water Quality (avoid future limit)

Increase Revenue (water quality trading)

Stabilize Process

Save Energy

Recover Nutrients (P)

3

Energy Intensity Benchmarking

4

Joint WEF/WERF Webcast: Net‐Zero Energy Solutions for Water Resource Recovery Facilities

Wednesday, October 29th, 2014

1,412

1,9341,853

1,955

973

1,2491,118

1,202

0

500

1,000

1,500

2,000

2,500

BasicSecondary

Nitrification BNR ENR

kW

h / M

G

Typical

Best Practice

Human

WWTPPlantsIndustry

Agriculture

Rivers &

lakes

Sediments

Phosphate

rock

Discharge

SedimentationTectonic

uplift

Fertilization

Detergent

WeatheringRunoff

Mining

Cornel et al (2009)

P

Recovery

X

P Removal and Recovery

Nitrogen Monitoring

6

Cabinet Analyzer

7

Ion Selective Electrode

8

Specifications – IQSN Nutrient ISEs

Specification Ammonium Nitrate Potassium Chloride

Measuring Range

mg /L (as N)*

0.1 to 100 /

1.0 to 2,000

0.1 to 100

1.0 to 1,000

0.1 to 100

1.0 to 1,000

0.1 to 100

1.0 to 1,000

Resolution

mg /L (as N)*0.1 / 1.0 0.1 / 1.0 0.1 / 1.0 (as K) 0.1 / 1.0 (as Cl)

Response Time

min.< 3

9

Response Time

10

Automation of Wastewater Treatment Facilities, 3rd Edition, WEF MOP-21, WEF Press, Alexandria,

VA, 2007.

Optical

11

ISE vs. Optical Nitrate Monitoring -

Optical ISE

Measuring range, mg/L as N 60 / 150 0 to 1,000

Resolution 0.01 0.1

Pressure resistance, bar 1 0.2

Power Consumption, W Up to 8 0.2

Response time (t90), min. Programmable < 3

Temperature measurement No Yes

Additional Parameters / probeCOD/BOD/TOC,

NO2, TSS

NH4, K, Cl

Warranty (probe), yrs 2 2

Warranty (electrodes), yrs NA 1

Nitrogen Removal

13

The Microbiological Nitrogen Cycle

AOB

NOB

OHO NO2-

Clarifier

Nitrogen Removal Configuration

15

Anoxic Oxic

RAS

WW

NO3-N

NO3-N NO3-N

NH3 NO3NO3 N2

NO3

NH3

3-4 Q NO3-N

BOD

IMLR or NRCY

Delaware County RSD

Anoxic Oxic

A NA N O HO

Denitrification Process Control Chart

17

4-Stage Bardenpho

BOD

NH3-N

NO3-N

Internal MLSS Recycle

3-4 Q NO3-N

Anoxic

Aerobic

Aerobic AerobicAnoxic

Distance

RAS

Q

Methanol

or Glycerin

3-5 mg/L

TN

Denitrification Monitoring – WSSC Seneca

5 x NitraVis 701 TS (1 in each train) w/

supplemental air cleaning (MIQ/CHV)

Goals:

Effluent < 4.0 mg N/L (permit)

Effluent < 3.0 mg N/L ($300k credit)

Minimize Methanol

19

N

Step Feed Denitrification

20

NYC DEP

63 x NitraVis 701 IQ

Goals:

Target Effluent TN = 7 to 8 mg N/L

Monitoring of oxic zone nitrate

Feed forward – Feedback control of

carbon addition (NIC-NOT)

Phosphorus Monitoring

21

Orthophosphate (PO43-)

Environmental P is Phosphate

Soluble P is orthophosphate

Colorimetry is the primary method of

detection

Phosphorus Characterization

TP

OP

Orthophosphate Analyzer

Low reagent consumption

Suitable for outdoors

Automatic calibration

Integrated permeate pump

Filter module

24

Technical Specifications

Range

(mg P / L) Accuracy

Response

time

(min.)

Detection limit

(mg P / L)

Reagent

Replenishment

Lo: 0.05 to

15 mg P / L 2% or 0.05

mg P / L< 5 0.05 mg P / L 2.5 L / 4 mths.

Hi: 1 to 50

mg P / L

25

Phosphorus Removal

26

How is ‘P’ Removed?

1. Biological

2. Chemical

Basic concept:

‘P’ soluble ‘P’ Particulate

‘P’‘P’

Chemical P Removal

• Pre-precipitation

• Simultaneous

precipitation

• Post precipitation

Fe/ Al Fe / Al Fe / Al

‘P’ ‘P’

Fe / Al

Chemical Dosing Control

Manual

Flow-proportioned (Feed Forward)

Feedback with analyzer

29

Feedback Control Example

‘P’

Fe

P700

0.65 0.05

9000.50%

0.10

0.61

HOLD

Chemical Dosing System Operation

31

Phosphorus Accumulating Organism (PAO)

Anaerobic Aerobic

Ortho-P

3 x Infl. Ortho-P

BODPHB

Storage

BOD Oxidized

Concentrations

in Bioreactor

Location in Bioreactor

Net P

Removal

RAS

P-Rich

WAS

PAO

VFA

P

PAO

P

A / O Process

Flow Sheet – GC Sugar Creek

Effluent

Ultraviolet

Disinfection

Process Control - ORP

Summary

There are many compelling reasons to consider nutrient removal

Multiple reliable online monitoring technologies are available for

nitrogen monitoring.

Nitrogen removal is achieved through modification of the well-known

activated sludge process to exploit the microbiological nitrogen

cycle

Online phosphorus monitoring requires a cabinet analyzer but the

technology is improving to reduce maintenance and cost

Phosphorus removal can be achieved chemically or through

enrichment of phosphate accumulating organisms (PAO)

36

Questions?

37