Mark LedgerMD Agua Africa

Mark TitusProduct Manager HACH

Original Equipment Manufacturer

Custom Design and Fabrication

Full Spectrum of FiltrationSingle Media, Dual Media

Cartridge Filtration, Bag Filtration

Decolourisation, Ion Exchange, DI

Iron Removal

Ultrafiltration

Nanofiltration

Reverse Osmosis

Disinfection

Process Chemicals

Marine Engineering

®

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Custom Bio Augmentation programs

Selective Bacterial / Enzyme solutions

Powders, Solids & Liquid formulations:

Industrial / Institutional

Agriculture

Waste Water Treatment

Environmental Bio – Remediation

Aqua Culture

HTH Scientific – Industrial, Municipal & Commercial

Products IndustrialHTH Chips Aquaculture Beverage

Granular Chlorine Breweries Dairy

Stabalised Chlorine Tablets Canneries Meat Process

Chlorine Tablets Vinyards Orchards

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Metal Removers Tanneries Vegetables

Commercial MunicipalClinical Pools and Tanks Industrial Water

Miscellaneous Potable Water

Restaurant Private Water

In Line Feeder Systems

Reservoir Chlorination System

HTH Controller Units, On line Control & Dosing

On line chlorine monitoring and control

Automated dosing systems

Cal Hypo chips, TCIA, HTH granules

Reservoir treatment scientific floaters

HACH Scientific Analytical Laboratory Equipment

Laboratory Chemicals,Reagents and MediaAll parameters ( Acidity – Zinc )

Fine chemicals and Supplementary Reagents

Single Parameter Test Kits

Multi Parameter Test Kits

Test Kit Replacement Parts & Reagent re orders

Microbiological Laboratory supplies

Laboratory and Field instrumentsMeters and Probes

Spectrophotometers and Colorimiters

Sample Cells

Laboratory and Portable Turbidity Meters

General Laboratory Equipment SuppliesA – Z of laboratory requirements

Linkages & Considerations……

• No plant can be designed to be effective without correct analytical information

• No plant can be operated correctly without accurate analytical information

• No process can be properly managed without correct analytical information

• Environmental impact cannot be evaluated without correct analytical information

• Effective chemical treatment programs cannot be managed and assessed without accurate analytical information.

• Key is…… understanding and following the correct methodology, process selection, procedures, interpretation and management of your results and information.

Application and desired quality of analysis

LDO – Luminescent Dissolved Oxygen

HACH IntelliCAL Probes

• Why measure DO ?• Applications / Where ?• Considerations / Factors• Technology / Uniqueness• How ?• Benefits / Advantages

What is Dissolved Oxygen?

• Dissolved oxygen (DO) is simply a measurement of the amount of oxygen gas dissolved in water.

O2

O2

O2

Why Measure Dissolved Oxygen?

• Important indicator of water quality

• Related to:– Water pollution– Water treatment processes– Chemistry of metals– Biological activity

Where is DO Measured?

• DO Monitoring Points:– Equalization

Basin

– Aeration Basin

– Nitrification Basin

– Aerobic/Anaerobic Digester

– Plant Effluent

EqualizationBasin

PrimaryClarifier

Aerobic / AnaerobicSludge Digester

Gravity SludgeThickener

SecondaryClarifier

NitrificationBasinAeration Basin

Plant Inlet(Influent)

FinalFiltration

Disinfection

Plant Effluent

Return Activated Sludge (RAS)

Waste Activated Sludge (WAS)

SludgeDewatering

SludgeDisposalSludge

Disposal

Centrate

1

1

1

1111 1

Why is DO Measured?

• Wastewater collection – H2S control– Aeration control – i.e. Compressors– Chemical control – i.e. Hydrogen peroxide

• Equalization basin & Raw junction chamber– Odor control– Pre-aeration to reduce BOD loading– Sudden DO drop may indicate industrial discharge

Why is DO Measured…?

• Aeration basin– Maintain adequate DO level for aerobic organisms,

yet low enough DO to conserve energy!

• Oxidation ditch– Maintain rotor depth and speed

• Sequencing batch reactor– Use DO levels, rather than time, to control process

Where is DO Measured?

• Trickling filter/RBC effluent channel– Measure effluent channel DO to ensure low recycle

rates while maintaining adequate aeration– Ensure proper aeration exists from zoogleal slime

development

• Biological nutrient removal process– Nitrification process maintains DO between 2 - 3 mg/L– Anoxic zone DO < 0.5 mg/L– Anaerobic zone DO < 0.2 mg/L

Where is DO Measured…?

• Final effluent channel– Ensure plant effluent meets

discharge/permit /legislative requirements

• Up and downstream from plant effluent– Ensure effluent does not damage receiving

waters

Factors Affecting DO

DO Saturation tables provide DO saturation concentration

based on temperature and pressure

Factors Affecting DO

DO Solubility as a function of temperature and salinity

DO Meter intelliCAL

• DO meter and probe are used to measure dissolved oxygen concentration electrochemically.

DO Meter Advantages

• Ease of use

• Limits exposure to chemicals

• Safe disposal of samples

• Fast

• Accurate measurement in colored samples or samples containing suspended solids

The Hach LDO™ Sensor :

Thermistor

Blue LED

Red LED

Photo diode

Luminescent Dissolved Oxygen

How Does HachLDO™ Work?

• A sensor is coated with a luminescent material.

• Blue light from an LED strikes the luminescent chemical on the sensor.

• The luminescent chemical instantly becomes excited.

LEDPhoto Diode

Probe

Sensor

LED

0,0

0,2

0,4

0,6

0,8

1,0

1,2

0 10 20 30 40 50 60 70 80 90 100

Zeit [us]

Normierte IntensitätExcitation Pulse

How does HachLDO™ work ?

LDO™ Sensor

Sensorcap

LEDPhoto Diode

Sensor

LED

How Does HachLDO™ Work?

• As the excited chemical relaxes, it releases red light.

• The red light is detected by a photo diode.

• The time it takes for the chemical to return to a relaxed state is measured

LEDPhoto Diode

Probe

Sensor

LED

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 10 20 30 40 50 60 70 80 90 100

Time [us]

Normierte Intensität

1without O2

Emission Profile

Excitation Pulse

How Does HachLDO™ Work?

LDO™ Sensor

Sensorcap

LEDPhoto Diode

Sensor

LED

How Does HachLDO™ Work?

• When oxygen contacts the luminescent chemical, the intensity of the red light decreases

• The amount of time it takes for the material to relax is reduced

LEDPhoto Diode

Probe

Sensor

LED

Oxygen

LuminescentIndicator

Molecules Gas PermeablePolymer Matrix

Clear, GasImpermeable

Substrate

0,0

0,2

0,4

0,6

0,8

1,0

1,2

0 10 20 30 40 50 60 70 80 90 100

Time [us]

Intensity (normed)

1

without O2

Emission profile

Excitation

Pulse

2with O2

How Does HachLDO™ Work?

LDO™ Sensor

Sensorcap

LEDPhoto Diode

Sensor

LED

Oxygen

How Does HachLDO™ Work?

• The higher the oxygen concentration, the less red light that is given off by the sensor.

Oxygen Concentration

Red Emission Light

How Does HachLDO™ Work?

• The intensity of the red light is not what’s being measured.

• What’s being measured is the time it takes after excitation for red light to be given off. – Lifetime of

luminescence

LEDPhoto Diode

Probe

Sensor

LED

How Does HachLDO™ Work?

• A red LED is also present in the probe.

• Between flashes of the blue LED, a red LED of known intensity, is flashed on the sensor.

• The red LED acts as an internal standard (or reference) for a comparison to the red light given off by the luminescent chemical.

LEDPhoto Diode

Probe

Sensor

LED

Advantages of LDO

• Reduced Maintenance– No membrane to replace

• No more stretching of Teflon and worrying about air bubbles

– No electrolyte to foul or poison• No H2S poisoning of the electrolyte

• No more punctured membranes

Advantages of LDO

• Reduced Maintenance

– No anode or cathode• No cleaning of anodes• No more coating of electrodes

Advantages of LDO

• Frequent Calibration Not Required– No anode to consume and no electrolyte to

deplete means extremely stable measurements

– Internal standard with Red LED– No interference from pH swings, wastewater

chemicals, H2S, or heavy metals

Advantages of LDO

• Accurate and Stable Readings – With nothing to interfere with the readings,

HachLDO™ produces more stable measurements for a longer time

• Speed!– Turn it on and it’s running!– Response time of less than 30 seconds to 90%!

Simple Operation and Maintenance

Only one replacement partInexpensive sensor cap is simple to replace quickly

TNTplus – Auto detecting and running of analytical methods

BarcodingMultiple cell capabilityAutomatic method detectionAutoblanking240 pre programmed water analysis methods50 possible user entered calibrations

The selection criteria……application and results

What’s the benefit of correct and accurate analytical testing

and reporting?• Regulations or Permits

– Am I in compliance?

• Process control– Is my plant operating correctly?– Is it time for preventative maintenance?

• Problems and Troubleshooting– What is wrong with my system?– How can I fix it?

Thank you for your attention

Mark LedgerMD Agua Africa

Mark TitusProduct Manager HACH