Award winning coagulant control system for water and wastewater treatment plants
Compass

Award winning coagulant control system for water and wastewater treatment plants





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60
sites

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6,576 MLD
under compass control


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1,737 MGD
under compass control


Key Features

Fast

Responds instantly to changing conditions

Stable

Process control is not effected by other variables

Performance

Eliminates under-dosing and improves plant performance

Savings

Eliminates over-dosing and reduces operating costs

Product Overview

Compass is a predictive control system that continuously optimises coagulant dosing for water and wastewater treatment plants.

Compass reduces operating costs and improves treatment plant process reliability by determining the coagulant demand of raw water or treatment plant influent.

Compass reacts instantly to changes in raw water / influent quality, ensuring the correct coagulant dose at all times. It works for any type of raw water and any type of coagulant chemical.

Compass has been proven at many treatment plants delivering measurable benefits such as:

  • Reduced chemical use
  • Reduced plant downtime
  • Increased filter run times
  • Maximised TOC removal
  • Reduced sludge production in drinking water treatment
  • Increased sludge production in wastewater primary clarifiers
  • Improved phosphorous removal in wastewater

Improved treatment plant reliability also reduces the need for jar testing and close monitoring of plant performance.

There are four Compass models, two for water treatment and two for wastewater treatment.

 

The basic Compass model is designed for turbidity removal in drinking water treatment. It requires a single UV-vis spectrophotometer and a turbidity meter measuring raw water quality. This model controls coagulant dosing to meet filtered water turbidity targets at the lowest coagulant dose rate. The Compass software runs within a UV-Vis spectrophotometer controller.

The enhanced organics removal (EOR) model is designed for dissolved organics removal in drinking water treatment. It provides the optimum dose to meet filter turbidity targets and maximise dissolved organics removal at the lowest coagulant dose. It requires a UV-vis instrument and turbidity meter on the source water and a UV-Vis meter on the filtered water. The Compass algorithms run within a stand-alone controller.

The chemical phosphate removal (CPR) model is designed for P removal in wastewater treatment. It provides the optimum dose to meet P discharge targets at the lowest coagulant dose. It requires a single UV-vis instrument on the influent prior to coagulant dosing. The Compass algorithms run within the UV-Vis spectrophotometer controller.

The chemically enhanced pre-treatment (CEP) model is designed for pre-treatment in wastewater treatment. It provides the optimum dose to meet performance targets at the lowest coagulant dose. It requires a single UV-vis instrument on the influent prior to coagulant dosing. The Compass algorithms run within the UV-Vis spectrophotometer controller.

How it works

Compass is a feed forward or “predictive” control system. By measuring raw water/influent quality, Compass determines how much coagulant is required to meet treatment aims.

The unique feature of Compass is the characterisation of dissolved natural organic matter (NOM) using proprietary algorithms. This is in addition to the measurement of both the amount of NOM and the particulate matter (turbidity) present. By continuously characterising the type of NOM present in the source water, Compass can determine how both NOM and particulate matter will influence coagulant demand and assign weightings to the component algorithms.

A UV-Vis spectrophotometer and turbidity meter are required to collect the online data required by Compass. The Compass software may run in the UV-Vis probe controller or in a stand-alone controller depending on the model and instrument selection.

In feed forward process control, the coagulant dose is unaffected by fluctuations in flocculation pH, by sample lag times, or by coagulant mixing issues. The only variables that affect the coagulant dose prediction are source water quality variables. This means that feed forward control responds instantly to changes in source water conditions. It also means the coagulant dose will have fewer fluctuations and will be more stable.

The tighter process control provided by Compass means that coagulant doses can be reduced by up to 20% when compared to other control methods.

Compass also results in more stable plant performance which has added benefits such as reduced plant outages and a significant increase in filter run times. This leads to reduced filter wash frequency and a corresponding reduction in power use, sludge disposal costs, and wash water volumes.  Operator confidence in plant reliability improves and less attention is required to monitor plant performance.

Put simply if you wish to meet your filtered water turbidity targets (e.g. <0.1NTU) at the lowest possible dose then select the basic Compass model. The payback period is typically less than 2 years.

In some instances, the treatment objectives are quite different. For example, if Disinfection By Product (DBP) formation is an issue, then the objective is to maximise the amount of DBP pre-cursors that can be removed through coagulation and subsequent solids separation. Our Compass EOR model is designed for this purpose. We ensure that there is no over-dosing, however, a higher coagulant dose is typically required to achieve high organics removal.

In wastewater treatment, coagulants are used for either chemical phosphate removal or in chemically enhanced pre-treatment. The same advanced process control principles equally apply to these applications. The potential for coagulant savings is very high in these applications due to the high coagulant doses employed. Compass has achieved payback in 7 months on relatively small plants.

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