Process Optimization System can Help Water Plants Meet DBP Rule

A new process optimization system uses proprietary technology to maximize performance of existing coagulation and filtration processes in water treatment plants (WTPs) to help them comply with the stringent requirements of the Disinfection Byproduct (DBP) Rule while avoiding complex and capital-intensive process upgrades.

For conventional filtration water treatment plants, the DBP Rule requires removal of specific percentages of organic materials, measured as total organic carbon (TOC), that may react with disinfectants to form disinfection byproducts. Removal must be achieved through a treatment technique (enhanced coagulation or enhanced softening). In some cases, WTPs have not been able to meet the required TOC removal even after implementation of enhanced coagulations; in others, enhanced coagulation resulted in poor filtration performance.

Many membrane filtration WTPs have experienced heavy membrane fouling after implementation of coagulation processes to reduce TOC. Like their conventional counterparts, many membrane WTPs will not be able to meet Stage 2 MCL requirements for DBPs.

Implementation of the site-specific Clearlogx™ process optimization system from Siemens can help WTPs meet DBP requirements and maximize filter performance while minimizing capital expenses in both conventional and membrane treatment systems.

The Clearlogx process optimization system combines the use of specialty coagulants, state-of-the-art optimization algorithms for coagulation and filtration processes, and Siemens' technical expertise, to yield the simplest, lowest capital cost alternative to DBP Rule compliance.

The systems can be integrated into Siemens' Memcor® membrane systems, or retrofitted into existing installations, to support greater membrane performance for especially difficult-to-treat water sources.

Application Modes

When applying a Clearlogx system with membrane filtration, there are two possible approaches: direct feed mode and clarifier feed mode. Selection of the appropriate operational mode depends on feed water turbidity and TOC concentrations.

Direct feed mode should typically be used with lower turbidity (< 10 NTU) and lower TOC (< 4 ppm) source waters. This mode provides for coagulant addition, precipitation and charge control, and then allows the stream to feed directly onto the membranes. Direct feed mode requires minimal capital investment.

Clarifier mode is well-suited for flashier waters with higher turbidity (> 10 NTU) and higher TOC (> 4 ppm) loads. This mode incorporates coagulant addition with clarification as well as a particle charge control tank between the clarifier and membranes where the acid or base is dosed.

Clearlogx systems have been tested on a variety of chemical coagulants including aluminum and iron-based compounds. Prior to piloting or demonstration, Siemens offers laboratory analysis and jar-testing, either on-site or at a Siemens facility, to determine if the system is a fit for a particular plant.

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