New Jersey Water Science Center
Great Falls of the Passaic River at Paterson, N.J.
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Removal of UOCs in Water Treatment Processes
Project Title: Removal of UOCs in Water Treatment Processes
This project is a collaborative study partially funded through the Water Research Foundation (formerly known as AWWARF) and includes the following partners: Black & Veach, NJDEP, USGS, and six New Jersey water treatment utilities. The overall objective of this project is to obtain more full-scale data for a variety of conventional and advanced water treatment processes on the removal efficiency of UOCs found in drinking water supplies. As indicated previously, recent research on UOCs has focused on their occurrence, and limited research has been conducted on treatment to remove these chemicals, specifically overall removal in a drinking water plant. There is very limited information on the removal of UOCs through specific unit processes used in drinking water treatment. This project will serve to fill this knowledge gap.
This project will evaluate a variety of treatment processes (different design and operating criteria) and water supplies that are used in New Jersey. Additionally, this study will provide new treatment information on various clarification processes including, conventional settling, solids contactors, upflow clarification and ballasted flocculation. More specifically this project will investigate the removal of at least 130 UOCs at six water treatment plants across New Jersey, each with a unique set of raw water quality, treatment process and operating conditions. Samples will be taken after each unit process to assess the removal efficiency of each individual process. Sampling events will occur seasonally to evaluate removal under variable raw water quality conditions. Sample events will include collection of baseline water quality and operational data to complement the UOC removal data. The resulting data set will be comprehensive allowing for analysis of the removal efficiency of various unit processes, the effect of raw water quality and operating parameters on unit process efficiency and the effect of seasonal variability on process efficiency.
Statement of Problem
Numerous organic chemicals are used every day for industrial, commercial and household purposes. Recent investigations have indicated that a number of these chemicals have found their way into many of the nationís wastewater treatment facilities, receiving waters, aquifers and drinking water treatment facilities. A recent report by the Environmental Working Group indicated that 141 unregulated contaminants were detected in tap waters from 42 states.
The various types of organic chemicals that have been detected in raw waters include:
State and Federal agencies, environmental groups and the public are raising concerns regarding these chemicals as emerging contaminants of interest even though many of the chemicals have only been found at trace concentrations (<1.0 ug/L) and only sparse data are available regarding their possible health and/or environmental effects. The rising concern over the presence of these compounds in the nationís waters is demonstrated by the fact that the entire December 2006 issue of Environmental Science and Technology was devoted to the topic of emerging contaminants in the environment. The fact that organic chemicals are being detected in drinking water supplies and that there is concern regarding their health effects raises several fundamental questions:
Strategy and Approach
The project will focus on evaluating UOC removal through the drinking water treatment processes at multiple treatment plants in New Jersey with the goal of evaluating as many different source waters, unit processes and operating scenarios as possible. The goal is to further the understanding of the fate of UOCs during drinking water treatment in New Jersey and industry wide. Some of the important aspects of our technical approach are summarized below:
Currently, six NJ water treatment plants have committed to participating in the project. These systems utilize a range of unit processes:
These systems also reflect varied source water qualities, both reservoir and river, in urban, suburban and rural watersheds. The raw water sources include the Passaic River, the Delaware River, Oradell Reservoir, the Manasquan River, wells under the influence of surface water, and the Rahway River. The wells under the influence are located adjacent to the Delaware River.
Water samples will be collected from each treatment plant during four sampling periods – fall, winter, spring and summer. Sampling will be conducted seasonally in order to capture seasonal changes in water quality and process efficiency. We propose to collect at least 4 samples each sampling period at each treatment plant – raw water, clarified water, filtered water, and finished water. In addition, at plants that utilize advanced processes, we will collect samples after each of those processes.