Powdered or granular activated carbon adsorption has been widely used in drinking water treatment plants primarily for taste, odor, and synthetic organic contaminant (SOC) removal. However, carbon adsorption has not been widely used for controlling DOM due to the low equilibrium capacities and slow adsorption kinetics. The main reason for these drawbacks is that the majority of commercial activated carbons have been developed primarily to remove small molecular weight hydrophobic SOCs from water. As a result, many commercial carbons do not provide feasible engineering solutions for removing large molecular weight and heterogeneous mixtures of DBP precursors. This research was undertaken to develop a fundamental understanding of tailoring activated carbons for DBP control. The main objectives of this project were to (1) conduct a systematic investigation for developing a fundamental understanding of how activated carbons should be tailored for enhanced removal of dissolved organic matter (DOM) from natural waters; and (2) investigate the effectiveness of some carbon tailoring approaches for disinfection by-products (DBP) formation control at typical drinking water treatment conditions. This project showed that the removal of DBP precursor by GAC adsorption can be significantly improved. GAC adsorption, using modified GACs, can provide another alternative to some water utilities for meeting the Stage 2 requirements of the Disinfectant/Disinfection By-Products Rule.

Disinfection By-Products in Water Treatment describes new government regulations related to disinfection by-products. It explains the formation of microorganism by-products during water treatment and the methods employed to control them. The book includes several chapters on chlorine by-products and discusses techniques for the removal of chloroform from drinking water. It also describes gamma radiation techniques for removing microorganic by-product precursors from natural waters and the removal of bromate from drinking water.

There are many by-products of water disinfection that are still not fully understood and can be potentially harmful. In this volume all the current research in this area is discussed, along with an examination of the role of NOM (natural organic matter) and its relationship to DBP (disinfection by-product) formation and control in drinking water. Understanding the relationship of NOM to DBP may well lead to new techniques for analyzing and treating water and enable reasonable choices to be made for source-water protection, treatment plant process optimization, and distribution system operation to control DBP's. This volume emphasizes the characterization and reactivity of polar natural organic matter. It examines analytical methods which better characterize NOM and determines some of the polar and nonvolatile DBP forms. It presents innovative new methods, sich as capillary electrophoresis for haloacetic aceids and LC/MS for the identification of polar dinking water DBPs.

As part of the effort to balance water treatment processes between allowing pathogenic infection by doing too little, and raising the risk of cancer with by-products of the treatment, 20 papers from a symposium in Chicago, August 1995, present information on the chemical identity of natural organic matter and its interactions with the inorganic precursor bromide ion. They review the history of natural organic matter in water treatment and the impact of regulations, then plunge into reports on an economical experimental approach to developing predictive models for by-products of disinfection, a comparison of analytical techniques for determining cyanogen chloride in chloraminated drinking water, the effect of ozonation and biotreatment on molecular size and hydrophilic fractions of natural organic matter, removing bromate ion by electric-arc discharge and high-energy electron beam processes, and other topics. Annotation copyrighted by Book News, Inc., Portland, OR

This study provides cost estimates of construction and operation for granular activated carbon (GAC) adsorption of total organic carbon (TOC), and packed tower aeration (PTA) for air stripping of trihalomethanes (THMs). Costs were developed by employing software published by the United States Environmental Protection Agency (USEPA) through its Drinking Water Research Division (DWRD). Cost estimation for both methods required preliminary GAC and PTA designs based on data collected in the field and from earlier published sources, as well as modifications to the software used in this study. The resultant designs were focused on compliance with certain aspects of the Stage 2 Disinfection By-Product Rule (Stage 2 DBPR) for THM and haloacetic acid (HAA) concentrations in drinking water. Formation of disinfection by-products (DBPs) occurs when natural organic matter (NOM) found in water sources reacts with disinfectants, typically chlorine based, that are used for the inactivation of water-borne pathogens. DBPs included several groups of compounds that, when ingested, are known to be carcinogenic and have been linked to other serious health effects. Two principle locations were used in this study to represent a medium system (serving 10,000 to 99,999 people) and a large system (serving 100,000 or more people). Overall system cost estimates for GAC adsorption were between 24 and 41 cents per 1000 gallons with an apparent economy of scale existing for larger systems. Investigations into GAC reactivation suggest that off-site reactivation is more cost effective for small to medium systems while some type of on-site reactivation would be a more cost effective method for larger systems. Overall PTA system cost estimates were between 8 and 9.6 cents per 1000 gallons. Both methods are effective at THM control while GAC adsorption has the added ability to reduce non-volatile DBPs and naturally occurring material (NOM), as well as reducing taste and odor problems if present.

The occurrence of disinfection by-products (DBPs) in drinking water has been an issue of major concern during several decades. The formation of many DBPs species during water disinfection has been documented, while new by-products are still being detected, as the analytical instrumentation available becomes more accurate and sensitive. Most of the DBPs have been proven to have toxic effects on living organisms; therefore they pose risks to human health during drinking water consumption. The factors affecting their formation have been extensively investigated, their transport and fate have been studied, modelling efforts for several of them have been performed, in order to understand better their behaviour and therefore try to minimise their occurrence in waters. Techniques for their removal from water have also been applied, and a variety of disinfection methods or combinations of disinfecting agents have been investigated with the aim to produce safe drinking water containing the minimum possible concentrations of DBPs. This book deals with the advances in control of DBPs in drinking water systems. Further than an providing an overview of existing disinfection techniques and by-products, up-to-date information on the parameters affecting the procedures of DBPs formation, analytical methods for their determination, toxicity, regulation, it pays special emphasis on the advanced treatment methods applied recently for DBPs control and presents recent promising findings as well as case studies in this field, as the relevant research is proceeding, producing more knowledge and practical solutions in regard to the disinfected drinking water quality.