Series:

Water Research Foundation Report

15 total works

Cover of Removal of EDCs and Pharmaceuticals in Drinking Water
EDCs and pharmaceuticals are groups of emerging contaminants that have been detected at trace concentrations in waters around the world. These contaminants encompass a vast range of molecular structure and properties. Sparse data exist on the occurrence and fate of these emerging contaminants during water treatment. This project investigated EDC/pharmaceutical occurrence in U.S. drinking water and the efficacy of conventional and advanced water treatment processes to reduce the concentrations of these contaminants.


The objectives of this study were to (1) select a diverse group of representative endocrine disrupting chemicals (EDCs) and pharmaceuticals, (2) develop a robust analytical methodology capable of trace detection of target compounds in a variety of water matrices, (3) determine the occurrence of target compounds in U.S. drinking waters, (4) evaluate the EDC/pharmaceutical removal potential of conventional and advanced drinking and reuse water processes, and (5) evaluate computer models to predict target compound properties and fate.



This report provides fundamental information on the removal of several classes of pharmaceuticals, personal care products, and suspected endocrine disrupting chemicals by conventional and advanced water treatment processes. A detailed description of analytical methods is provided, including information on sample preservation, extraction, and instrumental analysis. The report provides some of the first U.S. occurrence data for these emerging contaminants in raw and finished drinking water supplies. From the treatment and occurrence information, compounds with likely occurrence can be selected for monitoring programs that will represent the fate of various classes of emerging contaminants. Computer models are described that can be used to predict properties and fate of future water contaminants.

Cover of Contribution of Wastewater to DBP Formation
In addition to water recycling and reclamation programs, indirect potable reuse of wastewater has occurred as upstream wastewater treatment plants discharge water into rivers or lakes that serve as downstream drinking water supplies. Wastewater treatment plants are sources of DBPs, if chlorine disinfection is practiced, and DBP precursors. Many different biological, physical, and chemical unit processes are employed by wastewater treatment plants, which can produce a wide range of treated water qualities.


The objectives of this project were to (1) determine the formation, occurrence, and control of disinfection by-products (DBPs) and DBP precursors in wastewater and their impact on downstream drinking water sources; (2) evaluate the fate and transport of wastewater-derived DBPs and precursors in receiving waters, as well as their removal through different drinking water unit processes; and (3) evaluate treatment strategies at wastewater and drinking water treatment plants to reduce DBPs that best balance societal benefits. The researchers (1) conducted a full-scale survey of wastewater and drinking water plants, as well as effluent-impacted rivers, lakes, and groundwaters; (2) compiled a database of first-principle fate-and-transport parameters for DBPs; (3) performed DBP and DBP precursor fate-and-transport bench-scale experiments; (4) evaluated the treatability of EfOM with drinking water treatment processes.; (5) used simple and advanced NOM characterization techniques; (6) measured regulated and emerging DBPs, as well as conducted formation potential tests; and (7) analyzed for a pharmaceutical (primidone) that is a conservative tracer of wastewater influences in drinking water supplies. This report will be available as a Pay-Per-View item only

Cover of Communicating the Value of Water
Communication, both within the utility and with external stakeholders, is essential for the long term sustainability of utilities. One of the biggest challenges that utilities face is the ability to obtain the finances necessary to complete projects related to water quality and water quantity. If the utility can effectively communicate the value of the water services it provides and the value of water as a life-sustaining resource, customers may be more prudent in their use of water and more willing to pay higher rates, city decision makers will be more likely to approve rate increases, and the utility will be more likely to gain the finances needed for long term sustainability. The goal of this project was to develop practical guidance and tools that can be used by water officials to properly communicate the value of water.


The specific objectives were as follows:
  • Research available studies related to communication with customers and stakeholders both in the water utility field as well as other organizations that require public support to glean "lessons learned"
  • Supplement the available studies with surveys and workshops that are directly related to communicating the value of water
  • Develop a branding strategy that builds public trust and communicates the utility value proposition to the customer and stakeholder
  • Develop specific guidelines, plans, and processes, along with communication tools, that can be used by water utilities to devise a communication program for their water utility


The approach for completing this project started with an extensive literature search on the topic of communicating the value of water followed by several workshops, meetings, focus groups, and interviews to help identify key messages to be used in communications plans. The information collected in these project activities was summarized and used to develop a step-by-step model for communications planning. The model incorporates aspects of strategic planning, communications gap analysis, behavioral gap analysis, branding, and national communications efforts. An electronic Communications Toolkit providing various tools and example communications materials to assist utilities was also developed.

Cover of Natural Organic Matter Fouling of Low-Pressure Membrane Systems
Low-pressure (LP) membrane use has increased dramatically over the last decade in response to more stringent pathogen-related drinking water regulations, water reclamation and the need for more effective reverse osmosis pretreatment, and from dramatically reduced membrane costs. More cost-effective and reliable operation of LP membrane systems is constrained, however, by fouling, in particular fouling by NOM. NOM fouling is poorly understood because of both the complexity and types of NOM that exists in natural sources and wastewater effluent and NOM-membrane interactions.


This report is available as a Pay-Per-View item only.



NOM exists in three primary forms (allochthonous, autochthonous, and effluent-derived), with a variety of components having differing fouling tendencies. LP membranes comprise hollow fibers of differing polymeric materials, with a range of properties that likewise influence fouling propensity. Fouling management strategies (backwash, air scrub, chemical cleaning) employed with LP membrane systems differ from supplier to supplier. This, combined with a number of the methods used to reduce NOM levels prior to membrane treatment (e.g., coagulation, clarification), further complicate the understanding of NOM fouling.



The overall goal of this project was to investigate the specific contributions of the different types of natural organic matter (NOM) to microfiltration/ultrafiltration (MF/UF) fouling. The intent was to develop a surrogate test or index that could be used to predict NOM fouling at low cost through a combination of source water characterization and rapid bench-scale testing. The research incorporated bench-, pilot- and full-scale investigations. Testing was conducted with four source waters, selected to capture the fouling characteristics of the three primary types of NOM. Bench testing use a stirred, cell apparatus and three flat sheet membrane types, representing commercially dominant MF and UF hollow fiber membranes of the same polymer types. Hollow fiber bench testing used two PVDF and two PES membranes operated in both sequential and alternating filtration/backwash mode. Pilot testing included PVDF MF and UF and PES UF systems operated on three of the four source waters and incorporated a host of fouling management strategies. Full-scale investigations captured operating data from several plants having differing levels and types of NOM.

Cover of Addressing Concerns About Tastes and Odors and Cyanotoxins in Tap Water
Consumers today demand drinking water that looks, smells, and tastes good. The occurrence of aesthetically unpleasing T&O compounds in water creates a perception of unsafe water. The main sources of T&O problems in municipal water supplies are certain types of algae, mainly blue-green algae (cyanobacteria) and fungi (actinomycetes). Although many compounds may impart T&O to water, by far the most commonly reported are two chemicals: geosmin and MIB.


Treatment removal of algal metabolites demonstrated that microcystins measured lower after the addition of powdered activated carbon (PAC). Treatment removal showed that low levels of chlorine oxidize microcystins given sufficient contact time. Water distribution samples were split between a flavor profile analysis (FPA) panel and a gas chromatograph mass spectrometer (GC/MS). Data generated between the FPA and the GC/MS showed high variability for geosmin and MIB. FPA results showed a direct correlation with MIB and geosmin, but were weak for cyclocitral. FPA results could be predicted with MIB/geosmin plots and with a MIB, geosmin, and cyclocitral plot.

Cover of DBP Control in High Bromide Water While Using Free Chlorine During Distribution
The source water for the treatment investigations was California State Project Water (SPW). SPW is characterized by low turbidity, moderate total organic matter concentrations (average of 3.9 mg/L), and high bromide concentrations (up to 0.45 mg/L). This water tends to readily form chlorinated DBPs when free chlorine is used as the secondary disinfectant. From 2001 to 2004, the running annual average (RAA) of TTHMs has approached 80 ug/L at the Palmdale Water District. This study provides operating conditions and costs for four advanced processes to achieve sufficient precursor (bromide and organic matter) removal to comply with the Stage 1 and 2 D/DBP Rules. Processes investigated include the MIEXTM process, fixed-bed ion exchange (using both bromide-specific and organic matter-specific resins), and GAC (for both precursor and THM adsorption). Also, the combination of MIEXTM resin and ceramic membranes showed promise for DBP control and is recommended for further study.

Cover of Membrane Biofilm Reactor Process for Nitrate and Perchlorate Removal
The objectives of this project were to evaluate the performance of an innovative hydrogen-fed membrane biofilm reactor (MBfR) for nitrate and perchlorate removal, and identify the system operational and design parameters that affect the biological reduction process. The MBfR contained hollow-fiber membranes within a cylindrical module. Hydrogen was fed to the fibers filling the inside and passively diffusing through the membrane avoiding the formation of a hydrogen atmosphere and serving as an electron donor for the biofilm growing on the outside of the hollow fibers. The biofilm within the reactor was developed from the indigenous bacteria present in the groundwater and was not artificially inoculated or amended. Following the MBfR, an aeration process was employed to oxygenate the water in preparation for its introduction into a distribution system as a drinking water source. A subsequent media filter captured any sloughed biomass and provided a support for aerobic organisms to remove any residual dissolved hydrogen. Process Demonstration The MBfR process was demonstrated at pilot-scale to reduce perchlorate contaminated groundwater (55 ?g/L) to below the current 4 ?g/L California Department of Health Services (CaDHS) perchlorate action limit. The simultaneous removal of influent dissolved oxygen and nitrate to below detection limits was also observed. Their removal has been observed with the MBfR system operated at system flow rates corresponding to theoretical hydraulic residence times between 15 and 60 minutes. In addition, measured hydrogen consumption closely matches theoretical calculations based on stoichiometry and anaerobic biomass development. Microbial Ecology Bench-scale investigations into the microbial ecology of the mixed cultures in MBfRs revealed that perchlorate reducing bacteria (PCRB) were found to be present in a denitrifying system that had not been previously exposed to perchlorate. However, a dominant PCRB species increased from 14 to 21 percent of total bacteria when 100-?g/L perchlorate was added to the influent. Increasing perchlorate reduction led to further increases in the dominant PCBR and the perchlorate-removal capacity of MBfRs. Another important finding is that oxygen alone can serve as a primary acceptor for perchlorate reduction, and that the oxygen reduction appeared to be more favorable for perchlorate reduction than was nitrate reduction. Ultimately, full-scale application MBfR technology could effectively and economically be used to replace costly treatment technologies currently used by municipalities to treat perchlorate-contaminated drinking water sources. This research defined the critical parameters and operating conditions required for full-scale application and provided an extensive review of the critical water quality issues considered for drinking water by CaDHS and other state primacy agencies. In addition, this project has direct relevance to the application of biological treatment for the removal of nitrate (or other biologically reducible compounds) from contaminated groundwater. For a long time, biological denitrification has long been used in wastewater treatment, but not in drinking water treatment. Due to concerns about operating a biological process in a water treatment plant, nitrate removal in the United States has been largely limited to ion-exchange or membranes, both of which are expensive processes and can generate difficult to handle residuals. The results obtained in this study looked at simultaneous biological perchlorate removal and denitrification. Originally published by AwwaRF for its subscribers in 2004. This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Cover of Improvement of the Ozonation Process Through the Use of Static Mixers
Among the known disinfectants, ozone has been demonstrated to be very effective in inactivating protozoans. Current and proposed regulations impose additional treatment requirements for Cryptosporidium parvum. These regulatory trends tend to place more stringent performance demands on disinfection systems and have therefore increased the need for improvements in the design. The static mixer offers one alternative method for improving the efficiency of the dissolution of ozone and optimizing its use in the disinfection process.The overall objective of this research was to quantify the potential benefits of ozone application through the use of static mixers in terms of increased transfer efficiency, disinfection capacity, and enhanced chemical reactions at laboratory-, pilot-, and full-scale systems. Specific goals were to identify and quantify the effect of several water quality parameters and environmental/engineered factors on the disinfection capacity of the ozone-static mixer system and assess bromate formation under optimum conditions for microbial inactivation.Originally published by AwwaRF for its subscribers in 2003 This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Cover of Organic Nitrogen in Drinking Water and Reclaimed Wastewater
In the past, relatively minor attention has been focused on DON despite observations that both low and high molecular weight molecules containing organic nitrogen (e.g., simple amino acids, peptides, algal-derived humic substances) have been implicated as precursors of DBPs such as trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), nitromethanes, and nitrosamines like nitrosodimethylamine (NDMA). Nitrogenous organic matter has also been implicated as membrane foulant material. Dissolved organic carbon (DOC) is usually used as the surrogate for natural organic matter (NOM); NOM contains various ratios of carbon, oxygen, hydrogen, nitrogen, sulfur, and trace metals. While information exists on NOM removal through DOC measurements, it is unclear if DON is distributed equally among different molecular weight fractions.


The project involved three phases. First, several pretreatment processes were evaluated to selectively remove inorganic nitrogen from samples, thus allowing more accurate and a potentially direct quantification of DON. Second, a survey of 28 water treatment plants was conducted during two different seasons to assess DON and related organic matter occurrence. Additional sampling of reclaimed wastewater systems was also conducted. Third, laboratory experiments were conducted with alum and cationic polymer coagulants, activated carbon, or disinfectants (free chlorine or monochloramine) to assess the ability to remove DON and understand its reactions with disinfectants.

Cover of Optimization of Membrane Treatment for Direct and Clarified Water Filtration
The early applications of MF/UF relied on cartridge filtration to protect the membranes. The success of these stand-alone membrane installations has increased interest in MF/UF membranes from utilities with a wide variety of source waters. In order to treat challenging water supplies, additional processes must be considered for pretreatment before MF/UF, both to maintain the productivity of the membrane process and to meet treatment objectives that are not met by the membranes alone.


To evaluate the impact of pretreatment and water quality on the membrane performance, this project was implemented with four major tasks: literature review, bench-, pilot-, and full-scale studies. The literature review covers conference proceedings and journal papers regarding the effects of pretreatment on membrane filtration. The primary focus of the bench-scale testing is to examine membrane fouling mechanisms by specific fractions of constituents in natural water. The effects of various pretreatment chemicals and pretreatment processes on each fraction were also assessed. Pilot testing is conducted on three different water sources using similar pretreatment conditions of the bench-scale study for providing the correlation among the different scales. The full-scale evaluation provides insight on operational and design issues that were impacted by membrane pretreatment The project findings provide guidance to water utilities for integrating MF/UF membrane process into existing or new water treatment plants. It is important to note, however, that results presented in this study may not apply to all cases and situations. Therefore, it is recommended that the overall conclusions be used to inform and guide utilities with the most cost-effective and suitable approach (i.e., bench-, or pilot-scale) to address specific concerns and optimize membrane performance.

Cover of Micro and Ultrafiltration Performance Specifications Based on Microbial Removal
This project develops a systematic performance testing protocol and specification for microfiltration (MF) and ultrafiltration (UF) membranes with respect to removal of viral and submicron bacterial pathogens. Both UF and MF have the capability to remove viruses (and submicron bacteria); however, the extent of removal is based on a number of factors including the membrane and the organism, as well as water quality and operational conditions. If membranes are to be employed on a more widespread basis for microbial removal, then their classification should be based on their ability to remove microorganisms, not on their nominal pore size. Rigorous microbial challenge studies at pilot scale are often prohibitively costly or considered hazardous.


This report provides a peer-reviewed, standardized methodology with which to characterize membranes from a microbial perspective at bench scale, which is a benefit to both utilities and manufacturers. From a regulatory perspective, low pressure membranes are part of the microbial toolbox associated with the Long-Term 2 Enhanced Surface Water Treatment Rule. As a result of this project, bench-scale testing of Cyrptosporidum removal was included as methodology to evaluate new membrane products. It is important to note that the protocol was designed for both scientific rigor and ease of implementation.

Cover of Removal of MTBE with Advanced Oxidation Processes
The purpose of this project was to perform a careful evaluation of the technical and economic feasibility of advanced oxidation processes (AOPs) for methyl tertiary butyl ether (MTBE) removal. Specifically, the first objective of this project was to identify and fill data gaps related to the implementation and operation of AOPs with respect to MTBE removal. The second objective was to select and optimize the design of the most promising AOP(s) as a function of water quality parameters. The third objective was to determine conceptual-level engineering costs for these selected AOPs. The AOP technologies that were evaluated as part of this study included ozone/peroxide, continuous wave UV/peroxide, pulsed UV/peroxide, and E beam. The AOP technologies were compared with treatment costs, qualitative factors (e.g., technology reliability, flexibility), and influent and treated water quality considerations. Based on the comparative analysis, it was concluded that all the AOP technologies that were evaluated in this study are capable of removing MTBE at 95% or higher efficiencies. Ozone/peroxide and continuous UV/peroxide appear to be the most feasible technologies for AOP treatment of MTBE in drinking water sources. Originally published by AwwaRF for its subscribers in 2003

Cover of Comparing Nanofiltration and Reverse Osmosis for Treating Recycled Water
Membrane treatment of source water of impaired quality by an integrated membrane system (IMS), such as microfiltration (MF) pretreatment followed by RO, represents the industry standard for drinking water augmentation projects. An alternative IMS involving NF membranes and ULPRO membranes in place of conventional RO membranes provides an opportunity for lower pressure/higher flux operating conditions and higher selectivity (e.g., targeting trace organics over monovalent salts).


The purpose of this study was to explore whether nanofiltration (NF) and ultra-low pressure reverse osmosis (ULPRO) membranes can consistently meet potable water quality requirements with respect to total organic carbon (TOC), total nitrogen, and regulated and unregulated trace organic compounds. The goals were also to determine whether or not operating characteristics of NF and ULPRO membranes (such as flux, fouling/scaling, and cleaning frequencies) are comparable to conventional thin-film composite RO membranes and operating feed pressure requirements are significantly lower than conventional RO.



This work involved the development and validation of a laboratory-scale membrane testing protocol to select viable membranes for pilot- and full-scale operation. This selection protocol balanced operational characteristics with product water quality and allowed for a pre-selection of potentially viable candidate membranes. Membranes considered for selection were characterized as thin-film composite polyamide membranes and included commercially available ULPRO and NF membrane products. Three candidate membranes were selected and each tested using a 70 L/min (18 gpm) membrane pilot skid for at least 1,300 hours on microfiltered feed water at two full-scale facilities. Findings of this study were compiled into a model framework to describe and predict the rejection of organic micropollutants during NF or RO treatment.

Cover of Treatability of Perchlorate-Containing Water by RO, NF and UF Membranes
The California Department of Health Services has established a provisional action level of 4 ug/L for perchlorate in drinking water due to its toxicity. There are 14 states in the United States that have thus far confirmed perchlorate in ground or surface waters. Ongoing research is investigating other treatment technologies for perchlorate rejection, including biological degradation, ion exchange, and activated carbon. The major objectives of this project were to: determine the removal/rejection of perchlorate (ClO4-) ion by high pressure membranes, including reverse osmosis (RO), nanofiltration (NF), and tight ultrafiltration (UF); evaluate the effects of water quality parameters, pH, ionic strength (conductivity), and co-ions and counter-ions, on process performance; and study membrane operating conditions (e.g., recovery) on perchlorate rejection and potential scaling. Water quality is a determining factor in applying high pressure membranes to perchlorate rejection. Effective rejection of perchlorate by RO, NF, and tight UF has been demonstrated according to two rejection mechanisms: steric (size) versus electrostatic (charge) exclusion. Based on its size (hydrodynamic radius), perchlorate is selectively rejected over chloride through size exclusion; however, based on charge exclusion, sulfate is selectively rejected over perchlorate. Originally published by AwwaRF for its subscribers in 2003. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online

Cover of POU/POE Implementation Feasibility Study for Arsenic Treatment
The objective of this project was to perform an overall feasibility analysis of point of use (POU) and point of entry (POE) systems for arsenic treatment, and to develop industry-wide recommendations for use of such systems as an alternative to centralized treatment, considering factors such as costs, process reliability, public perception, liability, and regulatory acceptance. The researchers also planned to assess water quality criteria that may limit the performance of POU/POE systems and determine at what size POU/POE treatment systems are cost-effective. Given the operational, financial, and implementation constraints of arsenic removal for very small systems, installation of "under the sink" POU devices may be a more viable and cost-effective option. The 1996 Safe Drinking Water Act amendments allow the use of POU and POE devices for compliance with certain MCLs (e.g., inorganics, organics, radionuclides) for small and rural systems. Since ingestion is the only exposure route of concern for arsenic, whole house treatment would not be necessary.