Water Research Foundation Report Series – serie

Utilities must decide whether to modify their existing treatment practices to achieve compliance with the D/DBP regulations. A regulatory impact analysis predicted that up to 70% of large surface-water systems would need to make some treatment modifications.  Meeting multiple water-quality objectives plays an important role in the decision-making process of water utilities. Utilities must meet other regulatory requirements and secondary drinking-water standards. In addition, there are operational, financial, and engineering issues that affect the selection of treatment technologies. Because of the uncertainty of how stringent certain regulations will be and the high costs of advanced treatment technologies, many utilities have implemented treatment modifications in stages. Most utilities have made treatment modifications that have been cost-effective to meet their site-specific needs and objectives, while continuing to study or implement long-term treatment changes to meet more stringent future regulations. Utilities must factor in other regulatory requirements and secondary drinking-water standards when selecting a treatment modification for compliance with the D/DBP Rule. Some utilities chose advanced treatment processes (e.g., ozonation, membranes) that would enable them to satisfy other current and anticipated future regulations or other water quality objectives. Some systems chose ozone, in part because of its ability to destroy taste-and-odor-causing contaminants. Likewise, granular activated carbon was added to filters for taste-and-odor control. In addition, space and retrofit considerations affected technology choices.   Many utilities have implemented treatment modifications in stages. To meet Stage 1 of the D/DBP Rule, most utilities have made treatment modifications that have been cost-effective to meet their site-specific needs and objectives, while continuing to study or implement long-term treatment changes to meet more stringent future regulations. The major disadvantage to staged implementation was that the treatment process was re-optimized each time treatment modifications were made. However, this problem was minimized if the full range of changes in treatment was envisioned in advance and if incremental modifications were made that were part of and consistent with long-term modifications.  Originally published by AwwaRF for its subscribers in 2003   This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Technology offers one of the significant levers that utility managers have available to truly “do more with less.” But it often is difficult for managers to know how much to spend on technology, where the expenditures should be, and what the expected return on that investment should be.The objective of this study was to determine successful approaches for implementing utility IT systems considering the range of factors influencing today’s utility IT environment. The study cites leading practices that create effective IT solutions (not technology-specific solutions). While specific technology evolves quickly, what does endure are the management and business practices around how technology is selected, implemented, used, and managed. Those practices are process-oriented, repeatable, and measurable and are the focus of this project.A benchmarking consortium of 13 leading North American utilities and three research organizations was formed to initiate the research project, drawing on utilities that included leading practitioners in many IT areas, all of whom wanted to improve their IT effectiveness. The following steps summarize the overall project approach:Plan: Secondary research identified IT practice elements and grouped them into focus areas that significantly contribute to the effectiveness and value of IT services.       Collect data: For each focus area, specific practice elements and metrics were developed to identify leading practices using a survey instrument.        Analyze data: Completed surveys from the consortium were analyzed to identify case study candidates. Benchmarking partners were identified via the same survey to complement areas for other best practices.        Report effective practices: Detailed survey information, analyses, and conclusions were documented from the case studies. The survey results of the case studies were compared to the other participating utilities. A number of observations and possible implications were drawn from the findings. In general, the average scores of the case studies were notably higher than the average scores of the participating utilities, indicating that the case study organizations do derive greater results from their technology investments. Some other key differences were noted between the case studies and other respondents. In general, the case study organizations:have a higher total annual revenue per customer for all services provided;       have a lower IT budget as a percentage of total operating budget;       have a higher percentage of internal IT staff (versus external contractors);       have a higher training budget as a percentage of total IT budget; and       support fewer PCs per IT staff.Possible implications and additional research hypotheses could be drawn from the observations including the extent to which investments should be made in training, staff levels, and redesigning internal practices, compared to hardware and software investments. Ensuring that value is received from an investment in information technology requires constant attention and skilled management. Information technology is a very young field—just barely 50 years old. This has many implications, including the ongoing and continuous development of new technologies. This causes misguided thinking that it is the technology that is important, rather than how technology is employed and the changes that technology enables. Because the science of information technology is still developing so rapidly, “leading” or “best” practices will also need to be developed and evolve quickly. It is important to continue searching for the most effective means of ensuring value for IT investments. Originally published by AwwaRF for its subscribers in 2003.

Although ingestion of high levels of arsenic is believed to cause certain cancers, estimates of cancer risk resulting from exposure to low levels of arsenic are the subject of considerable debate. An improved understanding of arsenic toxicity and the dose-response relationship for relatively low levels of arsenic could improve the risk assessment process. The overall objective of this study was to contribute to a better understanding of arsenic health effects. A specific aim was to investigate the cellular response of exposure to arsenic. This includes the analysis of cells treated with arsenic alone or in combination with other DNA-damaging agents in order to identify mechanisms of DNA damage, the influence of arsenic on DNA repair, and potential critical genes responsible for repair of DNA damage. The researchers conducted the following steps as part of the project approach: 1. Measured cell killing by arsenic compounds, using human and hamster cells harboring mutations in specific DNA repair genes, to determine if arsenic kills cells by causing DNA damage and, if so, which DNA repair pathway(s) would be involved in repairing the damage. 2. Measured cell killing to assess the relationship between ionizing radiation and arsenic, i.e., to define if the combination of the two treatments is additive or synergistic. 3. Conducted assays for DNA damage using capillary electrophoresis laser-induced fluorescence. 4. Monitored the effects of arsenite and benzo[a]pyrene diol epoxide (BPDE) in the induction and repair of BPDE-DNA adducts in A549 cells. 5. Performed arsenic speciation analysis and test species stability. 6. Measured the interaction of arsenicals with metallothionein Project highlights include: Cells from the cancer-prone disorder, Ataxia telangiectasia, were hypersensitive to killing by arsenite, but this may not be due to DNA damage.             The toxicity of the combination of arsenite and gamma-radiation was additive, not synergistic, implying that radiation and arsenic kill cells by distinct mechanisms.             Arsenite enhanced the formation of benzo[a]pyrene-DNA adducts but the kinetics of repair remained unaltered. Arsenite, therefore, either renders DNA more accessible to DNA damaging agents or inhibits other processes that inactivate benzo[a]pyrene metabolites, such as reaction with glutathione.             Trivalent methylation metabolites of arsenic readily reacted with metallothionein, a small cysteine-rich protein. Through this project, analytical techniques were developed for the determination of arsenic species. These techniques are useful for monitoring the occurrence of arsenic. They are also useful for determining exposure and metabolism of arsenic compounds ingested from drinking water. It is also important to recognize that genetic variation may make some individuals more sensitive to the harmful effects of arsenic. Originally published by AwwaRF for its subscribers in 2004.   This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

The operation of ozone contactors needs to be optimized to provide adequate disinfection while minimizing the formation of disinfection by-products. However, measuring the actual disinfection efficiency is impractical in a full-scale system. The objective of this project was to demonstrate of the use of polystyrene microspheres to assess and optimize the performance of full-scale ozone disinfection systems. Specifically, the researchers developed and optimized microspheres with laboratory-scale experiments, demonstrated the use of microsphere method with a full-scale ozone contactor, and applied a mathematical model for the prediction of disinfection efficiency and bromate formation in the full-scale ozone contactor. This study has shown that microspheres can be used as a surrogate for assessing the inactivation efficiency of C. parvum oocysts in ozone contactors. It is therefore recommended that water utilities using ozone as disinfectant consider performing such tests. This study has also shown that a mathematical model could be used to predict the performance of the contactor. Mathematical simulation revealed that reducing dispersion would result in more disinfection with minimal effect on bromate formation.  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

When water leaves a treatment works and travels through a distribution system, its quality, with respect to many chemical and biological parameters, will degrade. The quality of the delivered water will be largely influenced by: The quality of treated water supplied into the network   The condition of distribution assets within the network   The retention time within the network. The water industry has focused predominantly on the quality of treated water and the physical condition of distribution assets when improving the quality of water at the customer?s tap. However the quality of the water delivered is also affected by the time the water is retained in the different elements of the distribution network. Retention time is controlled both by the physical characteristics of the system and the operational regime. Physical characteristics such as pipe roughness may change throughout the life of the asset or be modified by rehabilitation. The aim of this research is to demonstrate that water quality within distribution networks can be managed effectively by controlling retention time and to develop practical and pragmatic methodologies for doing so.

Phosphorus in surface runoff from agricultural lands is often implicated in the degradation of surface water quality. Many states are developing soil phosphorus application limits. Utilities must develop and implement new best management practices (BMPs) to control phosphorous. The objective of this project was to investigate the beneficial use of water treatment residuals (WTRs) to control non-point source (NPS) phosphorus pollution and protect surface water quality. Specifically, the researchers planned to examine the unique chemical characteristics of WTRs, namely the large concentration of aluminum and iron hyrdroxides, to combine them with phosphorus in high phosphorus soils, biosolids, and manures to reduce the likelihood of phosphorus release to aquatic environments. Several types of WTRs were selected and characterized based on the coagulant used (aluminum and iron based) and their form - dewatered or liquid. The research developed valuable new insight for the beneficial use of WTRs and demonstrated WTRs' potential as a BMP for phosphorus control in surface runoff from agricultural lands and for protecting surface water quality. In particular, the potential role of WTRs in Phosphorous Index programs was confirmed. Future research and full-scale demonstrations are needed to confirm the potential of land applied WTRs as a BMP for phosphorus control in runoff from agricultural lands. Land application of WTRs within a utility?s source water watershed, while subject to local and state regulations, can be implemented as part of an overall watershed protection program.