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The design of wastewater treatment plants with redundancy to assure a quality end product may be in conflict with efforts to assure effectiveness. Redundancy of major system components is to assure compliance with regulations and protection of the environment and the health and safety of the public and treatment plant staff. However, the capital costs and maintenance associated with redundant equipment does not necessarily enhance facility performance. There are a number of forces driving the level of redundancy in plant designs. Federal and state compliance regulations and the design engineer?s past experiences will influence the plant design. To some extent the plant staff may also provide input into the plant design and, therefore, contributes to the redundancy. This report determines alternative methods to address treatment plant redundancy, including examples of methods currently in place and, ideally, insight on the premises leading to these applications. A secondary objective is to identify the similarities and differences in redundancy requirements associated with federal and state regulatory agencies. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

This project examined the development of ambient water quality criteria (AWQC) for the protection of wildlife for mercury. Mercury is considered a serious risk to wildlife in many areas. As a result, the Great Lakes Water Quality Initiative and others have developed AWQC. These AWQC have been controversial, however, because (1) the AWQC were single values that did not account for site-specific conditions; (2) derivation of the AWQC relied on a single NOAEL, and (3) the AWQC had an unknown level of conservatism because of reliance on both average and conservative assumptions and uncertainty factors. Rather than develop a single value AWQC for total mercury, we derive an AWQC model that explicitly incorporates factors controlling bioavailability, methylation rates and bioaccumulation in the aquatic environment (e.g., pH, DOC, sulfate). To derive our AWQC model, field data was collected including numerous water quality parameters and total mercury and methylmercury concentrations in whole body fish tissue from 31 lakes in Ontario and an additional 10 lakes in Nova Scotia. An independent dataset consisting of 51 water bodies in the United States was then used to confirm the validity and robustness of the AWQC model. Next we combined the results of chronic-feeding studies with similar protocols and endpoints, in a meta-analysis to derive a dose-response curve for mink exposed to mercury in the diet. Using this approach, one can derive an LD5 or other similar endpoint that can then be used as the basis for deriving -wildlife AWQC. In the final step, we used a probabilistic risk model to estimate the concentrations of methylmercury in water that would lead to levels in fish sufficient for there to be a 10% probability of exceeding the mink LD5. This analysis was repeated for various combinations of pH and DOC. The result is an AWQC model for mercury for the protection of wildlife that can be used for a variety of site-specific conditions. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Preventing Legionellosis covers the biology of Legionella and presents a comprehensive review of best practices for legionellosis prevention from around the world. Recent outbreaks, climbing incidence rates and pending lawsuits have raised public awareness about legionellosis, a serious, preventable form of pneumonia that can be contracted from water systems in buildings. Legionellosis has harmed millions of people worldwide and causes annual monetary losses in the billions. However, to really understand the effects of the disease, one must listen carefully as the victims, or their survivors, describe the suffering they have endured. Preventing Legionellosis provides concise detail for: Improving awareness and education Implementing water management plans Mitigating against commercial conflict of interest The book will give the scientific basis for the worldwide technical consensus on the prevention of legionellosis. It will be an invaluable source of information for public health administrators, epidemiologists, infection control professionals, facility safety managers, industrial hygienists, and academic engineers and scientists.

"Process Science and Engineering for Water and Wastewater Treatment" is the first in a series of distance learning course books from IWA Publishing. The ne series intends to help readers become familiar with design, operation and management of water and wastewater treatment processes without having to refer to any other texts

"Sludge into Biosolids" gives up-to-date coverage of sludge treatments and of its use and disposal, focusing on the practical aspects of sludge/biosolids management. Operational variables and sludge properties affecting each management operation are discussed.

Simultaneous biological nutrient removal (SBNR) is the removal of nitrogen and/or phosphorus in excess of that required for biomass synthesis in biological wastewater treatment systems where there are no defined anaerobic and/or anoxic zones. The hypothesis is that one or more of three mechanisms is responsible within individual systems: variations in the bioreactor macroenvironment created by the mixing pattern, gradients within the floc microenvironment, and/or novel microorganism activity. Understanding of the mechanisms of SBNR can be expected to lead to improved efficiency and reliability in its application. Preliminary work documented SBNR in 7 full-scale OrbalTM closed loop bioreactors. A batch assay demonstrated that novel microorganism activity was of little importance in SBNR at the three plants tested. While the floc microenvironment likely plays an important role in nitrogen removal in such plants, it cannot explain phosphorus removal. A computational fluid dynamics (CFD) model was developed to elucidate the role of the bioreactor macroenvironment in SBNR. This is the first reported application of CFD to activated sludge biological wastewater treatment. Although the software and computational requirements limited model complexity, it still simulated the creation of dissolved oxygen gradients within the system, demonstrating that the anaerobic zones required for SBNR could occur.

Disinfection of wastewater is a necessary treatment process for protecting the public from potential exposure to pathogenic microorganisms because many wastewater effluents are discharged into water bodies that may be used for recreation or as future drinking water supplies. Two common forms of disinfection are chlorine and ultraviolet (UV) light. However, microorganisms differ in their susceptibility to UV and chlorine disinfectants. It is necessary to understand how different classes of pathogens respond to UV and chlorine disinfection processes in wastewater to better develop strategies for optimizing the treatment of pathogens in wastewater. It is also recognized that water quality may impact disinfection effectiveness, such as protection of pathogen by particles and disinfectant demand. This study investigated bacteria, viruses and protozoan pathogens. All species of bacteria tested were susceptible to both UV and chlorine, despite differences in antibiotic resistance and tendency to aggregate. Upon exposure to disinfection conditions that could indicate viability of the bacteria tested, but not culturability using common methods, it was found that UV and chlorine were effective in eliminating the capability of viable but non-culturable bacteria to resuscitate and become re-infective. Clostridium spores were resistant to free chlorine and UV disinfection but found to be susceptible to long exposure to monochloramine. Cryptosporidium was resistant to all chlorine forms but very susceptible to UV irradiation. Pathogenic and indicator viruses tested were very susceptible to free chlorine and UV disinfection. UV radiation throughout the 200 to 300 nm range was effective for inactivation of viruses and C. parvum, but wavelengths between 260-270 nm and below 220 nm appeared to be more effective for viruses, suggesting a possible advantage for polychromatic UV sources. Sequential disinfection strategies were proposed and tested to enhance inactivation of various microorganisms. One scenario integrated UV disinfection followed by dynamic chloramination through addition of free chlorine and subsequent transformation to combined chlorine. Further, disinfection of microorganisms in wastewater presents challenges that are inherent to the water matrix, such as pathogens associated with particles. UV and chlorine were both effective for disinfection of coliform in wastewater but chlorine was found to be more effective during long contact times for inactivation of particle associated coliform. In addition to coliform, both Cryptosporidium parvum and Salmonella typhimurium were identified as being particle associated in wastewater using molecular approaches developed to detect microbes in environmental samples

This research attempts to evaluate nitrification treatment performance in combined carbon/nitrogen municipal wastewater reactors using traditional physical/chemical methods and modern molecular techniques. Bench scale activated sludge reactors were operated at different SRTs under varying DO levels and temperatures over a 21-month period. Real-time PCR assays were used to determine cell concentrations of total bacterial 16S rDNA, a gross measure of biomass content, the amoA gene, a measure of ammonia-oxidizing bacteria (AOB), and the Nitrospira 16S rDNA gene, a measure of nitrite-oxidizing bacteria (NOB). As expected, gravimetric biomass and total bacterial 16S rDNA levels increased with increasing SRT. Ammonia oxidation rates and N. oligotropha-type AOB concentrations did not follow similar trends with respect to changes in SRT, temperature, and DO nor were they highly correlated. The concentration of available nitrite and SRT were positively correlated with Nitrospira cell densities, while DO concentration and temperature were negatively correlated with NOB levels. The percentage of the total population comprised of AOB and NOB obtained with the real-time PCR assays were compared to predicted values estimated from design equations using typical kinetic parameters. While the percentages of NOB measured using the real-time PCR assay corresponded very well with the predicted values, the measured percentages of AOB were much lower than those estimated from the design equations, suggesting that N. oligotropha-type AOB were not the dominant ammonia-oxidizing species in these reactors. This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Several options to recover energy out of organic solid waste from domestic, agricultural, and industrial origin are presented and discussed. This text also demonstrates existing economically feasible treatment systems that produce energy out of solid waste.

Two methods for the detection of important human pathogens, Cryptosporidium parvum and Helicobacter pylori, were investigated: a fiber optic biosensor, and real time PCR. The mechanism for specific detection in both methods is, recognition of specific DNA sequences in the target organisms. The Analyte 2000 was the biosensor that was used.

Mathematical modeling is a useful tool for the design, analysis and control of wastewater treatment systems. The activated sludge process is one of the most common processes used in wastewater treatment, and therefore is a particularly important candidate for the application of mathematical models.

The IWA Task Group for Mathematical Modelling of Anaerobic Digestion Processes was created with the aim to produce a generic model and common platform for dynamic simulations of a variety of anaerobic processes. This book presents the outcome of this undertaking and provides a unified basis for anaerobic digestion modelling.

Anaerobic/aerobic (AnA) and completely aerobic (CA) laboratory-scale sequencing batch reactors operating on an acetate- and casamino acids-based synthetic wastewater were used to investigate the suitability of the AnA process for treating nutrient?deficient wastewaters in plants that have stringent effluent nutrient requirements. Of particular interest is the case where phosphorus (P)-deficient wastewaters with highly variable influent COD loading are being treated to meet both effluent TSS and P limits. At a 4 d mean cell residence time, AnA activated sludge had an approx. 20% lower P requirement than CA activated sludge. The difference between the end-of-aerobic cycle polyhydroxyalkanoate and carbohydrate contents of the sludges indicated that the AnAsludge used more influent carbon than the CA sludge for synthesis of non-P-containing storage products. The nitrogen requirements of AnA sludge were similar to those of the CA sludge. The AnA and CA SBRs were subjected to three different transient influent COD loading patterns that simulated (#1) daily COD Loading fluctuations, (#2) low weekend COD loading, and (#3) extended low COD loading periods. During the Loading Pattern #1 experiment, the average effluent soluble P concentrations for the AnA and CA SBRs were 0.4 and 1.0 mgP/L respectively, and complete removal of influent acetate was observed. During the Loading Pattern #2 experiment, the average effluent soluble P concentrations for the AnA and CA SBRs were 0.3 and 0.9 mgP/L respectively, but effluent acetate was detected during the first high COD loading cycle following the low weekend COD loading period. During the Loading Pattern #3 experiment, the VSS content of both reactors dropped sharply, effluent acetate breakthrough occurred, and effluent P concentrations exceeding 1 mgP/L were detected in both the AnA and CA SBRs. Based on these findings, the AnA process has potential as a technologically and economically superior alternative for wastewater treatment plants treating P-deficient wastewasters to meet stringent effluent TSS and P limits. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

While pond treatment technology offers relative simplicity in its application, it incorporates a host of complex and diverse mechanisms that work to treat and cleanse polluted waters before their return to our environment. This book offers a comprehensive review of the pond technology field including the various ideas and findings.

This Scientific and Technical Report (STR) describes the main reasons for the growth of the different filamentous microorganisms in activated sludge, and the biological molecular tools today available for the identification of the main biomass components.

The book covers the subject of membrane bioreactors (MBR) for wastewater treatment, dealing with municipal as well as industrial wastewaters. The book details the 3 types of MBR available and discusses the science behind the technology, their design features, operation, applications, advantages, limitations, performance, current research activities and cost. As the demand for wastewater treatment, recycling and re-use technologies increases, it is envisaged that the membrane separation bioreactor will corner the market. Contents Membrane Fundamentals Biological Fundamentals Biomass Separation Membrane Bioreactors Membrane Aeration and Extractive Bioreactors Commercial Membrane Bioreactor Systems Membrane Bioreactor Applications Case Studies

The ability to measure sludge network strength is important in sludge dewatering applications because it can be used to determine optimum polymer dose for conditioning to achieve good dewaterability. This was demonstrated in laboratory and in full-scale dewatering and thickening. The network strength increased as the polymer dose was increased, however, at the optimum dose a "e;drop"e; in the network strength occurred. Further research is needed to verify this concept at full scale and to provide a robust technology to the water and wastewater treatment industry. A second phase is sought through WERF funding. Rheometry was used for determining the sludge network strength. This report also formulated and demonstrated a standard protocol for measuring network strength in terms of energy dissipated in a certain volume of sludge. Two protocols for measuring network strengths by either torque or concentric cylinder rheometers are described in this report. A mathematical derivation has shown that area under rheograms, namely the curves which were developed by plotting shear rate (1/sec) versus shear stress (Pa) and time (sec) versus torque (mNm), indicated the rate of energy dissipation within the sludge system and the total dissipated energy was related to the network strength. The research did not intend to measure the "e;absolute"e; network strength, rather a comparative strength of different aggregates using the same instrument and under the same measuring conditions.

This research focused on the use of sonication to destroy surfactants and surface tension properties in industrial wastewaters that affect traditional water treatment processes. We have investigated the sonochemical destruction of surfactants and a chelating agent to understand the release of metals from surfactants during sonication. In addition, the effects of physical properties of surfactants and the effect of ultrasonic frequency were investigated to gain an understanding of the factors affecting degradation. Successful partial or total destruction of surfactants resulting in the release of metals bound to surfactants may result in a significant cost savings of treatment plants.

Cyanide occurs in many industrial and municipal wastewaters and is often an expected constituent of typical treatment plant wastewater streams. However, a growing number of wastewater treatment plants (WWTPs) across the USA have detected cyanide in cholorinated effluents at levels exceeding influent concentrations. Because water quality criteria and related discharge limits are typically low some of these WWTPs periodically exceed effluent cyanide standards. Potential causes include cyanide formation during wastewater cholrination processes, the presence of interferences that cause false negatives, and false positives caused by artifacts of sample handling or analytical techniques. The possible causes of the apparent cyanide formation phenomenon were investigated in this study. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Over the past 20 years, the use of Best Management Practices (BMPs) in the United States has been instrumental in reducing both the detrimental impacts to receiving water quality and the exacerbated flooding caused by urbanization and storm water drainage. More recently, Sustainable Urban Drainage Systems (SUDS) have started to be used in the United Kingdom. Both SUDS and BMPs attempt to mimic the drainage patterns of the natural watershed, and can also provide a degree of treatment needed to improve the quality of the water discharged to an acceptable level. The costs of conventional stormwater collection systems are determined primarily in terms of initial capital expenditure. Long-term maintenance costs are absorbed by stormwater authorities that are responsible for maintaining their infrastructure as part of their "e;asset base"e;. Currently, only a few of these responsibilities exist for BMPs and SUDS, which generally incorporate surface components and are often dependent on landscaping rather than on traditional construction techniques, but may require significant regular maintenance. Any potential adopting organization will require guidance on the maintenance regimes of different types of systems and how such regimes translate into long-term adoption costs. The project is being conducted in two phases. Phase 1, which is the subject of this report, includes a literature review and a survey of stormwater authorities and organizations in the US and UK to identify the most commonly used BMPs and SUDS and to determine the availability of data on their cost and performance. As part of Phase 2, the operation of selected BMPs and SUDS will be monitored over a one-year period in terms of pollutant removal and hydrologic/hydraulic efficiency, and applicability of their design criteria and maintenance regime. The protocols developed in Phase 1 will be used to assess BMPs/SUDS performance and whole-life costs.

In other words, any grass added to the surface of a swale system would represent a positive influence on metal uptake. However centipede is possibly be the best choice for its resilience to drought, its nutritional frugality, and its greater ability to accumulate key contaminant metals such as Cu, Zn and Pb.

A scientifically sound approach is needed to ensure that flushable consumer products are compatible with household plumbing fixtures, as well as wastewater collection and treatment systems. In addition to assessing disposal system compatibility, an assessment approach should also ensure that flushable consumer products do not become an aesthetic nuisance in surface waters and soil environments. This document presents an overall approach for assessing the fate and compatibility of consumer products in wastewater disposal systems. While the focus of this document is on the United States, it is believed that the conceptual approach and many of the test methods could be used to assess the compatibility of flushable consumer products in wastewater disposal systems throughout the world.

Non-potable and potable (principally in-direct potable) water reuse initiatives in the United States have faced increasing public opposition. Several high-profile initiatives have been halted after several years of planning and tremendous expenditures. To understand why the public holds the perceptions they do and what public participation options exist to address water reuse more constructively, a multidisciplinary analysis was undertaken by a team of social scientists, engineers, and water professionals. Through a comprehensive literature review, three in-depth case studies, and a 2-day interactive symposium this framework was developed for water professionals. The framework summarizes five underlying principles that contribute to shaping public perception and acts as a guide for water professionals in their selection of public outreach, education, and participation activities. Adhering to the principles outlined in this report contributes to building public confidence and trust, which in turn helps water utilities engage constructively with the public on challenging, contentious issues. The five principles are: ? Manage information for all ? Maintain individual motivation and demonstrate organizational commitment ? Promote communication and public dialog ? Ensure fair and sound decision making and decisions ? Build and maintain trust However, no checklist of "e;to-do's"e; exists for establishing public confidence and trust. Quite the opposite, this research suggests that a one-size-fits-all model cannot work because the most appropriate ways to achieve the principles can vary from case to case. Thus, the framework includes an analytical structure to assess the community in which a water reuse initiative is underway. Using diagnostic questions and analytical techniques, a comprehensive picture of the community can be generated and monitored over time. Through application of the diagnostic tools and a commitment to the principles outlined above, water professionals can build the public confidence and trust they need to engage with the public on difficult water reuse issues.

Under the National Pollution Discharge Elimination System (NPDES), many municipal and industrial wastewater treatment facilities must perform Whole Effluent Toxicity (WET) Testing. Regulatory agencies determine the level of compliance of each facility by making inferences about the results of these tests. There has been some concern regarding appropriate ways to integrate WET tests into NPDES permits. The central issue of this concern involves determining the relationship between WET tests and instream biological conditions. Previous research (WERF project 95-HHE-1) has examined this issue using historical data. Because of issues with data comparability, i.e. questionable data quality, and project design, results were inconclusive. This study plan was designed to collect new data on method performance for both WET and bioassessment that would help answer the outstanding question. The study plan was designed using a Data Quality Objective (DQO) approach in which DQOs and MQOs were defined. These DQOs and MQOs were characterized using technical input from many scientists from federal, state, and private organizations. It was through this effort that certain technical design issues arose that needed further investigation before implementing the definitive study. Among these issues were determining if DQOs and MQOs were achievable, and determining appropriate biological assessment methods for various ecoregions (e.g. effluent dependent streams in the arid west). In order to appropriately address these issues, it was determined that a pilot study would be implemented before the definitive study. The pilot study is designed as a one-year study in which participating facilities will perform quarterly WET tests (Ceriodaphnia, P. promelas, Selenastrum) and at least one bioassessment (macroinvertebrate, fish, algae) as well as providing other prescribed data requirements. Results of the pilot will provide answers to technique design issues and will ultimately determine the most appropriate study design for the definitive study.

TMDLs, or total maximum daily loads, are required under the Clean Water Act, Section 303(d), for waterbodies that do not attain water quality standards. The objective of this research was to review the existing TMDL process and to develop an improved design for TMDL development where improvements are needed. This objective was accomplished through: (1) Identifying and verifying problems with the existing TMDL program; (2) Formulating a range of recommended improvement options on specific topics that address identified weaknesses; and (3) Providing case studies examples that highlight these recommended changes to improve the TMDL process. The research team identified ten specific areas for improvement, based on a review of approved TMDLs, a survey of state programs, and an in-depth review of specific case study examples. Each topic is addressed in a separate chapter of the report, with a discussion, recommendation of improved approaches where appropriate, and specific examples to help guide water quality professionals when developing or reviewing TMDLs.

Presenting a survey of wetland design techniques and operational experience from treatment wetlands, this global synthesis discusses types of constructed wetlands, major design parameters, role of vegetation, hydraulic patterns, loadings, treatment efficiency, construction, operation and maintenance costs in depth.