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...

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...

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 biosensor that was used, the Analyte 2000, was originally developed for the detection of chemicals. It utilizes a fiber optic wave guide that propagates an evanescent light wave of very specific wavelength. The light excites fluorescent molecules bound to the waveguide, but not in the bulk solution,...

Plant-availability of metals in biosolids-treated soils may be mathematically described by Mt = C x 1 - e- (k x t)] where Mt (mg kg-1) is the cumulative metal removal from the biosolids-treated soils by growing and harvesting plants for t years, C is the total phytoavailable metal pool of the soil (mg kg-1) at t = 0, and k is the metal absorption rate coefficient (yr-1). The total available metal pool, C, is defined as metals extractable by organic acids in the rhizosphere of growing plants and k is related to the kinetics of metal release by organic acids. Half-life of the available metals...

This study, on innovative methods for the capture of metals from stormwater, mainly focused on two major areas of investigation: media filters and swales. Twelve media were chosen for initial evaluation. The three best performing media: peat-sand mix, compost, and zeolite were then selected for in-depth study. The results of this investigation emphasize the importance of characterizing the stormwater before selecting a treatment media since the type and quantity of metals, pH, and other runoff characteristics can vary a great deal between sites.

Thermal enrichment of coldwater streams by heated stormwater in summer months is often overlooked and even exacerbated by traditional management practices that typically account for flow moderation and pollutant removal only. Initiated in 1999, this study evaluated and identified innovative and traditional approaches to moderate this temperature impact by monitoring and analyzing the hydrologic and thermal regimes of an urban stormwater treatment system consisting of two traditional wet detention ponds and an enhanced natural wetland. Data analysis clearly shows temperature increases in the...

This investigation reviewed and evaluated methodologies used for microbial risk assessment with respect to their applicability for reclaimed water applications. The investigation was comprised of five primary components: a comprehensive database of articles, reports and books describing microbial risk assessment methodologies was established and reviewed. Risk assessment techniques and models were identified for estimating the public health risk from exposure to microorganisms via reclaimed water applications. Two models were identified for further evaluation: a static (individual based) and...

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...

This project was undertaken in response to needs by the wastewater treatment industry to better understand the generation of odors from biosolids produced by wastewater treatment plants (WWTPs). Its primary objective is to begin to establish relationships between WWTP process parameters and biosolids odors, so that more effective techniques for minimizing biosolids odors can be developed. The project consisted of a detailed field study involving extensive sampling and analyses at 11 WWTPs across North America with capacities from 13 to 350 million gallons per day (mgd). Biosolids samples were...

The objective of this project was to develop and evaluate a practical technique to indicate the probability of the presence of bacterial pathogens in receiving waters. A practical method was defined as one that would limit the use of defined culture-based microbiological methods, and would be based on: (1) validating indicator organisms that predicted the presence of pathogens, or (2) detection of pathogens by polymerase chain reaction (PCR)-based assays. The study also assessed the utility of PCR-based technology for bacterial pathogen detection with respect to technology transfer to a wider...