Wastewater collection system odors and corrosion issues continue to grow in importance to the community and to system owners and operators. Odor and corrosion prevention in collection systems has historically been as much art as science. Common control methods are selected based on practical experience as opposed to a fundamental understanding of why and when methods will be successful. Although much is known regarding the cause of odorous gases in the collection system, the underlying science and mechanisms of odor generation, sewer ventilation, odor characterization and monitoring, and...

Approximately 23 percent of the estimated 115 million occupied homes in the United States are served by onsite wastewater systems. The vast majority of onsite wastewater treatment systems include a septic tank, grease trap, or both for primary treatment. These units are efficient, simple, low-energy treatment units whose performance is critically important to the overall functioning of onsite wastewater systems. Regulations, industry standards, guidance materials and engineering texts vary widely and are often incomplete in their consideration of the factors that may influence primary unit...

This research study explores the relationship of urbanization to ecology in the wadeable streams of developing watersheds and describes a protocol, which urban stormwater management agencies can apply in their jurisdiction, to prevent the severe ecologic deterioration that presently occurs in urban streams as a watershed develops. The protocol comprises an 8-step process that involves data collection and analysis integrated with mathematical modeling of runoff from existing and proposed urban development to determine how biologic health indices such as the benthic index of biotic integrity...

The objective of this research was to develop guidance for collecting samples of biosolids for microbial analysis to ensure representative samples are tested. The types of biosolids products studied included liquid, cake and compost. To accomplish the research objective, three phases of research and development of a suite of communications documents were undertaken.
The first Phase involved information gathering and establishing the status of sampling guidance and practices for biosolids. Phase II involved conducting sampling and microbial analysis of biosolids products from four target...

The sudden increase in indicator bacteria, including fecal coliforms (FCs) and E. coli, was evaluated at several full-scale facilities, in addition to the increase measured during cake storage. The results showed that the sudden increase was a statistically verifiable occurrence at some facilities, but not all, as was the additional increases measured during cake storage. The sudden increase and growth were much more prevalent in processes that utilized centrifuge dewatering compared to belt filter press dewatering. The sudden increase appears to be a result of the reactivation of...

The purpose of this User's Guide is to provide guidance on modeling watershed-scale problems associated with decentralized wastewater-treatment systems (DWTS), with a particular focus on onsite wastewater systems (OWS). The guide focuses on modeling transport and fate of the nutrients nitrogen (N) and phosphorus (P) because these are the most common OWS constituents of concern, and because these pollutants are regulated in surface waters (N and P) and in ground water (N). However, limited but useful information is also provided regarding the modeling of organic wastewater contaminants, such...

The literature review described in this report is part of a larger research project to assess STU performance with respect to treatment of important wastewater constituents. The overall goal of the project is to provide a toolkit and tool-use protocol that is easy to implement and available to a wide range of users to assess STU performance. This literature review is not a preview of tools that we will develop and propose, but rather an analysis of the information and data and the literature, to help guide our tool development. All tools developed will be based on rigorous experimental data...

Phase 1 of this project demonstrated the technical feasibility of using decentralized stormwater controls in urban areas for retrofits and controlling combined sewer overflows. This technical feasibility was illustrated by a number of early adopters using decentralized controls to complement their existing municipal stormwater and wastewater infrastructure. However, institutional and programmatic issues required further study to broaden the use of a distributed, decentralized stormwater approach.
This research evaluates implementation strategies for incorporating decentralized controls...

Treated wastewater effluents contain high concentrations of particles; many of these particles are large (with diameters greater than 100 m) and consist of densely-packed bacterial cells. Microorganisms occluded in wastewater particles can be difficult to inactivate in chlorine disinfection systems, as the chlorine must first diffuse through the macro- and microscopic pore spaces prior to inactivating the occluded microorganisms. The impact of microorganisms occluded in particles is evident in disinfection, where reduced inactivation rates occur even with increasing doses of the disinfectant....

This project provides WERF subscribers with a state-of-knowledge report that is a synthesis of existing work and provides guidance on effective risk communication practices, public perception and message effectiveness.
Communication principles are applicable to a wide variety of potential health and environmental risks; however, the report is written with a focus on trace organic compounds. Project findings are drawn from: 1) a focused literature review of communication materials published in the environmental industry; 2) documents describing risk communication practices in other...