Biogas Production from Anaerobic Co-Digestion of Waste Activated Sludge Co-Substrates and Influencing Parameters

Access to safe drinking-water is essential to health, a basic human right and a component of effective policy for health protection. The importance of water, sanitation and hygiene for health and development has been reflected in the outcomes of a series of international policy forums. These have included health-oriented conferences such as the International Conference on Primary Health Care, held in Alma-Ata, Kazakhstan (former Soviet Union), in 1978. Access to safe drinking-water is important as a health and development issue at national, regional and local levels. In some regions, it has been shown that investments in water supply and sanitation can yield a net economic benefit, as the reductions in adverse health effects and health-care costs outweigh the costs of undertaking the interventions. Experience has also shown that interventions in improving access to safe water favour the poor in particular, whether in rural or urban areas, and can be an effective part of poverty alleviation strategies. The World Health Organization (WHO) published three editions of the Guide-lines for drinking-water quality in 1983–1984, 1993–1997 and 2004, as successors to previous WHO International standards for drinking water, published in 1958, 1963 and 1971. From 1995, the Guidelines have been kept up to date through a process of rolling revision, which leads to the regular publication of addenda that may add to or supersede information in previous volumes as well as expert reviews on key issues preparatory to the development of the Guidelines.

INTRODUCTION The U.S. Environmental Protection Agency (EPA) completed a review of discharges from water treatment plants (WTPs). The purpose of this report is to summarize the data collected during this review (principally covered in Sections 2, 3, 9, 10, and 11) and to serve as a technical resource to permit writers (primarily covered in Sections 4 through 8 and Sections 12 and 13). EPA selected the drinking water treatment (DWT) industry for a rulemaking as part of its 2004 Biennial Effluent Limitations and Guidelines Program planning process. EPA is not at this time continuing its effluent guidelines rulemaking for the DWT industry. In the 2004 Plan, EPA announced that it would begin development of a regulation to control the pollutants discharged from medium and large DWT plants. See 69 FR 53720 (September 2, 2004). Based on a preliminary study and on public comments, EPA was interested in the potential volume of discharges associated with drinking water facilities. The preliminary data were not conclusive, and the Agency proceeded with additional study and analysis of treatability, including an industry survey. After considering extensive information about the industry, its treatment residuals, wastewater treatment options, and discharge characteristics, and after considering other priorities, EPA has suspended work on this rulemaking.