1,523,150 research outputs found

    Sludge Production and Disposal for Small Cold Climate Bio-Treatment Plants

    Get PDF
    Ultimate disposal of wastewater sludge has long been a problem which to a large degree has been ignored. Haney (1971) stated that: "Until process sludge can be handled with minimum environmental impact, we cannot claim to have a viable wastewater treatment process". The relationship of sludge disposal to total treatment processes is emphasized by the fact that sludge handling and disposal represents up to 50 percent of the total treatment capital and operating costs (Burd, 1968). Processing of wastewater sludge will, no doubt, receive increased attention in the future because of environmental concerns for our air, land and water. The present technology for processing wastewater treatment plant sludge is well established and includes conditioning, dewatering, and disposal. Many of these processes are highly sophisticated and relatively expensive. Most of the more advanced processes are unsuitable for small wastewater treatment facilities in Alaska.The work upon which this report is based was supported in part by funds (Proj. A-033-ALAS) provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964, as amended

    An evaluation of metal removal during wastewater treatment: The potential to achieve more stringent final effluent standards

    Get PDF
    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2011 Taylor & Francis.Metals are of particular importance in relation to water quality, and concern regarding the impact of these contaminants on biodiversity is being encapsulated within the latest water-related legislation such as the Water Framework Directive in Europe and criteria revisions to the Clean Water Act in the United States. This review undertakes an evaluation of the potential of 2-stage wastewater treatment consisting of primary sedimentation and biological treatment in the form of activated sludge processes, to meet more stringent discharge consents that are likely to be introduced as a consequence. The legislation, sources of metals, and mechanisms responsible for their removal are discussed, to elucidate possible pathways by which the performance of conventional processes may be optimized or enhanced. Improvements in effluent quality, achievable by reducing concentrations of suspended solids or biochemical oxygen demand, may also reduce metal concentrations although meeting possible requirements for the removal of copper my be challenging

    Physical/chemical closed-loop water-recycling

    Get PDF
    Water needs, water sources, and means for recycling water are examined in terms appropriate to the water quality requirements of a small crew and spacecraft intended for long duration exploration missions. Inorganic, organic, and biological hazards are estimated for waste water sources. Sensitivities to these hazards for human uses are estimated. The water recycling processes considered are humidity condensation, carbon dioxide reduction, waste oxidation, distillation, reverse osmosis, pervaporation, electrodialysis, ion exchange, carbon sorption, and electrochemical oxidation. Limitations and applications of these processes are evaluated in terms of water quality objectives. Computerized simulation of some of these chemical processes is examined. Recommendations are made for development of new water recycling technology and improvement of existing technology for near term application to life support systems for humans in space. The technological developments are equally applicable to water needs on Earth, in regions where extensive water recycling is needed or where advanced water treatment is essential to meet EPA health standards

    Land Use and Water Management in Israel- Economic and environmental analysis of sustainable reuse of wastewater in agriculture

    Get PDF
    We will analyze land use and water management issues in Israel by focusing on wastewater irrigation. Irrigation with treated effluents has become an important water source in Israel due to scarcity of natural water resources. Treated wastewater reuse serves as source of water and nutrients and assists with wastewater discard. Wastewater also carries pollutants including micro and macro organic and inorganic matter and its treatment and use should adapt to sustainability criteria. Wastewater treatment processes can decrease pollutants levels, while salinity is not influenced unless combining relatively expensive desalination processes. Advantages of using wastewater in irrigation include: supporting agricultural production, highly reliable supply, low cost water source, solution for effluent disposal and saving of chemical fertilizers. Disadvantages include quality problems as related to human health, damage to crops, contamination of groundwater, problems related to irrigation system, increased water requirement and need for continuous follow up and control. The higher is the treatment level, the higher are the treatment costs but the environmental potential hazards are lower. Regarding sustainable use we will assess advantages and disadvantages of treating and irrigating with treated effluents. We will focus on the economic and environmental analysis of sustainable reuse of wastewater in agriculture regarding its impact on groundwater, soil and society.

    Automation of the Continuous Coagulation Monitor

    Get PDF
    The development of automation in the past 50 years has paralleled the accelerating growth of today’s vast technological society. Automatic control systems are indispensable extensions of man\u27s brain that enable him to monitor and regulate his complex environment. The principles of automatic control have a wide range of applications and interests in virtually every scientific field. The need for automatic control systems in vital applications of environmental engineering is both real and urgent. Extensive pollution has resulted in unavoidable water re-use and in the inevitable establishment of stringent effluent standards. Both water and wastewater treatment processes have necessarily become more advanced and complicated. Automation can reliably provide the critical, sophisticated control required to maintain adequate treatment. In his pollution abatement or water quality program, the environmental engineer can employ automatic control systems to continuously and accurately monitor contaminant levels or the removal efficiencies of treatment processes and to effect rapid responses when treatment adjustment becomes necessary by automatically adjusting processes

    Field testing of an onsite sanitation system on apartment building blackwater using biological treatment and electrochemical disinfection

    Get PDF
    The Closed Loop Advanced Sanitation System (CLASS) was designed to treat, disinfect, and recycle toilet blackwater from existing flush toilets in a multi-story apartment building. Two systems were tested at two unique sites in Coimbatore, India for a combined 7500+ treatment hours resulting in more than 180 000 L of treated water. The CLASS prototypes used a combination of biological pretreatment and electrochemical oxidation processes to produce treated water that nearly met the stringent requirements outlined in the standard ISO 30500. The nutrient and organic loading from the toilet blackwater was predominantly reduced by over 85–95% and 80–87%, respectively, through biological processes that were achieved using either a sequencing batch reactor (SBR, site A) or an anaerobic–aerobic biodigester (EcoSan, site B). Complete disinfection of E. coli with nil CFU per ml was achieved using electrochemical processes that also served to remove the remaining organic and nutrient loading to over 90–96%. The treated water was reused for flushing by the residents of the apartment building for 89 days

    Optimal design of water treatment processes

    Get PDF
    Predicted water shortages assign water treatment a leading role in improving water resources management. One of the main challenges associated with the processes remains early stage design of techno-economically optimised purification. This work addresses the current gap by undertaking a whole-system approach of flowsheet synthesis for the production of water at desired purity at minimum overall cost. The optimisation problem was formulated as a mixed-integer non-linear programming model. Two case studies were presented which incorporated the most common commercial technologies and the major pollution indicators, such as chemical oxygen demand, dissolved organic carbon, total suspended solids and total dissolved solids. The results were analysed and compared to existing guidelines in order to examine the applicability of the proposed approach

    Domestic applications for aerospace waste and water management technologies

    Get PDF
    Some of the aerospace developments in solid waste disposal and water purification, which are applicable to specific domestic problems are explored. Also provided is an overview of the management techniques used in defining the need, in utilizing the available tools, and in synthesizing a solution. Specifically, several water recovery processes will be compared for domestic applicability. Examples are filtration, distillation, catalytic oxidation, reverse osmosis, and electrodialysis. Solid disposal methods will be discussed, including chemical treatment, drying, incineration, and wet oxidation. The latest developments in reducing household water requirements and some concepts for reusing water will be outlined
    corecore