Rationale for constant flow to optimize wastewater treatment and advanced water treatment performance for potable reuse applications.

Population growth, the impacts of climate change, and the need for greater water security have made the reuse of wastewater, including potable use, increasingly desirable. As interest in potable reuse of wastewater increases, a variety of processes have been proposed for advanced water treatment following conventional wastewater treatment. In all cases, the operation and performance of advanced water treatment facilities (AWTFs) is improved when the treated wastewater feed is of the highest quality that can be achieved and the advanced water treatment (AWT) processes are operated at a constant flow.

Performance evaluation of first full-scale primary filtration using a fine pore cloth media disk filter.

Over the past 20 years, various new filter technologies have been developed that can be used to (a) enhance the performance of or (b) replace conventional primary treatment facilities. To enhance the performance of a primary sedimentation facility, primary effluent is filtered to further reduce the constituent concentrations discharged to the secondary treatment facilities. This form of primary enhancement is known as primary effluent filtration (PEF).

Urban net-zero water treatment and mineralization: experiments, modeling and design.

Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb.

Performance evaluation of an anaerobic/aerobic landfill-based digester using yard waste for energy and compost production.

The objective of this study was to evaluate a new alternative for yard waste management by constructing, operating and monitoring a landfill-based two-stage batch digester (anaerobic/aerobic) with the recovery of energy and compost. The system was initially operated under anaerobic conditions for 366 days, after which the yard waste was aerated for an additional 191 days. Off gas generated from the aerobic stage was treated by biofilters.

Relative risk assessment of cruise ships biosolids disposal alternatives.

A relative risk assessment of biosolids disposal alternatives for cruise ships is presented in this paper. The area of study encompasses islands and marine waters of the Caribbean Sea. The objective was to evaluate relative human health and ecological risks of (a) dewatering/incineration, (b) landing the solids for disposal, considering that in some countries land-disposed solids might be discharged in the near-shore environment untreated, and (c) deep ocean disposal.

Methane, carbon dioxide, and nitrous oxide emissions from septic tank systems.

Emissions of CH4, CO2, and N2O from conventional septic tank systems are known to occur, but there is a dearth of information as to the extent. Mass emission rates of CH4, CO2, and N2O, as measured with a modified flux chamber approach in eight septic tank systems, were determined to be 11, 33.3, and 0.

Quantifying factors limiting aerobic degradation during aerobic bioreactor landfilling.

A bioreactor landfill cell at Yolo County, California was operated aerobically for six months to quantify the extent of aerobic degradation and mechanisms limiting aerobic activity during air injection and liquid addition. The portion of the solid waste degraded anaerobically was estimated and tracked through time. From an analysis of in situ aerobic respiration and gas tracer data, it was found that a large fraction of the gas-filled pore space was in immobile zones where it was difficult to maintain aerobic conditions, even at relatively moderate landfill cell-average moisture contents of 33-36%.

Sustainable use of water in the Aegean Islands.

Water demands in the Aegean Islands have increased steadily over the last decade as a result of a building boom for new homes, hotels, and resorts. The increase in water demand has resulted in the disruption of past sustainable water management practices. At present, most freshwater needs are met through the use of the limited groundwater, desalinated seawater, and freshwater importation.

Clogging in intermittently dosed sand filters used for wastewater treatment.

Clogging in intermittent sand filter (ISF) systems was analyzed using an unsaturated flow model coupled with a reactive transport model. Based on the results of a model sensitivity analysis, several variables were determined to be important in the clogging phenomena observed in ISFs, including hydraulic loading rate, influent chemical oxygen demand (COD) concentration, filter dosing frequency, and time of operation. Several modes of operation were identified that minimize the growth of bacteria at the filter surface.

Full cost accounting as a tool for the financial assessment of Pay-As-You-Throw schemes: a case study for the Panorama municipality, Greece.

In the present paper, implementation scenarios of a Pay-As-You-Throw program were developed and analyzed for the first time in Greece. Firstly, the necessary steps for implementing a Pay-As-You-Throw program were determined. A database was developed for the needs of the full cost accounting method, where all financial and waste-production data were inserted, in order to calculate the unit price of charging for four different implementation scenarios of the "polluter-pays" principle.

The role of satellite and decentralized strategies in water resources management.

Existing and projected water shortages and related factors have helped focus attention on the need for water reuse. With recent technological advances in wastewater treatment, it is now possible to produce reclaimed water of any quality. Thus, the use of reclaimed water will depend on the reuse opportunities and the cost of the required infrastructure.

A public health evaluation of recreational water impairment.

Water quality objectives for body contact recreation (REC-1) in Newport Bay, CA are not being attained. To evaluate the health implications of this non-attainment, a comprehensive health-based investigation was designed and implemented. Bacterial indicator data indicate that exceedances of the water quality objectives are temporally sporadic, geographically limited and most commonly occur during the time of the year and/or in areas of the bay where the REC-1 use is low or non-existent.

Modeling depth filtration of activated sludge effluent using a compressible medium filter.

A new filter, using a compressible-filter medium, has been evaluated for the filtration of secondary effluent. The ability to adjust the properties of the filter medium by altering the degree of the medium compression is a significant departure from conventional depth-filtration technology. Unlike conventional filters, it is possible to optimize the performance of the compressible-medium filter (CMF) by adjusting the medium properties (i.

Comparative assessment of municipal wastewater disposal methods in southeast Florida.

A comparative assessment of the risks of three effluent disposal alternatives currently available to wastewater utilities in Southeast Florida is presented in this paper. The alternatives are: deep well injection and ocean outfalls following secondary treatment, and surface water (canal) discharges following secondary wastewater treatment, filtration and nutrient removal. Water quality data, relative to disposal of wastewater treatment plant effluent were gathered, along with water quality data on the receiving waters, from utilities.

Performance evaluation of a cloth-media disk filter for wastewater reclamation.

A cloth-media disk filter (CMDF) was evaluated as an alternative to granular-medium filtration for use in wastewater recycling applications. The CMDF was effective for filtration of effluent from an activated-sludge treatment process. Effluent turbidity values from the CMDF were consistently less than California's wastewater recycling application limit of 2 nephelometric turbidity units (NTU) for influent turbidity values of up to 25 NTU at hydraulic loading rates varying between 7 and 15 m/h (2.

Sludge accumulation, characteristics, and pathogen inactivation in four primary waste stabilization ponds in central Mexico.

To support the development of safe and feasible sludge management strategies, the accumulation rates of sludge and its characteristics were studied in four primary wastewater stabilization ponds (WSPs) in central Mexico (three facultative and one anaerobic). The accumulation rates and distribution of sludge were determined by measuring the thickness of the sludge layer at 8-40 locations throughout each pond. The average, per capita sludge accumulation rates ranged from 0.

Risk-based approach to evaluate the public health benefit of additional wastewater treatment.

The City of Stockton, CA operates a wastewater treatment facility that discharges tertiary treated effluent during the summer and secondary treated effluent during the winter to the San Joaquin River. Investigations were carried out between 1996 and 2002 to provide insight regarding the potential public health benefit that may be provided by year-round tertiary treatment. A hydraulic model of the San Joaquin River and a dynamic disease transmission model integrated a wide array of disparate data to estimate the level of viral gastroenteritis in the population under the two treatment scenarios.