NUTR1R06t
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Available as an ebook
Please purchase via www.iwaponline.comOpens in new window
Also part of Water Intelligence Online Digital Reference Library
Standard ePrice: £29.00
+ VAT
The need to control and remove phosphorus (P) in discharges from wastewater treatment facilities (WWTF) to prevent eutrophication of receiving waters is well known. Regulatory initiatives are further contributing to the addition of stringent P limits to discharge permits. Accordingly, many agencies are facing increasingly stringent standards of effluent P and as a result the effluent limit of 0.1 mg P/L total phosphorus (TP) or lower is being achieved. Since the reliable performance limit of enhanced biological phosphorus removal (EBPR) is commonly accepted at about 0.1 mg P/L in the dissolved form, these facilities will need to utilize tertiary chemical phosphorus removal (CPR) to reliably achieve limits lower than 0.1 mg P/L (ultra-low limits) (Pagilla and Urgun-Demirtas, 2007).
The mechanistic basis for P removal using chemical precipitant addition is generally considered to be more than simple precipitation. The role of adsorption and/or surface complexation in removal of reactive or unreactive phosphorus to the already formed chemical precipitates or complexes has been reported. Omoike and VanLoon (1999) showed that the most likely mechanism involves sorption of P species on Al(OH)3(s) formed by Al salt addition to water for P removal, and further precipitation/complexation of P onto the Al hydroxyl precipitate for additional P removal. In tertiary P removal, usually a non-stoichiometric dose or several times stoichiometric dose of the precipitant is needed. The chemical precipitates formed upon addition of such high doses of chemical precipitant are likely to serve as nuclei for further aggregation of newly formed precipitates, thus enhancing the overall tertiary P removal. The excess precipitant added to the secondary effluent produces hydroxyl precipitates which could serve as adsorbents for additional P removal. It is well proven that alum sludge from water treatment plants have high capacity for wastewater effluent P removal depending on their structure and/or age of the sludge solids. The role of mixing, pH, contact time, precipitated solids concentration in the mixing tank, and feed secondary effluent characteristics could influence this process of tertiary P removal. The investigation of such variables and the process along with careful analytical measurements would explain the basis for precipitation/solids contact P removal from wastewater effluents.
This project addresses the successful nitrogen and phosphorus removal technologies being implemented at existing wastewater treatment plants (WWTPs), some key challenges...
The development of this WERF anaerobic digester (AD) foaming guidance document is based on the need for a specific detailed methodology that water reclamation and recovery facilities (WRRF)...
This project addresses the dissolved organic nitrogen (DON) content in the effluents of different wastewater treatment plants (WWTPs). In this report, information is presented on the occurrence...
The overall aim of this research was to evaluate membrane bioreactor (MBR) process designs to meet low effluent nitrogen and/or phosphorus concentrations from municipal wastewater treatment...
The results of this project should enhance our ability to proactively improve the protection of public health. Equating the presence of pathogens to broad land use categories may help mitigate...
This project evaluated the quality of data needed to determine relationships between chronic Whole Effluent Toxicity (WET) test results and in-stream biological condition. A data quality...
The Santa Ana River (SAR) is the primary source of groundwater recharge for the Orange County Groundwater Basin. Approximately 85% of the baseflow in the SAR comes from wastewater treatment...
With the advent of improved analytical detection capabilities, a variety of organic chemicals have been found in trace amounts (Trace Organic Chemicals, TOrCs) in surface waters, sediment, and...
Most households regularly use products containing trace organic compounds (TOrC), including endocrine disrupting compounds (EDCs) pharmaceutically active compounds (PhACs), personal care products...
This report is a summary of a WERF/NOWRA workshop on Research Needs in Decentralized Wastewater, Stormwater, and Related Fields held on March 14-15, 2007 in Baltimore, MD. The purpose of the...
The purpose of this study was to assess the economic feasibility of using large-scale, restored wetlands to assist publicly owned treatment works (POTWs) in meeting the U.S. Environmental...
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WERF and NYSERDA, in conjunction with Brown and Caldwell, Black & Veatch, Hemenway Inc., and NEBRA, are leading a research project to determine...