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 guidance document incorporates the systematic approach for integrated capacity assessment of a wastewater treatment plant and identifying performance limiting factors. Based on evaluation by...
This project addresses the successful nitrogen and phosphorus removal technologies being implemented at existing wastewater treatment plants (WWTPs), some key challenges...
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...
Phosphorus measurements at very low concentrations have been tested and proven to be unreliable. The establishment of stricter phosphorus discharge requirements has challenged the wastewater...
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...
Online monitoring of water quality is an powerful enabler in the water industry. It is a crucial component in the pro-active management of processes and assets, and helps improve performance and...
The primary goal of the Optimization Challenge is to develop an approach that will allow the wastewater sector to achieve treatment goals while reducing the resources expended by 20% or more. The...
Long Island Sound was designated as an "estuary of national significance" in 1998, and the Long Island Sound Study (LISS) was directed to develop a comprehensive conservation and management plan (...
Today there is increasing pressure on the water infrastructure and although unsustainable water extraction and wastewater handling can continue for a while, at some point water needs to be managed...
Most households regularly use products containing trace organic compounds (TOrC), including endocrine disrupting compounds (EDCs) pharmaceutically active compounds (PhACs), personal care products...
The importance of small towns is gaining increased recognition as a result of two developments. The first development concerns the possible role of small towns in migration flows and urbanization...
Frontiers in Urban Water Management presents the state-of-the art in urban water management at the beginning of the 21st century.
The book marks the end of the fifth phase...