Conventional Water Treatment Plants Research Articles

Expanding in Place

When the time came for a water utility in southeastern Pennsylvania to expand the capacity of its 20 mgd (75,700 m3/d) conventional water treatment plant, the entity opted to upgrade its facility to include membrane technology and replace its gravity sand filters. In doing so, the facility became one of the first to install membranes in the same footprint as that required by the sand filters. At the same time the utility positioned its facility to accommodate the more stringent regulatory requirements seen on the horizon.

Disinfection characteristics of the dissolved organic fractions at several stages of a conventional drinking water treatment plant in Southern China

Dissolved organic matter (DOM) influences many aspects of drinking water treatment, including the formation of harmful disinfection by-products (DBPs) when disinfectants are applied. DOM was isolated and fractionated using membrane ultra-filtration (UF) and reverse osmosis (RO) to eight individual fractions based on molecular weight cut-offs from a conventional surface water treatment plant (WTP) in Guangzhou of PR China. Molecular weights of these eight fractions were further calibrated using high performance size exclusion chromatography (HPSEC) and they ranged from 0.36 to 182.6 kDa. Fractions with molecular weight <0.80 kDa obtained by YC-05 UF membrane and RO were the major ones in all four stages of the water treatment processes; both ZM-500 and YM-100 membranes showed the highest removal efficiency when coupling with conventional coagulation and sedimentation processes. The elemental analysis showed that YC-05 fraction had greater polarity and aromaticity than any of the others. Furthermore, disinfection characteristics and trihalomethane formation potential (THMFP) were determined for all DOM fractions obtained in this study. YC-05 fraction was the major precursor for trihalomethane (THMs) formation among the samples tested and could be removed effectively by particulate activated carbon (PAC) adsorption. RO fraction could not be removed by PAC adsorption and, as a result, consumed more chlorine in the disinfection process. The results suggested that advanced drinking water treatment should focus on the removal of low molecular weight DOM in the source water.

Assessing the feasibility of a water treatment plant quality index

Research Article| August 01 2009 Assessing the feasibility of a water treatment plant quality index Marcelo Libânio; Marcelo Libânio Search for other works by this author on: This Site PubMed Google Scholar Vanessa Cristina Lopes Vanessa Cristina Lopes Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2009) 58 (5): 354–362. https://doi.org/10.2166/aqua.2009.002 Article history Received: January 17 2009 Accepted: May 09 2009 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation Marcelo Libânio, Vanessa Cristina Lopes; Assessing the feasibility of a water treatment plant quality index. Journal of Water Supply: Research and Technology-Aqua 1 August 2009; 58 (5): 354–362. doi: https://doi.org/10.2166/aqua.2009.002 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex This paper focuses on the development of a quality index applied to conventional water treatment plants (WTPQI) with the objective of providing a more consistent way of evaluating performance and comparing different plants. The methodology, based on the Delphi method, relies on the same principles used at the beginning of the 1970s in the formulation of the Water Quality Index (WQI). Afterwards, the WTPQI was applied to ten different Brazilian conventional water treatment plants, with horizontal sedimentation basins and variable sizes (average flow rates range from 100–4,300 L s−1) and the results pointed out its usefulness as an instrument for plant evaluation. A significant correlation between plant performance and the WTPQI values was confirmed based on the filtered water turbidity, mainly for the rainy season when the raw water quality becomes harder to reach compliance with the drinking water standards. Therefore, these results open up the perspective of the use of the WTPQI as a reliable tool for the management of water supply systems. Delphi method application, water treatment plant evaluation, water treatment plant index This content is only available as a PDF. © IWA Publishing 2009 You do not currently have access to this content.

Development and implementation of the software mEnCo© to predict coagulant doses for DOC removal at full-scale WTPs in South Australia

Research Article| June 01 2009 Development and implementation of the software mEnCo© to predict coagulant doses for DOC removal at full-scale WTPs in South Australia J. van Leeuwen; J. van Leeuwen 1University of South Australia, Centre for Water Management and Reuse, School of Natural and Built Environments, H-Building Level 3, Mawson Lakes Campus, Adelaide South Australia, Australia E-mail: john.vanleeuwen@unisa.edu.au Search for other works by this author on: This Site PubMed Google Scholar M. Holmes; M. Holmes 2United Water International, GPO Box 1875, Adelaide 5501, SA, Australia Search for other works by this author on: This Site PubMed Google Scholar U. Kaeding; U. Kaeding 2United Water International, GPO Box 1875, Adelaide 5501, SA, Australia Search for other works by this author on: This Site PubMed Google Scholar R. Daly; R. Daly 3Australian Water Quality Centre, SA Water, Hodgson Road, Bolivar 5110, SA, Australia Search for other works by this author on: This Site PubMed Google Scholar D. Bursill D. Bursill 1University of South Australia, Centre for Water Management and Reuse, School of Natural and Built Environments, H-Building Level 3, Mawson Lakes Campus, Adelaide South Australia, Australia Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2009) 58 (4): 291–298. https://doi.org/10.2166/aqua.2009.054 Article history Received: June 18 2008 Accepted: October 21 2008 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation J. van Leeuwen, M. Holmes, U. Kaeding, R. Daly, D. Bursill; Development and implementation of the software mEnCo© to predict coagulant doses for DOC removal at full-scale WTPs in South Australia. Journal of Water Supply: Research and Technology-Aqua 1 June 2009; 58 (4): 291–298. doi: https://doi.org/10.2166/aqua.2009.054 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Conventional surface water treatment plants (WTPs) rely on optimised coagulation for effective clarification, filtration and chlorination performance. WTPs operated at sub-optimal coagulation conditions are at risk from failing treated water microbial, disinfection by-product, chemical and aesthetic quality goals as well as incurring excessive sludge production and treatment cost. This is especially important when treating water that contains a high concentration of natural organic matter (NOM). Removal of NOM by coagulation can be enhanced by optimising the inorganic coagulant dose and coagulation pH. This paper describes the development and implementation of a software model mEnCo© (referring to modelling enhanced coagulation) that enables WTP operators to rapidly determine coagulation chemicals. Implementation was carried out in a four-stage process comprising model evaluation by (1) jar tests and pilot-scale studies, (2) comparison of mEnCo© predictions with historical water quality and coagulant dose trends at Adelaide metropolitan WTPs, (3) parallel studies where mEnCo© predictions were compared with the usual methods applied by operators for chemical dose determination and (4) application of mEnCo© for dose determination and review. United Water International (UWI) began using mEnCo© in July 2003 for prediction of chemical doses for coagulation control and have used the model from July 2004 to adjust coagulant doses. coagulation, DOC, model, optimization, software, water treatment This content is only available as a PDF. © IWA Publishing 2009 You do not currently have access to this content.

Comparison of nanofiltration efficiency with GAC adsorption and air stripping processes for CHCl3 removal from Tehran drinking water

Research Article| June 01 2009 Comparison of nanofiltration efficiency with GAC adsorption and air stripping processes for CHCl3 removal from Tehran drinking water M. T. Samadi; M. T. Samadi 1Environmental Health Department, School of Health and Center for Health Research, Hamadan University of Medical Sciences, PO Box 4171, Hamadan 65175, Iran E-mail: samadi@umsha.ac.ir Search for other works by this author on: This Site PubMed Google Scholar S. Nasseri; S. Nasseri 2Center for Environmental Research, Tehran University of Medical Sciences, PO Box 6446, Tehran 14155, Iran Search for other works by this author on: This Site PubMed Google Scholar A. R. Mesdaghinea; A. R. Mesdaghinea 2Center for Environmental Research, Tehran University of Medical Sciences, PO Box 6446, Tehran 14155, Iran Search for other works by this author on: This Site PubMed Google Scholar M. R. Alizadehfard M. R. Alizadehfard 3Polymer Engineering Department, Amirkabir University of Technology, Tehran, Iran Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2009) 58 (4): 285–290. https://doi.org/10.2166/aqua.2009.001 Article history Received: January 15 2008 Accepted: December 24 2008 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation M. T. Samadi, S. Nasseri, A. R. Mesdaghinea, M. R. Alizadehfard; Comparison of nanofiltration efficiency with GAC adsorption and air stripping processes for CHCl3 removal from Tehran drinking water. Journal of Water Supply: Research and Technology-Aqua 1 June 2009; 58 (4): 285–290. doi: https://doi.org/10.2166/aqua.2009.001 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex The effectiveness of nanofiltration (NF) was compared with granular activated carbon (GAC) and air stripping (AS) using a packed column in water treatment for the removal of chloroform (CHCl3), which is a basic indicator of trihalomethane (THM) compounds in many water resources. Pilot GAC and AS columns were designed and set up with nanofiltration polyamide and cellulose acetate blend spiral-wound modules with MWCO of 300 Da and 600 Da. The study was carried out for the two cases of deionized and chlorinated Tehran tap water. CHCl3 concentrations for both inlet and outlet samples were detected by gas chromatography (GC) and using electron capture detector (ECD). Results showed that the maximum CHCl3 removal efficiencies for NF 300 Da, NF 600 Da, GAC and AS packed columns under various operating conditions were 87.8%, 85%, 87.4% and 97.6% for deionized water and 86.1%, 72.3%, 85.1, and 91.2% for chlorinated Tehran tap water, respectively. Although NF, GAC and AS showed acceptable performance for CHCl3 removal from drinking water, NF was significantly more effective (p<0.05), providing simultaneously a higher flow rate and simpler operating conditions. This method may be considered for conventional water treatment plant finishing water. air stripping, chloroform, GAC, nanofiltration, water treatment This content is only available as a PDF. © IWA Publishing 2009 You do not currently have access to this content.

Application of a novel polarity method for the characterization of natural organic matter during water treatment

The changes in polarity of natural organic matter (NOM) across a pilot-scale conventional water treatment plant with pre-ozonation and biofiltration were analyzed using the polarity rapid assessment method (PRAM). PRAM is a novel method developed for the characterization of the polarity of NOM in environmental samples. Characterization was accomplished by monitoring UV absorbance (UVA) at 254 nm. Under ambient conditions, the NOM was characterized as highly anionic (>50%), with limited hydrophobic (10―25%) and hydrophilic (0―10%) domains. Results showed temporal variations in the polarity of NOM entering the pilot plant. These differences were ascribed to changes in water blend and variability in NOM characteristics. Changes in NOM chemistry were also observed as the organics passed through the treatment process. Ozonation decreased the hydrophobicity and increased the polarity of NOM , confirming results from previous research utilizing resin fractionation methods. Coagulation, flocculation and biofiltration resulted in the decrease of the hydrophobic and hydrophilic character of the chromophoric NOM. However, these polarity changes varied during the pilot plant run, suggesting a more precise evaluation of NOM through unit operations is warranted.

Synthetic Musk Fragrances in a Conventional Drinking Water Treatment Plant with Lime Softening.

Synthetic musk fragrances are common personal care product additives and wastewater contaminants that are routinely detected in the environment. This study examines the presence eight synthetic musk fragrances (AHTN, HHCB, ATII, ADBI, AHMI, musk xylene, and musk ketone) in source water and the removal of these compounds as they flow through a Midwestern conventional drinking water plant with lime softening. The compounds were measured in water, waste sludge, and air throughout the plant. HHCB and AHTN were detected in 100% of the samples and at the highest concentrations. A mass balance on HHCB and AHTN was performed under warm and cold weather conditions. The total removal efficiency for HHCB and AHTN, which averaged between 67% to 89%, is dominated by adsorption to water softener sludge and its consequent removal by sludge wasting and media filtration. Volatilization, chlorine disinfection, and the disposal of backwash water play a minor role in the removal of both compounds. As a result of inefficient overall removal, HHCB and AHTN are a constant presence at low levels in finished drinking water.

A review of the effects of emerging contaminants in wastewater and options for their removal

The occurrence of emerging or newly identified contaminants in our water resources is of continued concern for the health and safety of consuming public. The existing conventional water treatment plants were not designed for these unidentified contaminants. The endocrine disrupting chemicals (EDCs) comprise pharmaceuticals, personal care products, surfactants, various industrial additives and numerous chemicals purported to be endocrine disrupter. These have become a threat to our water supply network. The current wastewater treatment system is not effective in elimination of these different classes of emerging contaminants as these have not been monitored due to the absence of stringent regulation specific to these contaminants. These undesirable compounds are being released, knowingly or unknowingly, into the aquatic environment that affect the whole living organism. The paper discusses adverse effects of these emerging contaminants to water consumers and discusses the potential removal processes. The use of activated carbon, oxidation, activated sludge, nanofiltration and reverse osmosis membranes, and their efficiencies in removal of these pollutants, are reviewed. In particular, the nanofiltration removal mechanism is emphasized because of its utmost importance in eliminating micropollutants.

Study on ultrafiltration for surface water by a polyvinylchloride hollow fiber membrane

Low pressure membrane filtration processes are increasingly competing against conventional surface water treatment plants. In comparison with conventional processes, UF technology has many advantages, but it is also important that a kind of membrane is suitably selected and operated. In this paper, a pilot plant study on a polyvinylchloride ultrafiltration (MWCO of 80 kD) hollow fiber membrane process was performed for the treatment of surface water. The new membrane had an optimized pore size distribution over membrane thickness while membrane material and fiber dimensions remained the same, the modification resulted in a much higher pure water flux (160 l/(m 2 h bar) at 20°C). The membrane system was operated in the dead-end filtration modes with different constant permeate fluxes. The results showed that the permeate quality was stable, regardless of different surface water for a long duration of filtration. The transmembrane pressure should be operated in less than 1 bar to avoid irreversible fouling. Treating cold raw water below 5°C in constant pressure operation mode was better than in constant permeate flux.

Fate of THMs and HAAs in low TOC surface water

A total of 30 conventional surface water treatment plants (WTPs) implementing prechlorination and postchlorination simultaneously from different regions in Korea were investigated to assess formation and removal of THMs and HAA 5. All water was low in total organic carbon (TOC) ranging from 0.74 to 6.20 mg/L with an average of 1.63 mg/L. The ranges of THMs and HAA 5 levels were 4.5–84.3 μg/L and 1.5–90.8 μg/L, respectively. THMs concentration was more sensitive to water temperature than HAA 5 and the ratio of THMs in summer over winter was 2.06. The sum of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) was 97% of HAA 5. The extent of formation and speciation of DBPs varied greatly by season and geography. The concentration of DCAA and TCAA of the finished water was comparable on a yearly base, but more TCAA was noticed in summer and the opposite trend was noticed in winter. This can be caused by different biodegradability in the sand filter between DCAA and TCAA that formed through prechlorination. Investigation on the removal of preformed DBPs in the GAC filter–adsorber (FA) revealed that breakthrough of THMs and HAA 5 was noticed after 3 months of operation. However, gradual improvement (>90%) in HAA 5 removal was observed again after breakthrough, which could be attributable to biodegradation. Heterotrophic plate counts confirmed active biological activity in the GAC FA.

Application of Computational Fluid Dynamics for Optimal Design of Horizontal-Flow Baffled-Channel Powdered Activated Carbon Contactors

For more efficient design of a horizontal-flow baffled-channel powdered activated carbon (PAC) contactor (hBPC), which might be used to cope with taste and odor problems at conventional water treatment plants, computational fluid dynamics (CFD) using FLOW-3D was applied. In order to verify the performance of the CFD simulations, the experimental results of tracer tests from a pilot-scale hBPC were compared to those from the simulation. Results from the CFD simulation were very similar to those of the tracer tests. Velocity distributions showed that there were stagnant regions on the back side of the baffles. These stagnant regions would be expected to decrease the overall adsorption efficiency of the PAC particles. The size of the stagnant regions and retention times in the simulated hBPC increased as the length to width (L/W) ratio increased and the bend width decreased. The L/W ratio, bend width, and the number of baffles for optimal design of the hBPC were successfully generated by the simulation. When designing a full-scale hBPC, the designer should consider the L/W ratio, number of baffles, and bend width in order to maximize the hBPC performance.

To what extent are pesticides removed from surface water during coagulation–flocculation?

AbstractThe occurrence of pesticides in drinking water sources is of concern for drinking water production companies as well as for the end users. However, it is still unclear which pesticides are removed, and to what extent, in widely used treatment methods such as coagulation–flocculation. Pesticides possibly interact with colloidal particles by adsorption on the flocs during coagulation–flocculation. In this study, removal of four pesticides (aldrin, dieldrin, atrazine, bentazon) was observed during jar test experiments in distilled and surface water (Dijle river, Belgium), using aluminium sulphate as a coagulant in different amounts ranging from no coagulant to high doses (300 mg/L). Without aiming at an accurate description of the removal process, the purpose of this study was to evaluate how much of the pesticides can be removed by changing the concentration, the dosage, the water matrix and the properties of the pesticides. The results show that the removal is usually low. The efficiency was worse when the matrix was distilled water than for Dijle river water, which is consistent with the idea that the removal of micropollutants only occurs through adsorption on the available organic material, and not on inorganic coagulants. Sorption on the natural material available in the Dijle river water seemed to be the main mechanism controlling the removal of micropollutants with coagulation/flocculation, rather than the amount of coagulant added. The hydrophobicity of the compounds was found to be a major factor in determining the removal efficiency with coagulation–flocculation; the most hydrophobic compound had the highest removal efficiency. Nevertheless, the removal was below 50% under all the tested circumstances. The results of this study prove that pesticide removal in conventional water treatment plants depends on physico‐chemical interactions, but is insufficient even with extreme doses of alum.

Stimulatory Drugs of Abuse in Surface Waters and Their Removal in a Conventional Drinking Water Treatment Plant

The presence of psychoactive stimulatory drugs in raw waters used for drinking water production and in finished drinking water was evaluated in a Spanish drinking water treatment plant (DWTP). Contamination of the river basin which provides raw water to this DWTP was also studied. In surface waters, illicit drugs such as cocaine, benzoylecgonine (cocaine metabolite), amphetamine, methamphetamine, MDMA (ecstasy), and MDA were detected at mean concentrations ranging from 4 to 350 ng/L. Nicotine, caffeine, and their metabolites were also found at the microg/L level. The elimination of these compounds during drinking water treatment was investigated in a real waterworks. Amphetamine-type stimulants (except MDMA) were completely removed during prechlorination, flocculation, and sand filtration steps, yielding concentrations lowerthan their limits of detection (LODs). Further, ozone treatment was shown to be effective in partially eliminating caffeine (76%), while subsequent granulated activated carbon (GAC) filtration removed cocaine (100%), MDMA(88%), benzoylecgonine (72%), and cotinine (63%). Postchlorination achieved the complete elimination of cocaine and nicotine and only one parent compound (caffeine) and two metabolites (cotinine and benzoylecgonine) persisted throughout treatment although reductions of 90% for caffeine and benzoylecgonine and 74% for cotinine were obtained.

Application of an Air Ionization Device Using an Atmospheric Pressure Corona Discharge Process for Water Purification

Pesticides presently being discharged into the aquatic environment are not only toxic but also only partially biodegradable, they are not easily removed by conventional water treatment plants. Air ionization devices using an atmospheric pressure corona discharge process show great promise in improving degradation of chemical and biological contaminants in water purification plants. In order to assess the effectiveness of this air ionization apparatus, laboratory scale degradation experiments were carried out systematically in a bubble column reactor containing a variety of pesticides such as triazines, carbamates, phenyl urea derivates and chlorophenols relative to the addition of humic acid and inorganic chemicals as well as to pH variation. Chemical oxygen demand (COD) decreased with air ionization treatment and the rate of the biological oxygen demand related to this (BOD/COD) showed improved pesticide biodegradability. Changes in water toxicity were monitored by Daphnia- and Luminescence Bacteria tests. This novel water treatment process is shown to be a potent oxidation technique for persistent organic pollutants such as pesticides.

Filter Aid Injection Manifold Enhances Operations

This article discusses the Filter Aid Injection Manifold that uses ram water from the house system water supply lines to break the head of the influent water to the filter. Filter aid is fed at low feed rates of about 0.16 mg/L. The ram water and manifold nozzles provide a more uniform and constant dispersion of the chemical, and the higher velocity of the solution creates cleaner feed lines. Results and benefits of using the manifold at the Eugene (Oregon) Water and Electric Board's 72‐mgd conventional surface water treatment plant are discussed.

Expanding a Conventional Water Treatment Plant With Low–pressure Membranes

This article provides details of one approach for evaluating whether to install low‐pressure membranes as part of a water treatment plant (WTP) expansion. Even though the conventional WTP at the Modesto (California) Irrigation District (MID) was exceeding all state and federal water quality requirements, the decision was made to switch to a new filtration technology for the expansion. To verify the membranes' applicability and performance, the MID embarked on an extensive pilot testing program. It also evaluated options for residuals handling and for treating membrane cleaning wastes. Even a well‐operated conventional water treatment plant can have good reasons to expand with a newer technology, such as low‐pressure membranes. For the MID, the anticipated regional population growth and limited land for future water plant expansions, were significant reasons for expanding its conventional water plant with membranes. The authors have presented information that will be useful for utility managers facing their own treatment plant expansions by providing an example of one approach to evaluating a new technology for a plant expansion. Water utilities can see how MID proceeded with evaluation of low‐pressure membranes and how decisions were made. They can also learn about the design considerations for ozone, residuals handling, and disposal of membrane cleaning wastes. Readers will also be interested in the use of a siphon arrangement for drawing water through the membranes, a technique that will help to lower the overall energy use at the expanded facility.

Inactivation of Bacillus subtilis spores during ozonation in water treatment plant: Influence of pre-treatment and consequences for positioning of the ozonation step

This study reports on quantitative methodology for rational selection of the ozone injection point within unit processes of conventional drinking water treatment plants to improve disinfection efficiencies. The method is based on the fact that a specific inactivation level of microorganisms is achieved at a unique value of ozone exposures, independent of ozone dose and type of water, and quantitatively described by a Delayed Chick–Watson model ( C ¯ T lag : 1.03 mg l −1, k: 1.44 mg −1 l min −1). This study demonstrated this phenomenon by performing the inactivation of Bacillus subtilis ( B. subtilis) spores with ozone in various types of water collected from a series of unit processes in a water treatment plant. Simple measurements of the ozone decomposition behavior in waters from each unit process of a water treatment plant can allow the quantitative evaluation of the ozone needed to achieve a required level of inactivation. This methodology will be useful for drinking water treatment plants which intend to improve the disinfection efficiencies of their ozonation process.

Degradation of Endocrine Disrupting Chemicals by Ozone/AOPs

The presence of endocrine-disrupting compounds (EDCs) in the aqueous environment is of increasing concern due to their adverse impact on aquatic life, and potential risk to human health. Among the EDCs of concern are steroidal estrogenic hormones such as estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2), which have a high environmental prevalence and strong estrogenic activity. In addition, the extensive use of alkylphenol ethoxylates (APnEOs), bisphenol A (BPA) and phthalate compounds have resulted in an environmental presence at significant concentrations, although they appear to have a lower estrogenic activity than the steroidal hormones. As water and wastewaters are some of the primary routes of exposure to EDCs, it is important to determine at what levels EDCs are found in these media and how these levels may be reduced. Hence, it is necessary to understand the fate of EDCs in conventional water and wastewater treatment plants, as well as the efficacy of more specialized treatment methods, such as adsorption and oxidation. This paper is a summary of the latest information on the degradation of prominent EDCs by ozone and ozone-based advanced oxidation processes (AOPs). From this review, it is clear that ozone and AOPs are effective in degrading these EDCs, with the possible exception of phthalates, which are relatively stable to ozone oxidation. Knowledge of the formation of reaction products from the treatment by ozone and AOPs is relatively poor at present, and particularly for the non-steroid compounds.

Is Phosphorus Recovery from Waste Water Feasible?

Phosphorus (P) recovery from waste water must become a predominant goal of all countries to face the limited resources of this essential nutrient. The induced crystallisation of calcium phosphates straight from the waste water phase applying tobermorite-rich calcium silicate hydrate compounds (CSH) from the construction industry as the trigger material has proved to be a suitable method. Laboratory and semi-technical scale experiments were carried out in fixed bed, stirred reactor and expanded bed mode. P-loads of the crystallisation substrates of up to 13 wt-% total P (P-tot) (30 wt-% P2O5) were achieved. Recycling options of the generated products, both as substitute for phosphate rock in the phosphate industry and as a new fertiliser in agriculture, were demonstrated. Indicative operating and investment costs were estimated for conversion of conventional waste water treatment plants (WWTP) designed for nutrient removal and P-precipitation with iron and aluminium reagents to the proposed new crystallisation technology for simultaneous P-removal and P-recovery.

IMPROVING RESIDUALS HANDLING AT THE WAUKEGAN, ILLINOIS WATER TREATMENT PLANT

IMPROVING RESIDUALS HANDLING AT THE WAUKEGAN, ILLINOIS WATER TREATMENT PLANTThe City of Waukegan's 18-mgd conventional water treatment plant (WTP) currently collects sedimentation basin residuals and filter backwash waste in an on-site Reclaim Basin. Decanted water from the basin is recycled to the head of the plant, while the solids are discharged to the sanitary sewer. However, these practices have led to several operational restrictions and water quality...Author(s)Stephen McGowanThomas LachcikJeff MusinskiAmy SamuelsonSarah HasanSourceProceedings of the Water Environment FederationSubjectSession 19: Water Plant Residuals IIDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2007ISSN1938-6478SICI1938-6478(20070101)2007:3L.1035;1-DOI10.2175/193864707787975480Volume / Issue2007 / 3Content sourceResiduals and Biosolids ConferenceFirst / last page(s)1035 - 1041Copyright2007Word count336