bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying water–energy links and related carbon emissions in cities
Authors: Kenway S. J. , Lant P. , Priestley T.
Published: February 2013

To date, key water–energy connections have not been systematically quantified. Nor has their potential for contributing to greenhouse gas mitigation been evaluated. Lack of knowledge of these links, particularly within cities, is viewed as a major limitation to energy-sensitive urban water management and integrated urban design. This paper fills part of this void. The key contribution is a new conceptual model coupled with a systematic review of the connections of influence. Drawing on Australian and international data, the results provide a structured estimate of water-related energy use and associated emissions in a hypothetical city of 1,000,000 people. This demonstrates that water-related energy use accounts for 13% of total electricity and 18% of the natural gas used by the population in the average case. This represents 9% of the total primary energy demand within Australia or 8% of total national territorial greenhouse gas emissions. Residential, industrial and commercial water-related energy use constitutes 86% of water-related greenhouse gas emissions. We conclude that urban water is a significant and overlooked lever that could significantly influence urban energy consumption.
Water-demand management: assessing impacts of climate and other changes on water usage in Central Arizona
Authors: Chhetri Netra B.
Published: February 2013

Planning for sustainable water management in the arid region of the southwestern USA is challenging mostly due to only partial understanding of factors converging around water supply and demand. Some of the factors that prompt concern about the adequacy of water resources are: (a) a growing urban population seeking a range of services, including the need to preserve and enhance aquatic ecosystems; (b) dwindling water storage due to multi-year drought conditions; and (c) the prospect of human-induced climate changes and its consequences in the hydrologic system of the region. This study analyzes the potential for water saving in the Phoenix Active Management Area (AMA) of Central Arizona, which includes the city of Phoenix, one of the fastest growing metropolitan areas in the country. Based on an extensive literature review and secondary data analysis, this paper investigates multiple factors that place increasing strain on current water resources, and attempts to extend this analysis to 2025. Outdoor water use within the residential landscape is the most important factor that strains water resources in Phoenix AMA. Any gain in efficiency through agricultural water demand management would not only improve the availability of water for other uses in the AMA, but would facilitate adaptation of the agricultural system to climate and other ongoing changes.
How can we involve stakeholders in the development of water scenarios? Narew River Basin case study
Authors: Gielczewski Marek , Stelmaszczyk Mateusz , Piniewski Mikolaj , Okruszko Tomasz
Published: February 2013

This paper present the results of the water scenario development process carried out in the Narew River Basin within the SCENES (Water Scenarios for Europe and Neighbouring States) Project. The overall project objective was to create water scenarios on the Pilot Area level as well as at the Pan-European level. Therefore, in the Narew River Basin, which was one of the Pilot Areas, three scenario development workshops were organised to establish future water visions by qualitative, semi-quantitative and quantitative methods proposed within the project. The scenarios were elaborated in the participatory process by invited key water stakeholders representing varied sectors and institutions. The paper shows the main current drivers for the study area, present and future relations between them as well as possible scenarios and challenges to achieve them. It also draws conclusions on suitability of the proposed methods in water scenario development for river basins in general and for the Narew River Basin in particular. The proposed approach has involved the stakeholders intensively in the scenario development process, resulting in the set of scenarios suitable for further quantification and use in modelling exercises.
Participatory scenarios for regional water management planning: an Eastern Baltic case study
Authors: Veidemane Kristina , Iital Arvo , Gielczewski Marek
Published: February 2013

Ambitious mid- and long-term water protection goals currently exist regionally and globally. Setting policy goals means commitments not only for the environmental sector but also for all water users. This paper aims to contribute to the enhancement of mid- (2015) and long-term (2030 and 2050) regional water policy development by addressing the role of participatory scenarios in river basin management planning. It presents selected results of a participatory scenario development process on water resources in the Eastern Baltic region and how the process relates to certain aspects of the river basin management. The paper concludes that a Fuzzy Cognitive Map containing information on the present water management issues has a strong link with the assessment of significant drivers and pressures for the characterisation of river basins according to the Water Framework Directive. As the Eastern Baltic region does not generally have water shortage problems, the quality of available water was assessed as the major issue. Surprisingly, stakeholders did not recognise climate change as an important factor affecting the present water system in the region. The paper also shows that participatory scenarios can contribute to identifying the likelihood of failure to meet the set water policy objectives.
Are Dutch water safety institutions prepared for climate change?
Authors: van den Brink Margo , Termeer Catrien , Meijerink Sander
Published: February 2013

For the water sector, adapting to the effects of climate change is a highly complex issue. Due to its geographical position, The Netherlands is vulnerable to sea level rise, increasing river discharges and increasing salt intrusion. This paper deals with the question of to what extent the historically developed Dutch water safety institutions have the capacity to cope with the ‘new’ challenges of climate change. The Adaptive Capacity Wheel provides the methodological framework. The analysis focuses on three recent and major planning practices in the Dutch water safety domain: the development and implementation of the Room for the River project, the introduction of the flood risk approach and the introduction of the Second Delta Plan. The results show that Dutch water safety institutions enable climate change adaptation, but to a limited extent. They face five institutional weaknesses that may cause risks in particular in the long term. The paper concludes that for The Netherlands to be prepared for climate change, it is necessary to build capacity to improvise, to invest in and create room for collaborative leaders, and to find ways to generate financial resources for long-term innovative measures.
Levels and patterns of fecal indicator bacteria in stormwater runoff from homogenous land use sites and urban watersheds
Authors: Tiefenthaler Liesl , Stein Eric D. , Schiff Kenneth C.
Published: February 2013

Routine stormwater monitoring programs focus on quantification of average fecal indicator bacteria (FIB) concentration at the terminal watershed discharge point. While important for permit compliance, such monitoring provides little insight into relative bacteria levels from different land use types or the mechanisms that influence FIB concentrations. The goal of this study was to quantify the relative levels and flux patterns of Escherichia coli, enterococci, and total coliforms from representative land use (LU) types. Bacteria concentrations were measured over the entire storm duration from 8 different LU types over 13 storm events in 5 southern California watersheds during the 2000–2005 storm seasons. In addition, runoff samples were collected from 8 bottom of the watershed mass emission (ME) sites. Intra-storm and intra-season patterns were investigated in order to identify mechanisms that influence patterns of FIB concentrations. Mean FIB event mean concentrations (EMCs) at LU sites ranged from 103 to 105 MPN/100 ml. Recreational (horse stables) LU sites contributed significantly higher storm EMCs than other LU types. Early season storms repeatedly produced higher EMCs than comparably sized late season storms. For most storms sampled, the highest bacterial concentrations occurred during the early phases of stormwater runoff with peak concentrations usually preceding peak flow.
Water- and wastewater-related disease and infection risks: what is an appropriate value for the maximum tolerable additional burden of disease?
Authors: Mara Duncan
Published: February 2013

The maximum additional burden of water- and wastewater-related disease of 10_6 disability-adjusted life year (DALY) loss per person per year (pppy), used in the WHO Drinking-water Quality Guidelines and the WHO Guidelines for Wastewater Use in Agriculture, is based on US EPA's acceptance of a 70-year lifetime waterborne cancer risk of 10_5 per person, equivalent to an annual risk of 1.4×10_7 per person which is four orders of magnitude lower than the actual all-cancer incidence in the USA in 2009 of 1.8×10_3 pppy. A maximum additional burden of 10_4 DALY loss pppy would reduce this risk to a more cost-effective, but still low, risk of 1.4×10_5 pppy. It would increase the DALY loss pppy in low- and middle-income countries due to diarrhoeal diseases from the current level of 0.0119 pppy to 0.0120 pppy, and that due to ascariasis from 0.0026 pppy to 0.0027 pppy, but neither increase is of public-health significance. It is therefore recommended that the maximum additional burden of disease from these activities be increased to a DALY loss of 10_4 pppy as this provides an adequate margin of public-health safety in relation to waterborne-cancer deaths, diarrhoeal disease and ascariasis in all countries.
Opportunistic pathogens relative to physicochemical factors in water storage tanks
Authors: Al-Bahry S. N. , Elshafie A. E. , Victor R. , Mahmoud I. Y. , Al-Hinai J. A.
Published: February 2013

Household water in Oman, as well as in other countries in the region, is stored in tanks placed on house roofs that can be subjected to physicochemical factors which can promote microbial growth, including pathogens and opportunistic pathogens which pose health risks. Water samples were collected from 30 houses in a heavily populated suburb of Muscat. The tanks used were either glass reinforced plastic (GRP), polyethylene or galvanised iron (GI). Heterotrophic bacteria, coliforms, faecal coliforms and iron sulphur bacteria varied significantly in the three tanks. Yeast and mould count showed significant variations. Isolation of Aeromonas spp., fluorogenic and pathogenic Pseudomonas, Pasteurella, Salmonella, Serratia and Tatumella, and Yersinia and Legionella in biofilms varied in the three tanks. The fungi isolates in the three tanks were Penicillium, Cladosporium and Aspergillus. Nephelometric turbidity unit, threshold odour number and free chlorine varied significantly in the three tanks. True colour unit values did not show a significant difference; however, GRP tanks had algae, autotrophic and pigmented microorganisms. In addition, GI tanks had sediments and corrosion. The results of this investigation are important to evaluate the status of the present household water tanks in countries with high annual temperatures, which may affect public health.
A performance assessment of arsenic-iron removal plants in the Manikganj District of Bangladesh
Authors: Brennan R. , McBean E.
Published: February 2013

In Bangladesh, arsenic contamination of groundwater, microbial contamination of surface water and seasonally variable rainfall make reliable access to acceptable quality drinking water a challenge. Arsenic-iron removal plants (AIRPs) are a relatively inexpensive way of removing arsenic from groundwater for access to safer drinking water. This study evaluated the performance of 21 (of 105) AIRPs installed by a local non-governmental organization (Society for People's Action in Change and Equity) with financial assistance from the Australian High Commission, Dhaka, under the Direct Aid Program of the Australian Government. All AIRPs achieved the Bangladesh standard for arsenic in drinking water of 50 μg L−1 and 17 achieved the World Health Organization guideline of 10 μg L−1. The AIRPs removed 87% of influent arsenic, on average. After cleaning, poor arsenic and iron removal was observed for about 2 days due to inadequate residence time. Chemical processes that may influence AIRP performance are also discussed herein, including iron and arsenic oxidation, arsenic co-precipitation with iron, multiple iron additions, interference by organics, and iron crystallization. Effluent faecal coliform counts were generally low, though were slightly higher than influent counts. Overall, AIRPs were shown to possess considerable promise for use in areas with high natural iron where users are concerned about arsenic and/or iron in their drinking water.
Bacteriological assessment of drinking water supply options in coastal areas of Bangladesh
Authors: Islam Md. Atikul , Sakakibara Hiroyuki , Karim Md. Rezaul , Sekine Masahiko , Mahmud Zahid Hayat
Published: February 2013

This study was conducted to assess the bacteriological quality of alternative drinking water supply options in southwest coastal areas of Bangladesh. A total of 90 water samples were collected during both dry and wet seasons from household based rainwater harvesting systems (RWHSs), community based rain water harvesting systems (CRWHSs), pond-sand filters (PSFs) and ponds. The samples were evaluated for faecal coliform, Escherichia coli and Heterotrophic Plate Count, as well as Vibrio cholerae, Salmonella spp., Shigella spp. and Pseudomonas spp. Physico-chemical parameters (pH, electrical conductivity, and color) were also examined. In addition, sanitary inspections were conducted to identify faecal contamination sources. All options showed varying degrees of indicator bacterial contamination. The median E. coli concentrations measured for RWHSs, CRWHSs, PSFs, and ponds were 16, 7, 11, and 488 cfu/100 ml during the wet season, respectively. Vibrio cholerae O1/O139, Salmonella and Shigella spp. were not found in any samples. However, Vibrio cholerae Non-O1/Non-O139 and Pseudomonas spp. were isolated from 74.4% and 91.1% of the water samples collected during the wet season. A maximum pH of 10.4 was found in CRWHSs. Estimation of the disease burden for all options in disability adjusted life years (DALYs) showed an increased disease burden during the wet season. According to sanitary inspections, poor maintenance and unprotected ponds were responsible for rainwater and PSF water contamination, respectively. The findings of the present study suggest that alternative drinking water supply options available in southwest coastal Bangladesh pose a substantial risk to public health.
Microbial safety of air-dried and rewetted biosolids
Authors: Rouch Duncan A. , Mondal Tania , Pai Sneha , Glauche Florian , Fleming Vennessa A. , Thurbon Nerida , Blackbeard Judy , Smith Stephen R. , Deighton Margaret
Published: February 2013

To assess microbial safety of treated sewage sludge (biosolids), we examined the inactivation of microbial indicators for potential bacterial, viral and protozoan pathogens. The levels of indicators were determined throughout the air-drying and storage phases of anaerobically digested sewage sludge. Samples were collected from two wastewater treatment plants (WWTPs) in Victoria, Australia. Established methods were applied for analysis of bacteria and coliphages, based on membrane filtration and layered plates, respectively. In the pan drying phase, the prevalence of Escherichia coli was reduced by >5 log10 compared with sludge entering the pan. Thus, after pan drying of 8-11 months at WWTP A and 15 months at WWTP B, the numbers of E. coli were reduced to below 102 cfu/g dry solids (DS). This level is acceptable for unrestricted use in agriculture in Australia (P1 treatment grade), the UK (enhanced treatment status) and the USA (Class A pathogen reduction). Coliphage numbers also decreased substantially during the air-drying phase, indicating that enteric viruses are also likely to be destroyed during this phase. Clostridium perfringens appeared to be an overly conservative indicator. Survival, but not regrowth, of E. coli or Salmonella was observed in rewetted biosolids (15–20% moisture content), after being seeded with these species, indicating a degree of safety of stored biosolids upon rewetting by rain.
Suspended particles in wastewater: their optical, sedimentation and acoustical characterization and modeling
Authors: Pallarès A. , François P. , Pons M.-N. , Schmitt P.
Published: February 2013

Wastewater regulation and treatment is still a major concern in planetary pollution management. Some pollutants, referred to as particulate matter, consist of very small particles just suspended in the water. Various techniques are used for the suspended particles survey. Few of them are able to provide real-time data. The development of new, real time instruments needs the confrontation with real wastewater. Due its instability, the modeling of wastewater in terms of suspended solids was explored.

Knowing the description of real wastewater, we tried to produce a synthetic mixture made of basic organic ingredients. A good agreement in terms of turbidity and settling velocity was observed between the artificial wastewater matrix and the real one. The investigation of the individual contribution of the different compounds to the acoustical signal showed a more complex dependance. Thus the modeling of wastewater with reference to turbidity and settling velocity is not sufficient to describe it acoustically. Further studies should lead to a good comparison of the acoustical and turbidity behavior of wastewater.
Developing a public information and engagement portal of urban waterways with real-time monitoring and modeling
Authors: Cochrane T. A. , Wicke D. , O’Sullivan A.
Published: February 2013

Waterways can contribute to the beauty and livelihood of urban areas, but maintaining their hydro-ecosystem health is challenging because they are often recipients of contaminated water from stormwater runoff and other discharges. Public awareness of local waterways’ health and community impacts to these waterways is usually poor due to of lack of easily available information. To improve community awareness of water quality in urban waterways in New Zealand, a web portal was developed featuring a real-time waterways monitoring system, a public forum, historical data, interactive maps, contaminant modelling scenarios, mitigation recommendations, and a prototype contamination alert system. The monitoring system featured in the web portal is unique in the use of wireless mesh network technology, direct integration with online modelling, and a clear target of public engagement. The modelling aims to show the origin of contaminants within the local catchment and to help the community prioritize mitigation efforts to improve water quality in local waterways. The contamination alert system aims to keep managers and community members better informed and to provide a more timely response opportunity to avert any unplanned or accidental contamination of the waterways. Preliminary feedback has been positive and is being supported by local and regional authorities. The system was developed in a cost-effective manner providing a community focussed solution for quantifying and mitigating key contaminants in urban catchments and is applicable and transferable to other cities with similar stormwater challenges.
Characteristics of different fractions of microbial flocs and their role in membrane fouling
Authors: Lin H. J. , Gao W. J. , Leung K. T. , Liao B. Q.
Published: February 2013

Characteristics of different fractions (small flocs vs. large flocs) of sludge flocs from a submerged anaerobic membrane bioreactor treating thermomechanical pulping (TMP) whitewater were determined using various analytic techniques, including extraction and chemical analysis of extracellular polymeric substances (EPS), particle size analyzer, and polymer chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). The results showed that the fraction of smaller flocs contained a higher level of bound EPS and had a higher fractal dimension as compared to the fraction of larger flocs. PCR-DGGE analysis indicated that there were significant differences in microbial community between the fraction of smaller flocs and large flocs. The microbial community of the smaller flocs was similar to that of the sludge cake layers, indicating the pioneering role of the microbial community in smaller flocs in membrane fouling. These findings provide a new insight in the difference of membrane fouling potential between smaller flocs and larger flocs fraction.
Comprehensive review and compilation of pretreatments for mesophilic and thermophilic anaerobic digestion
Authors: Bordeleau É. L. , Droste R. L.
Published: February 2013

Organic matter hydrolysis prior to anaerobic digestion has been shown to improve biogas production (30–50%) and reduce solids (20–60%) by ultrasound, chemical, conventional heating, and microwave pretreatments. Numerous studies have been performed to determine the extent of digestion improvement but few focus on financial feasibility of these processes. A comprehensive model was created using Microsoft Excel and its Visual Basic Assistant to evaluate pretreatment permutations for conventional wastewater treatment plants. The four above-mentioned processes were evaluated for energetic and financial demands. Well-established energy equations and wastewater characteristics, both average and high, were used. Average and high flows were 460 and 750 × 103 m3/d, respectively. Net costs per influent flow for ultrasound, chemical, conventional heating, and microwave were 0.0166, 0.0217, 0.0124, 0.0119 $/m3 and 0.0264, 0.0357, 0.0187, and 0.0162 $/m3 for average and high conditions, respectively. The average cost increase from results excluding pretreatment use for all processes was 0.003 and 0.0055 $/m3 for average and high conditions, respectively. No matter the permutation, pretreatments requiring more energy to achieve required hydrolysis levels were costlier. If energetic recoveries are substantial, dewaterability is positively affected, and solids meet environmental constraints to be handled and disposed at lower costs, pretreatments can be viable.
Ozonation of endogenous residue and active biomass from a synthetic activated sludge
Authors: Labelle M. -A. , Ramdani A. , Deleris S. , Gadbois A. , Dold P. , Comeau Y.
Published: February 2013

Coupling the activated sludge and the ozonation processes is an efficient, although expensive, solution for sludge reduction. A better knowledge of the mechanisms involved in the degradation of various sludge fractions by ozone is needed to optimize the coupled process. The objectives of this study were to determine the biodegradability of ozone-solubilized endogenous residue, the action of ozone on the active biomass and the solubilization yield of these two main sludge fractions. Batch tests were conducted with slug input of ozone stock solution into fresh or aerobically digested synthetic sludge. Biodegradability of the solubilized endogenous residue was increased by ozonation by up to 0.27 g BOD5/g CODi. Ozone caused biomass lysis, as opposed to an increase in maintenance needs, as shown by a correlation between the decrease in microbial activity and viability. Lysis caused by ozonation was associated with a solubilization of 20% of the lyzed cell COD mass. Solubilization yields were of 9.6 and of 1.9 to 3.6 g COD/g O3 for fresh and aerobically digested sludge, respectively. Design of sludge ozonation processes should account for the variability between the solubilization yield and biodegradability of the various sludge fractions.
Advanced treatment of Membrane Bioreactor (MBR) effluents for effective wastewater reclamation
Authors: Sarp Sarper , Chon Kangmin , Kim In S. , Cho Jaeweon
Published: February 2013

One of the two main objectives of this work is to oxidize MBR effluents with ozone/peroxide in high pH conditions in order to improve oxidation of pharmaceuticals, which could efficiently be rejected by the nanofiltration (NF) stage. The other main objective is to effectively oxidize of dissolved organic carbon (DOC) in MBR effluents in order to decrease fouling in the filtration stage. In this work, ozone/peroxide oxidation was applied to the MBR effluents in high pH conditions in order to improve the formation of OH radicals, and oxidized effluents were filtered by the NF membrane (NE90) in order to investigate fouling potentials and the removal of pharmaceuticals. Natural and synthetic wastewater samples were used as feed solutions for the MBR system, which was equipped with a U-shaped hollow fiber membrane module. The flux decline was decreased from 29% to 15% when 9 mg/L of ozone was used, the same decline was also observed when 6 mg/L ozone and hydrogen peroxide (1/1 ozone/peroxide mol ratio) were used. A further decrease in flux decline was observed when pH was adjusted to 9.00 (29% to 9%) prior to the ozone/peroxide oxidation. In most cases, the increase in the ozone dose, the addition of hydrogen peroxide and the adjustment of the pH level led to an increase in the removal of pharmaceuticals. Iopromide, TCEP and Naproxen were found to be more resistant to the oxidation when pH was increased.
P-Recovery from sewage by seeded crystallisation in a pilot plant in batch mode technology
Authors: Ehbrecht A. , Schönauer S. , Fuderer T. , Schuhmann R.
Published: February 2013

P-Recovery from actual sewage by P-RoC-technology (Phosphorus Recovery by Crystallisation of phosphate mineral phases from waste- and processwater) was studied in a pilot scale. Therewith the practicability of the pilot plant was tested and the quality of the so generated products was investigated.
Could nitrite/free nitrous acid favour GAOs over PAOs in enhanced biological phosphorus removal systems?
Authors: Pijuan M. , Ye L. , Yuan Z.
Published: February 2013

Enhanced biological phosphorus removal (EBPR) normally occurs together with nitrogen removal in wastewater treatment plants (WWTPs). In recent years, efforts have been devoted to remove nitrogen via the nitrite pathway (oxidation of ammonia to nitrite and reduction of nitrite to nitrogen gas without going through nitrate), reducing the requirement for carbon and oxygen in the plant. However nitrite and free nitrous acid (FNA), the protonated species of nitrite, have been shown to cause EBPR deterioration under certain concentrations. This study provides a direct comparison between the different levels of FNA inhibition in the aerobic processes of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) by reviewing the studies published in this area. Also, new data is presented assessing the FNA effect on the anaerobic metabolism of these two groups of bacteria. Overall, FNA has shown inhibitory effects on most of the processes involved in the metabolism of PAOs and GAOs. However, the inhibition-initiation levels are different between different processes and, even more importantly between the two groups. In general, PAOs appear to be more affected than GAOs at the same level of FNA, thus giving GAOs competitive advantage over PAOs in EBPR systems when nitrite is present.
Evaluation of DNA isolation procedures for detecting and quantifying environmental Legionella by real-time quantitative PCR
Authors: Chen N.-T. , Chang C.-W. , Wu J.-D.
Published: February 2013

Six methods, QiAamp DNA Mini Kit (Q), Q with Sepharose 4B gel column (Q/G), Q with low melting point agarose (Q/L), freeze-thaw/phenol-chloroform lysis (FT-PC), FT-PC/G, and FT-PC/L, were evaluated for their ability to isolate DNA of sufficient quality to quantify Legionella using qPCR. Samples of mixing Legionella pneumophila (ATCC33152) and humic acid (HA, 0–126.8 mg/l) were treated by the six methods. Q, Q/G, Q/L, FT-PC/G, and FT-PC/L removed HA from 1.9–126.8 to <1 mg/l determined by A260 with a spectrophotometer. Q obtained the highest DNA yield, followed by Q/G. Dilution (10- to 100-fold) of DNA arising from extraction using Q, Q/G, FT-PC, or FT-PC/G prevented qPCR inhibition. The highest recovery of cells was found in DNA extracted by Q and diluted 100-fold, and followed by Q/G. The applicability of Q and Q/G with dilution was further validated with cooling tower waters. Q or Q/G with 10-fold dilution increased L. pneumophila detection, whereas 100-fold dilution obtained the highest cell concentrations. Similar results were found for Legionella spp. except that both 10- and 100-fold dilutions increased cell concentrations. Thus, Q with 10-fold dilution is suggested to detect and quantify Legionella spp. and detect L. pneumophila. For L. pneumophila-positive samples, 100-fold diluted DNA must be re-analyzed to accurately quantify L. pneumophila.
Radial distribution modeling of liquid-phase phenol concentration in a liquid–solid fluidized bed photoreactor
Authors: Dong Shuangshi , Zhou Dandan , Bi Xiaotao
Published: February 2013

A fluidized bed photoreactor with titanium dioxide-immobilized spherical activated carbon particles was examined. The light intensity profile was modeled using the Lambert–Beer rule for the modeling of the radial distribution of liquid-phase phenol concentration in the fluidized bed photoreactor, when considering the reactor composed of numerous differential annular drums and no mass transfer between drums. The model could be well matched with the experimental data which indicated the liquid flow rate of 13.8 L/min was the optimum in the balance of flow rate-related light penetration and photocatalyst concentration. By integration of liquid-phase phenol concentration along the radius, photocatalytic oxidation performance of the photoreactor was evaluated in comparison with the experimental data and model prediction. The results showed that the errors were less than 30% for most of the predictions. It is suggested that mass transfer and flow rate difference along the radial direction should be considered to obtain more precise prediction.
Application of an anaerobic hybrid reactor for petrochemical effluent treatment
Authors: Jafarzadeh Mohammad Taghi , Mehrdadi Naser , Hashemian Seyed Jamaladdin
Published: February 2013

An anaerobic hybrid reactor (UASB/Filter) was used for petrochemical wastewater treatment in mesophilic conditions. The seeded flocculent sludge from a UASB plant treating dairy wastewater, acclimatized to the petrochemical wastes in a two-stage operation. After start up, under steady-state conditions, experiments were conducted at OLRs of between 0.5 and 24 kg TCOD m−3 d−1, hydraulic retention times (HRT) of 4–48 h and up-flow velocities 0.021–0.25 mh−1. Removal efficiencies in the range of 42–86% were achieved at feed TCOD concentrations of 1,000–4,000 mg L−1. The results of reactor performance at different operational conditions and its relations are presented and discussed in this paper. Then, the obtained data are used for determination of kinetic models. The results showed that a second-order model and a modified Stover–Kincannon model were the most appropriate models for this reactor. Finally, the biogas production data were used for the determination of biogas production kinetics.
Flocculation mechanism by a novel combined aluminum–ferrous–starch flocculant (CAFS)
Authors: Lin Qintie , Pan Hanping , Huang Haoping , Liu Guoguang , Yin Guangcai
Published: February 2013

A combined flocculant (CAFS) was prepared with Al2(SO4)3·18H2O, FeSO4·7H2O and starch. The flocculation mechanism of reactive brilliant red X-3B was studied. The results showed that CAFS was a cationic polymeric flocculant with high charge density, and its mesh starch chains grafted polyaluminum and polyferrous. At the preliminary stage, the main flocculation mechanism was adsorption and charge neutralization. At a later stage, the high molecular weight and flexible linear chains of CAFS initiated bridge-aggregation and sweep-flocculation. Moreover, the zeta potential and dynamic changes of flocs were closely related to flocculant dosages and the pH. The optimum dosage of CAFS and pH value were 0.990 mg/L and 5.0. Taken together, these results suggested CAFS as a novel flocculant in water treatment, with good results for the studied conditions.
Phosphorus recovery as struvite from eutropic waters by XDA-7 resin
Authors: Li Huanwen , Ye Zhiping , Lin Ying , Wang Fengying
Published: February 2013

Phosphorus releases into aquatic environment and its subsequent contribution to eutrophication have resulted in a widespread global pollution issue. However, phosphorus is a non-renewable source. The potential supplies of phosphorus are decreasing worldwide. Therefore, removal and recovery of phosphorus from the eutropic waters is important, emergent and necessary. In this research, experiments for recovering phosphate from eutropic waters by anion exchange combined with struvite precipitation were conducted. The results indicated that the prepared XDA-7 resin was an effective adsorbent for phosphate. The adsorption isotherm of XDA-7 resin was found to be a modified Freundlich type. The maximum phosphate adsorption (20.9 mg/g) occurred in the pH range of 6.0–8.0. Phosphate adsorbed on the XDA-7 resin was effectively desorbed with 8% NaCl solution, and the resin was able to be regenerated with 3% NaClO and 4% NaOH solutions. Phosphate desorbed from the resin was recovered as magnesium ammonium phosphate (struvite). The obtained struvite was analyzed by acid dissolution method, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The struvite precipitate was found to be 75.8% in purity, a high-value fertilizer.
The effect of certain biochemical factors on well clogging under suboxic and mildly anoxic conditions
Authors: Dimkić M. , Pušić M. , Obradović V. , Kovačević S.
Published: February 2013

Research conducted at the Belgrade Groundwater Source in Serbia has shown that significant well screen clogging processes take place under reduced oxic and initial anoxic conditions. Criteria for the prevention, or deceleration, of clogging are becoming more relevant to well ageing, compared with classical, mechanical clogging criteria and the permissible entrance velocities derived from them. The research project was later expanded to encompass other alluvial sources, which feature distinct oxic conditions. This paper presents some of the outcomes of this project, which shed light on the correlation between certain important indicators of well screen clogging (such as the redox potential and iron concentration) and the rate of increase in local hydraulic resistance at the wells.
Electrochemical treatment of Baker's yeast wastewater containing melanoidin: optimization through response surface methodology
Authors: Gengec E. , Kobya M. , Demirbas E. , Akyol A. , Oktor K.
Published: February 2013

Effluents from Baker's yeast production plant contain a high percentage of color and a large amount of organic load. In the present study, Baker's yeast wastewater (BYW) is treated with the electrocoagulation (EC) process using Al electrodes. Operating parameters (pH, current density, color intensity and operating time) are optimized by response surface methodology (RSM). Quadratic models are developed for the responses which are removal efficiencies of color, chemical oxygen demand (COD) and total organic carbon (TOC) and operating cost (OC). Optimum operating parameters and responses are determined as initial pH 5.2, current density of 61.3 A/m2 and operation time of 33 min, and 71% of color, 24% of COD, 24% of TOC removal efficiencies and OC of 0.869 €/m3, respectively. The quadratic model fits for all responses very well with R2 (>0.95). This paper clearly shows that RSM is able to optimize the operating parameters to maximize the color, COD and TOC removal efficiencies and minimize the OC.
Impact of sewer condition on urban flooding: an uncertainty analysis based on field observations and Monte Carlo simulations on full hydrodynamic models
Authors: van Bijnen M. , Korving H. , Clemens F.
Published: February 2013

In-sewer defects are directly responsible for affecting the performance of sewer systems. Notwithstanding the impact of the condition of the assets on serviceability, sewer performance is usually assessed assuming the absence of in-sewer defects. This leads to an overestimation of serviceability. This paper presents the results of a study in two research catchments on the impact of in-sewer defects on urban pluvial flooding at network level. Impacts are assessed using Monte Carlo simulations with a full hydrodynamic model of the sewer system. The studied defects include root intrusion, surface damage, attached and settled deposits, and sedimentation. These defects are based on field observations and translated to two model parameters (roughness and sedimentation). The calculation results demonstrate that the return period of flooding, number of flooded locations and flooded volumes are substantially affected by in-sewer defects. Irrespective of the type of sewer system, the impact of sedimentation is much larger than the impact of roughness. Further research will focus on comparing calculated and measured behaviour in one of the research catchments.
Model-based knowledge acquisition in environmental decision support system for wastewater integrated management
Authors: Prat Pau , Benedetti Lorenzo , Corominas Lluís , Comas Joaquim , Poch Manel
Published: February 2013

The main goal of the Water Framework Directive is to achieve good chemical and ecological status of water bodies by 2015. The implementation of integrated river basin management, including sewer systems, wastewater treatment plants and receiving water bodies, is essential to accomplishing this objective. Integrated management is complex and therefore the implementation of control systems and the development of decision support systems are needed to facilitate the work of urban wastewater system (UWS) managers. Within this context, the objective of this paper is to apply integrated modelling of an UWS to simulate and analyse the behaviour of the ‘Congost’ UWS in Spain, and to optimize its performance against different types of perturbations. This analysis results in optimal operating set-points for each perturbation, improves river water quality, minimizes combined sewer overflows and optimizes flow lamination from storm water tanks. This is achieved by running Monte Carlo simulations and applying global sensitivity analysis. The set-points will become part of the knowledge base composed of a set of IF-THEN rules of the environmental decision support system being developed for this case study.
Water quality trends in the last decade for ten watersheds dominated by diffuse pollution in Québec (Canada)
Authors: Patoine M. , Hébert S. , D'Auteuil-Potvin F.
Published: February 2013

The aim of this work is to evaluate and discuss river water quality trends over the last decade in ten watersheds where diffuse pollution represents more than half of the annual load of phosphorus (P) and nitrogen (N). Trend analyses taking into account flow data indicate a significant reduction of total P in eight rivers, of ammonia N in five rivers, of nitrate + nitrite in four rivers, of total filtered N in three rivers and of suspended solids in two rivers. An increase of turbidity was observed in four rivers and, for fecal coliforms, no trends. P decrease can be explained by reduced mineral P inputs on cropped lands related to means such as agro-environmental fertilization plans and addition of phytase in pig and poultry feed. However, for seven of them, median P concentrations remain at least two times greater than the Québec water quality guideline for protection of rivers against eutrophication. Concentrations of other parameters remain problematic in some rivers too. These results indicate the need to continue the efforts for further diffuse pollution reduction. Future work should better quantify actions taken at the watershed scale to reduce diffuse pollution.
Influence of surface modification of polyethylene biocarriers on biofilm properties and wastewater treatment efficiency in moving-bed biofilm reactors
Authors: Chen Sheng , Cheng Xiang , Zhang Xu , Sun Dezhi
Published: February 2013

Two methods of surface modification of polyethylene biocarriers, chemical oxidation-surface covering with ferric ion (CO-SCFe) and chemical oxidation-surface grafting with gelatin (CO-SGG), were studied for improving the efficiency of wastewater treatment by moving-bed biofilm reactors. The results showed that two surface modifications caused corrosion pits to increase surface roughness, and brought –(C=O)–/–O–C–O– groups and ferric ions to the biocarrier surface, respectively. The positively charged surface increased the hydrophilicity and biological affinity of the biocarrier. The biofilm formation rate was improved by 37.5 and 60% after surface modifications of CO-SCFe and CO-SGG; the concentration of biomass on the biocarriers was improved by 54.8 and 76.1% and the COD removal efficiencies were increased by 10.63 and 8.64%, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis showed that the microbial populations in the biofilm were almost the same after surface modifications, but the biomass concentration was greatly increased.
An approach for phosphate removal with quartz sand, ceramsite, blast furnace slag and steel slag as seed crystal
Authors: Qiu Liping , Wang Guangwei , Zhang Shoubin , Yang Zhongxi , Li Yanbo
Published: February 2013

The phosphate removal abilities and crystallization performance of quartz sand, ceramsite, blast furnace slag and steel slag were investigated. The residual phosphate concentrations in the reaction solutions were not changed by addition of the ceramsite, quartz sand and blast furnace slag. The steel slag could provide alkalinity and Ca2+ to the reaction solution due to its hydration activity, and performed a better phosphate removal performance than the other three. Under the conditions of Ca/P 2.0, pH 8.5 and 10 mg P/L, the phosphate crystallization occurred during 12 h. The quartz sand and ceramsite did not improve the phosphate crystallization, but steel slag was an effective seed crystal. The phosphate concentration decreased drastically after 12 h after addition of steel slag, and near complete removal was achieved after 48 h. The XRD analysis showed that the main crystallization products were hydroxyapatite (HAP) and the crystallinity increased with the reaction time. Phosphate was successfully recovered from low phosphate concentration wastewater using steel slag as seed material.
Effects of surfactant on bubble hydrodynamic behavior under flotation-related conditions in wastewater
Authors: Li Yanpeng , Zhu Tingting , Liu Yanyan , Tian Ye , Wang Huanran
Published: February 2013

Bubble behavior is fundamental to the performance of froth flotation operations used in wastewater treatment processes. To fully understand and characterize bubble behavior under flotation-related conditions in wastewater, the high-speed photographic method has been employed to examine the motion of single bubbles and size distribution of bubble swarms with intermediate sizes ranging from 1 to 4 mm in the presence of surfactants in a laboratory scale flotation column. Both distilled water and synthetic municipal wastewater have been used to make solutions as well as two types of common surfactants. The instantaneous bubble motion has been recorded by a high speed camera. Subsequently, bubble trajectory, dimensions, velocity and distribution have been determined from the recorded frames using the image analysis software. The experimental results show that the addition of surfactant into wastewater has similar effects on bubble hydrodynamic behavior as in pure water (e.g., improving trajectory stabilization, dampening bubble deformation, slowing down terminal velocity, reducing bubble size and increasing the specific surface area of bubble swarm) due to the Marangoni effect. However, it is interesting to note that surfactant effects on single bubble hydrodynamics in wastewater are slightly stronger than those in pure water while surfactant effects on size parameters of bubble swarms in wastewater are significantly stronger than those in pure water. This finding suggests that besides surfactant, inorganic salts present in synthetic wastewater have an important influence on bubble dispersion.
Critical modeling parameters identified for 3D CFD modeling of rectangular final settling tanks for New York City wastewater treatment plants
Authors: Ramalingam K. , Xanthos S. , Gong M. , Fillos J. , Beckmann K. , Deur A. , McCorquodale J. A.
Published: February 2013

New York City Environmental Protection is in the process of incorporating biological nitrogen removal (BNR) in its wastewater treatment plants (WWTPs) which entails operating the aeration tanks with higher levels of mixed liquor suspended solids (MLSS) than a conventional activated sludge process. The objective of this paper is to discuss two of the important parameters introduced in the 3D CFD model that has been developed by the City College of New York (CCNY) group: (a) the development of the ‘discrete particle’ measurement technique to carry out the fractionation of the solids in the final settling tank (FST) which has critical implications in the prediction of the effluent quality; and (b) the modification of the floc aggregation (KA) and floc break-up (KB) coefficients that are found in Parker's flocculation equation (Parker et al. 1970, 1971) used in the CFD model. The dependence of these parameters on the predictions of the CFD model will be illustrated with simulation results on one of the FSTs at the 26th Ward WWTP in Brooklyn, NY.
Seasonal variation of fecal indicator bacteria in storm events within the US stormwater database
Authors: Pan Xubin , Jones Kim D.
Published: February 2013

Bacteria are one of the major causes of surface water impairments in the USA. Over the past several years, best management practices, including detention basins, manufactured devices, grass swales, filters and bioretention cells have been used to remove bacteria and other pollutants from stormwater runoff. However, there are data gaps in the comprehensive studies of bacteria concentrations in stormwater runoff. In this paper, the event mean concentration (EMC) of fecal indicator bacteria (Enterococcus, Escherichia coli, fecal Streptococcus group bacteria, and fecal coliform) across the USA was retrieved from the international stormwater best management practices database to analyze the seasonal variations of inflow and outflow event mean concentrations and removal efficiencies. The Kruskal–Wallis test was employed to determine the seasonal variations of bacteria indicator concentrations and removals, and the two-sample Kolmogorov–Smirnov test was used for comparing different seasonal outcomes. The results indicate that all the inflow EMC of FIB in stormwater runoff is above the water quality criteria. The seasonal differences of fecal Streptococcus group bacteria and fecal coliform are significant. Summer has the potential to increase the bacteria EMC and illustrate the seasonal differences.
A data-driven model for maximization of methane production in a wastewater treatment plant
Authors: Kusiak Andrew , Wei Xiupeng
Published: February 2013

A data-driven approach for maximization of methane production in a wastewater treatment plant is presented. Industrial data collected on a daily basis was used to build the model. Temperature, total solids, volatile solids, detention time and pH value were selected as parameters for the model construction. First, a prediction model of methane production was built by a multi-layer perceptron neural network. Then a particle swarm optimization algorithm was used to maximize methane production based on the model developed in this research. The model resulted in a 5.5% increase in methane production.