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The load has significant effect on sludge reduction efficiency and biofilm microenvironment. When the load was 1 ~ 4 kgCOD/ (m3 · d), the sludge yield of the system changed little. When the system was greater than 4 kgCOD/ (m3·D), the sludge yield of the system increased doubly and the maximum load of the system was 4 kgMLSS/ (m3·D). At this time, the excess sludge yield is 0.0292 kgMLSS/kgCOD. The ORP aeration and aeration end of the biofilm were respectively (-74.73 ~ 187.89mV) and (-53.21 ~ 260.74mV). The corresponding biofilm aerobic and anoxic environment accounted for 9%, 17% and 91% and 83% respectively, forming a microenvironment of alternating aerobic / anoxic environment. When the load is 4kgCOD/ (m3·D), the change of ATP in sludge in the aeration stage and the shutdown stage is the largest, which is conducive to the dissipation of energy. To promote the sludge reduction, the COD, NH4+-N, TN and SS indexes of the effluent of the system all reached the first grade B standard of the pollutant discharge standard for urban sewage treatment (GB18918-2002). [ABSTRACT FROM AUTHOR]

Multiple clades within a microbial taxon often co-exist within natural and engineered environments. Because closely related clades have similar metabolic potential, it is unclear how diversity is sustained and what factors drive niche differentiation. In this study, we retrieved three near-complete Competibacter-lineage genomes from activated sludge metagenomes at a full-scale pure oxygen activated sludge wastewater treatment plant. The three genomes represent unique taxa within the Competibacteraceae. Comparison of genomes revealed differences in capacity for extracellular polysaccharide (EPS) biosynthesis, glucose fermentation to lactate, and motility. Using quantitative PCR (qPCR), we monitored these clades over a two-year period. The clade possessing genes for motility and lacking genes for EPS biosynthesis (CPB_P15) was dominant during periods of suspended solids in the effluent. Further analysis of operational parameters indicate that dominance of the CPB_P15 clade is associated with low return activated sludge recycle rates and low wasting rates, conditions that maintain relatively high levels of biomass within the system. [ABSTRACT FROM AUTHOR]

Abstract The importance of natural gas as a primary energy source is expected to increase significantly in Europe. However, a rising consumption of natural gas leads to increased import dependency, while greenhouse gas emissions are only reduced by a fraction. Renewable methane, as could be produced by biogas and sewage treatment plants, offers an interesting substitute for natural gas. This article assesses the potentially available amount of methane from the existing plant stock within an Austrian region. It further analyses the production costs of existing biogas and sewage treatment plants according to type of upgrading and injection. The results show average production costs of 115.6 € MWh−1 (biogas plants), 150.4 € MWh−1 (sewage treatment plants) and 105.4 € MWh−1 (collective plant systems). Despite the higher production costs when compared to natural gas, expanding the domestic production capacity of renewable gas can be advantageous. Due to the regional increase in value-added, revenues resulting from the production of methane provide valuable income, especially in economically lagging regions. In order to maintain the infrastructure in future, it is necessary that renewables use the natural gas grid. Highlights • The theoretical connection rate of existing biogas plants to gas grid is about 90%. • A connection of plants via gas pipeline can reduce biomethane production costs. • Using sewage treatment plants for biomethane production need to be checked carefully. • Additional measures are needed to meet the goals of an European Energy Union. [ABSTRACT FROM AUTHOR]

The performance of wastewater treatment plants (WWTPs) depends on various technical, non-technical, and human factors. A total of 245 small and medium-size WWTPs were studied during 2014-2015 and evaluated according to a novel method for rapid assessment of their performance and complexity. The suggested method creates a comparable system of ratings for all treatment solutions by analysing simultaneously influential characteristics, system complexity, operational practices, and process parameters in comparison with designed and/or standardized values and their impact on the overall system performance. Total evaluation of complexity and total evaluation of performance are new unified tools, which were applied for comparing WWTPs that applied different technologies and had a wide variety of loadings. The study revealed that the greater the designed loading, the more treatment steps were usually needed and employed. The complexity of these treatment steps can vary a lot depending on the plant capacity. There was a positive relationship between complexity and performance: a higher complexity provided a better performance of WWTPs. This suggests that combining automation as a tool for the process control with a more advanced equipment (higher complexity) could prevent many process disturbances and therefore improve the overall plant performance. [ABSTRACT FROM AUTHOR]

The Australian Antarctic Division (AAD) operates Australia's Davis Station in the Antarctic. In 2005, Davis Station's wastewater treatment plant failed and since then untreated, macerated effluent has been discharged to the ocean. The objectives of this study were to determine whether an advanced water treatment plant (AWTP) commissioned by the AAD and featuring a multi-barrier process involving ozonation, ceramic microfiltration, biologically activated carbon filtration, reverse osmosis, ultraviolet disinfection and chlorination was capable of producing potable water and a non-toxic brine concentrate that can be discharged with minimal environmental impact. The AWTP was tested using water from a municipal wastewater treatment plant in Tasmania, Australia. We used spot water and passive sampling combined with two multi-residue chromatographic-mass spectrometric methods and a range of recombinant receptor-reporter gene bioassays to screen trace organic chemicals (TrOCs), toxicity and receptor activity in the Feed water, in the environmental discharge (reject water), and product water from the AWTP for six months during 2014–15, and then again for three months in 2016. Across the two surveys we unambiguously detected 109 different TrOCs in the feed water, 39 chemicals in the reject water, and 34 chemicals in the product water. Sample toxicity and receptor activity in the feed water samples was almost totally removed in both testing periods, confirming that the vast majority of the receptor active TrOCs were removed by the treatment process. All the NDMA entering the AWTP in the feed and/or produced in the plant (typically < 50 ng/L), was retained into the reject water with no NDMA observed in the product water. In conclusion, the AWTP was working to design, and releases of TrOCs at the concentrations observed in this study would be unlikely cause adverse effects on populations of aquatic organisms in the receiving environment or users of the potable product water. [ABSTRACT FROM AUTHOR]

Poor nitrogen removal efficiency (mainly nitrate, NO 3 − -N) at low temperatures strongly limits application of subsurface wastewater infiltration systems (SWISs). Seven psychrophilic strains (heterotrophic nitrifying bacteria and aerobic denitrifying bacteria) were isolated and added to SWISs to investigate the effect of embedding and direct-dosing bioaugmentation strategies on sewage treatment performance at low temperature. Both bioaugmentation strategies improved ammonium (NH 4 + -N) removal efficiencies, and the embedding strategy also exhibited satisfactory NO 3 − -N and total nitrogen (TN) removal efficiencies. Pyrosequencing results of the bacterial 16S rRNA gene indicated that the embedding strategy significantly decreased the indigenous soil microbial diversity ( p  < .05) and altered the bacterial community structure, significantly increasing the relative abundance of Clostridia, which have good nitrate-reducing activity. [ABSTRACT FROM AUTHOR]

Energy recovery through local hydropower generation is a way of coping with high electricity expenditures in wastewater systems (WWS). Installing small hydropower plants within WWS is already in some countries eligible for incentive policy mechanisms to renewable energy production. Some examples exist of hydropower units operating in wastewater treatment plants, showing that there is an interest for this type of small-hydro, but there is still a lack of awareness of its potential. This study presents a methodology to assess the potential for hydropower in wastewater systems, either upstream or downstream of wastewater treatment plants (WWTP). An algorithm was developed in two phases, first to estimate the annual electricity production in selected areas based on GIS data and the inflows to each WWTP and second to carry out an economic evaluation of the feasibility of each scheme considering local investment costs and local electricity sell tariffs. The developed method was applied to the case study of Switzerland, covering more than 41'000 km 2 and approximately 8 million inhabitants. Nineteen profitable sites were identified in the country with cumulated 9.3 GWh/year of potential energy production. Among these sites, six are already equipped for hydropower production representing 3.5 GWh/year and validated the proposed methodology. [ABSTRACT FROM AUTHOR]

In Romania, the critical situation of the wastewater treatment plants is caused by the old sewage networks and the purification installations, the modification of the sewage capacity without its adaptation to the constructive parameters, the poor managerial capacity and the poor financial situation of the public utility operators. The wastewater treatment plant from Cluj-Napoca, was recently upgraded, the technology was innovated and introduced the tertiary wastewater treatment stage. This unit collects and treats the wastewater from the city of Cluj-Napoca and from the adjacent areas. To evaluate the quality of the wastewater and of the treated water, the samples were collected over a period of 8 months (September 2015 - April 2016), daily, at the entrance and exit point from the treatment plant. Because our focus was mainly on the tertiary stage, the analyzed parameters were: pH, COD(Cr), BOD5, total suspensions, ammonium, nitrates, total N, total P. With regard to the quality of the analyzed waters, it can be concluded that all of the eight analyzed parameters show high values in the wastewater and after purification the values decrease, within the maximum permissible limits given by law. In the months with higher temperatures the quality of the wastewater is weaker, and we noticed that the monitored parameters are slightly higher but also the amount of wastewater increases. On the basis of the results we can say that the efficiency of the purification processes is very good and the tertiary stage introduced in the wastewater treatment process is of high importance especially in the reduction of the phosphorus content. [ABSTRACT FROM AUTHOR]

The performance and stabilization of biological wastewater treatment systems 1 are closely related to the microbial community structure and dynamics. In this paper, the effects and mechanisms of influent composition, process configuration, operating parameters (dissolved oxygen [DO], pH, hydraulic retention time [HRT] and sludge retention time [SRT]) and environmental condition (temperature) to the change of microbial community structure and process performance (nitrification, denitrification, biological phosphorus removal, organics mineralization and utilization, etc.) are critically reviewed. Furthermore, some strategies for microbial community structure regulation, mainly bioaugmentation, process adjustment and operating parameters optimization, applied in the current wastewater treatment systems are also discussed. Although the recent studies have strengthened our understanding on the relationship between microbial community structure and wastewater treatment process performance, how to fully tap the microbial information, optimize the microbial community structure and maintain the process performance in wastewater treatment systems are still full of challenges. [ABSTRACT FROM AUTHOR]

Increase of population, development of industry, environmental problems and continuous energy consumption in the world render renewable energy resources crucial. This paper focuses on multiple criteria decision making (MCDM) models for energy saving and using energy resources efficiently in order to maintain sustainable operations at wastewater treatment plants (WWTPs). An integrated fuzzy quality function deployment (FQFD) framework and technique for order preferences by similarity to an ideal solution (TOPSIS) selection algorithm is proposed. Fuzzy analytic hierarchy process (FAHP) is used to determine importance weights of attributes in MCDM model to avoid inconsistent results of crisp QFD analyses caused by the variability of human judgment. Fuzzy analytical network process (FANP) is used to consider both symmetrical and asymmetrical relationships between customer requirements (CRs) and engineering characteristics (ECs) for constituting internal and external correlation matrices in the house of quality (HOQ). The comprehensive weight vector of ECs is used as the weights of the selection criteria in the TOPSIS side of the integrated methodology. The proposed MCDM methodology is used for the goal of choosing the ideal gas fuel at WWTPs. Regarding to the results of application of the proposed MCDM model at a WWTP in Turkey, the most important EC regarding to the goal is hydrocarbons with the weight value of 0.32, while gas processing system with 0.21 is the second and impurities with 0.19 is the third EC. Biogas is chosen as the ideal gas fuel. In addition, natural gas is the second, liquefied natural gas is the third, compressed natural gas is the fourth and landfill gas is the fifth gas fuels in turn at the WWTP in Turkey. [ABSTRACT FROM AUTHOR]

Identifying critical land-uses or source areas is important to prioritize resources for cost-effective stormwater management. This study investigated the use of information on ionic composition as a fingerprint to identify the source land-use of stormwater runoff. We used 12 ionic species in stormwater runoff monitored for a total of 20 storm events at five sites with different land-use compositions during the 2012-2014 wet seasons. A stepwise forward discriminant function analysis (DFA) with the jack-knifed cross validation approach was used to select ionic species that better discriminate the land-use of its source. Of the 12 ionic species, 9 species (K+, Mg2+, Na+, NH4+, Br-, Cl-, F-, NO2-, and SO42-) were selected for better performance of the DFA. The DFA successfully differentiated stormwater samples from urban, rural, and construction sites using concentrations of the ionic species (70%, 95%, and 91% of correct classification, respectively). Over 80% of the new data cases were correctly classified by the trained DFA model. When applied to data cases from a mixed land-use catchment and downstream, the DFA model showed the greater impact of urban areas and rural areas respectively in the earlier and later parts of a storm event. [ABSTRACT FROM AUTHOR]

In this work, a regression model obtained from response surface methodology (RSM) was proposed for the electrocoagulation (EC) treatment of textile wastewater. The Reactive Black 5 dye (RB5) was used as a model dye to evaluate the performance of the model design. The effect of initial solution pH, applied current and treatment time on RB5 removal was investigated. The total number of experiments designed by RSM amounted to 27 runs, including three repeated experimental runs at the central point. The accuracy of the model was evaluated by the F-test, coefficient of determination (R2), adjusted R2 and standard deviation. The optimum conditions for RB5 removal were as follows: initial pH of 6.63, current of 0.075 A, electrolyte dose of 0.11 g/L and EC time of 50.3 min. The predicted RB5 removal was 83.3% and the percentage error between experimental and predicted results was only 3-5%. The obtained data confirm that the proposed model can be used for accurate prediction of RB5 removal. The value of the zeta potential increased with treatment time, and the X-ray diffraction pattern shows that iron complexes were found in the sludge. [ABSTRACT FROM AUTHOR]

Waste stabilization ponds (WSPs) and their variants are one the most widely used wastewater treatment systems in the world. However, the scarcity of systematic performance data from fullscale plants has led to challenges associated with their design. The objective of this research was to assess the performance of 388 full-scale WSP systems located in Brazil, Ecuador, Bolivia and the United States through the statistical analysis of available monitoring data. Descriptive statistics were calculated of the influent and effluent concentrations and the removal efficiencies for 5-day biochemical oxygen demand (BOD5), total suspended solids (TSS), ammonia nitrogen (N-Ammonia), and either thermotolerant coliforms (TTC) or Escherichia coli for each WSP system, leading to a broad characterization of actual treatment performance. Compliance with different water quality and system performance goals was also evaluated. The treatment plants were subdivided into seven different categories, according to their units and flowsheet. The median influent concentrations of BOD5 and TSS were 431 mg/L and 397 mg/L and the effluent concentrations varied from technology to technology, but median values were 50 mg/L and 47 mg/L, respectively. The median removal efficiencies were 85% for BOD5 and 75% for TSS. The overall removals of TTC and E. coli were 1.74 and 1.63 log10 units, respectively. Future research is needed to better understand the influence of design, operational and environmental factors on WSP system performance. [ABSTRACT FROM AUTHOR]

With the MBBR IFAS (moving bed biofilm reactor integrated fixed-film activated sludge) process, the biomass required for biological wastewater treatment is either suspended or fixed on free-moving plastic carriers in the reactor. Coarse- or fine-bubble aeration systems are used in the MBBR IFAS process. In this study, the oxygen transfer efficiency (OTE) of a coarse-bubble aeration system was improved significantly by the addition of the investigated carriers, even in-process (~1% per vol-% of added carrier material). In a fine-bubble aeration system, the carriers had little or no effect on OTE. The effect of carriers on OTE strongly depends on the properties of the aeration system, the volumetric filling rate of the carriers, the properties of the carrier media, and the reactor geometry. This study shows that the effect of carriers on OTE is less pronounced in-process compared to clean water conditions. When designing new carriers in order to improve their effect on OTE further, suppliers should take this into account. Although the energy efficiency and cost effectiveness of coarse-bubble aeration systems can be improved significantly by the addition of carriers, fine-bubble aeration systems remain the more efficient and cost-effective alternative for aeration when applying the investigated MBBR IFAS process. [ABSTRACT FROM AUTHOR]

To demonstrate the effects of increased extraneous water on operation, purification, and energy efficiency, two wastewater treatment plants (WWTPs) have been investigated in detail under the research project 'Sealing of sewer pipes - Effects on the purification performance of WWTPs and their impact on the local water balance'. Both treatment plants, after evaluating and analyzing the measurement data and information about them, were compared in the light of existing literature and other practical investigations. Furthermore, the results were assessed with respect to transferability to other treatment plants. In WWTP 1, extraneous water reduction led to lower energy consumption of certain plant components such as the pumping station and aeration. An increased percentage of extraneous water had an impact on the wastewater characteristics (e.g. organic load) in WWTP 2. A decrease in extraneous water increases the concentration of biodegradable matters; however, an increase in extraneous water increases the loads in the effluent. The results are in accordance with the theoretical approaches described in the literature and confirm the correlations between extraneous water and purification efficiency and energy consumption of WWTPs. [ABSTRACT FROM AUTHOR]

The purposes of this work are to monitor certain operating parameters in influent and effluent of domestic wastewater treatment plant in Tunceli, Turkey, to determine the relationships among these parameters, and also to evaluate the effectiveness of the treatment plant. The mean values of the parameters measured in the samples taken from the plant influent like pH, temperature, electrical conductivity, dissolved oxygen, total dissolved solids, suspended solids, the total solids, volatile suspended solid, biological oxygen demand, and chemical oxygen demand, are 7.60 ± 0.07, 11.66 ± 0.74°C, 1,070.75 ± 10.67 μs/cm, 3.78 ± 0.32 mg/L, 524.42 ± 5.28 mg/L, 390.58 ± 40.22 mg/L, 857.50 ± 61.30 mg/L, 496.17 ± 82.30 mg/L, 195.33 ± 8.11 mg/L, and 653.67 ± 42.12 mg/L, respectively. The values of these parameters after the treatment are 7.68 ± 0.08, 10.61 ± 0.70°C, 1,041.25 ± 15.31 μs/cm, 8.38 ± 0.10 mg/L, 510.17 ± 7.49 mg/L, 49.17 ± 8.88 mg/L, 443.08 ± 38.95 mg/L, 152.33 ± 27.95 mg/L, 13.67 ± 2.33 mg/L, and 44.66 ± 12.72 mg/L, respectively. Correlation analyses conducted to explain the potential relationship between the analyzed parameters demonstrated that there were both negative and positive correlations between the influent and effluent operational parameters. Results supported the fact that there were significant improvements in wastewater quality after treatment. [ABSTRACT FROM PUBLISHER]

This work presents operating costs and energy consumption of Austrian municipal wastewater treatment plants (WWTPs) (≥10,000 PE-design capacity) that have been classified into different size groups. Different processes as well as cost elements are investigated and processes with high relevance regarding operating costs and energy consumption are identified. Furthermore, the work shows the cost-relevance of six investigated cost elements. The analysis demonstrates the size-dependency of operating costs and energy consumption. For the examination of the energy consumption the investigated WWTPs were further classified into WWTPs with aerobic sludge stabilisation and WWTPs with mesophilic sludge digestion. The work proves that energy consumption depends mainly on the type of sludge stabilisation. The results of the investigation can help to determine reduction potential in operating costs and energy consumption of WWTPs and form a basis for more detailed analysis which helps to identify cost and energy saving potential. [ABSTRACT FROM AUTHOR]

Recent studies into the estimation and control of an activated sludge process (ASP) at a wastewater treatment plant suggest that artificial-intelligence methods, such as neural networks, fuzzy systems and genetic algorithms, can improve the plant performance in terms of reduced operation costs and improved effluent quality. In this paper, a neural-network-based soft sensor is developed for the on-line prediction of effluent concentrations in an ASP in terms of primary hard-to-measure variables, such as chemical oxygen demand, total nitrogen content and total suspended solids, starting from secondary on-line easy-to-measure variables, such as oxygen and nitrogen compound concentrations in biological tanks, input flow rate and alkalinity, among others. An algorithm based on principal component analysis is applied to select the optimal net input vectors for the soft sensor, using an appropriated number of samples of the secondary variables set. The proposed soft sensor is tested on the ASP of a large-scale municipal wastewater treatment plant running under the GPS-X simulation frame and validated with operational gathered data. Satisfactory low values for mean and maximum absolute prediction errors are obtained, even when high values of sampling time of primary variables are set, as it is frequently done during monitoring operation. In this way, data-driven soft-sensors based on neural networks can become valuable tools for plant operators for the recognition of operational states in terms of low cost and efficient prediction of primary process variables such as chemical oxygen demand, total nitrogen content and total suspended solids, therefore avoiding the acquisition of expensive and sometimes unreliable instruments for measuring nutrient concentrations in plant. [ABSTRACT FROM AUTHOR]

Evaluation of anionic surfactant (AS) quantities in the environment has been the subject of intensive worldwide investigation. Even so, significant questions related to their presence in Algerian wastewaters discharged into the Mediterranean Sea remain. For the first time, monitoring of AS in a wastewater treatment plant (WWTP) located about 30 km west of Algiers was carried out. Four sampling points were selected to inspect the behavior of AS and investigate surfactant removal efficiencies of the WWTP: untreated wastewaters (UW), samples clarified via primary treatment, samples biologically treated and treated waters. To achieve this work, a spectrophotometric method of AS determination has been developed. Dioctyl sulfosuccinate sodium was chosen as a reference because of its low costs and its high response, compared to other AS commonly used by this method. The effects of pH, time of extraction, and washing step were studied. The volume of solvent was optimized. The calibration curve was linear and exhibited a significant coefficient of correlation. The lower limit of detection was found to be around 10 M. Mechanical and biological treatments remove 53 % of AS from wastewaters before being discharged into the aquatic environment. It was found that the concentration of AS discharged into the Mediterranean Sea in the studied region reaches 10 M. [ABSTRACT FROM AUTHOR]

A methodology is developed to systematically design the membership functions of fuzzy-logic controllers for multivariable systems. The methodology consists of a systematic derivation of the critical points of the membership functions as a function of predefined control objectives. Several constrained optimization problems corresponding to different qualitative operation states of the system are defined and solved to identify, in a consistent manner, the critical points of the membership functions for the input variables. The consistently identified critical points, together with the linguistic rules, determine the long term reachability of the control objectives by the fuzzy logic controller. The methodology is highlighted using a single-stage side-stream partial nitritation/Anammox reactor as a case study. As a result, a new fuzzy-logic controller for high and stable total nitrogen removal efficiency is designed. Rigorous simulations are carried out to evaluate and benchmark the performance of the controller. The results demonstrate that the novel control strategy is capable of rejecting the long-term influent disturbances, and can achieve a stable and high TN removal efficiency. Additionally, the controller was tested, and showed robustness, against measurement noise levels typical for wastewater sensors. A feedforward-feedback configuration using the present controller would give even better performance. In comparison, a previously developed fuzzy-logic controller using merely expert and intuitive knowledge performed worse. This proved the importance of using a systematic methodology for the derivation of the membership functions for multivariable systems. These results are promising for future applications of the controller in real full-scale plants. Furthermore, the methodology can be used as a tool to help systematically design fuzzy logic control applications for other biological processes. [ABSTRACT FROM AUTHOR]

A practical-scale down-flow hanging sponge (DHS) reactor using third-generation (G3) sponge carriers was applied for treatment of the effluent from an up-flow anaerobic sludge blanket (UASB) reactor treating municipal sewage. The process performance of the DHS reactor filled with G3 sponge carriers (DHS-G3) was evaluated by conducting an on-site experiment in India over one year. The performance of the DHS-G3 for removal of organic matter and ammonium-nitrogen at a relatively short hydraulic retention time (HRT) of only 0.66 h satisfied the Indian effluent quality standards except for fecal coliform. The removal rate constants for total biochemical oxygen demand (BOD) and fecal coliform determined based on the water quality profiles along the DHS-G3 almost reached equilibrium approximately four months after the start of operation, i.e., 2.45 h −1 for BOD and 2.30 h −1 for fecal coliform, respectively. The oxygen utilization activity of retained sludge was determined to assess the distribution of heterotrophic and autotrophic bacteria along the DHS-G3. Nitrification was promoted in the lower portion of the DHS-G3 reactor in the duration with low organic load, while it decreased when the organic load was increased, probably due to proliferation of heterotrophic bacteria. [ABSTRACT FROM AUTHOR]

The interest in the presence of pharmaceutical compounds (PhC) in the environment has increased significantly because of their potential impact on human health. Many studies have demonstrated that PhCs can be found in hospital and municipal wastewaters, mainly due to the inefficiency of the treatment plants. However, the question is how significant the hospital contribution represents in the total municipal wastewater generated. Therefore, the objective of this paper is to perform a comparison between hospital and municipal wastewaters based on literature review, serving as a base for the implementation of more efficient management policies in hospitals and municipal wastewater treatment plants. Results indicate that there are some compounds found in higher concentrations in hospital effluents than in municipal inffluent, particularly the class of antibiotics. [ABSTRACT FROM AUTHOR]

Bioelectrochemical systems (BESs) are integrated water treatment technologies that generate electricity using organic matter in wastewater. In situ use of bioelectricity can direct the migration of ionic substances in a BES, thereby enabling water desalination, resource recovery, and valuable substance production. Recently, much attention has been placed on the microbial desalination cells in BESs to drive water desalination, and various configurations have optimized electricity generation and desalination performance and also coupled hydrogen production, heavy metal reduction, and other reactions. In addition, directional transport of other types of charged ions can remediate polluted groundwater, recover nutrient, and produce valuable substances. To better promote the practical application, the use of BESs as directional drivers of ionic substances requires further optimization to improve energy use efficiency and treatment efficacy. This article reviews existing researches on BES-driven directional ion transport to treat wastewater and identifies a few key factors involved in efficiency optimization. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) offer great promise as a technology that can produce electricity whilst at the same time treat wastewater. Although significant progress has been made in recent years, the requirement for cheaper materials has prevented the technology from wider, out-of-the-lab, implementation. Recently, researchers have started using ceramics with encouraging results, suggesting that this inexpensive material might be the solution for propelling MFC technology towards real world applications. Studies have demonstrated that ceramics can provide stability, improve power and treatment efficiencies, create a better environment for the electro-active bacteria and contribute towards resource recovery. This review discusses progress to date using ceramics as (i) the structural material, (ii) the medium for ion exchange and (iii) the electrode for MFCs. [ABSTRACT FROM AUTHOR]

The driver for waste-based economic growth is long-term strategic design, and a paradigm-shift from waste treatment to resource recovery. This study aims to use an integrated modelling approach to evaluate the holistic economic and environmental profiles of three alternative nitrogen removal and recovery methods integrated into wastewater treatment systems, including conventional nitrification–denitrification, Anammox, and the anaerobic ion exchange route, to provide insights into N recovery system designs which are key elements in building a sustainable circular economy. Our results suggest that ion exchange is a promising technology showing high N removal–recovery efficiency from municipal wastewater and delivering competitive sustainability scores. In comparison with the well-developed conventional route, ion exchange and Anammox are undergoing significant research and development; as highlighted in sensitivity analyses, there is considerable room for process design and optimisation of ion exchange systems to achieve economically and environmentally optimal performance. [ABSTRACT FROM AUTHOR]

The current approach for protecting the receiving water environment from urban stormwater pollution is the adoption of structural measures commonly referred to as Water Sensitive Urban Design (WSUD). The treatment efficiency of WSUD measures closely depends on the design of the specific treatment units. As stormwater quality is influenced by rainfall characteristics, the selection of appropriate rainfall events for treatment design is essential to ensure the effectiveness of WSUD systems. Based on extensive field investigations in four urban residential catchments based at Gold Coast, Australia, and computer modelling, this paper details a technically robust approach for the selection of rainfall events for stormwater treatment design using a three-component model. The modelling results confirmed that high intensity-short duration events produce 58.0% of TS load while they only generated 29.1% of total runoff volume. Additionally, rainfall events smaller than 6-month average recurrence interval (ARI) generates a greater cumulative runoff volume (68.4% of the total annual runoff volume) and TS load (68.6% of the TS load exported) than the rainfall events larger than 6-month ARI. The results suggest that for the study catchments, stormwater treatment design could be based on the rainfall which had a mean value of 31 mm/h average intensity and 0.4 h duration. These outcomes also confirmed that selecting smaller ARI rainfall events with high intensity-short duration as the threshold for treatment system design is the most feasible approach since these events cumulatively generate a major portion of the annual pollutant load compared to the other types of events, despite producing a relatively smaller runoff volume. This implies that designs based on small and more frequent rainfall events rather than larger rainfall events would be appropriate in the context of efficiency in treatment performance, cost-effectiveness and possible savings in land area needed. [ABSTRACT FROM AUTHOR]

Both the presence and diversity of plants are integral to the development and functional abilities of microbial communities within constructed wetlands (CWs). The aim of this study was to assess the impacts of different individual and paired plant species combinations on microbial community function in HSSF mesocosm CWs. Experimental systems were quadruplicated and operated as two mesocosms in series planted with Phragmites australis (X) or Phalaris arundinacea (O), giving four possible sequential combinations (XX, XO, OX, OO). Wastewater was loaded each day into position 1 mesocosm with the outflow entering position 2 mesocosm, and the corresponding position 2 mesocosm outflow representing an overall experimental system effluent. The metabolic function of the interstitial-based microbial communities within each of the 16 mesocosm pairs was assessed at a single time point in the spring (May) based on community-level physiological profiles (CLPPs) gathered using Biolog ® EcoPlates. Microbial activity and metabolic richness (number of carbon sources utilised) were found to be higher in position 1 mesocosms compared to position two. Microbial community carbon source utilisation patterns (CSUPs), overall activity and metabolic richness were similar between all mesocosms from position 1—irrespective of plant species. When assessing microbial communities in position 2 of each pairing a greater variety of CSUPs, activities and metabolic richness' could be found suggesting the sequence and choice of plant can alter the microbial community function in the HSSF mesocosms. Of particular interest were the mesocosm/plant species combinations containing Phalaris in the position 2 which led to higher overall microbial activity and richness, distinct carbon source utilisation patterns (CSUPs) and an increased utilisation of specific carbon sources further from the inlet. More specifically the XO pairings ( Phragmites-Phalaris ) seemed to offer the most promising overall microbial function throughout both positions 1 and 2 in series suggesting plant diversity may help enhance microbial community function, and therefore microbial based water treatment capacity. The findings also suggest that the microbial communities associated with each plant species respond differently to factors such as nutrient availability, and although not yet clearly defined, further highlights the potential for improved or tailored water treatment in CWs through selection of specific plant species and combinations. Broader microbial community function or greater activity did not correlate with improved water treatment efficiency in this study. This may have been due to the relatively low contaminant loads utilised, or the limited amount of data collected. Further study across several seasons or with higher contaminant loads is recommended. [ABSTRACT FROM AUTHOR]

Six different full-scale willow evapotranspiration systems receiving both septic tank and secondary treated domestic effluent from single houses in Ireland have been investigated as a potential solution to the problem of on-site effluent disposal in areas with very low permeability subsoils. Continuous monitoring of rainfall, reference evapotranspiration, effluent flows and water level in the sealed systems revealed varying evapotranspiration rates across the different seasons with annual rates ranging from 576 to 929 mm/yr. The results showed that no system managed to achieve zero discharge in any year remaining at maximum levels for much of the winter months, indicating some loss of water by lateral exfiltration at the surface. This was attributed partly to the fact that the in-situ low permeability soil that had been excavated to form the lined basin was shown to have a much lower effective (useful) porosity when used to backfill the systems than had been assumed in the original designs. In addition, the Irish maritime climate, with its typical high relative humidity levels throughout the year (>85% on average), resulted in muted evapotranspiration performance of the systems. However, chemical and microbiological sampling of the water in the sumps and ponded water over the winter periods demonstrated that the systems were acting as excellent passive pollutant attenuation processes. [ABSTRACT FROM AUTHOR]

Free-water surface constructed wetlands (FWSs) are designed to treat wastewater. Previous studies have indicated that hydraulic efficiency influences treatment performance and that shallow-water FWSs always yield greater hydraulic efficiency than do deep-water FWSs. This study presents effective ways to improve the flow uniformity and hydraulic efficiency of deep-water FWSs by utilizing different allocations and varying numbers of obstructions. A reliable computational model is employed to simulate the flow conditions and tracer concentrations from numerous hypothetical cases. The differences between emergent obstructions (EOs) and submerged obstructions (SOs) were examined. Improving the efficiency of shallow-water and deep-water FWSs is discussed. Installing obstructions on the same side of the inlet and outlet is recommended for avoiding flow circulation. Meandering flow formed by EOs can avoid short-circuiting flow and reduce dead zones, thus resulting in more uniform flow and greater hydraulic efficiency. SOs were found to have minor and inconsistent effects in improving hydraulic efficiency. We conclude that an alternative method for increasing the aspect ratio of a fixed-dimension wetland is to use EOs to create a meandering flow pattern and longer flow path. The findings of this study encourage wetland scientists and wetland engineers to plan the restoration/creation of deep-water wetlands and combination wetlands with both shallow-water and deep-water areas. [ABSTRACT FROM AUTHOR]

In order to comply with effluent standards, wastewater operators need to avoid hydraulic overloading of the wastewater treatment plant (WWTP), as this can result in the washout of activated sludge from secondary settling tanks. Hydraulic overloading can occur in a systematic way, for instance when sewer network connections are extended without increasing the WWTP's capacity accordingly. This study demonstrates the use of rule-based real-time control (RTC) to reduce the load to the WWTP while restricting the overall overflow volume of the sewer system to a minimum. Further, it shows the added value of RTC despite the limited availability of monitoring data and information on the catchment through a parsimonious simulation approach, using relocation of spatial system boundaries and creating required input data through reverse modelling. Focus was hereby on the accurate modelling of pump hydraulics and control. Finally, two different methods of global sensitivity analysis were employed to verify the influence of parameters of both the model and the implemented control algorithm. Both methods show the importance of good knowledge of the system properties, but that monitoring errors play a minor role. [ABSTRACT FROM AUTHOR]

The Wastewater Treatment plants are designed and constructed with an aim to control wastewater so that it helps to reduce the quantity of pollutants, nutrients, biological organism, bacteria, etc. The study is based on continuous monitoring and collection of data for six months (July 2015 to December 2015) of two plants, Kodra and Ponghat plants in Allahabad city. Both the plants are based on Bio-Tower Technology, which is an improved or modified version of trickling filters. The research work presents the results of the evaluation carried out for the efficiency analysis of STP based on Improved Bio-Tower Technology located in Allahabad city for handling and treating the municipal wastewater. [ABSTRACT FROM AUTHOR]

Atorvastatin (ATO), rosuvastatin (RST) and simvastatin (SIM) are commonly used drugs that belong to the statin family (lowering human blood cholesterol levels) and have been detected as contaminants in natural waters. Stability and removal of ATO, RST and SIM from spiked wastewater produced at the Al-Quds University campus were investigated. All three statins were found to undergo degradation in wastewater (activated sludge). The degradation reactions of the three drugs in wastewater at room temperature follow first-order kinetics with rate constants of 2.2 × 10−7 s−1(ATO), 1.8 × 10−7 s−1(RST) and 1.8 × 10−6 s−1(SIM), which are larger than those obtained in pure water under the same conditions, 1.9 × 10−8 s−1(ATO), 2.2 × 10−8 s−1(RST) and 6.2 × 10−7 s−1(SIM). Degradation products were identified by LC-MS and LC/MS/MS. The overall performance of the wastewater treatment plant (WWTP) installed in the Al-Quds University campus towards the removal of these drugs was assessed showing that more than 90% of spiked ATO, RST and SIM were removed. In order to evaluate the efficiency of alternative removal methods to replace ultra-filtration membranes, adsorption isotherms for the three statins were investigated using both activated carbon and clay–micelle complex as adsorbents. The batch adsorption isotherms for the three statins were found to fit the Langmuir equation, with a larger number of adsorption sites and binding affinity for micelle–clay composite compared with activated carbon and filtration experiments of the three statins and their corresponding metabolites demonstrated a more efficient removal by micelle–clay filters. [ABSTRACT FROM PUBLISHER]

The article provides an update on the Nereda wastewater treatment technology and discusses its cost-effectiveness and sustainability. The municipal and industrial treatment plants in several countries, including South Africa, Portugal,and the Netherlands, that used Nereda are explored. Also mentioned are the design details and effluent quality of the Wemmershoek wastewater treatment plant (WWTP).

Synthetic musks have been used for a long time in personal care and household products. In recent years, this continuous input has increased considerably, to the point that they were recognized as emerging pollutants by the scientific community, due to their persistence in the environment, and hazardous potential to ecosystems even at low concentrations. The number of studies in literature describing their worldwide presence in several environmental matrices is growing, and many of them indicate that the techniques employed for their safe removal tend to be ineffective. This is the case of conventional activated sludge treatment plants (WWTPs), where considerable loads of synthetic musks enter mainly through domestic sewage. This review paper compiles and discusses the occurrence of these compounds in the sewage, effluents and sludge, main concentration levels and phase distributions, as well as the efficiency of the different methodologies of removal applied in these treatment facilities. To the present day, it has been demonstrated that WWTPs lack the ability to remove musks completely. This shows a clear need to develop new effective and cost-efficient remediation approaches and foresees potential for further improvements in this field. [ABSTRACT FROM AUTHOR]

The main goal of a wastewater treatment plant (WWTP) is to comply with the treated wastewater (TWW) quality requirements. However, the assessment of this compliance is a rather complex process for WWTPs in the EU Member States, since it requires the integration of a large volume of data and several criteria according to EU Directives 91/271/EEC and 2000/60/EC. A tool for a comprehensive assessment of TWW quality in this context is herein presented. The tool's novelty relies on an integrated analysis of performance indicators (PIs) and new performance indices (PXs). PIs integrate the several compliance criteria into a single framework, supported by flowcharts for a straightforward assessment of TWW compliance by practitioners. PXs are obtained by applying a performance function to the concentration values analysed in the TWW for discharge or reuse. PXs are dimensionless and the scale adopted (0–300) defines three performance levels: unsatisfactory, acceptable and good performance. The reference values proposed for these levels and for the PIs were based on the EU legislation. The PXs complement the information provided by the PIs. While the latter assess the plant effectiveness in a given year (i.e. the TWW compliance with the requirements), PXs tackle the plant reliability, i.e. they allow to easily compare the performance of different parameters over the time and to identify when the performance did satisfy or fail the pre-established objectives and the distance that remains to achieve these targets. The tool was tested in 17 WWTPs and the most representative results are herein illustrated. [ABSTRACT FROM AUTHOR]

This pilot scale study aims to test the effectiveness of an innovative compact biological system (SBBGR - Sequencing Batch Biofilter Granular Reactor) for treating municipal wastewater in tourist areas characterised by intense seasonal water demand and wastewater discharge. The results obtained after a long term operation of 463 days have shown that the proposed system is able to assure average removal efficiencies higher than 90% for COD (chemical oxygen demand), total suspended solids and TKN (total Kjeldahl nitrogen) independently of the influent concentration values and organic loading, which ranged from 0.2 to 5.1 kg COD /m 3 biofilter .d Furthermore, the plant showed a high degree of operation flexibility and stability in response to the organic load variations occurring in tourist areas. In fact, no significant deterioration in the plant's effluent quality was observed even during a sudden several-fold increase in organic loading. High nitrogen removal efficiencies (80%, on average) were also achieved thanks to the establishment of simultaneous nitrification-denitrification process favoured by the plant's high biomass concentration and operating conditions. Finally, the system was characterized by an excess sludge production much lower (60-80% lower) than that of conventional biological systems operating without a primary clarifier. An acceptable level of stabilization of excess sludge was also obtained so that a further stabilization process was no longer required. [ABSTRACT FROM AUTHOR]

The occurrence of 8 drugs of abuse and metabolites in the influent and effluent of the 3 Wastewater Treatment Plants (WWTP) that treat wastewater from Valencia was studied in 2011, 2012 and 2013. Target drugs except 6-monoacetylmorphine (6-ACMOR) were detected in 100% of the influents. The WWTPs eliminate cocaine (COC), amphetamine (AMP), methamphetamine (MAMP) and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH). Benzoylecgonine (BECG) was also efficiently eliminated (93–98%), whereas 3,4-methylenedioxymethamphetamine (MDMA) presented removal rates of 32–57% and ketamine (KET) was not eliminated. The most consumed illicit drugs, according to the estimated concentrations of each compound in the studied WWTPs, were cannabis and COC followed by KET, AMP, MAMP, MDMA and heroin. Environmental risk assessment was evaluated by calculating Risk Quotient (RQ). MDMA and KET could pose a medium risk and low risk, respectively, to the aquatic organisms. Although short-term environmental risk is not worrisome, long-term effects cannot be known exactly. [ABSTRACT FROM AUTHOR]

Benzotriazoles are widely used domestic and industrial corrosion inhibitors and have become omnipresent organic micropollutants in the aquatic environment. Here, the range of aerobic biological degradation mechanisms of benzotriazoles in activated sludge was investigated. Degradation pathways were elucidated by identifying transient and persistent transformation products in batch experiments using liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). In addition, initial reactions were studied using compound-specific isotope analysis (CSIA). Biodegradation half-lives of 1.0 days for 1H-benzotriazole, 8.5 days for 4-methyl-1H-benzotriazole, and 0.9 days for 5-methyl-1H-benzotriazole with activated sludge confirmed their known partial persistence in conventional wastewater treatment. Major transformation products were identified as 4- and 5-hydroxy-1H-benzotriazole for the degradation of 1H-benzotriazole, and 1H-benzotriazole-5-carboxylic acid for the degradation of 5-methyl-1H-benzotriazole. These transformation products were found in wastewater effluents, showing their environmental relevance. Many other candidate transformation products, tentatively identified by interpretation of HR-MS/MS spectra, showed the broad range of possible reaction pathways including oxidation, alkylation, hydroxylation and indicate the significance of cometabolic processes for micropollutant degradation in biological wastewater treatment in general. The combination of evidence from product analysis with the significant carbon and nitrogen isotope fractionation suggests that aromatic monohydroxylation is the predominant step during the biotransformation of 1H-benzotriazole. [ABSTRACT FROM AUTHOR]

To meet surging water demands, water reuse is being sought as an alternative to traditional water resources. However, contamination of water resources by trace organic compounds (TOrCs), including pharmaceuticals, personal care products, disinfection byproducts, and industrial chemicals is of increasing concern. These compounds are not readily removed by conventional water treatment processes and require new treatment technologies to enable potable water reuse. Forward osmosis (FO) has been recognized in recent years as a robust process suitable for the treatment of highly impaired streams and a good barrier to TOrCs. To date, at least 14 studies have been published that investigated the rejection of various TOrCs by FO membranes under a variety of experimental conditions. In this paper, TOrC rejection by FO has been critically reviewed, evaluating the effects of membrane characteristics and orientation, experimental scale and duration, membrane fouling, feed solution chemistry, draw solution composition and concentration, and transmembrane temperature on process performance. Although it is important to continue to investigate the removal of diverse TOrCs by FO, and especially with new FO membranes, it is critically important to adhere to standard testing conditions to enable comparison of results between studies. Likewise, feed concentration of TOrCs during FO testing must be environmentally relevant (most commonly 10-100 ng/L range for most wastewaters) and not excessively high, and in addition to testing TOrC rejection in clean feedwater, the effects of real water matrix and membrane fouling on TOrC rejection must be evaluated. [ABSTRACT FROM AUTHOR]

With the rapid economic development, a better living condition leads to longer life expectancy, which increased the total population, in particular the elderly group. It may result in increase in the demand of pharmaceuticals for people in domestic use or in hospital. Although most sewage treatment plants or waste water treatment plants met the regulatory requirement, there are still many pharmaceuticals removed incompletely and thus discharged to the environment. Therefore, the pharmaceuticals residue draws the public concern because they might cause adverse effects on the organism even human beings. Recently, many studies have published on the source and occurrence as well as the fate of pharmaceuticals all over the world. This paper summarized and reviewed the recent studies on the sources, occurrence, fate and the effects of the most common pharmaceuticals. Finally, it gave the suggestion and risk management for controlling the pharmaceuticals. [Copyright &y& Elsevier]

Extensive use of bisphenol A and its analogues has caused increasing concern over the potential adverse health impacts of these chemicals. In this study, the presence and profiles of 13 bisphenols (BPs) were investigated in 52 municipal sewage sludge samples collected from 30 cities in China. Tetrabromobisphenol A was the most frequently observed analogue (geometric mean: 20.5 ng/g dw). Bisphenol A (4.69 ng/g dw), bisphenol S (3.02 ng/g dw), and bisphenol F (3.84 ng/g dw) were found with similar frequency. Other BP analogues such as tetrachlorobisphenol A, bisphenol AF, bisphenol E, and dihydroxybiphenyl were identified for the first time in sewage sludge in China. Significant correlations were found among BP concentrations, but no relationships were found with wastewater treatment plant characteristics. Profiles of the relative estradiol equivalents suggested that the estrogenic potential of BP mixtures may be associated with the occurrence and contributions of specific analogues. [Copyright &y& Elsevier]

Occurrence and removal of 81 representative Pharmaceutical Active Compounds (PhACs) were assessed in a municipal WWTP located in a highly industrialized area, with partial water reuse after UV tertiary treatment and discharge to a Mediterranean river. Water monitoring was performed in an integrated way at different points in the WWTP and river along three seasons. Consistent differences between therapeutic classes were observed in terms of influent concentration, removal efficiencies and seasonal variation. Conventional (primary and secondary) treatment was unable to completely remove numerous compounds and UV-based tertiary treatment played a complementary role for some of them. Industrial activity influence was highlighted in terms of PhACs presence and seasonal distribution. Even if global WWTP effluent impact on the studied river appeared to be minor, PhACs resulted widespread pollutants in river waters. Contamination can be particularly critical in summer in water scarcity areas, when water flow decreases considerably. [Copyright &y& Elsevier]

The system of “Service Objectives”, introduced by the Italian National Strategic Framework 2007–2013, is an innovative results-oriented programme concerning 4 thematic areas (education, care for the elderly and children, management of municipal solid wastes and integrated water service) in which the Ministry of Economic Development and eight Southern Italy districts are involved. The system was initially associated to an incentive mechanism which provided subsidies for a total amount of EUR 3 billion from the national Underdeveloped Areas Fund, according to the achievement of specific targets set for 11 service indicators in 2013. The indicators used for the integrated water service refer to the efficiency in water supply service as well as the coverage of wastewater treatment service. The aim of the study is to describe the activities carried out in Italy by the ENEA Agency in order to define a new performance indicator for wastewater treatment service taking into account the appropriateness and efficiency of existing plants equipment and, consequently, evaluating economic incentives. The proposed procedure takes into account both wastewater treatment demand and quality of wastewater treatment service offered to citizens. Input data, provided by the National Institute of Statistics (ISTAT), were elaborated in order to define appropriate parameters, with a multi-criteria analysis being used to define the new performance indicator. The applicability of the proposed procedure was verified considering all the 8 Southern Italy and Island districts (Abruzzo, Molise, Campania, Apulia, Basilicata, Calabria, Sicily and Sardinia) involved in the programme. The obtained results show that the quality of municipal wastewater may influence the calculation of the incentive amount. The performance indicators defined in this work might be conveniently extended to other contexts similar to the assessed geographical area (Southern Italy and Islands). [Copyright &y& Elsevier]

Abstract: The objective of this study was the investigation of the potential use of protistan species as quality indicators of the activated sludge performance in sequential batch processes receiving toxic compounds. Two laboratory scale sequential batch reactors (SBR) were used, a conventional one and a system with plastic biofilm carriers (SBBR), treating wastewater containing phenol at concentrations ranging from 1 up to 40mg/L. Physicochemical analyses of the samples included the determination of MLSS, effluent suspended solids, BOD5, nitrogen–ammonia, nitrogen–nitrate and phenol. The activated sludge protistan community was identified and enumerated in each reactor. Statistical analyses included Canonical Correspondence Analysis and Indicator Species Analysis of the collected experimental data. Canonical Correspondence Analysis showed inversely proportional relationships between the protozoa and the physicochemical parameters of the effluent as well as protozoan species competition. Indicator species analysis revealed the presence and the prevalence of different species under various phenol influent concentrations. No indicator species were observed for the period of operation under 5mg/L influent phenol in both reactors, while no indicator species were observed for 20mg/L influent phenol in the SBR reactor. Carchesium and Epistylis sp. showed the higher values for 1mg/L phenol in the SBR, while Holophrya sp. showed lower indicator values for the same period in the SBBR. Although several species showed a good correlation to the treatment efficiency of the reactors, Blepharisma sp., could be used as the primary indicator species in both reactors for the operation period under 40mg/L phenol, as deduced by statistical analysis. [Copyright &y& Elsevier]

The automobile industry's wastewater not only contains high levels of suspended and total solids such as oil, grease, dyestuff, chromium, phosphate in washing products, and coloring, at various stages of manufacturing but also, a significant amount of dissolved organics, resulting in high BOD or COD loads. The study reveals the performance, evaluation and operational aspects of effluent treatment plant and its treatability, rather than the contamination status of the real property. The Results revealed that the treated effluent shows most of the parameters are within permissible limits of Central Pollution Control Board (CPCB), India and based on the site visits, discussion with operation peoples, evaluation of process design, treatment system, existing effluent discharge, results of sample analyzed and found that effluent treatment plant of automobile industry are under performance satisfactory. [ABSTRACT FROM AUTHOR]