Comparative study of different wavelet-based neural network models to predict sewage sludge quantity in wastewater treatment plant.

In this study, artificial neural networks (ANNs) including feed forward back propagation neural network (FFBP-NN) and the radial basis function neural network (RBF-NN) were applied to predict daily sewage sludge quantity in wastewater treatment plant (WWTP). Daily datasets of sewage sludge have been used to develop the artificial intelligence models. Six mother wavelet (W) functions were employed as a preprocessor in order to increase accuracy level of ANNs. In this way, a 4-day lags were considered as input variables to conduct training and testing stages for the proposed W-ANNs. To compare performance of W-ANNs with traditional ANNs, coefficient of correlation (R), root mean square error (RMSE), mean absolute error (MAE), and Nash-Sutcliffe efficiency coefficient (NSE) were considered. In the case of all wavelet functions, it was found that W-FFBP-NN (R = 0.99 and MAE = 5.78) and W-RBF-NN (R = 0.99 and MAE = 6.69) models had superiority to the FFBP-NN (R = 0.9 and MAE = 21.41) and RBF-NN (R = 0.9 and MAE = 20.1) models. Furthermore, the use of DMeyer function to improve ANNs indicated that W-FFBP-NN (RMSE = 7.76 and NSE = 0.98) and W-RBF-NN (RMSE = 9.35 and NSE = 0.98) approaches stood at the highest level of precision in comparison with other mother wavelet functions used to develop the FFBP-NN and RBF-NN approaches. Overall, this study proved that application of various mother wavelet functions into architecture of ANNs led to increasing accuracy of artificial neural networks for estimation of sewage sludge volume in the WWTP.

Achieving the Sustainable Development Goal 06 in Brazil: the universal access to sanitation as a possible mission.

Sanitation (which includes national public policies for drinking water, sewage services and waste management) is precarious in Brazil and therefore poses a challenge to a range of actors. Poor sanitation impacts public health, education, the environment, and daily life. Globally, it emits increasing greenhouse gases. Universalization of any major public service appears difficult, if not impossible; however, Brazil's program to universalize access to electricity proves the opposite, as will be shown in this paper. By describing the successful implementation of electricity for everyone, we show that planned public efforts, coordinated with private initiatives and local communities, have worked, and the same can be achieved for the sanitation sector. An overview of all sectors that touch on sanitation and emissions is also provided, highlighting the challenges and possibilities for infrastructure projects.

Diurnal variations of the energy intensity and associated greenhouse gas emissions for activated sludge processes.

A model was developed for a water resources recovery facility (WRRF) activated sludge process (ASP) in Modified Ludzack-Ettinger (MLE) configuration. Amplification of air requirements and its associated energy consumptions were observed as a result of concurrent circadian variations in ASP influent flow and carbonaceous/nitrogenous constituent concentrations. The indirect carbon emissions associated with the ASP aeration were further amplified due to the simultaneous variations in carbon emissions intensity (kgCO2,eq(kWh)-1) and electricity consumption (kWh). The ratio of peak to minimum increased to 3.4 (for flow), 4.2 (for air flow and energy consumption), and 5.2 (for indirect CO2,eq emission), which is indicative of strong amplification. Similarly, the energy costs for ASP aeration were further increased due to the concurrency of peak energy consumptions and power demands with time of use peak electricity rates. A comparison between the results of the equilibrium model and observed data from the benchmark WRRF demonstrated under- and over-aeration attributed to the circadian variation in air requirements and limitations associated with the aeration system specification and design.

Prevalence of selected pharmaceuticals in surface water receiving untreated sewage in northwest Pakistan.

This study investigated the occurrence of four non-steroidal anti-inflammatory drugs (NSAIDs) and four benzodiazepines/anti-depressants (ADs) in municipal wastewater in Mardan city, Pakistan, and in River Kabul and River Indus receiving untreated sewage. Liquid chromatography with a triple quadrupole tandem mass spectrometry (LC-MS/MS) was used for the analysis of paracetamol, diclofenac, ibuprofen, and codeine (NSAIDs) and diazepam, bromazepam, lorazepam, and temazepam (ADs). Except codeine and lorazepam, all the target compounds were observed in sewage and surface water in various concentrations. In sewage, paracetamol was found at the higher end (32.4 µg/L) of the reported ranges in literature for other countries. Results of river samples showed that the target compounds were usually lower in concentration than the respective EC50 values for aquatic organisms. However, the levels for paracetamol and ibuprofen were critical depicting the consequence of untreated disposal. Environmental risk assessment by estimating the risk quotient (RQ) as the ratio of measured environmental concentration and predicted no-effect concentration showed medium to high (RQ > 1 and 0.1 < RQ < 1) risk from paracetamol and ibuprofen to aquatic organisms in River Kabul and Kalpani stream, Pakistan.

Sludge quantification at water treatment plant and its management scenario.

Large volume of sludge is generated at the water treatment plants during the purification of surface water for potable supplies. Handling and disposal of sludge require careful attention from civic bodies, plant operators, and environmentalists. Quantification of the sludge produced at the treatment plants is important to develop suitable management strategies for its economical and environment friendly disposal. Present study deals with the quantification of sludge using empirical relation between turbidity, suspended solids, and coagulant dosing. Seasonal variation has significant effect on the raw water quality received at the water treatment plants so forth sludge generation also varies. Yearly production of the sludge in a water treatment plant at Ghaziabad, India, is estimated to be 29,700 ton. Sustainable disposal of such a quantity of sludge is a challenging task under stringent environmental legislation. Several beneficial reuses of sludge in civil engineering and constructional work have been identified globally such as raw material in manufacturing cement, bricks, and artificial aggregates, as cementitious material, and sand substitute in preparing concrete and mortar. About 54 to 60% sand, 24 to 28% silt, and 16% clay constitute the sludge generated at the water treatment plant under investigation. Characteristics of the sludge are found suitable for its potential utilization as locally available construction material for safe disposal. An overview of the sustainable management scenario involving beneficial reuses of the sludge has also been presented.

Biosolids and Sludge Management.

This review section covers journal articles and conference papers related to biosolids and sludge management that were published in 2015. The literature review has been divided into the following sections: • Biosolids regulations and management issues; • Biosolids characteristics, quality and measurement including microconstituents, pathogens, nanoparticles and metals; • Sludge treatment technologies including pretreatment and sludge minimization, conditioning and dewatering, digestion, composting and innovative technologies; • Disposal and reuse including combustion/incineration, agricultural uses and innovative uses; • Odor and air emissions; and • Energy issues.

[The impact of socio-economic factors and lifestyle on the health of the population in the Voronezh region].

There are presented results of research of the impact of socio-economic factors, environmental factors and lifestyle on the health of the population. Among the socio-economic indices there are analyzed: the health expenditure; per capita income; living wage; the cost of the minimum food basket; the percentage ofpersons with income below the subsistence minimum; the amount of living space per person; the percentage of apartments that do not have running water; the percentage of apartments that do not have sewage systems; the proportion of living space, equipped with central heating; housing area per overall per capita at the end of the year. Also there are considered negative lifestyle factors: the abuse of alcohol and tobacco. The results of the study allow to select factors of the negative character and to identify measures for their elimination for the improvement ofpublic health.

[Hygienic assessment of conditions of the exploitation of facilities of the urban drainage system].

The aim of the study was the hygienic characteristics of the location of sewage pumping stations (SPSs) in the residential area of the city and the assessment of working conditions for the staff. The features of the technological process at the SPSs resulted in the formation of specific working conditions characterized by the presence of a cooling microclimate, noise production, technological vibration, air pollution by microorganisms. The assessment of working conditions has allowed to refer them to the 3 class (harmful working conditions) of the 2 and 3 degree. Preventive measures for SPSs should include the use of equipment for cleaning the air of working zone, having a combined odourremoving and microbicidal action; the automation of the labor process; the installation of additional equipment for filtering air circulating in workplaces and emitting into the atmosphere; provision of sealing equipment with the use of noise insulating materials.

Risk factors associated with an outbreak of dengue fever/dengue haemorrhagic fever in Hanoi, Vietnam.

Dengue fever/dengue haemorrhagic fever (DF/DHF) appears to be emerging in Hanoi in recent years. A case-control study was performed to investigate risk factors for the development of DF/DHF in Hanoi. A total of 73 patients with DF/DHF and 73 control patients were included in the study. The risk factor analysis indicated that living in rented housing, living near uncovered sewers, and living in a house discharging sewage directly into to ponds were all significantly associated with DF/DHF. People living in rented houses were 2·2 times more at risk of DF/DHF than those living in their own homes [adjusted odds ratio (aOR) 2·2, 95% confidence interval (CI) 1·1-4·6]. People living in an unhygienic house, or in a house discharging sewage directly to the ponds were 3·4 times and 4·3 times, respectively, more likely to be associated with DF/DHF (aOR 3·4, 95% CI 1-11·7; aOR 4·3, 95% CI 1·1-16·9). These results contribute to the understanding of the dynamics of dengue transmission in Hanoi, which is needed to implement dengue prevention and control programmes effectively and efficiently.

Operational decision support system for large combined sewage systems: Lisbon/Tagus estuary case study.

Managing combined sewage systems in large cities discharging to coastal waters, often bearing recreational activities, remains a challenge. Studying the impacts of such discharges requires the development of specific models. Hydrodynamic and water quality modelling of coastal waters employs numerical methods and algorithms, leading to the design of complex models which require expert use. The use of such models as decision support tools to simulate discharge impacts and define adequate corrective measures could represent a key part in meeting this challenge. In this paper, the authors describe the work undertaken to develop an operational decision support system (ODSS) methodology aiming to enable wastewater utilities' non-expert staff to carry out user-friendly scenario analysis based on computational fluid dynamics simulations. This article depicts the application and validation of the ODSS to the combined sewage system and the Tagus estuary of the city of Lisbon in Portugal. The ODSS was used for simulating the effects in the receiving coastal waters of a discharge caused by a scheduled maintenance operation in the sewage infrastructure. Results show that the use of such ODSS by non-expert staff increases their decision capabilities and knowledge of the wastewater utility's contribution to reducing negative impacts of sewage discharges on the receiving water bodies.

Seasonal dynamics of phytoplankton community in a tropical wetland.

Phytoplankton species composition and seasonal changes were investigated in the Bhoj wetland Bhopal. Taxonomic composition, diversity, and abundance of phytoplankton were studied at nine stations from March 2008 to February 2010, in relation to various physico-chemical factors. Total phytoplankton species composition in the Bhoj wetland was represented by 360 species. Among phytoplankton, diversity belonged to seven groups. Chlorophyceae was the dominant group (48%) followed by Bacillariophyceae (26%), Cyanophyceae (15%), and Euglenophyceae (9%), while Pyrophyceae, Chrysophyceae, and Xanthophyceae contributed 2% of the population. Phytoplankton on the basis of seasonal studies recorded 1651 units l(-1) during summer season which was contributed mainly by Chlorophyceae (39.3%), with Spirogyra sp. (14.2%) and Closteriopsis sp. (9.1%) contributing maximum to the total group in the first year, while during the second year of summer period, a total of 2095 units l(-1) was recorded which was contributed mainly by group Pyrophyceae (51%) with the main dominant species represented by Ceratium hirundinella (98.46%). The highest Shannon-Wiener diversity index (H') value (4.27) was recorded. Simpson values are approaching 1, signifying that sites have high relative diversity due to its supporting surrounding components. The trend of variation in evenness values was more or less the same as Shannon diversity index. Thus, the highest diversity indices recoded at all the stations in the present study justify the diverse nature of species inhabiting the different ecological niches in the ecosystem. The very high phosphate and nitrate concentrations in the wetland are indicators of pollution which may be due to the discharge of agricultural and sewage wastes enriched with nutrients as well as the human activities there. Our recommendation is to avoid as far as possible the discharge of sewage and agriculture wastes into the Bhoj wetland. The effects of various physicochemical water quality parameters on the seasonal distribution and succession of the above mentioned phytoplankton population as well as the interaction and eutrophication are discussed.

Physicochemical parameters aid microbial community? A case study from marine recreational beaches, Southern India.

A total of 176 (water and sediment) samples from 22 stations belonging to four different (urban, semi-urban, rural, and holy places) human habitations of Tamil Nadu beaches were collected and analyzed for physiochemical and microbial parameters during 2008-2009. Bacterial counts were two- to tenfold higher in sediments than in water due to strong bacterial aggregations by dynamic flocculation and rich organic content. The elevated bacterial communities during the monsoon explain rainfalls and several other wastes from inlands. Coliform counts drastically increased at holy and urban places due to pilgrimage and other ritual activities. Higher values of the pollution index (PI) ratio (>1) reveals, human fecal pollutions affect the water quality. The averaged PI ratio shows a substantial higher microbial contamination in holy places than in urban areas and the order of decreasing PI ratios observed were: holy places > urban areas > semi-urban areas > rural areas. Correlation and factor analysis proves microbial communities were not related to physicochemical parameters. Principal component analysis indicates 55.32 % of the total variance resulted from human/animal fecal matters and sewage contaminants whereas 19.95 % were related to organic contents and waste materials from the rivers. More than 80 % of the samples showed a higher fecal coliform and Streptococci by crossing the World Health Organization's permissible limits.

Characterization of domestic wastewater treatment in Oman from three different regions and current implications of treated effluents.

Treated effluents become one of the most significant sources for irrigation and other activities in arid and semi arid countries such as Oman. This study focuses on characterizing the quality of domestic wastewater in chosen three regions: Muscat, Sohar, and Salalah. The knowledge on treatment processes, quality, and proper management of domestic wastewater reuse for various purposes is essential. Wastewater samples were collected from six different sewage treatment plants (STPs) over a period of 1 year in 2009 on a monthly basis. The raw sewage (RS) and treated effluent (TEs) samples were collected from different sampling points in each STP. Both types of samples were analyzed for physicochemical and microbiological assessment. All tests were conducted according to the standard method for the examination of water and wastewater. The results revealed that the TEs electrical conductivity, biological oxygen demand, chemical oxygen demand, heavy metals, sodium, potassium, and total dissolved solids values were found within Omani Standards (OS). The RS in all STPs was categorized as high strength concentration and samples exceeded the acceptable range for ammonia in most of the selected plants except Sohar and Salalah. Nitrate values in RS were also observed in higher concentrations. In general, the produced TEs have met most of regulatory limits stated by OS except for nitrate, Escherichia coli and total suspended solids (TSS). Furthermore, it should be noted that the performance of Salalah and Darsayt STPs can be classified as the best compared to the other four STPs studied in Oman.

Identifying fecal pollution sources using 3M(™) Petrifilm (™) count plates and antibiotic resistance analysis in the Horse Creek Watershed in Aiken County, SC (USA).

Sources of fecal coliform pollution in a small South Carolina (USA) watershed were identified using inexpensive methods and commonly available equipment. Samples from the upper reaches of the watershed were analyzed with 3M(™) Petrifilm(™) count plates. We were able to narrow down the study's focus to one particular tributary, Sand River, that was the major contributor of the coliform pollution (both fecal and total) to a downstream reservoir that is heavily used for recreation purposes. Concentrations of total coliforms ranged from 2,400 to 120,333 cfu/100 mL, with sharp increases in coliform counts observed in samples taken after rain events. Positive correlations between turbidity and fecal coliform counts suggested a relationship between fecal pollution and stormwater runoff. Antibiotic resistance analysis (ARA) compared antibiotic resistance profiles of fecal coliform isolates from the stream to those of a watershed-specific fecal source library (equine, waterfowl, canines, and untreated sewage). Known fecal source isolates and unknown isolates from the stream were exposed to six antibiotics at three concentrations each. Discriminant analysis grouped known isolates with an overall average rate of correct classification (ARCC) of 84.3 %. A total of 401 isolates from the first stream location were classified as equine (45.9 %), sewage (39.4 %), waterfowl (6.2 %), and feline (8.5 %). A similar pattern was observed at the second sampling location, with 42.6 % equine, 45.2 % sewage, 2.8 % waterfowl, 0.6 % canine, and 8.8 % feline. While there were slight weather-dependent differences, the vast majority of the coliform pollution in this stream appeared to be from two sources, equine and sewage. This information will contribute to better land use decisions and further justify implementation of low-impact development practices within this urban watershed.

Urgency for sustainable development in coastal urban areas with reference to weather pattern, land use, and water quality.

Water pollution is one of the most critical problems affecting mankind. Weather pattern and land use of catchment area have significant role in quality of water bodies. Due to climate change, there is frequent variation in weather pattern all over the world. There is also rapid change in land use due to increase in population and urbanization. The study was carried out to analyze the effect of change in weather pattern during the monsoon periods of 2008 and 2012 on water quality of a tropical coastal lake system. The nature and extent of variation in different water quality parameters namely electrical conductivity (EC), magnesium (Mg), sodium (Na), chloride (Cl), sulphate (SO4), turbidity, Secchi disk depth, biochemical oxygen demand (BOD), phosphate (PO4), calcium (Ca), and water temperature as well as the effect of various land use activities in the lake basin on water quality have also been studied. There is significant reduction in precipitation, EC, Mg, Na, Cl, SO4, turbidity, and Secchi disk depths whereas a significant rise in the BOD, PO4, Ca, and water temperature were observed in 2012. This significant reduction in electrical conductivity during 2012 revealed that because of less precipitation, the lake was separated from the sea by the sandbar during most of the monsoon period and thereby interrupted the natural flushing process. This caused the accumulation of organic matter including phosphate and thereby resulting reduction in clarity and chlorophyll-a (algae) in the lake. The unsustainable development activities of Thiruvanathapuram city are mainly responsible for the degradation of water bodies. The lack of maintenance and augmentation activities namely replacement of old pipes and periodical cleaning of pipe lines of the old sewer system in the city results in the bypass of sewage into water bodies. Because of the existence of the old sewerage system, no effort has been taken by the individual establishment/house of the city to provide their own treatment system for sewage and sullage and the untreated wastes are discharged into these old sewer pipes and ultimately the wastes reach the water bodies. In this context, decentralized treatment of sewage, sullage, and garbage by individual houses/establishments/hotels/hospitals is a better option for the developing countries. With the rapid developmental activities, and due to the variation of precipitation due to climate change, it is highly essential to provide proper waste treatment/augmentation facilities in urban lake system because a slight variation in the weather pattern can result in serious implications in the already polluted water bodies.

Genotoxic effects of water pollution on two fish species living in Karasu River, Erzurum, Turkey.

Karasu River, which is the only river in the Erzurum plain, is the source of the Euphrates River (Eastern Anatolia of Turkey). The river is in a serious environmental situation as a result of pollution by agricultural and industrial sewage and domestic discharges. The present study aims to evaluate genotoxic effects of toxic metals in chub, Leuciscus cephalus, and transcaucasian barb, Capoeta capoeta, collected from contaminated site of the Karasu River, in comparison with fish from an unpolluted reference site. Heavy metal concentrations in surface water of the river were determined. The condition factor (CF) was taken as a general biomarker of the health of the fish, and genotoxicity assays such as micronucleus (MN) and other nuclear abnormalities (NA) were carried out on the fish species studied. MN and NA such as kidney-shaped nucleus, notched nucleus, binucleated, lobed nucleus, and blebbed nucleus were assessed in peripheral blood erythrocytes, gill epithelial cells, and liver cells of the fish. A significant decrease in CF values associated with a significant elevation in MN and NA frequencies was observed in fish collected from the polluted sites compared with those from the reference site. Results of the current study show the significance of integrating a set of biomarkers to identify the effects of anthropogenic pollution. High concentrations of heavy metals have a potential genotoxic effects, and the toxicity is possibly related to industrial, agricultural, and domestic activities.

[On the risk of spread of E. coli/EHEC O104:H4 stx 2 positive bacteria via sewerage treatment plants during the 2011 EHEC outbreak in north Germany]. / Zum Risiko der Ausbreitung von E. coli/EHEC O104:H4 stx 2 positiven Bakterien über Kläranlagen während der EHEC - Epidemie 2011 in Norddeutschland.

During an EHEC outbreak with E. coli O104:H4 stx2-pos in northern Germany 2 sewage treatment plants (Cuxhaven and Stade) of highly affected areas were monitored for the presence of the outbreak strain. 7 efflux water samples were collected at 1 h and 6 h intervals. The overall E. coli content of the treated sewage water was approximately 35 000 CFU/100 mL in both treatment plants. Among these about 500 were ESBL-E. coli (1.4%). ESBL-Agar was used as selective medium as the outbreak strain is highly resistant to 3rd generation cephalosporins. From the ESBL-isolates 208 strains have been typed by molecular methods for markers specific to the outbreak strain (O104rfb -351 base pairs (bp), flic H4-201 bp, stx2-584 bp, Tellur D - 434 bp). No outbreak strain was detected. The number of E. coli O104:H4 stx2-pos was calculated to be less than 3 per 100 mL in the treated sewage at the time of the study. Therefore it can be concluded that there was no threat for bathers to fall sick with this highly pathogenic strain from possibly sewage-contaminated bathing waters during the outbreak. The national limit value of 1 800 E. coli in 100 mL offers a high safety margin.

A review of the sustainable value and disposal techniques, wastewater stabilisation ponds sludge characteristics and accumulation.

Based on worldwide works available in international literature, this paper describes the status of sewage sludge resulting from settleable solids in waste stabilisation ponds (WSP). This review presents, in detail, sludge characteristics, production and accumulation rates in order to provide background information to those who expect to advise or get involved with sewage disposal in situations where resources are limited. Knowing that several years are usually required for a sludge removal operation and that the long-term sustainability of WSP systems is dependent on the safe and effective management of their sludge, its cost must be estimated and taken into account in the annual maintenance costs of the processes. Thus, this paper intends to summarise desludging methods and their financial estimation. Even when ponds have been functioning for several years, most of the sediments are stabilised well, the final disposal is an issue in terms of risk due, for example, to their content in nematode eggs. More generally, the pathogen content in sludge from WSP ponds has to be known to define an appropriate management and to safeguard public health. Based on existing data, the rates and distribution of helminth eggs will be presented and practical treatment methods will be suggested. A number of sludge utilisation and disposal pathways will also be summarised. Sludge activity in terms of oxygen consumption is also discussed in order to gather more information to improve pond design and keep an economic and sustainable value of WSP. The objectives of the present review are to advance knowledge and gather scientific and technical information on all aspects of sludge management including production, characterisation, management, agricultural reuse and ultimate disposal.

Spatial and temporal trends in water quality in a Mediterranean temporary river impacted by sewage effluents.

This paper analyzes how changes in hydrological conditions can affect the water quality of a temporary river that receives direct inputs of sewage effluents. Data from 12 spatial surveys of the Vène river were examined. Physico-chemical parameters, major ion, and nutrient concentrations were measured. Analyses of variance (ANOVA) and multivariate analyses were performed. ANOVA revealed significant spatial differences for conductivity and major ion but no significant spatial differences for nutrient concentrations even if higher average concentrations were observed at stations located downstream from sewage effluent discharge points. Significant temporal differences were observed among all the parameters. Karstic springs had a marked dilution effect on the direct disposal of sewage effluents. During high-flow periods, nutrient concentrations were high to moderate whereas nutrient concentrations ranged from moderate to bad at stations located downstream from the direct inputs of sewage effluents during low-flow periods. Principal component analysis showed that water quality parameters that explained the water quality of the Vène river were highly dependent on hydrological conditions. Cluster analysis showed that when the karstic springs were flowing, water quality was homogeneous all along the river, whereas when karstic springs were dry, water quality at the monitoring stations was more fragmented. These results underline the importance of considering hydrological conditions when monitoring the water quality of temporary rivers. In view of the pollution observed in the Vène river, "good water chemical status" can probably only be achieved by improving the management of sewage effluents during low-flow periods.