The water cycle, from catchment to discharge, is a sector that involves an important investment and operation and maintenance costs. In particular, sewage treatment is a challenge for governments ...because they are having to consider economic, environmental, and social aspects. Within the European Union, implementation of Directive 91/271/EEC is responsible for the location of wastewater treatment facilities in the territory, due to the requirement that all urban areas must have this infrastructure to reduce the environmental impact of treated water in water bodies. Different sizes of municipalities affect the design of each wastewater treatment plant (WWTP) and cause variations in the operation process. The presence of scale economies in this sector has a significant influence on the efficiency of the wastewater treatment process and has a direct impact on the operational costs. Based on the pursuit of economic and environmental efficiency, this analysis extends the scope of the current literature because it recommends a specific, population equivalent (p.e.) range for which it would be suitable to achieve efficiency in wastewater treatment facilities—shedding light on the open debate about scale economies in WWTPs.
•Different sizes of wastewater treatment plants provoke imbalance in production costs.•Use of DEA methodology on 217 wastewater treatment plants sample of Valencia Region.•Small facilities (biggest groups in sample) are highly influenced by scale economies.•Several improvements in wastewater treatment plants are necessary to reduce the costs.
With the rapid development of urban transportation and the increase in per capita car ownership, the problem of urban traffic congestion is becoming increasingly prominent. Due to the uneven ...distribution of crowd in different regions of the city, it is difficult to determine and solve the traffic dynamics congestion. In order to solve the problem that it is difficult to determine the dynamics of traffic congestion areas caused by uneven distribution of vitality in different regions of mountainous cities, a crowded mega mountainous city is selected as research object and it proposes a model to calculate the change characteristics of regional crowd gathering. Baidu Heatmap is used as it could distinguish crowd gathering in certain urban core area. The heat map pictures in dozens of consecutive days is extracted and researchers conducted pixel statistical classification on thermal map images. Based on the pixel data of different levels of the pictures, the calculation model is established and an algorithm based on particle swarm optimization is proposed. The calibration of the relative active population equivalent density is conducted, and the distribution characteristics of crowd gathering in time and space are analyzed. The results show that there are obvious spatiotemporal characteristics for this selected city. In time, holidays have an important impact on crowd gathering. The peak time of crowd gathering on weekdays is different from that on rest days. The research in this paper has a direct practical value for the identification of traffic congestion areas and the corresponding governance measures. The dynamic identification of population gathering areas in mountainous mega cities, demand prediction for various transportation regions, and future population OD(Origin—Destination) planning are of great significance.
With the rapid development of urban transportation and the increase in per capita car ownership, the problem of urban traffic congestion is becoming increasingly prominent. Due to the uneven ...distribution of crowd in different regions of the city, it is difficult to determine and solve the traffic dynamics congestion. In order to solve the problem that it is difficult to determine the dynamics of traffic congestion areas caused by uneven distribution of vitality in different regions of mountainous cities, a crowded mega mountainous city is selected as research object and it proposes a model to calculate the change characteristics of regional crowd gathering. Baidu Heatmap is used as it could distinguish crowd gathering in certain urban core area. The heat map pictures in dozens of consecutive days is extracted and researchers conducted pixel statistical classification on thermal map images. Based on the pixel data of different levels of the pictures, the calculation model is established and an algorithm based on particle swarm optimization is proposed. The calibration of the relative active population equivalent density is conducted, and the distribution characteristics of crowd gathering in time and space are analyzed. The results show that there are obvious spatiotemporal characteristics for this selected city. In time, holidays have an important impact on crowd gathering. The peak time of crowd gathering on weekdays is different from that on rest days. The research in this paper has a direct practical value for the identification of traffic congestion areas and the corresponding governance measures. The dynamic identification of population gathering areas in mountainous mega cities, demand prediction for various transportation regions, and future population OD(Origin—Destination) planning are of great significance.
With the rapid development of urban transportation and the increase in per capita car ownership, the problem of urban traffic congestion is becoming increasingly prominent. Due to the uneven ...distribution of crowd in different regions of the city, it is difficult to determine and solve the traffic dynamics congestion. In order to solve the problem that it is difficult to determine the dynamics of traffic congestion areas caused by uneven distribution of vitality in different regions of mountainous cities, a crowded mega mountainous city is selected as research object and it proposes a model to calculate the change characteristics of regional crowd gathering. Baidu Heatmap is used as it could distinguish crowd gathering in certain urban core area. The heat map pictures in dozens of consecutive days is extracted and researchers conducted pixel statistical classification on thermal map images. Based on the pixel data of different levels of the pictures, the calculation model is established and an algorithm based on particle swarm optimization is proposed. The calibration of the relative active population equivalent density is conducted, and the distribution characteristics of crowd gathering in time and space are analyzed. The results show that there are obvious spatiotemporal characteristics for this selected city. In time, holidays have an important impact on crowd gathering. The peak time of crowd gathering on weekdays is different from that on rest days. The research in this paper has a direct practical value for the identification of traffic congestion areas and the corresponding governance measures. The dynamic identification of population gathering areas in mountainous mega cities, demand prediction for various transportation regions, and future population OD(Origin—Destination) planning are of great significance.
Small scale hydropower is among the most attractive and cost-effective sustainable energy technologies available, by harnessing electricity through moving water. Naturally, moving water can be found ...in rivers and also man-man conduits where there is a continuous water flow. The sewage treatment facility has continuous water flow at the effluent pipe that can generate electricity by means of small-hydropower system. However, there are no sewage treatment plants (STP) in Malaysia that reclaim the energy through the usage of water turbines. This study is conducted to evaluate the feasibility of a micro-hydropower (MHP) system at the continuous flow of effluent discharge point of domestic STP that comprises of a low head with high flow fluctuations. This work comprises of evaluation of the potential power output of MHP generator which attached to different type of STP. The work starts with selection of a five STP which have maximum current population equivalent (PE) over design PE loading ratio. Next, the effluent discharge flow rate & outfall head are collected and recorded. Finally the potential output power for all selected STPs is calculated. The highest continuous effluent discharge flow rate contributing in high potential power and will be identified as the feasible STP for the MHP system installation.
The objective of this study was to examine the occurrence of parabens (5 congeners), triclosan (TCS) and triclocarban (TCC) at the scale of the Parisian sewer network and to provide representative ...knowledge on these compounds in France for a large area. For this purpose and in collaboration with the Parisian public sanitation service (SIAAP) in charge of the collect and treatment of the Parisian wastewater, this study focused on seven main sewer trunks of the Paris conurbation, accounting for 1900000m3d−1, i.e., about 8million inhabitants. Concentrations lying in the 2000–20000ngl−1 ranges were found in wastewater, confirming the ubiquity of parabens, TCS and TCC in our environment and household products. Parabens (>97%) and to a lesser extent TCS (68% in median) were mainly associated to the dissolved fraction, as demonstrated by low KD and KOC values. For the first time, this study also evaluated the pollutant mass loads per population equivalent (PE) of parabens, TCS and TCC at the large and representative scale of the Parisian conurbation. Hence, the median mass loads varied from 176 to 3040μgPE−1d−1 for parabens and from 26 to 762μgPE−1d−1 for TCS and TCC. Based on these results and according to the assumptions done, the extrapolation of the mass loads at the national scale pointed out an annual mass loads between 51.8 and 100.7ty−1 for methyl paraben (MeP) and between 11.2 and 23.5ty−1 for TCS. Mass loads per equivalent habitant and national mass loads are both extremely relevant and innovative data. Contrary to other countries, such data are nowadays rather difficult to gain in France and neither enquiry nor database provides access to information on the use and production of these chemicals. Since cosmetic industries are voluntarily and fully engaged in the substitution of parabens, triclosan and triclocarban in personal care product, this study could constitute a “time reference status” which could be used as a basis for future monitoring.
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•High levels of parabens, triclosan and triclocarban are found in wastewater.•Mass loads vary from 176 to 3039μg PE−1 d−1 for parabens.•Mass loads vary from 26 to 762μg PE−1d−1 for triclosan and triclocarban.•French mass loads vary between 11.2 and 100.7ty−1 for parabens and triclosan.
The research study aims to analyze the discharges of solely domestic wastewater from 15 single-family dwellings. This sizable dataset, containing over 300 unique and insightful data points, makes it ...possible to accurately qualify the raw wastewater in terms of concentrations, volumes and pollutant loads. Findings quantify the extremely wide data variability. As such, for single-family households of fewer than six residents, it is suggested not to use the standard P.E. pollution value as the design load, but rather a load range defined by the interval 10th percentile, 90th percentile of the data distribution, i.e. 123; 568 L·d
and 30; 281 g BOD
·d
, respectively, for the daily hydraulic and organic loads. Also, an analysis of the hydraulic peak factor would tend to lobby in favor of a collective sewer solution. For subdivisions and residential zones with little economic activity and similar French lifestyle, the daily domestic pollution per resident is now determined with the values: 40 g suspended solids, 94 g carbon oxygen demand, 40 g five-day biochemical oxygen demand, 6.7 g NH
-N, 10.4 g Kjeldhal nitrogen, and 1.2 g total phosphorus for a volume of 83 L. Those data could be used to optimize design and operation of decentralized or small-scale wastewater treatment plant.
The data article is related to the generation of raw wastewater from 15 single-family dwellings. Such a dataset is rare. They are complicated to set up due to the technical difficulty of deriving a ...representative sample of this kind of pollution, composed of suspended solids potentially very coarse in size, compounded by the administrative difficulty of performing these measurements on private property. The data were obtained by means of two distinct and complementary monitoring campaigns: i) continuous measurement of the volumes discharged by three of the 15 dwellings during more than one year, and ii) characterization, in terms of both quality and quantity, of more than 300 raw wastewater samples discharged over 24 consecutive hours by all 15 houses during weekly periods of seven consecutive days, which deliberately included weekend days. Their acquisition methodologies are described. The validation's methodologies, also described, include a R script. The data analysis can be used for i) designing and operating onsite and small wastewater treatment systems and ii) characterising the strictly domestic pollution. Therefore, this data article is associated with the manuscript “Quantification and qualification of the urban domestic pollution discharged per households and per resident”.The hydraulic values obtained with continuous measurement are available in two units: in l.s−1 as primary data and in l.h−1 as secondary data. They can be reused at any time step. These elements could be incorporated into future research or innovations related to single-family dwellings. In a general point of view, such data could be introduced in databases used for Life Cycle Assessment. These values can also be used in sanitation (collection, design and operation) and be useful to better specify the potential for the recovery of domestic wastewater.
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With the increasing number and volume of chemicals used in modern life, their adverse effects on human health and aquatic organisms have increased concerns as well. To formulate appropriate ...management plans, the amounts/volumes used and emitted of these chemicals must be regulated. However, no data are available on the use of most chemicals, particularly daily-use chemicals such as pharmaceuticals and personal care products (PPCPs). Herein, we tested eight activated sludge wastewater treatment plants (WWTPs) across Japan, each servicing populations of over 200,000, to investigate the emissions of 484 chemicals including 162 PPCPs. Twenty-four-hour composite samples were collected before and after the activated sludge component of treatment in each season of 2017. Targeted substances were solid-phase extracted and subsequently measured by LC-QTOF-MS-Sequential Window Acquisition of All Theoretical Fragment-Ion Spectra Acquisition. The mean number of the detected substances and their mean total concentrations in inflows (n=32) and outflows (n=32) were 87 and 92 and 108,517 and 31,537 ng L−1, respectively. Pharmaceuticals comprised 50% of the screened chemicals in the inflow. The median removal efficiency was 31.3%: 29.2% for pharmaceuticals and 20.2% for pesticides, which were similar to those in the literature. Cluster analysis showed that spatial differences among the WWTPs are larger than seasonal differences in the same WWTP. Regardless, we detected seasonal differences in the amounts of substances in the inflows: the amounts of sucralose, UV-filters, and insecticides were larger in summer than in winter, whereas those of ibuprofen and chlorpheniramine were larger in winter than in summer. The total inflow and outflow population equivalent loads estimated using wastewater volume, detected concentrations, and populations were 44.7 and 13.0 g 1,000 capita−1 d−1, respectively. The extrapolated total annual Japan-wide inflow and outflow loads were 2,079 and 671 tons y−1, respectively. Using the data obtained in this study, we identified 13 candidates of marker substances for estimating real-time population in a sewage treatment area and 22 candidates of marker substances for sewage contamination.
The paper presents the results of the analysis concerning the verification of the actual hydraulic load and the load of organic pollutants compared to the conditions designed for 4 household ...wastewater treatment plants. The researches were carried out in the annual period from May 2015 to April 2016. Based on the conducted analysis, it was found that objects act as underloaded hydraulically and the actual inflow of sewage to the analysed objects during the research period ranged from 7.3% to 32.7% in relation to the inflow assumed in the project. Furthermore, in the case of loading the treatment plant with the load of pollutants expressed as
, it was fund that the actual
values were lower than assumed in the project. Therefore, it is important that the sizes of the series of household sewage treatment plants were selected depending on the individual conditions of household, i.e. the number of inhabitants or the amount of consumed water.
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