Inlet Of Wastewater Treatment Plant Research Articles

Multisite community-scale monitoring of respiratory and enteric viruses in the effluent of a nursing home and in the inlet of the local wastewater treatment plant.

The aim of this study was to evaluate whether community-level monitoring of respiratory and enteric viruses in wastewater can provide a comprehensive picture of local virus circulation. Wastewater samples were collected weekly at the wastewater treatment plant (WWTP) inlet and at the outlet of a nearby nursing home (NH) in Burgundy, France, during the winter period of 2022/2023. We searched for the pepper mild mottle virus as an indicator of fecal content as well as for the main respiratory viruses [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza, and respiratory syncytial virus] and enteric viruses (rotavirus, sapovirus, norovirus, astrovirus, and adenovirus). Samples were analyzed using real-time reverse transcription PCR-based methods. SARS-CoV-2 was the most frequently detected respiratory virus, with 66.7% of positive samples from the WWTP and 28.6% from the NH. Peaks of SARS-CoV-2 were consistent with the chronological incidence of infections recorded in the sentinel surveillance and the nearby hospital databases. The number of positive samples was lower in the NH than in WWTP for the three respiratory viruses. Enteric viruses were frequently detected, most often sapovirus and norovirus genogroup II, accounting both for 77.8% of positive samples in the WWTP and 57.1% and 37%, respectively, in the NH. The large circulation of sapovirus was unexpected in particular in the NH. Combined wastewater surveillance using simple optimized methods can be a valuable tool for monitoring viral circulation and may serve as a suitable early warning system for identifying both local outbreaks and the onset of epidemics. These results encourage the application of wastewater-based surveillance (WBS) to SARS-CoV2, norovirus, and sapovirus.IMPORTANCEWBS provides valuable information on the spread of epidemic viruses in the environment using appropriate and sensitive detection methods. By monitoring the circulation of viruses using reverse transcription PCR methods in wastewater from the inlet of a wastewater treatment plant and the outlet of a nearby retirement home (connected to the same collective sewer network), we aimed to demonstrate that implementing combined WBS at key community sites allows effective detection of the occurrence of respiratory (influenza, respiratory syncytial virus, and SARS-CoV-2) and enteric (norovirus, rotavirus, and sapovirus) virus infections within a given population. This analysis on a localized scale provided new information on the viral circulation in the two different sites. Implementing WBS to monitor the circulation or the emergence of infectious diseases is an important means of alerting the authorities and improving public health management. WBS could participate actively to the health of humans, animals, and the environment.

Wastewater Surveillance of SARS-CoV-2: A Comparison of Two Concentration Methods.

Wastewater surveillance is crucial for the epidemiological monitoring of SARS-CoV-2. Various concentration techniques, such as skimmed milk flocculation (SMF) and polyethylene glycol (PEG) precipitation, are employed to isolate the virus effectively. This study aims to compare these two methods and determine the one with the superior recovery rates. From February to December 2021, 24-h wastewater samples were collected from the Ioannina Wastewater Treatment Plant's inlet and processed using both techniques. Subsequent viral genome isolation and a real-time RT-qPCR detection of SARS-CoV-2 were performed. The quantitative analysis demonstrated a higher detection sensitivity with a PEG-based concentration than SMF. Moreover, when the samples were positive by both methods, PEG consistently yielded higher viral loads. These findings underscore the need for further research into concentration methodologies and the development of precise protocols to enhance epidemiological surveillance through wastewater analysis.

Metagenomic analysis of sewage for surveillance of bacterial pathogens: A release experiment to determine sensitivity.

Accurate monitoring of gastro-enteric and other diseases in large populations poses a challenge for public health management. Sewage represents a larger population, is freely obtainable and non-subject to ethical approval. Metagenomic sequencing offers simultaneous, multiple-target analysis. However, no study has demonstrated the sensitivity of metagenomics for detecting bacteria in sewage. In this study, we spot-released 1013 colony-forming units (CFU) of Staphyloccus hyicus (non-pathogenetic strain 842J-88). The strain was flushed down a toilet into the sewer in the catchment area of a public wastewater treatment plant (WWTP), serving a population of 36,000 people. Raw sewage was continuously sampled at the WWTP's inlet over 30- and 60-minute intervals for a total period of seven hours. The experiment was conducted twice with one week in-between release days and under comparable weather conditions. For the metagenomics analyses, the pure single isolate of S. hyicus was sequenced, assembled and added to a large database of bacterial reference sequences. All sewage samples were analyzed by shotgun metagenome sequencing and mapped against the reference database. S. hyicus was identified in duplicate samples at both of two release days and these sequence fragment counts served as a proxy to estimate the minimum number of sick people or sensitivity required in order to observe at least one sick person at 95% probability. We found the sensitivity to be in the range 41-140 and 16-36 sick people at release days 1 and 2, respectively. The WWTP normally serves 36,000 people giving a normalized sensitivity in the range of one in 257 to 2,250 persons.

Predicting Biochemical Oxygen Demand at the Inlet of Al-Rustumiya Wastewater Treatment Plant Using Different Mathematical Techniques

Water quality planning relies on Biochemical Oxygen Demand BOD. BOD testing takes five days. The Particle Swarm Optimization (PSO) is increasingly used for water resource forecasting. This work designed a PSO technique for estimating everyday BOD at Al-Rustumiya wastewater treatment facility inlet. Al-Rustumiya wastewater treatment plant provided 702 plant-scale data sets during 2012-2022. The PSO model uses the daily data of the water quality parameters, including chemical oxygen demand (COD), chloride (Cl-), suspended solid (SS), total dissolved solids (TDS), and pH, to determine how each variable affects the daily incoming BOD. PSO and multiple linear regression (MLR) findings are compared, and their performance is evaluated using mean square error, relative absolute mistake, and coefficient of determination. PSO utilised COD, TDS, SS, pH, and Cl- as inputs, generating a mean square error of 1029.10, an average absolute relative error of 9.41%, and a coefficient of determination of 0.89. Comparisons demonstrated that the PSO model could accurately calculate the daily BOD at Al-Rustumiya wastewater treatment plant's inlet.

He who seeks finds: surveillance of Enteroviruses and Human Bocaviruses in Northern Italy wastewaters

Abstract Background Wastewaters surveillance has proven to be a valuable tool in detecting the spread of SARS-CoV-2 and other pathogens. Enterovirus (EV) and Human bocavirus (HBoV) are viruses that can infect humans, causing mild to severe pathologies transmitted also through the fecal-oral route. EVs are ssRNA viruses, grouped among four taxonomic species EV-A to D. HBoV is ssDNA virus mainly affects infants. Genus Bocavirus includes 4 genotypes: HBoV1 to 4, detected mainly in feces. EVs and HBoVs infections are often not notified, causing loss of data on the actual incidence. The aim of this study was to investigate the presence and diffusion of EVs and HBoVs in wastewaters. Methods 200 wastewater samples were collected during 2022, at the inlet of wastewater treatment plants in three cities of the Lombardy Region (i.e.: Brescia, Bergamo, and Cremona). EVs and HBoVs were detected by RT Real-time PCR and Real-time PCR respectively using specific primers for target region of the viral genome. Positive samples were genotyped by Sanger sequencing. Prevalence was calculated with the Blaker's method. Results Overall EV and HBoV prevalences were 20.5% (CI95% 15.5-26.2%) and 37% (CI95%.30.6-43:9%), respectively. EV was mainly detected in the mild season with a prevalence of 68.3% (CI95% 53.0-80.4%). Sequence analysis reported that EV-B species was the most prevalent in this study (9 samples). HBoVs positive samples’ prevalence was higher in cold season (71.6% CI95% 60.5-80.6%), than mild season. HBoV2 showed higher prevalence (85.6% CI95% 75.6-92.0%) than HBoV3. Conclusions This study provided insight into the seasonal spread of EVs and HBoVs circulating and can contribute to understand the disease burden. Wastewaters surveillance provides a wide and more complete epidemiological data than the clinical one of a single person, rather providing information of a community of individuals making the data very valuable to the competent authorities. Key messages • Wastewaters surveillance is a useful tool for investigating the spread and circulation of viruses in population. • EVs and HBoVS are widespread in Northen Italy population.

Oxidation method using H2O2 on leachate from wastewater treatment plant inlet of Bantargebang integrated waste processing unit

Leachate produced from old landfills has a low level of biodegradability making it suitable for physico-chemical treatment. Low level of biodegradability is characterized by a concentration ratio of BOD5/COD ≤ 0.1. The leachate at the Bantargebang Integrated Waste Management Unit (UPST) has a BOD5/COD concentration ratio of 0.05. The current state of processing leachate at a wastewater treatment plant (IPAS) employs biological processing technology. This research uses inlet leachate from IPAS 3 UPST Bantargebang, with a batch system reactor. The reactor is a glass beaker with capacity of 1 L, operated using a magnetic stirrer with a stirring speed of 200 rpm. The reactor is covered with aluminum foil to prevent oxidation caused by light. The dosage used is based on H2O2/COD concentration ratios, which are 1.0625 and 2.125. Reactions time applied are 60 minutes and 180 minutes. The initial pH levels of the leachate used are 5, 6, 7 and 8. The variations which has optimum values are at pH 6, H2O2/COD 2.125, and a 60-minutes reaction time, resulting in average color removal, BOD5, COD, TSS, TN, and H2O2 reacted by 65%.

Genomic insight into transmission mechanisms of carbapenem-producing Citrobacter spp. isolates between the WWTP and connecting rivers

Carbapenem-resistant Enterobacteriaceae (CRE) poses major health risks worldwide. Most studies have focused on carbapenem resistance in Klebsiella pneumoniae and Escherichia coli; however, the occurrence and transmission of carbapenem-resistant Citrobacter spp. (CRCS) are poorly understood. In this study, we investigated the occurrence and potential transmission patterns of CRCS in different functional areas of an urban wastewater treatment plant (WWTP) and connecting rivers during one-year monitoring in Shandong Province, China. In total, 14 CRCS were detected in 376 environmental samples, including those from the WWTP inlet (n = 7), WWTP anaerobic tank (n = 2), and rivers (n = 5). Citrobacter braakii (n = 6) was the dominant subtype among 14 CRCS isolates, followed by Citrobacter freundii (n = 5), Citrobacter sedlakii (n = 2), and Citrobacter werkmanii (n = 1). All CRCS were resistant to imipenem, meropenem, ampicillin, amoxicillin/clavulanic acid, cefotaxime, ceftazidime, trimethoprim/sulfamethoxazole, and ciprofloxacin. Plasmid analysis showed that the blaKPC-2 gene was located on IncN and IncFII (Yp) plasmids, whereas the blaNDM gene was located on IncX3 and IncN2 plasmids. Clonal transmission of CRCS harboring carbapenem genes occurred between the WWTP and connecting rivers on a temporal or spatial scale. High genomic relatedness of NDM-5-producing C. sedlakii was identified between river water and WWTP aerosol, suggesting a potential exposure risk of CRCS for workers and surrounding residents near the WWTP. Furthermore, NDM-5-producing C. sedlakii isolated from rivers was related to C. sedlakii isolated from soil and well water in different regions of China, indicating that NDM-5-producing C. sedlakii may be widespread in China. These findings indicate that rare healthcare-associated pathogens such as CRCS can contribute to widespread carbapenem production in the environment; thus, CRCS should be continuously monitored.

Dissemination of carbapenemase-producing Enterobacterales through wastewater and gulls at a wastewater treatment plant in Sweden

Here we report the detection of carbapenemase-producing Enterobacterales (CPE) isolated from Swedish wastewater and gull faeces. CPE have not been detected in samples from animals in Sweden preceding this report. Sampling of wastewater treatment plant (WWTP) inlet and outlet, sedimentation basins, surface seawater from key aquatic bird habitats and freshly deposited gull faeces was done on six separate occasions during May to September 2021. Following broth enrichment, selective screening of putative CPE was performed on mSuperCarba™ (CHROMagar). Species identification was done with MALDI-TOF. Antimicrobial susceptibility testing was performed according to EUCAST. In total, seventeen CPE were verified by genome sequencing carrying blaGES-5, blaIMI-3, blaOXA-181 or blaOXA-244. The blaGES-5 was carried on IncP plasmids in four different species; Escherichia coli ST10 isolated from WWTP outlet, Raoultella ornithinolytica isolated from WWTP inlet, outlet and sedimentation basins as well as gull faeces collected at the WWTP and Klebsiella spp. isolates from WWTP inlet and outlet. The genetic environment surrounding blaGES-5 was similar in two Citrobacter freundii causing human infections. The blaIMI-3 was carried on IncFII(Yp) plasmids in four Enterobacter ludwigii, isolated from WWTP outlet and gull faeces collected at a recreational city park 2 km from the WWTP. The blaOXA-181 was located on a COLKP3 plasmid found in an E. coli, while blaOXA-244 was chromosomally located in an E. coli ST10, both isolated from WWTP inlet. Phylogenetic analysis of R. ornithinolytica and E. ludwigii isolates indicate that the gulls carried strains related to those identified in the WWTP samples. The results thus add to the increasing evidence of WWTPs as anthropogenic reservoirs for mobile genetic elements with antibiotic-resistance functionality. Such environments could profoundly impact the dissemination and spread of such genetic elements via for example aquatic birds, thereby warranting further study and surveillance.

Impact of nitrate addition on the resistome and mobilome from a full-scale sewer

Oxidative chemicals, such as nitrate, are periodically added to sewer systems to mitigate sulfide production and its accumulation but data are lacking on how these treatments affect sewage microbiota and alter their gene expression and mobilization. The present study investigated such effects on the biofilm of a full-scale sewer collected at two different locations, namely a pumping station and at the inlet of an urban wastewater treatment plant (WWTP), before and 15 days after nitrate dosage using a combination of culture-dependent and -independent approaches. Nitrate dosing resulted ineffective on the concentration of antibiotic-resistant Escherichia coli (AR-EC) in biofilms but greatly affected the composition of biofilm bacterial communities and the associated resistome and mobilome, especially at the pumping station where nitrate was dosed. Such responses consisted of a clear reduction on strict anaerobes; an almost twofold increase on the expression of recA gene (stress-response marker); and a significant increase on the relative abundance of most antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs). In turn, the effects of nitrate dosing at the WWTP inlet were barely visible, suggesting that they vanished into the distance from the pumping site (2.4 km). Remarkably, however, the relative abundance of both resistance and mobilization gene biomarkers at the inlet of the studied WWTP clearly oversized that at the pumping station confirming that these facilities are sinks where these resistance determinants accumulate and propagate. Considering the abundance of resistant bacteria and genes in urban sewage, the effects of dosing chemicals should be carefully assessed to lessen the load of such biological pollutants into WWTPs.

City-wide model-based analysis of heat recovery from wastewater using an uncertainty-based approach

Around 90% of the energy requirement for urban water systems management is for heating domestic tap water. In addition, the energy content of wastewater is mainly in the form of heat (85%). Hence, there is an obvious interest in recovering a large portion of this heat. However, city-wide scenario analyses that evaluate heat recovery at various locations while considering impacts on wastewater treatment plant (WWTP) performance are currently very limited. This study presents a comprehensive model-based city-wide evaluation considering four different heat recovery locations (appliance, household, precinct and WWTP effluent) for a Swedish city with varying degrees of implementation using an uncertainty-based approach. Results show that heat recovery at the appliance level, with heat exchangers installed at 77% of the showers at domestic households, leads to a mean energy recovery of 127 MWh/day with a 0.25 °C reduction in mean WWTP inlet temperature compared to the default case without heat recovery. The highest mean temperature reduction compared to the default case is 1.5 °C when heat is recovered at the precinct level for 77% of the domestic wastewater flow rate. Finally, the impact on WWTP nitrification capacity is negligible in this case due to its large existing capacity and design.

Prediction of Wastewater Quality at a Wastewater Treatment Plant Inlet Using a System Based on Machine Learning Methods

One of the important factors determining the biochemical processes in bioreactors is the quality of the wastewater inflow to the wastewater treatment plant (WWTP). Information on the quality of wastewater, sufficiently in advance, makes it possible to properly select bioreactor settings to obtain optimal process conditions. This paper presents the use of classification models to predict the variability of wastewater quality at the inflow to wastewater treatment plants, the values of which depend only on the amount of inflowing wastewater. The methodology of an expert system to predict selected indicators of wastewater quality at the inflow to the treatment plant (biochemical oxygen demand, chemical oxygen demand, total suspended solids, and ammonium nitrogen) on the example of a selected WWTP—Sitkówka Nowiny, was presented. In the considered system concept, a division of the values of measured wastewater quality indices into lower (reduced values of indicators in relation to average), average (typical and most common values), and upper (increased values) were adopted. On the basis of the calculations performed, it was found that the values of the selected wastewater quality indicators can be identified with sufficient accuracy by means of the determined statistical models based on the support vector machines and boosted trees methods.

Full-scale investigation of ferrous dosing in sewers and a wastewater treatment plant for multiple benefits

This study demonstrates the full scale application of iron dosing in a metropolitan wastewater treatment plant (WWTP) and the upstream sewer system for multiple benefits. Two different dosing locations, i.e., the WWTP inlet works (Trial-1) and upstream sewer network (Trial-2) were tested in this study. Both dosing trials achieved multiple benefits such as sulfide control, phosphate removal and improved sludge dewaterability. During Trial-1, a sulfide reduction of >90% was achieved at high dosing rates (>19 kgFe ML−1) of ferrous chloride in the inlet works and in Trial-2 the in-sewer ferrous dosing had significant gas phase hydrogen sulfide (H2S) concentration reduction in the sewer network. The ferrous dosing enhanced the phosphate removal in the bioreactor up to 76% and 53 ± 2% during Trial-1 & 2, respectively. The iron ending up in the anaerobic sludge digester reduced the biogas H2S concentration by up to 36% and 45%, respectively. The dewaterability of the digested sludge was improved, with relative increases of 9.7% and 9.8%, respectively. The presence of primary clarifier showed limited impact on the downstream availability of iron for achieving the afore-mentioned multiple benefits. The iron dosing enhanced the total chemical oxygen demand removal in the primary clarifier reaching up to 49% at the high dose rates during Trial-1 and 42 ± 1% during Trial-2. This study demonstrated that multiple benefits could be achieved independent of the iron dosing location (i.e., at the WWTP inlet or in the network). Further, iron dosing at both locations enhances primary settling, beneficial for bioenergy recovery from wastewater.

How does urban wastewater treatment affect the microbial quality of treated wastewater?

The design of wastewater treatment plants (WWTP) includes facilities for the removal of suspended solids, organic matter, nitrogen and phosphorous, as required in current legislation, while removal of microorganisms is not literally emphasized. Although the different unit processes have some effect on microbial populations, disinfection is not achieved in many cases unless a specific step is included to regenerate wastewater. This study assesses the effect of the unit processes of six WWTPs that treat municipal wastewater on five microbiological parameters (total coliforms, E. coli, Enterococcus sp., Staphylococcus aureus and Pseudomonas aeruginosa), as well as their contribution to receiving waters. Bacterial concentration in the inlet of WWTPs varies from the lowest concentration of Staphylococcus aureus (104CFU/100mL), to the highest for total coliforms (108CFU/100mL), independently of the industrial activity discharging to the WWTP. Considering log bacterial removal of each step of treatment processes, trickling filters reduced 2.6 and 1.5-log Enterococcus sp. and Pseudomonas sp. respectively, secondary decanters achieved 2.5-log average removals and ponds reduced bacteria in a range from 1 to 2.2-log, being the processes with the highest bacteria removal, although in the case of secondary decanters this depends on design parameters such as hydraulic residence time, loads of solids, or types of previous biological treatments. The average of the bacteria concentration in the outlet of the six WWTPs was between 103–106CFU/100mL. The effect of discharging these bacteria on the quality of receiving waters was assessed by analyzing microbial concentration upstream and downstream of the discharge point. In almost all cases, the bacterial concentration upstream of the discharge point was similar to downstream concentration because the effluent is rapidly diluted in the receiving river, not representing a risk to ecosystems.

Modelling the potential for multi-location in-sewer heat recovery at a city scale under different seasonal scenarios

A computational network heat transfer model was utilised to model the potential of heat energy recovery at multiple locations from a city scale combined sewer network. The uniqueness of this network model lies in its whole system validation and implementation for seasonal scenarios in a large sewer network. The network model was developed, on the basis of a previous single pipe heat transfer model, to make it suitable for application in large sewer networks and its performance was validated in this study by predicting the wastewater temperature variation across the network. Since heat energy recovery in sewers may impact negatively on wastewater treatment processes, the viability of large scale heat recovery was assessed by examining the distribution of the wastewater temperatures throughout a 3000 pipe network, serving a population equivalent of 79500, and at the wastewater treatment plant inlet. Three scenarios; winter, spring and summer were modelled to reflect seasonal variations. The model was run on an hourly basis during dry weather. The modelling results indicated that potential heat energy recovery of around 116, 160 & 207 MWh/day may be obtained in January, March and May respectively, without causing wastewater temperature either in the network or at the inlet of the wastewater treatment plant to reach a level that was unacceptable to the water utility.

Monitoring of an urban water body under the influence of a wastewater treatment plant: assessment of environmental impacts

Urban streams are increasingly suffering from anthropogenic activities, mainly due to domestic sewage. Thus, this study aimed to assess the impact of treated domestic effluent on a receiving water body. Four sampling points were defined. The first was inside the stream, located upstream on the Wastewater Treatment Plant (WWTP), the second at the WWTP inlet, the third at the plant outlet and the last was located inside the stream, downstream of the WWTP discharge. The study was carried on for a three-year period (2013-2015). Chemical, physical and biological parameters were analyzed. Correlation analysis, Principal Component Analysis (PCA) and Euclidean distance dendrogram then assessed the results. At the sampling points related to the stream (spots 1 and 4), a significant distance between conductivity and the other parameters was observed, suggesting a low relation between them. A group of minor related variables (Trophic State Index - TSI - and Chemical Oxygen Demand - COD) was formed. At the sampling points within the WWTP (points 2 and 3), the formation of 3 clusters was observed, and two of them involved TSI, thus indicating that this parameter changes according to the season of the year and the monitoring point. Therefore, the WWTP influences in a significant and proportional way the TSI of the water body in different seasons of the year, suggesting that this is the main parameter to be controlled. The highest TSI were observed during spring and summer. http://dx.doi.org/10.18226/23185279.v6iss2p15a

Preliminary evidence of nanoparticle occurrence in water from different regions of Delhi (India).

The objective of this study was to obtain preliminary evidence of metal-based nanoparticle (NP) occurrence in Delhi (India). Six sampling locations (inlets and outlets of two different municipal wastewater treatment plants (WWTPs), groundwater, and river water) were collected in three independent sampling events. Microscopic analysis (TEM) found majority (40%) of the particles rangedbetween 150 and 200nm followed by particles of size 100-150nm (22%) at the inlet of WWTP, while at outlet, 90% of the particles were < 100nm. Compared with the outlet of the WWTPs, particles at the inlet were found to be greater than 40%. Intensity-based particle size distribution (PSD) revealed particle size at influent in the range of 210nm, while at effluent, particle size for both WWTPs ranged < 100nm. Particles of size between 100 and 200nm were found to get removed from both the treatment plants and thus making it evident that NP gets settled or adsorbed in sludge. Spectral analysis (EDX) further confirmed the presence of metals such as Al, As, Ag, Mn, Fe, Ti, and Zn at different weight percentages. Overall, findings of this study confirmed the presence of metal-based engineered NPs (ENPs) from anthropogenic sources and it cannot also be ruled out the possible formation of NPs within the wastewater from natural minerals. Moreover, to solve definitive clues for ascertaining the sources of NPs in complex samples, more sophisticated research techniques, such as inductively coupled plasma-mass spectrometry (ICP-MS) in combination with field flow fractionation, single-particle ICP-MS, and radio-labeling in combination or in single should be considered.

Batch leachate treatment using stirred electrocoagulation reactor with variation of residence time and stirring rate

This study aims to reduce pollutant levels of the leachate by electrocoagulation method using a stirred electrocoagulation reactor as the electrochemical water treatment. The release of active coagulants as metallic ions took place in the anode, while in the cathode, the electrolysis reaction in the form of hydrogen gas dischargeoccurred. The source of wastewater is Waste Water Treatment Plant inlet III of Bantar Gebang, Bekasi. Some parameters were analyzed in this research, i.e., Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), NH3, NO3-, NO2-, N-total, and organic substances as well as the microorganism growth before and after electrocoagulation, with variations of detention time (seconds) of 10, 20, 120, 600 and rapid mixing conditions (rpm) of 60, 100 and 200. The results show that the greater the rapid mixing speed and the detention time of electrolysis, the higher the removal of contaminants in liquid waste. The optimum condition of electrocoagulation was encountered at 200 rpm rapid mixing with 600 seconds of processing time. The removal efficiencies of electrocoagulation method for each parameter are TSS of 46.80%, BOD5 of 71.33%, COD of 73.77%, Pb of 62.5%,and NH3-N of 57.92%,whereas the pH value has been increased from 8.03 to 8.95. The electrocoagulation method can reduce levels of pollutants, complying with the environmental standards.

Treatment of industrial estate wastewater by the application of electrocoagulation process using iron electrodes

In this study electrocoagulation (EC) of industrial estate wastewater taken from the inlet of wastewater treatment plant was investigated using sacrificial iron electrodes. Employing a pole changer to homogenous consumption of electrodes, studies on the parameters such as current density, supporting electrolyte concentration and initial pH, which have significant effects on COD removal and hence the energy consumption, were performed. Hydrogen peroxide was used in different concentrations to observe its effects on COD removal efficiency and the energy consumption. Sludge productions were also calculated for all experiments. COD removal efficiency of ∼92% was obtained at the best experimental conditions (i = 30 mA/cm2, SE = 3 mM Na2SO4, pH = original pH (∼6) of the wastewater, 1500 mg/L H2O2) with an energy cost of €3.41/m3 wastewater treated and the sludge production of 5.45 g per g COD removed.

Status quo report on wastewater treatment plant, receiving water's biocoenosis and quality as basis for evaluation of large-scale ozonation process.

The project DemO3AC (demonstration of large-scale wastewater ozonation at the Aachen-Soers wastewater treatment plant, Germany) of the Eifel-Rur Waterboard contains the construction of a large-scale ozonation plant for advanced treatment of the entire 25 million m³/yr of wastewater passing through its largest wastewater treatment plant (WWTP). In dry periods, up to 70% of the receiving water consists of treated wastewater. Thus, it is expected that effects of ozonation on downstream water biocoenosis will become observable. Extensive monitoring of receiving water and the WWTP shows a severe pollution with micropollutants (already prior to WWTP inlet). (Eco-)Toxicological investigations showed increased toxicity at the inlet of the WWTP for all assays. However, endocrine-disrupting potential was also present at other sampling points at the WWTP and in the river and could not be eliminated sufficiently by the WWTP. Total cell counts at the WWTP are slightly below average. Investigations of antibiotic resistances show no increase after the WWTP outlet in the river. However, cells carrying antibiotic-resistant genes seem to be more stress resistant in general. Comparing investigations after implementation of ozonation should lead to an approximation of the correlation between micropollutants and water quality/biocoenosis and the effects that ozonation has on this matter.

Integrated stochastic modeling of pharmaceuticals in sewage networks

Pharmaceuticals and particularly antibiotics can harm sensitive aquatic species. Their occurrence in urban wastewater systems is the consequence of five successive processes: (i) ingestion of the substance, (ii) accumulation in the urine, (iii) excretion, (iv) degradation in the sewer system and (v) transport to the wastewater treatment plant (WTP). These processes were included in an integrated model that can be used to assess the dynamics of pharmaceuticals at a WTP inlet. First, information on sales data, posology, pharmacokinetics and toilet flushing frequency were combined to create a source model of pharmaceuticals entering a sewer system. This production function was then coupled with a transport/degradation model to simulate concentrations of pharmaceuticals at a WTP inlet. In an example application, the full model was applied to simulate the concentration of the antibiotic ciprofloxacin on an hourly time scale. In this application, the model was calibrated and validated for a case study at a WTP in Lausanne, Switzerland. Validation of the integrated approach was successful despite the high variability evident in the model results. This modeling approach has potential use in pollution management and epidemiology related to wastewater.