Efficiency Of Wastewater Treatment Plants Research Articles

Pathogenic potential of enterococcus isolated from healthy people and wastewater

Introduction. Efficiency of wastewater treatment plants is a key for protection of common health. At the same time, all criteria for its evaluation are concerned about the overall biomass reduction rather than on pathogens that, in low amount, can still be present in the efflux. 
 Purpose of the study. Therefore it seems important to evaluate the effect of purification procedures on the pathogenic potential of bacteria. In the current study, it is performed using Enterococcus isolates, since pathogenic strains present considerable threat for human health, causing endocarditis, infections of urogenic tract, nosocomial infections, etc. 
 Materials and methods. PCR was used to evaluate the presence of potentially pathogenic genes in the extracted DNA. Seven genes were tested: genes of adhesion proteins (Esp, Asa1), proteins with lytic activity (cytolysine CylA, hyaluronidase hyl and gelatinase gelE), and antibiotic resistance factors (vanA, vanB). Three hundred sixty six isolates from wastewater plants of Moscow agglomeration and 168 from feces of healthy people were screened. 
 Results. Percentage of pathogenic isolates varied in different wastewater treatment plants (from 36 to 55%), with no relation with the volumes of treated sewage and the purification scheme of the plant. Similar species were recovered from wastewater plants and feces, with E. faecium (36% and 53%, correspondingly) and E. faecalis (28% and 38%) as most abundant. E. hirae was presented in different numbers (24% и 1.2%) as well as E. casseliflavus (3% and 0,6%). 
 E. durans, E. thailandicus, E. avium, E. mundtii were found from 2.5 to 1%, in similar amounts from both sources. Minor species E. raffinosus, E. moraviensis, E. malodatus presented with single isolates in wastewater plants, and E. canintеstini – in feces. The E. faecalis was the leader in percentage of pathogenic potential (75–80%). The most abundant pathogenic gene was gelE (30–33% from both sources) and asa1 (18–19%). CylA was found at similar levels 
 (4,4–4,8%). Esp was found in 9% of wastewater plants isolates and in 14% from feces. Hyl was specific to isolates from wastewater plants (2,5%), and was present in all non-monor species (E. faecium, E. faecalis, E. hirae, E. durans, E. thailandicus) and at different stages of water treatment. Vancomycin resistance genes were not detected.
 Limitations. When studying the pathogenic potential of enterococcal isolates from wastewater treatment plants in the city of Moscow and the Moscow region and the feces of practically healthy people, two samples were compared, consisting of 366 and 168 isolates, respectively, which represents a sufficient reference sample. The sample was limited by geography, so the conclusions can be applied to wastewater treatment plants in the city of Moscow and the Moscow region, where similar treatment schemes were used.
 Conclusions. The data from this study suggests the pathogenic potential of bacteria from wastewater treatment plants to be a little bit more than that of isolates from feces of healthy people. The activated sludge can be a reservoir for pathogens and can bring contamination to the environment.

Modeling spatiotemporal domestic wastewater variability: Implications for measuring treatment efficiency

Continuously measuring the efficiency of wastewater treatment plants is crucial to progress in sanitation management. Regulations for decentralized wastewater treatment plants (WWTP) can include rudimentary specifications for sporadic sampling, unencouraging continuous monitoring, and missing crucial domestic wastewater (DW) variability, especially in low- and middle-income countries. However, few studies have focused on modeling and understanding spatiotemporal DW variability. We developed and calibrated an agent-based model (ABM) to understand spatial and temporal DW variability, its role in estimated WWTP efficiency, and provide recommendations to improve sampling regulations. We simulated DW variability at various spatial and temporal resolutions in Santa Ana Atzcapotzaltongo, Mexico, focusing on chemical oxygen demand (COD) and total suspended solids (TSS). The model results show that DW variability increases at higher spatiotemporal resolutions. Without a proper understanding of DW variability, treatment efficiency can be overestimated or underestimated by as much as 25% from sporadic sampling. Sensor measurements at 6-min intervals over 3 hours are recommended to overcome uncertainty resulting from temporal variability during heavy drinking water demand in the morning. Reporting of sewage catchment areas, population sizes, and sampling times and intervals is recommended to compare WWTP efficiencies to overcome uncertainty resulting from spatiotemporal variability. The proposed model is a useful tool for understanding DW variability. It can be used to estimate the impact of spatiotemporal variability when measuring WWTP efficiencies, support improvements to sampling regulations for decentralized sanitation, and alternatively for designing and operating WWTPs.

Machine learning modeling for the prediction of phosphorus and nitrogen removal efficiency and screening of crucial microorganisms in wastewater treatment plants

The effectiveness of wastewater treatment plants (WWTPs) is largely determined by the microbial community structure in their activated sludge (AS). Interactions among microbial communities in AS systems and their indirect effects on water quality changes are crucial for WWTP performance. However, there is currently no quantitative method to evaluate the contribution of microorganisms to the operating efficiency of WWTPs. Traditional assessments of WWTP performance are limited by experimental conditions, methods, and other factors, resulting in increased costs and experimental pollutants. Therefore, an effective method is needed to predict WWTP efficiency based on AS community structure and quantitatively evaluate the contribution of microorganisms in the AS system. This study evaluated and compared microbial communities and water quality changes from WWTPs worldwide by meta-analysis of published high-throughput sequencing data. Six machine learning (ML) models were utilized to predict the efficiency of phosphorus and nitrogen removal in WWTPs; among them, XGBoost showed the highest prediction accuracy. Cross-entropy was used to screen the crucial microorganisms related to phosphorus and nitrogen removal efficiency, and the modeling confirmed the reasonableness of the results. Thirteen genera with nitrogen and phosphorus cycling pathways obtained from the screening were considered highly appropriate for the simultaneous removal of phosphorus and nitrogen. The results showed that the microbes Haliangium, Vicinamibacteraceae, Tolumonas, and SWB02 are potentially crucial for phosphorus and nitrogen removal, as they may be involved in the process of phosphorus and nitrogen removal in sewage treatment plants. Overall, these findings have deepened our understanding of the relationship between microbial community structure and performance of WWTPs, indicating that microbial data should play a critical role in the future design of sewage treatment plants. The ML model of this study can efficiently screen crucial microbes associated with WWTP system performance, and it is promising for the discovery of potential microbial metabolic pathways.

Characteristics of dissolved organic matter in point-source wastewaters at a petrochemical plant: Molecular constituents and contributions to the influent of wastewater treatment plant

Dissolved organic matter (DOM) in point-source petrochemical wastewaters (PCWs) from different operating units is closely linked to the efficiency of wastewater treatment plant (WWTP). However, systematic studies on DOM characters of point-source PCWs and their influences on WWTP influents were seldom conducted. In this study, DOM in three low-salinity point-source PCWs and four high-salinity point-source PCWs at a typical petrochemical plant were comprehensively characterized at a molecular level. Orbitrap mass spectrometry results indicated that point-source PCWs had diverse DOM constituents tightly related to the corresponding petrochemical processes. Phenols in oily wastewaters (OW), phenols and N-containing compounds in coal partial oxidation wastewater (POXW), and naphthenic acids (NAs) and aromatic acids in crude oil electric desalting unit wastewater (EDW) were characteristic DOM constituents for low-salinity point-source PCWs. While S-containing compounds (mercaptans, thiophenes) and NAs in spent caustic liquors (SCL), alcohols and esters in butanol-octanol plant wastewater (BOW), high molecular weight aromatic ketones in phenol-acetone plant wastewater (PAW), and oxygenated NAs as well as short chain N-containing compounds in concentrate from reverse osmosis unit (ROC) were characteristic DOM constituents for high-salinity point-source PCWs. Spearman correlation analysis indicated that though with relative low pollutant contents (OW) and discharge volume (EDW), N/O/S-containing compounds of OW and EDW greatly contributed to the polar DOM constituents of low-salinity influent in WWTP (R > 0.5, P < 0.001). While N-containing compounds of ROC mainly contributed to the polar DOM of high-salinity influent (R > 0.5, P < 0.001). Though N-/S-containing species in PAW had low contents, they also posed obvious impacts on DOM constituents of high-salinity influent. Interestingly, some O-/S-containing species were newly formed during the confluent process of high-salinity point-source PCWs. The results strengthened the combined contributions of pollutants contents, discharge emission and DOM constituents of point-source PCWs to the water matrix of WWTP influents, which would provide reference for the management of PCW streams.

An Assessment of Irrigation Water Quality with Respect to the Reuse of Treated Wastewater in Al-Ahsa Oasis, Saudi Arabia

Irrigation water quality is important to sustain agricultural productivity. The primary irrigation water sources in Al-Ahsa Oasis, KSA, are groundwater wells, mixed with treated wastewater and agricultural drainage. This study sought to evaluate irrigation water quality in Al-Ahsa Oasis with the aid of using irrigation water quality indices (IWQIs). One hundred and forty-eight different water samples were collected from various irrigation water resources throughout Al-Ahsa Oasis. The investigated physiochemical characteristics include pH, temperature, TDS, EC, turbidity, free chlorine, total hardness, cations (Na, K, Ca, Mg), anions (Cl, CO3, HCO3, SO4), organic matter indices (DO, BOD, COD), and nutrients (NH4, NO3, PO4). The IWQIs used in this study include salinity hazard, sodium adsorption ratio (SAR), Kelly’s ratio (KR), soluble sodium percentage (SSP), Permeability index (PI), residual sodium carbonate (RSC), and magnesium hazard (MH). The results indicated that treated wastewater mixed with groundwater is acceptable for irrigation. Spatial variations in irrigation water quality throughout Al-Ahsa are associated with water resources. For instance, groundwater mixed with agricultural drainage has the highest values of TDS, cations, and anions, whereas the lowest values were reported for treated wastewater, reflecting the good efficiency of wastewater treatment plants. The IWQI results revealed that 4.1% and 62.1% of the investigated irrigation water samples were considered good (class III) and satisfactory (class IV) for irrigation, respectively, whereas 33.8% of the collected water samples fall within the severe irrigation restrictions. Moreover, 79.7% of the investigated water samples were classified to have high to very high salinity hazards (C3, C4) and medium to high sodium hazards (S2, S3). Regular monitoring and assessment of treated water quality and wastewater treatment plant efficiency are important factors in achieving the sustainability of treated wastewater reuse in irrigation and consequently food security.

Searching for pharmaceutically active products and metabolites in environmental waters of Peru by HRMS-based screening: Proposal for future monitoring and environmental risk assessment

The presence of pharmaceutical active products (PhACs) in the aquatic environment is a matter of current concern, and there is an increasing trend to include these compounds in water quality monitoring programs and environmental risk assessments. Several studies have reported the presence of PhACs in environmental waters worldwide, but only a few studies have focused on Latin American countries. Thus, available information on the occurrence of parent pharmaceuticals, especially their metabolites, is very scarce. Peru is one of the less monitored countries in terms of contaminants of emerging concern (CECs) in waters, and only one study has been found, which was focused on the quantification of selected PhACs in urban wastewater and surface water. The aim of this work is to complement the previous data reported on PhACs in the aquatic environment by application of a wide-scope high-resolution (HRMS)-based screening, making use of target and suspect approaches. In the present work, 30 pharmaceuticals, drugs or other compounds (sweeteners, UV filters, etc.) and 21 metabolites have been identified, with antibiotics (and metabolites) being the most prevalent compounds. The use of liquid chromatography (LC) coupled to ion mobility-HRMS allowed the tentative identification of parent compounds and metabolites, for which the analytical reference standard was not available, with a high level of confidence in their identification. Based on the results obtained, a strategy for the monitoring of PhACs and relevant metabolites in environmental waters from Peru and for subsequent risk assessment is proposed. Our data will also help to focus future studies to evaluate the removal efficiency of wastewater treatment plants and the impact of treated water in receiving water bodies.

Tracing the fate of microplastic in wastewater treatment plant: A multi-stage analysis of treatment units and sludge

Microplastic (MP) pollution is ubiquitous in the environment presenting a global problem for both scientists and the general public. One of the major pathways of MPs entering the natural environment is through wastewater treatment plants (WWTPs). Once MPs reach the natural environment, they are posing threat to aquatic ecosystems and public health. The aim of this study is to investigate the concentration, morphology, and composition of MPs in different treatment units of a WWTP. Sampling included different points across WWTP in the water and sludge lines. Pre-treatment of the samples consists of advanced Fenton oxidation, and alkaline and enzymatic digestion followed by density separation. Once the particles were isolated, their morphology and size were studied using a stereoscopic and optical microscope followed by final confirmation with ATR-FTIR and micro-FTIR spectroscopy. Microplastic particle concentrations exhibit significant reductions as water undergoes treatment in the WWTP. For summer sampling, concentrations decreased from 351 MP/L (influent) to 35 MP/L (primary clarifier), 32 MP/L (biological reactor), and 13 MP/L (2.3 MP/L) (secondary clarifier). Similarly, winter sampling showed reductions from 403 MP/L (influent) to 159 MP/L (primary clarifier), 178 MP/L (biological reactor), and 26 MP/L (5.6 MP/L) (secondary clarifier). Removal efficiency of WWTP is high and exceeds 96%. The most abundant morphology is fibers followed by fragments and films. Polymers such as PE, synthetic cellulose, PP, PVC, PE-PP, PEEA, PA, acrylamide, and PES are widely detected in different units of WWTP. The number of MPs that are avoided from being emitted into the environment through direct water discharge was estimated to be 9.1 × 1012 MP/year. Removed MPs tend to accumulate in the sludge that is used for agricultural purposes although it should be managed as waste properly, avoiding the transition of MPs pollutants to terrestrial ecosystems adding to the number of MPs that will inevitably end up in receiving water bodies through direct WWTP effluent discharge that was set in 5.1 × 1010 MP/year in the studied WWTP.

Assessment of the Efficiency of Wastewater Treatment Plant in Oil and Gas Firm in Eleme Rivers State, Nigeria

The study aimed to determine the efficiency of a wastewater treatment plant and the quality of effluent discharged by the plant into the receiving water body (Okochiri River) in Eleme, Rivers State. The study lasted for four months. Wastewater samples were collected at various stages of the treatment unit and tested for major water quality parameter such as Biological Oxygen Demand (BOD), oil/grease, phenol, Dissolved Oxygen (DO), Total Suspended Solids (TSS), and sulphide. In general, the composite wastewater treatment system (comprising dissolve air floatation, Rotary Bio-Disk, and sedimentation unit) was effective in pollutant removal, except for sulphide, which had a negative efficiency (-238%). In line with Pearson Correlation, there are strong positive relationships between several parameters, such as pH and Sulphide (0.93), Phenol and Oil/grease (1.00), and Phosphate and Sulphide (0.91). The Principal Component Analysis yielded four principal components (PC1-4): PC1 parameters with the highest loadings on the first factor (D1) were sulphates and phenols, whereas Chemical Oxygen Demand and Biological Oxygen Demand had the highest loadings on the second factor (D2). Dissolved oxygen was most strongly associated with the third factor (D3), and pH was the parameter with the highest loading on the fourth factor (D4). It is recommended that the wastewater treatment system's overall efficiency be improved for the system to consistently meet regulatory limits for pollutant control. Recommendations for improving system efficiency include (1) ensuring regular maintenance of individual units in the treatment plant; and (2) maintaining optimal operating conditions for the rotary bio-disk unit.

Carbon emission efficiency evaluation of wastewater treatment plants: evidence from China.

A scientific evaluation of the carbon emission efficiency is crucial for ensuring the sustainable development of wastewater treatment plants (WWTPs). In this paper, we applied a non-radial data envelopment analysis (DEA) model to calculate the carbon emission efficiency of 225 WWTPs located in China.The results showed that the average carbon emission efficiency of China's WWTPs was 0.59, indicating that the efficiencies of most samples still require improvement. The carbon emission efficiency of WWTPs from 2015 to 2017 decreased because of the decrease in technology efficiency. Among the influencing factors, different treating scales had positive impact on carbon emission efficiency improvement. WWTPs with anaerobic oxic process and the first-class A standard were likely to have higher carbon emission efficiency in the 225 WWTPs. By incorporating direct and indirect carbon emissions into WWTP efficiency evaluation, this study helped decision-makers and related water authorities to better understand the contribution of WWTPs to the aquatic and atmospheric environments.

Development of IoT-Based Real-Time Monitoring System and LFA to Improve the Efficiency and Performance of Wastewater Treatment Plant in Udayana University Hospital

Indonesia is one of the countries infected by the Coronavirus Disease 2019 (COVID-19) pandemic, which is caused by acute respiratory syndrome virus 2 (SARS-CoV-2). At the end of March 2020, the provincial government of Bali appointed Udayana University Hospital to handle COVID-19 patients because the province has experienced an increase in the number of positive cases. In September 2020, COVID-19 cases in Bali increased by more than 100%, resulting in a higher volume and content of hazardous liquid waste. Furthermore, hazardous liquid waste is the residue of activities that contain substances that can pollute and damage the environment and health, necessitating more efforts in managing the processing of hazardous wastewater produced by the hospital. Based on the background above, this study developed and applied an Internet of Things (IoT) based monitoring system to the Wastewater Treatment Plant (WWTP) in Udayana University Hospital. In principle, the IoT system can be used as a real-time monitoring tool and minimizes direct contact activities of officers’ WWTP sites. Moreover, the Liquid Film Aerator (LFA) was applied to improve the efficiency of WWTP. The developed IoT system successfully monitors pH, DO, and real-time temperature, and the monitoring results were presented in a web-based user interface. The result shows better power usage efficiency than conventional aeration. Furthermore, conventional aeration with a root blower requires 619.8 watts to produce 1 mg/L of DO, while LFA only requires 273.2 watts. The developed systems can be applied to other hospitals or similar wastewater plants that handle COVID-19 cases.

A comprehensive assessment of energy efficiency of wastewater treatment plants: An efficiency analysis tree approach

Wastewater treatment plants (WWTPs) are energy intensive facilities. Controlling energy use in WWTPs could bring substantial benefits to people and environment. Understanding how energy efficient the wastewater treatment process is and what drives efficiency would allow treating wastewater in a more sustainable way. In this study, we employed the efficiency analysis trees approach, that combines machine learning and linear programming techniques, to estimate energy efficiency of wastewater treatment process. The findings indicated that considerable energy inefficiency among WWTPs in Chile existed. The mean energy efficiency was 0.287 suggesting that energy use should cut reduce by 71.3 % to treat the same volume of wastewater. This was equivalent to a reduction in energy use by 0.40 kWh/m3 on average. Moreover, only 4 out of 203 assessed WWTPs (1.97 %) were identified as energy efficient. It was also found that the age of treatment plant and type of secondary technology played an important role in explaining energy efficiency variations among WWTPs.

Enhancing the Energy Efficiency of Wastewater Treatment Plants through the Optimization of the Aeration Systems

The current geopolitical landscape of the European Union has made it clear that the energy sector must be a top priority in EU policy, especially in light of the sudden escalation of Russian–Ukrainian conflicts. Energy efficiency has been used as the first tool of EU policy to tackle energy and climate crises, given the issues surrounding energy vulnerability and the need to limit gas emissions that contribute to climate change. The white certificate mechanism in Italy has played a pivotal role in encouraging measures to achieve the country’s energy-saving goals. Given the high energy requirements of Wastewater Treatment Plants (WWTPs), especially for aeration in the biological section, this paper examines the replacement of the air distribution system for a large WWTP as a viable intervention. In order to provide economic perspective for the plant, both the discounted Payback Period (dPBP) and the Net Present Value (NPV) were calculated for the investment. When viewed through an economic lens, the dPBP metric exhibits values that span from less than 1 year to nearly 4.5 years. Additionally, the investment’s cost-effectiveness was emphasized by the NPV, which, depending on the factors considered, can exceed 17.5 million euros. Finally, given the centrality of the theme of climate change, the avoided greenhouse gas emissions generated by the efficiency intervention were calculated, according to the GHG Protocol, resulting in a quantity of avoided emissions equivalent to over 57,770 tonnes of CO2e. These results highlight important achievements in terms of both the cost-effectiveness of the plant and the reduction of greenhouse gas emissions.

Occurrence and removal of microplastics in a municipal wastewater treatment plant with conventional activated sludge process: A case study in Isfahan, Iran

Background: Microplastics (MPs) are nowadays found in the air and in various terrestrial and aquatic environments and have become emerging pollutants. These particles can absorb other chemicals and microbial contaminants and release them into the environment and food chain. Despite the high efficiency of wastewater treatment plants (WWTPs) in removing MPs, WWTPs are still one of the major sources of MPs discharge to the environment. This study was conducted to evaluate the efficiency of MPs removal in a municipal WWTP with conventional activated sludge in Iran. Methods: MPs particles were counted using a stereomicroscope after the initial preparation steps (sieving, chemical digestion with the catalytic wet peroxidation-oxidation and density separation with NaCl) and then analyzed for particle composition using a Raman micro-spectrometer. Results: MPs concentration in the influent, grit chamber, primary sedimentation tank, and effluent were 843.2±147.5, 315.5±54.7, 80.2±19.1, and 11.13±3.14 items/L, respectively. The overall MPs removal efficiency of the WWTP was 98.7%, with the grit chamber, primary sedimentation tank, and secondary sedimentation tank removed 62.6%, 27.9%, and 8.2% of the total MPs, respectively. The most abundant polymers were polypropylene (PP) and polyethylene (PE). Conclusion: Despite the effective removal of MPs in WWTP, on average 4.47×1011±1.03×1011 MPs are discharged into the receiving waters through the effluent of this WWTP annually. This means that WWTPs can be one of the major sources of MPs in the environment and efforts should be made to increase the efficiency of WWTPs and equip them with advanced technologies.

Review on technologies for improving energy efficiency of wastewater treatment plants: the case of the Hellenic water supply and sewerage company (EYATH SA)

Review on technologies for improving energy efficiency of wastewater treatment plants: the case of the Hellenic water supply and sewerage company (EYATH SA)

Review on technologies for improving energy efficiency of wastewater treatment plants: the case of the Hellenic water supply and sewerage company (EYATH SA)

Review on technologies for improving energy efficiency of wastewater treatment plants: the case of the Hellenic water supply and sewerage company (EYATH SA)

Coagulation and Flocculation Optimization Process Applied to the Sidestream of an Urban Wastewater Treatment Plant

Ammonium (NH4+) recirculation from the streams generated in the dehydration stage of the sludge generated in the anaerobic digestion of urban wastewater treatment plants (WWTPs), known as centrate or sidestream, produces a reduction in the efficiency of WWTPs. Given this scenario and the formulation that a WWTP should be considered a by-product generating facility (biofactory), solutions for ammonia/ammonium recovery are being promoted. These include a nitrogen source that reduces the need for ammonia production through the Haber–Bosch process. Therefore, the recovery of nutrients from urban cycles is a potential and promising line of research. In the case of nitrogen, this has been aimed at recovering NH4+ to produce high-quality fertilizers through membrane or ion exchange processes. However, these techniques usually require a pretreatment, which could include an ultrafiltration stage, to eliminate suspended solids and organic matter. In this case, the coagulation/flocculation (C/F) process is an economical alternative for this purpose. In this work, the sidestream from Vilanova i la Geltrú WWTP (Barcelona, Spain) was characterized to optimize a C/F process before being treated by other processes for ammonium recovery. The optimization was performed considering a bibliographic and experimental analysis of several operating parameters: coagulant and flocculant agents, mixing velocity, and operation time, among others. Then, the removal efficiency of control parameters such as turbidity, chemical oxygen demand (COD), and total suspended solids (TSS) was calculated. This optimization resulted in the use of 25 mg/L of ferric chloride (FeCl3) combined with 25 mg/L of a flocculant composed of silicon (SiO2 3%), aluminum (Al2SO4 64.5%), and iron salts (Fe2O3 32.5%), into a 1 min rapid mixing process at 200 rpm and a slow mixing for 30 min at 30 rpm, followed by a final 30 min settling process. The numerical and statistical results of the process optimization reached 91.5%, 59.1%, and 95.2% removal efficiency for turbidity, COD, and TSS, respectively. These efficiencies theoretically support the enhanced coagulation/flocculation process as a pretreatment for a higher NH4+ recovery rate, achieving 570.6 mgNH4+/L, and a reduction in the dimensioning or substitution of other membrane processes process due to its high TSS removal value.

Ciliate Communities Respond via Their Traits to a Wastewater Treatment Plant With a Combined UASB–Activated Sludge System

Assessing functional diversity of communities is an efficient method to link community composition to ecosystem quality. Still, studies using functional traits of microeukaryote ciliate communities in biological wastewater treatment plants are lacking. The present work explores the functional diversity of the ciliate protist community in a wastewater treatment plant (WWTP) operating with a combined UASB-activated sludge system, and specifically to: 1) investigate the taxonomic and functional composition of the ciliate communities over time; 2) compare taxonomic and functional diversity indices with regard to its applicability in WWPS; 3) assess the relationship between the ciliate community’s functional composition and the WWTPs temporal conditions; and 4) investigate the potential use of functional diversity as an indicator of WWTP efficiency. Totally, we recorded 21 ciliate species throughout 37 samplings. The number of species was low compared to other plants. Bacterivorous and flake-forming species were the main functional strategies found in the samples. The correlation between taxonomic and functional richness was significant, indicating a functionally redundant community. There was a correlation between the Simpson and Rao’s quadratic entropy indexes suggesting that loss of taxonomic diversity leads to a loss of functional diversity. The homogeneity of the measured physical and chemical data led to functional homogenization and redundancy (homogenous CWM) of the ciliate community. The functional diversity is positively correlated with parameters of removal efficiency, indicating a promising application in WWTPs. Future studies will broaden knowledge on functional diversity in biological wastewater treatment systems, this being a first step with the unprecedented application of this methodology in artificial ecosystems.

Abundance and Niche Differentiation of Comammox in the Sludges of Wastewater Treatment Plants That Use the Anaerobic-Anoxic-Aerobic Process.

Complete ammonia oxidizers (comammox), which directly oxidize ammonia to nitrate, were recently identified and found to be ubiquitous in artificial systems. Research on the abundance and niche differentiation of comammox in the sludges of wastewater treatment plants (WWTPs) would be useful for improving the nitrogen removal efficiency of WWTPs. Here, we investigated the relative abundance and diversity of comammox in fifteen sludges of five WWTPs that use the anaerobic–anoxic–aerobic process in Jinan, China, via quantitative polymerase chain reaction and high-throughput sequencing of the 16S rRNA gene and ammonia monooxygenase gene. In the activated sludges in the WWTPs, comammox clade A.1 was widely distributed and mostly comprised Candidatus Nitrospira nitrosa-like comammox (>98% of all comammox). The proportion of this clade was negatively correlated (p < 0.01) with the dissolved oxygen (DO) level (1.7–8 mg/L), and slight pH changes (7.20–7.70) affected the structure of the comammox populations. Nitrospira lineage I frequently coexisted with Nitrosomonas, which generally had a significant positive correlation (p < 0.05) with the DO level. Our study provided an insight into the structure of comammox and other nitrifier populations in WWTPs that use the anaerobic–anoxic–aerobic process, broadening the knowledge about the effects of DO on comammox and other nitrifiers.

Performance Evaluation of Wastewater Treatment Plants in El-Fayoum

The present study has been undertaken to evaluate performance efficiency of wastewater treatment plants (WWTPs) in El-Fayoum Markaz, El-Fayoum governorate in Egypt. The wastewater treatment plants using different treatment techniques were Active sludge, Oxidation ponds, Secondary - active sludge and Chemical (nanotechnology) which wastewater samples were collected from both influent and effluent of each plant. The key performance of each plant is estimated based on the treated wastewater quality data. Based on the results, they showed that Old Quhafa (Secondary - active sludge technology) operates with removal efficiencies higher than 80% for biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) were established. While Ezbet Ashour accomplished lowest performance efficiency that operates with chemical-nanotechnology. This analysis applied to define a performance measuring plan based on the most important parameters that can be reliable and applicable for any WWTP. The study suggested formula for performance WWTPs that described by the expressing removal efficiencies as relative values or percentages and the remaining fraction. The study recommended that sedimentation units must be cleaned, monitoring frequently of sludge analysis and calculation of building capacity for all WWTPs.

Decentralized sanitation solutions for temporal Internally Displaced people (IDPs) and refugees camps and residential complexes in Duhok province – Case study

The conditions of the settlements are often very poor with deficiencies in basic supplies like water. This study aims to: (i) assess the sanitation service level for Internally Displaced People (IDPs) and refugee camps in Duhok province / Kurdistan of Iraq (ii) assess the performance of wastewater treatment plants (WWTPs) and offer different scenarios to improve the sanitation service level in the Duhok province (iii) propose various decentralized treatment approaches. To demonstrate the efficiency of WWTPs, samples of generated wastewater at the effluent of 12 residential projects were collected to conduct the COD test. The results of COD test were found to exceed the permissible level of 100 mg/L set by Iraqi wastewater standard except in New Zakho and Avro city projects. The highest generation rates of grey and black wastewater were in Chamishko and Kaberto1 IDP camps and were 1013 and 3000 m 3 /day respectively. Both Avro city and War city residential complexes were notably discharging the highest rates of wastewater at the effluent with 5610 and 2484 m 3 /day respectively. Lelav city, New Jin city, and Dabin projects were found to have the maximum organic loading rate of COD with 745, 578, and 332 kg/day respectively. This study proposed Waste Stabilization Pond (WSP) systems to be constructed in both Domiz1 refugee camp and Chameshko IDP camp. In order to be more achievable, it is suggested that the regulations of disposed wastewater at the effluent be amended and categorized on a class basis rather than using a single effluent number.