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Around the world, it is growing harder to provide clean and safe drinking water. In wastewater treatment, sensors are employed, and the Internet of Things (IoT) is used to transmit data. Chemical oxygen demand (COD), biochemical demand (BOD), total nitrogen (T-N), total suspended solids (TSS), and phosphorous (T-P) components all contribute to eutrophication, which must be avoided. The wastewater sector has lately made efforts to become carbon neutral; however, the environmental impact and the road to carbon neutrality have received very little attention. The challenges are caused by poor prediction. This research proposes deep learning modified neural networks (DLMNN) with Binary Spotted Hyena Optimizer (BSHO) for modeling and calculations to address this challenge. All efforts for resource recovery, water reuse, and energy recovery partially attain this objective. In contrast to previous modeling techniques, the DLMNN-training BSHOs and validation demonstrated outstanding accuracy shown by the model's high coefficient (R2) for both training and testing. Also covered are recent developments and problems with nanomaterials made from sustainable carbon and graphene quantum dots, as well as their uses in the treatment and purification of wastewater. The proposed model DLMNN-BSHO achieved 95.936% precision, 95.326% recall, 93.747% F-score, and 99.637% accuracy. HIGHLIGHTS The carbon neutrality has received much attention for water treatment.; The deep learning modified neural networks (DLMNN) with Binary Spotted Hyena Optimizer (BSHO) for modeling were used.; The proposed model DLMNN-BSHO achieved 95.936% precision, 95.326% recall, 93.747% F-score, and 99.637% accuracy.;

The design, implementation and use of wastewater treatment systems (WTS) are fundamental to mitigate hydrological and environmental problems, and to improve population health. Furthermore, the significant advances in treatment systems technology offer, nowadays, several alternatives and provide many combinations of WTS which must be correctly evaluated and constitute a decision problem for public and private investors and decision makers. Thus, this article presents a multi-criteria methodology based on six steps for the evaluation of WTS considering relevant economic, social, technical and environmental criteria. Particularly, forty-eight main criteria were identified and ranked considering their importance based on the previous literature. This methodology was applied in a Brazilian sanitation company in a specific treatment area of approximately five thousand inhabitants and with recurrent environmental problems, such as the contamination and low efficiency of wastewater treatment. Twenty available alternatives were considered and twelve criteria were selected for this application. The AHP and ELECTRE II methods were combined to weight the different criteria and to rank the most suitable WTS. This methodology can be extended and applied in different scenarios to improve the decision-making process. [ABSTRACT FROM AUTHOR]

Some developing countries do not have efficient wastewater treatment systems, either because of economic problems or limited knowledge of viable low-cost alternatives despite it is an option to improve water quality. This document presents a review, which analyzes different wastewater treatment plants in Colombia. The aim is to identify the evolution of these technologies and possible alternatives, processes of removal, costs, and feasibility regarding the operation. The analysis shows that in Colombia, the common treatments are activated sludge, stabilization ponds, and artificial wetlands. Most of these treatments achieve 80% removal of Biochemical Oxygen Demand, Chemical Oxygen Demand, and Suspended Solids. If these procedures are used together, the percentage of efficiencies will be higher than 90%, highlighting the economic viability of biological processes. Additionally, the study evidences the relevance of improving wastewater treatment systems to minimize pollution in surface and groundwater, considering that only about 30% of the total wastewater generated or received by the sewage systems is being intervened. [ABSTRACT FROM AUTHOR]

The ideal configuration of wastewater treatment system (WTS) for attending cities specificities has become a complex decision, due to the fact that there are several available technologies, and a diversity of characteristics presented in the scenario of each city. Considering the importance of economic analysis, especially in developing countries, this work aims to demonstrate the economic feasibility considering cost-related indicators for the ideal WTS selection for specific features in these cities. Based on a literature review, 37 main WTS and two economic cost-related indicators (Net Present Value and Annualized Net Present Value) were considered. First of all, using a multicriteria analysis these WTS were grouped in classes using the ELECTRE TRI method, based on criteria related to efficiency, and the weights were defined by appointments from research specialists in the literature appointments. The economic analysis was performed using the Monte Carlo Simulation (MCS) method, which has been applied specifically to each WTS class, thus generating a framework of economic viability for this context. The WTS with low and high costs were appointed, considering the development level in each applied scenario. This work contributes to expanding the WTS study horizons to select an ideal system, considering the economic aspect. [ABSTRACT FROM AUTHOR]

New EC standards published in 2009 led to a surge in onsite wastewater treatment systems reaching the European market. Here we summarize their technical aspects and compare them to known values used in centralized wastewater treatment. The paper deals with two types of processes: attached-growth systems (AGS) on fine media and suspended-growth systems (SGS). Covering 141 technical approvals and 36 manufacturers, we compare onsite design criteria against the centralized wastewater design criteria for each process. The systems use a wide range of materials for bacterial growth, from soil, sand or gravel to zeolite, coconut shavings or rockwool cubes, with a huge range of variation in useful surface, from 0.26 m 2 /PE for one rockwool cube filter to 5 m 2 /PE for a (traditional system) vertical sand filter. Some rockwool can handle applied daily surface load of 160 g BOD 5 /m 2 . SGS design parameters range from 0.025 to 0.34 kg BOD 5 per kg MLVSS/d with hydraulic retention times of 0.28–3.7 d. For clarifier design, water velocity ranges from 0.15 to 1.47 m/h. In the sludge line, sludge storage volume ranges from 0.125 down to just 0.56 m 3 /PE. [ABSTRACT FROM AUTHOR]

In this study, the current operation efficiency of the wastewater treatment plant (WWTP) in the city of Kłodzko in the Lower Silesia Voivodeship (Poland) was analyzed and the predicted amount of the wastewater flowing to the WWTP in a 20-year period (until the year 2036) was estimated. The data on the quality and the quantity of raw (entering to the WWTP) and treated sewage from the years 2012-2016 were analyzed. The five essential pollutants indicators: biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), total suspended solids (TSS), total nitrogen and total phosphorus, regulated in the water permit were used to evaluate the efficiency of contaminants removal. On the basis of the percentage reduction of the individual pollutants indicators and their acceptable concentrations in the treated sewage, the effectiveness of the operation of the object was determined. Furthermore, a so-called the treatment plant reliability factor (RF) was calculated and its value below 1.0 indicates the correct operation of the wastewater treatment plant. After determining the prospective amount of raw sewage in 2036 (based on the decreasing population in the city) it has been found that the WWTP will work with a significant reserve of capacity and the modernization of the treatment system, leading to a decrease of its capacity should be considered. [ABSTRACT FROM AUTHOR]

The occurrence of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs) has been intensively investigated for wastewater treatment systems treating single class of antibiotic in recent years. However, the impacts of alternately occurring antibiotics in antibiotic production wastewater on the behavior of ARGs in biological treatment systems were not well understood yet. Herein, techniques including high-capacity quantitative PCR and quantitative PCR (qPCR) were used to investigate the behavior of ARGs in an anaerobic-aerobic full-scale system. The system alternately treated three kinds of antibiotic production wastewater including ribostamycin, spiramycin and paromomycin, which referred to stages 1, 2 and 3. The aminoglycoside ARGs (52.1-79.3%) determined using high-capacity quantitative PCR were the most abundant species in all sludge samples of the three stages. The total relative abundances of macrolide-lincosamide-streptogramin (MLS) resistance genes and aminoglycoside resistance genes measured using qPCR were significantly higher ( P < 0.05) in aerobic sludge than in sewage sludge. However, the comparison of ARGs acquired from three alternate stages revealed that MLS genes and the aminoglycoside ARGs did not vary significantly ( P > 0.05) in both aerobic and anaerobic sludge samples. In aerobic sludge, one acetyltransferase gene ( aacA4) and the other three nucleotidyltransferase genes ( aadB, aadA and aadE) exhibited positive correlations with intI1 ( r = 0.83-0.94; P < 0.05), implying the significance of horizontal transfer in their proliferation. These results and facts will be helpful to understand the abundance and distribution of ARGs from antibiotic production wastewater treatment systems. [ABSTRACT FROM AUTHOR]

The current study developed a rationalized method for the quantification and identification of engineered nanoparticles (ENPs) in wastewaters. A review of current literature revealed that overall, presently available methods focused on single ENP mostly and were applicable mainly to samples of low organic loadings or under well-controlled laboratory conditions. In the present research, procedures including dialysis for desalting and low-temperature oxidation for organic removal were used to pretreat samples of high organic loadings, specifically, municipal wastewater and sludge. SEM mapping technique identified the presence of nanoparticles, which was followed by ICP-OES quantification of different engineering nanoparticles in wastewater and sludge samples collected from two major regional municipal wastewater treatment plants. Results showed successful identification and quantification of nano-size titanium and zinc oxides from wastewater treatment plants studied. Concentration profile was mapped out for the wastewater treatment plants (WWTPs) using the method developed in this research. Results also showed an overall 80% and 68% removal of titanium and zinc by primary and secondary sludge particulates, respectively. Mass flux of engineered nanoparticles (ENPs) was also calculated to estimate the daily flow of engineered nanoparticles in the system. [ABSTRACT FROM AUTHOR]

The operation quality of a wastewater treatment system influences its effluent quality, treatment cost, and performance stability. The aim of this research is to aid wastewater plants surpass extraordinary situations by using a neural network approach leading to an early warning system. Sensitivity analysis methods are proposed to evaluate influence and time interval. The factor majorly influencing the effluent quality is the recycle ratio, which has the fastest response time and can be selected as a crucial operational variable for the optimal dynamic operation of the wastewater treatment system. The results show that the use of statistical methods, network experiment designs, and sensitivity analyses of input or output variables of wastewater treatment plants can successfully build a wastewater prediction model. [ABSTRACT FROM AUTHOR]

The remediation of four estrogenic endocrine-disrupting compounds (EDCs), estrone (E1), estradiol (E2), ethinylestradiol (EE2) and estriol (E3), was measured in saturated and unsaturated carbonate sand-filled columns dosed with wastewater from a sewage treatment plant. The estrogen equivalency (EEQ) of inlet wastewater was 1.2 ng L and was remediated to an EEQ of 0.5 ng L through the unsaturated carbonate sand-filled columns. The high surface area of carbonate sand and associated high microbial activity may have assisted the degradation of these estrogens. The fully saturated sand columns showed an increase in total estrogenic potency with an EEQ of 2.4 ng L, which was double that of the inlet wastewater. There was a significant difference ( P < 0.05) in total estrogenic potency between aerobic and anaerobic columns. The breakdown of conjugated estrogens to estrogenic EDCs formed under long residence time and reducing conditions may have been responsible for the increase in the fully saturated columns. This may also be explained by the desorption of previously sorbed estrogenic EDCs. The effect of additional filter materials, such as basalt sediment and coconut fibre, on estrogenic EDC reduction was also tested. None of these amendments provided improvements in estrogen remediation relative to the unamended unsaturated carbonate sand columns. Aerobic carbonate sand filters have good potential to be used as on-site wastewater treatment systems for the reduction of estrogenic EDCs. However, the use of fully saturated sand filters, which are used to promote denitrification, and the loss of nitrogen as N were shown to cause an increase in EEQ. The potential for the accumulation of estrogenic EDCs under anaerobic conditions needs to be considered when designing on-site sand filtration systems required to reduce nitrogen. Furthermore, the accumulation of estrogens under anaerobic conditions such as under soil absorption systems or leachate fields has the potential to contaminate groundwater especially when the water table levels fluctuate. [ABSTRACT FROM AUTHOR]

Anaerobic processes in wastewater treatment and excess sludge digestion are desirable as these offer the prospect of energy recovery via the methane gas generated. However, hydrogen sulfide (H2S) generated from reduction of sulfate by sulfate reducing bacteria (SRB) during the process, is inhibitory to the methane producing bacteria (MPB). The SRBs and MPBs also compete for utilization of a key substrate in methanogenesis, volatile fatty acids. For development of effective methods to mitigate the adverse impact of SRBs on methanogenesis, it is important there is better understanding of the SRBs and this can begin with knowing which species are likely to be present in wastewater treatment. With this objective in mind, species of SRBs isolated from wastewater treatment systems reported in the literature have been summarized in this paper and discussed. [ABSTRACT FROM AUTHOR]

Wastewater infrastructure has a long lifetime and is subject to changing conditions and demands. When plans are made to upgrade or build new infrastructure, transdisciplinary planning processes and a robust analysis of future conditions are needed to make sustainable choices. Here, we provide a stepwise collaborative planning process in which future scenarios are developed together with local stakeholders and expert groups. The process was implemented at one of the largest wastewater treatment plants (WWTPs) in Scandinavia. With a combination of workshops and the use of a web-based digital tool, future scenarios including flows, pollutant loads, and treatment requirements could be created. Furthermore, sustainability prioritizations affecting the WWTP, were identified. The future scenarios developed for the WWTP in the case study, predict stricter and new regulations, constant or lower future loads and ambiguous future flows. The highest ranked sustainability priority was low resource and energy consumption t ogether with low CO 2 footprint. The quantified future scenarios developed in the planning process were used as input to a process model to show the consequences they would have on the WWTP in the case study. Applying this collaborative process revealed future scenarios with many, sometimes conflicting, expectations on future WWTPs. It also highlighted needs for improvements of both the collection system and the WWTP. [Display omitted] • A process involving stakeholders and experts to build future scenarios was developed. • Simulating future scenarios showed potential impacts and needs for upgrade. • Sustainability priorities were predicted. • New and stricter requirements on future WWTPs were predicted. • Future scenarios revealed conflicting expectations on future WWTPs. [ABSTRACT FROM AUTHOR]

Most wastewater treatment facilities were built when energy costs were not a concern; however, increasing energy demand, changing climatic conditions, and constrained energy supplies have resulted in the need to apply more energy-conscious choices in the maintenance or upgrade of existing wastewater treatment facilities. This research develops an integrated energy and environmental management systems model that creates a holistic view of both approaches and maps linkages capable of meeting high-performing energy management while meeting environmental standards. The model has been validated through a case study on the Rolla, Missouri Southeast Wastewater Treatment Plant. Results from plant performance data provide guidance to improve operational techniques. The significant factors contributing to both energy and environmental systems are identified and balanced against considerations of cost. [ABSTRACT FROM AUTHOR]

This paper refers generally to the Planned Industrial Estates (PIEs) established under Greek Law 2545/97. A number of key features of PIEs are discussed here, including the prefectures in which the estates are established, the Greek Official Gazettes in which the establishment acts were published, the surface area in acres to be covered by the estates, the years of completion of the infrastructure, and the numbers of established businesses involved. The paper also refers to the infrastructure that should exist in a PIE and, in particular, to the wastewater collection network and the wastewater treatment plants (WTPs). The key features of the wastewater treatment systems of all Planned Industrial Estates in Greece established under Law 2545/97 (14 case studies) are presented in the form of a table and are analysed using economical, environmental, and operational criteria. The analysis shows that for the small Planned Industrial Estates (i.e., industrial parks--IPs--and light industry parks--LIPs), it is economically, environmentally, and operationally preferable for industrial wastewater to be disposed of into large operating municipal wastewater treatment plants, rather than into decentralised systems within IPs and LIPs, given that the municipal plants have excess capacity, are at a relatively small distance from the PIEs, and are compatible with the required treatment. The analysis highlights the need to initiate an integrated techno-economic study in view of the new Operational Programme, "Competitiveness and Entrepreneurship", of the Greek Ministry of Economy for the period from 2007 to 2013, which was co-financed by the European Union, and will include actions related to the development of new PIEs. [ABSTRACT FROM AUTHOR]

The work reviewed here was published between 2008 and 2010 and describes research that involved aerobic and anoxic biofilm treatment of water pollutants. Biofilm denitrification systems are covered when appropriate. References catalogued here are divided on the basis of fundamental research area or reactor types. Fundamental research into biofilms is presented in two sections, Biofilm Measurement and Characterization and Growth and Modeling. The reactor types covered are: trickling filters, rotating biological contactors, fluidized bed bioreactors, submerged bed biofilm reactors, biological granular activated carbon, membrane bioreactors, and immobilized cell reactors. Innovative reactors, not easily classified, are then presented, followed by a section on biofilms on sand, soil and sediment. [ABSTRACT FROM AUTHOR]

The performance of seven small commercial greywater treatment systems installed in private gardens was tested and the effluent quality compared against current Israeli standards for irrigation in cities. Additionally, the potential environmental effects of irrigation with insufficiently treated greywater on soils and plants were evaluated in a pot study. The bulk of the small systems currently proposed for greywater treatment fall into one of two categories. Some are filtration systems that provide minimal treatment. The others are small-scale domestic wastewater-treatment systems. Neither system is designed to handle the differences in flow or composition that greywater presents. Both are thus unsuitable. Moreover, it was demonstrated that the use of insufficiently treated greywater for irrigation might have detrimental environmental effects. Proper standards, their enforcement and education are necessary to resolve the potential risks currently associated with greywater re-use. [ABSTRACT FROM AUTHOR]

The newly discovered process complete ammonia oxidation (comammox) has changed the traditional understanding of nitrification. In this study, three possible concepts of comammox were developed and incorporated as part of an extended two-step nitrification model. For model calibration and validation, two series of long-term biomass washout experiments were carried out at 12 °C and 20 °C in a laboratory sequencing batch reactor. The inoculum biomass was withdrawn from a large biological nutrient removal wastewater treatment plant. The efficiency of the examined models was compared based on the behaviors of ammonia, nitrite, and nitrate in the studied reactor. Predictions of the conventional approach to comammox, assuming the direct oxidation of ammonia to nitrate, were slightly better than the two other approaches. Simulation results revealed that comammox could be responsible for the conversion of >20% of the influent ammonia load. Therefore, the role of commamox in the nitrogen mass balance in activated sludge systems should not be neglected and requires further investigation. Furthermore, sensitivity and correlation analysis revealed that the maximum growth rates (μ), oxygen half-saturation (K O), and decay rates (b) of the canonical nitrifiers and comammox were the most sensitive factors, and the highest correlation was found between μ and b among all considered kinetic parameters. The estimated μ values by the best model were 0.57, 0.11, and 0.15 d−1 for AOB, NOB, and comammox bacteria, respectively. [Display omitted] • Three conceptual models of complete ammonia oxidation (comammox) were proposed. • Comammox was incorporated in ASM1 as part of a two-step nitrification model. • The expanded model accurately predicted the behavior of N components in a SBR. • Commamox can contribute to the conversion (>20%) of ammonia to nitrite/nitrate. • The μ value for commamox bacteria ranged from 0.2 to 0.6 d−1 depending on the model. [ABSTRACT FROM AUTHOR]

At present, most rivers, lakes, and reservoirs in Mexico have significant anthropogenic contamination. The lack of sanitation infrastructure, the increase in the number of nonoperational or abandoned sanitation facilities, limited enforcement of environmental regulations, and limited public policies for the reuse of treated wastewater all contribute to the contamination and water availability problem. The reasons for this are identified as (1) the high maintenance and operational costs in sanitation facilities (including electricity consumption); (2) poor planning and practices of wastewater management and reuse by municipalities; (3) national policies that do not favor the reuse of treated wastewater for agriculture, industry, and municipal services instead of using groundwater as at present; (4) failure to adopt a governance model at the three levels of government; and (5) transparency in the management of financial resources. Some measures to improve this situation include (a) transparent decision-making; (b) participation and accountability in budgeting and planning at the national, state, and municipal levels; and (c) planning for the reuse of treated wastewater to reduce groundwater extractions and to reduce discharges to surface waters from the beginning of every WWTP project. [ABSTRACT FROM AUTHOR]

Greenhouse gases (GHGs; particularly, CO 2 , CH 4 , and N 2 O) emission from wastewater treatment systems (WWTS) is one of the inevitable concerns for sustainable development. This indicator is directly linked with the carbon footprint and potential impacts of WWTS on climate change. In this view, various modeling, design, and operational tools have been introduced to mitigate the WWTS associated GHGs, at regional and global scales. In this study, authors have critically reviewed the selected potential operational control strategies for GHGs emission, particularly emitted from the operational stages of biological WWTS. The investigated operational control strategies and/or treatment configurations included intermittent aeration, varying dissolved oxygen, enhanced sludge retention time, coupled aerobic–anoxic nitrous decomposition operation, and microalgae integrated treatment process. Based on this analysis and considering the trade-off between treatment performance of WWTS and GHGs control, an integrated framework is also proposed for existing and upcoming WWTS. The findings of this study and proposed framework will play an instrumental role in mitigating the GHGs at various operational stages of WWTS. Future research works in this direction can lead to a better understanding of investigated operational GHGs emission control strategies in WWTS. • GHGs emissions control in WWTS is an inevitable sustainability concern. • Potential operational GHGs control strategies are discussed in this manuscript. • IA, DO, CANDO, microalgae assisted process, and enhanced SRT are investigated in this study. • An integrated framework for GHGs control through operational strategies is suggested. [ABSTRACT FROM AUTHOR]

Antibiotics can affect microbial community structure and promote antibiotic resistance. However, the course of microbial community recovery in wastewater treatment systems after antibiotic disturbance remains unclear. Herein, multiple molecular biology tools, including 16S amplicon sequencing, GeoChip 5.0, quantitative polymerase chain reaction (qPCR), and metagenomic sequencing, were used to investigate the year-long (352 d) recovery of the microbial community functional structure in an aerobic biofilm reactor. Nitrification was completely inhibited under 50 mg/L of streptomycin spiking (STM_50) due to the significant reduction of ammonia-oxidizing bacteria, but recovered to original pre-disturbance levels after streptomycin removal, indicating the high resilience of ammonia-oxidizing bacteria. Bacterial community richness and diversity decreased significantly under STM_50 (p < 0.05), but recovered to levels similar to those observed before disturbance after 352 d. In contrast, bacterial composition did not recover to the original structure. The carbon degradation and nitrogen cycling functional community significantly changed after recovery compared to that observed pre-disturbance (p < 0.05), thus indicating functional redundancy. Additionally, levels of aminoglycoside and total antibiotic resistance genes under STM_50 (relative abundance, 0.33 and 0.80, respectively) and after one year of recovery (0.12 and 0.29, respectively) were higher than the levels detected pre-disturbance (0.04 and 0.24, respectively). This study provides an overall depiction of the recovery of the microbial community functional structure after antibiotic exposure. Our findings give notice that recovery caused by antibiotic disturbance in the water environment should be taken more seriously, and that engineering control strategies should be implemented to prevent the antibiotic pollution of wastewater. Image 1 • Long-term microbiome restoration after streptomycin exposure were evaluated. • Nitrification and amoA gene abundance could be recovered. • Bacterial composition could not recover to the original structure. • Microbial functional community significantly changed. • ARG abundance did not return to original levels after one year of recovery. [ABSTRACT FROM AUTHOR]