Improved Wastewater Management Research Articles

Principal Component Analysis (PCA) of MALDI-TOF for the Identification of Waterborne Pathogenic Bacteria

The study focuses on the application of Principal Component Analysis (PCA) combined with MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry) for the identification of waterborne pathogenic bacteria in urban water networks. In this comprehensive research, 168 bacterial strains were meticulously isolated from the water networks of Abidjan, Côte d'Ivoire, a region known for its inadequate wastewater treatment infrastructure. The analysis aimed to rapidly and precisely identify these bacterial pathogens, leveraging the power of MALDI-TOF MS and the sophisticated data reduction capabilities of PCA. This approach not only accelerates the identification process but also enhances the accuracy of detecting various pathogens. The study identified a diverse range of pathogens, including Pseudomonas aeruginosa, Escherichia coli, Salmonella, Shigella, Vibrio cholerae, Morganella morganii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Providencia rettgeri, Providencia stuartii, Aeromonas hydrophila, Bacillus cereus, Lysinibacillus fusiformis, Lysinibacillus sphaericus, and Staphylococcus aureus. These findings underscore the critical public health risks posed by microbial contamination in water networks, particularly in areas with deficient waste management systems. This study highlights the necessity for improved wastewater management practices, robust public health strategies, and regular monitoring to mitigate the risks associated with waterborne pathogens. Moreover, the integration of PCA with MALDI-TOF MS proves to be a powerful tool for enhancing the efficiency and accuracy of pathogen identification in environmental water samples, offering a promising solution for better public health protection and water quality management in urban settings.

Effectiveness of Eco Enzymes in Reducing Chemical Parameters of Tofu Factory Liquid Waste in Klumutan Village, Saradan District

The tofu industry generates substantial liquid waste that poses environmental challenges due to its high chemical oxygen demand (COD), total suspended solids (TSS), and pH levels. This study aimed to determine the effectiveness of Eco Enzymes in reducing these chemical parameters in the tofu industry waste in Klumutan Village, Saradan District. Utilizing a Quasi-Experimental method, the research employed purposive sampling of liquid waste from tofu production. The findings revealed that the application of Ecoenzyme at doses of 5%, 10%, and 15%, with detention times of 10, 15, and 20 days, significantly reduced COD, TSS, and pH levels. The results showed that both the dosage and detention time had a substantial impact on the effectiveness of Ecoenzyme in treating the waste. The implications of this study suggest that Eco Enzymes can be an effective, eco-friendly solution for improving wastewater management in the tofu industry, thereby contributing to environmental sustainability.

Efficiency of EMB Medium Combined with MALDI-TOF in Isolating and Identifying Coliform Lactose Fermenters and Non-Lactose Fermenters from Wastewater

In Côte d'Ivoire, the sewer network is largely underdeveloped, resulting in the absence or incompleteness of sanitation infrastructure in many urban and rural areas. This lack of infrastructure leads to untreated wastewater being frequently discharged into rivers and other sources of drinking water. The contamination of water sources by untreated wastewater spreads waterborne diseases, which particularly affect children and vulnerable populations. Coliforms, as key indicators of the microbiological quality of water, play a crucial role in assessing health risks. The presence and diversity of these coliforms can provide insights into the extent of water contamination and the potential health risks to the population. This study focuses on the diversity of lactose-fermenting and non-lactose-fermenting coliforms in the wastewater of Abidjan. The objective is to use MALDI-TOF mass spectrometry for the rapid and accurate identification of these coliforms, thereby providing a detailed understanding of the microbiological quality of wastewater. The study aims to identify the predominant coliform species present in the wastewater and assess their potential impact on public health. Out of 80 wastewater samples collected from various locations in Abidjan, a preponderance of lactose-fermenting coliforms was found. The most frequently identified species were Klebsiella pneumoniae and Escherichia coli. The results showed that these species were present in significantly higher numbers compared to non-lactose-fermenting coliforms. The use of MALDI-TOF mass spectrometry allowed for rapid and precise identification of the coliforms, facilitating a comprehensive analysis of the microbiological quality of the wastewater. These findings underscore the urgent need for improved wastewater management strategies in Abidjan and similar urban settings in Côte d'Ivoire. The high prevalence of lactose-fermenting coliforms, particularly Klebsiella pneumoniae and Escherichia coli, in untreated wastewater poses significant public health risks. Effective wastewater treatment and management are essential to protect public health, reduce the spread of waterborne diseases, and limit the development of antimicrobial resistance. Implementing such measures will require coordinated efforts from local authorities, public health officials, and the community to ensure safe and sustainable water practices.

Biocomposite Based on Polyhydroxybutyrate and Cellulose Acetate for the Adsorption of Methylene Blue

Industrialization and globalization have caused severe environmental problems, such as contaminating water bodies by toxic agents from various industries, generating a significant loss of biodiversity and health risks. Globally, approximately 80% of wastewater is discharged without treatment, worsening the situation. However, in Colombia, initiatives have been taken to improve wastewater management, with ambitious investments and targets to improve treatment infrastructure. Recently, advanced technologies have been developed to treat wastewater, including more efficient and sustainable biological methods, such as using coconut-derived adsorbent biomaterials, rich in useful properties for the adsorption of pollutants in solutions. This research focuses on developing a composite biomaterial using cellulose acetate (CA) extracted from coconut mesocarp and polyhydroxy butyrate (PHB), by the casting method, to treat wastewater. Adsorption tests with the tracer methylene blue (MB) were carried out in the Energy and Environment laboratory of the University of Cartagena. For this, MB solutions were prepared with 5 to 50 ppm concentrations. The analyses showed that the composite biomaterial is thermally stable and has good homogeneity and porosity. At a concentration of 40 ppm and a dosage of 10 mg of adsorbent, the adsorption efficiency was 89%, with an adsorption capacity of 35.98 mg/g. The above indicates that the composite biomaterial is presented as a sustainable, improved, and efficient solution to remove contaminants from wastewater, benefiting the environment and human health.

Enhancing Rubber Industry Wastewater Treatment through an Integrated AnMBR and A/O MBR System: Performance, Membrane Fouling Analysis, and Microbial Community Evolution.

This study explores the effectiveness of an integrated anaerobic membrane bioreactor (AnMBR) coupled with an anoxic/oxic membrane bioreactor (A/O MBR) for the treatment of natural rubber industry wastewater with high sulfate, ammonia, and complex organic contents. This study was conducted at the lab-scale over a duration of 225 days to thoroughly investigate the efficiency and sustainability of the proposed treatment method. With a hydraulic retention time of 6 days for the total system, COD reductions were over 98%, which reduced the influent from 22,158 ± 2859 mg/L to 118 ± 74 mg/L of the effluent. The system demonstrates average NH3-N, TN, and total phosphorus (TP) removal efficiencies of 72.9 ± 5.7, 72.8 ± 5.6, and 71.3 ± 9.9, respectively. Despite an average whole biological system removal of 50.6%, the anaerobic reactor eliminated 44.9% of the raw WW sulfate. Analyses of membrane fouling revealed that organic fouling was more pronounced in the anaerobic membrane, whereas aerobic membrane fouling displayed varied profiles due to differential microbial and oxidative activities. Key bacterial genera, such as Desulfobacterota in the anaerobic stage and nitrifiers in the aerobic stage, are identified as instrumental in the biological processes. The microbial profile reveals a shift from methanogenesis to sulfide-driven autotrophic denitrification and sulfammox, with evidence of an active denitrification pathway in anaerobic/anoxic conditions. The system showcases its potential for industrial application, underpinning environmental sustainability through improved wastewater management.

Exploring the efficiency of tide flow constructed wetlands for treating mariculture wastewater: A comprehensive study on antibiotic removal mechanism under salinity stress

Antibiotic residues in aquaculture environment pose persistent threats to ecology and human health, exacerbated by salt-alkali mariculture wastewater. Yet, little is known about antibiotic removal in tidal flow constructed wetlands (TFCWs) under salinity stress, especially considering TFCW constitution, configuration, and influent water characteristics. Here, the removal performance and mechanism of different TFCWs for sulfonamide antibiotics (SAs: sulfadiazine, sulfamethazine, sulfamonomethoxine, and sulfamethoxazole) and trimethoprim (TMP) from mariculture wastewater (with low, medium, and high salinity) were evaluated alongside comparisons of environmental factors and microbial responses. Results showed substantial reduction in alkalinity (from 8.25–8.26 to 7.65–8.18), salinity (from 3.67–11.30 ppt to 3.20–10.79 ppt), and SAs concentrations (from 7.79–15.46 mg/L to 0.25–10.00 mg/L) for mariculture wastewater using TFCWs. Zeolite and yellow flag configurations exhibited superior performance in SAs removal from mariculture wastewater. Furthermore, the salt-alkali neutralization and oxygen transport capabilities of zeolite, along with the salt-alkali tolerance and biofilm formation characteristics of yellow flag, promoted the development of a biofilm in the rhizosphere dominated by oxidative stress tolerance and facultative anaerobic traits, thereby improving the TFCW microenvironment. Consequently, aerobic (Sulfuritalea and Enterobacter) and salt-tolerant (Pseudomonas) functional bacteria involved in antibiotic degradation were selectively enriched in the zeolite- and yellow flag-TFCWs, contributing to the effective biodegradation of SAs (achieving removal efficiency of 92–97 %). Besides, the high salt-alkali levels of mariculture wastewater and the strong oxygen-enriched capacity of the TFCWs not only enhanced the aerobic oxidation reaction of SAs, but also bidirectionally inhibited the substrate adsorption and anaerobic reduction process of TMP. These findings address a critical gap by investigating the efficacy of TFCWs in removing antibiotics from mariculture wastewater under various salinity conditions, providing essential insights for optimizing wetland design and improving wastewater management in mariculture environments.

Are native microalgae consortia able to remove microplastics from wastewater effluents?

Wastewater Treatment Plants (WWTPs) are potential sources of microplastics (MPs) in the aquatic environment. This study aimed to investigate the potential of wastewater-native microalgae consortia to remove MPs from the effluent of two different types of WWTPs as a dual-purpose solution for MPs mitigation and biomass production. For that purpose, the occurrence of MPs from two types of WWTP effluents was analysed over one year. MPs were characterized in terms of morphology (microbead, foam, granule, irregular, filament and film), colour and size. The wastewater characterisation was followed by the removal of MP loads, using native microalgae consortia, pre-adapted to the wastewater effluent. Microalgae consortia evolved naturally through four mitigation assays, adapted to seasonal conditions, such as temperature, photoperiod, and wastewater composition. MPs were present in all the effluent samples, ranging from 52 to 233 MP L−1. The characterisation of MPs indicated a predominance of white and transparent particles, with irregular and filament shapes, mainly under 500 μm in size. The μFTIR analysis revealed that 43% of the selected particles were plastic, with a prevalence of polypropylene (PP) (34%) and polyethylene terephthalate (PET) (30 %). In the mitigation experiments, substantial biomass production was achieved (maximum of 2.6 g L−1 (d.w.)), with successful removal of MPs, ranging from 31 ± 25% to 82 ± 13%. These results show that microalgae growth in wastewater effluents efficiently promotes the removal of MPs, reducing this source of contamination in the aquatic environment, while generating valuable biomass. Additionally, the strategy employed, requires minimal control of culture conditions, simplifying the integration of these systems in real-world WWTP facilities for improved wastewater management.

How a reservoir modulates downstream water quality under declining upstream loading and progressing climate change

Reservoirs regulate water flow and pollutant transport in catchments. However, climate change can significantly impact their ability to perform this function. This study analysed a multi-decadal time series of data to examine the complex relationship between climate and nutrient pollution trends in the Möhne reservoir catchment. The study aimed at understanding the effect of the reservoir on downstream nutrient pollution in the face of a changing climate. The analysis revealed that upstream nutrient concentrations were higher than downstream, indicating a general nutrient-trapping effect of the reservoir. Upstream stations exhibited a declining trend in total nitrogen (TN) and total phosphorus (TP) concentrations. This was due to improved wastewater management and reduced nutrient mobilisation resulting from decreasing surface runoff and streamflow. At the downstream station, whereas TN concentrations decreased, TP concentrations mildly increased. These opposite downstream trends were likely due to rising temperatures and declining dissolved oxygen concentration within the reservoir, which might have favoured nitrogen denitrification and internal phosphorus loading, causing the decline and increase in downstream TN and TP concentrations, respectively. The contrasting downstream TN and TP trends alter the nutrient stoichiometry, which can profoundly affect the ecosystem's biogeochemical functioning. Therefore, in a warming climate, reservoirs may modulate nitrogen and phosphorus nutrients differently, leading to ecological discontinuities along river networks due to changes in TN-to-TP ratios. The study highlights the need to develop adaptable and precise nutrient pollution management strategies in reservoir catchments to address the challenges of climate change effectively.

Assessing Heavy Metal Contamination Using Biosensors and a Multi-Branch Integrated Catchment Model in the Awash River Basin, Ethiopia

Metal pollution in rivers from untreated industrial and domestic wastewater is a major issue in economically developing countries worldwide. The Awash River Basin in Ethiopia is one of those rivers that faces rising heavy metal concentrations due to poor wastewater management and loose law enforcement controlling effluent discharge into rivers. In this study, surface water and wastewater samples were collected within the Awash River Basin, with metals analysis using ICP-MS techniques. Acute toxicity of water was determined using new molecular biosensor technology based on engineered luminescent bacteria. A multi-branch Integrated Catchment Model (INCA) for metals, including Arsenic, Cadmium, Chromium, Copper, Lead, Manganese, and Zinc was applied to the Awash River Basin to simulate the impact of tannery discharge on the river water pollution levels and to evaluate a set of treatment scenarios for pollution control. Results show that all samples from tannery wastewater have high levels of metals, such as Chromium and Manganese with high levels of toxicities. River water samples from upper Awash near Addis Ababa showed elevated concentrations of heavy metals due to the untreated wastewater from the dense population and a large number of industries in that area. The modeling scenarios indicate that improved wastewater management will reduce the metal concentration significantly. With a 50% reduction in effluent concentrations, the mean concentrations of heavy metals (such as Chromium) over two years would be able to reach 20 to 50% reduction in river water samples.

Microplastics in aquatic bodies: Assessing the role of governance mechanisms in industrial wastewater management

The purpose of this research is to examine the association between corporate governance mechanisms (board independence, board gender diversity, Chief Executive Officer (CEO) duality, and environmental, social and governance (ESG) linked compensation) and wastewater recycling as a strategy for managing the flow of microplastics into the aquatic environment. The study analysed an international sample of top companies on the Forbes 500 list over a 15-year period during the millennium development goals (MDGs) and sustainable development goals (SDGs) eras. Multiple regression analysis with fixed effect OLS, two-stage least squares regression, propensity score matching, and logistic regression were applied in the data analysis. The results show that, at the aggregate level, board gender diversity is positively associated with wastewater recycling, whilst CEO duality has a significant negative impact. When disaggregated into industries, board gender diversity is positively associated with wastewater recycling in high-polluting and low-polluting industries. In relation to the MDGs/SDGs eras, the impact of board gender diversity is more significant in the MDGs era than in the SDGs era. At the geographical region level, CEO duality has a significant negative impact on wastewater management in the America and Asia Pacific regions, whilst the effect of CEO duality is significantly positive in the Western Europe region. We also find that a minimum of two female directors is required to improve wastewater management practice. The study concludes that whilst board gender diversity is a notable driver of wastewater management, CEO duality diminishes the commitment of multinational entities (MNEs) to addressing wastewater management issues. Our result is robust to (i) alternative measures of wastewater management, (ii) alternate sample composition, (iii) alternate method of data analysis, and (iv) endogeneity checks. The study contributes to the limited literature on waste management and the circular economy, particularly governance mechanisms’ role in wastewater management in an international context.

Valorization of Acid Mine Drainage into an Iron Catalyst to Initiate the Solar Photo-Fenton Treatment of Municipal Wastewater

Acid mine drainage was utilized to catalyze the solar photo-Fenton treatment of wastewater coming from a sludge dewatering system. Acid mine drainage in the form of iron-rich liquid or synthesized minerals (namely magnetite, hematite, and goethite) was added in the wastewater, which was treated by means of the solar photo-Fenton process. The effects of operational parameters such as the amount of acid mine drainage, the wastewater matrix (i.e., synthetic and real wastewater), and the initial H2O2 concentration municipal wastewater’s organic content were explored. The results showed that using acid mine drainage (liquid phase) for wastewater treatment was more efficient than using the acid-mine-drainage-recovered minerals. Moreover, it was observed that the addition of acid mine drainage above 10.7 mL/L wastewater, which is equivalent to 50 mg/L iron, could substantially reduce the removal percentage of the chemical oxygen demand (COD). At the best conditions assayed, COD removal reached 99% after 90 min of photo-Fenton treatment under simulated solar light, in the presence of 30 mg/L Fe (i.e., 6.4 mL drainage/L of real wastewater) and 1000 mg/L H2O2 at a pH of 2.8. Therefore, the solar photo-Fenton treatment of municipal wastewater catalyzed by acid mine drainage may appear to be a promising method to effectively improve wastewater management, especially in areas with high solar energy potential.

The influence of structural topology of additively manufactured PEGDA monolith on adsorption performance for textile wastewater treatment

AbstractWith the rapid advancement of three dimensional (3D) printing technology that offers flexibility to achieve desired surface area and permeability for wastewater applications, structural topology design has the potential to significantly improve the adsorption performance. This present work involves fabricating the green water technology with four different complex monolithic structural designs (Kagome, gyroid, Fischer, and body‐centered cubic [BCC]) with specific surface areas varied from 19.4 to 39.84 mm2 via digital light processing (DLP) technique. All the monolithic structures with different structural topologies were grafted with chitosan to evaluate their adsorption performance in a batch process. The influence of different structural topology on the adsorption performance and efficiency was evaluated at an optimal temperature of 60°C with optimum pH of 6.3 for a reaction time of 2 h using synthetic methyl orange (MO) dye and textile wastewater. Results indicated that the body‐centered cubic (BCC) design exhibited the highest MO adsorption capacity (12.71 mg/g), with the highest permeability (2.57 10−7 m2) and surface area (39.84 mm2). Additionally, a direct relationship was found between the surface area and the permeability of the adsorbent as well as adsorption strength. Fifty percent of color and 2.46% of chemical oxygen demand (COD) removal efficiencies were achieved to verify the adsorbent feasibility in actual application. The present work mainly establishes the feasibility of 3D printing in fabricating different monolithic structures, which enables future topology optimization for improved wastewater management.

Nanotechnology as an efficient and effective alternative for wastewater treatment: an overview.

The increase in the surface and groundwater contamination due to global population growth, industrialization, proliferation of pathogens, emerging pollutants, heavy metals, and scarcity of drinking water represents a critical problem. Because of this problem, particular emphasis will be placed on wastewater recycling. Conventional wastewater treatment methods may be limited due to high investment costs or, in some cases, poor treatment efficiency. To address these issues, it is necessary to continuously evaluate novel technologies that complement and improve these traditional wastewater treatment processes. In this regard, technologies based on nanomaterials are also being studied. These technologies improve wastewater management and constitute one of the main focuses of nanotechnology. The following review describes wastewater's primary biological, organic, and inorganic contaminants. Subsequently, it focuses on the potential of different nanomaterials (metal oxides, carbon-based nanomaterials, cellulose-based nanomaterials), membrane, and nanobioremediation processes for wastewater treatment. The above is evident from the review of various publications. However, nanomaterials' cost, toxicity, and biodegradability need to be addressed before their commercial distribution and scale-up. The development of nanomaterials and nanoproducts must be sustainable and safe throughout the nanoproduct life cycle to meet the requirements of the circular economy.

Impact of a megacity on the water quality of a tropical estuary assessed by a combination of chemical analysis and in-vitro bioassays

Tropical estuaries are threatened by rapid urbanization, which leads to the spread of thousands of micropollutants and poses an environmental risk to such sensitive aqueous ecosystems. In the present study, a combination of chemical and bioanalytical water characterization was applied to investigate the impact of Ho Chi Minh megacity (HCMC, 9.2 million inhabitants in 2021) on the Saigon River and its estuary and provide a comprehensive water quality assessment. Water samples were collected along a 140-km stretch integrating the river-estuary continuum from upstream HCMC down to the estuary mouth in the East Sea. Additional water samples were collected at the mouth of the four main canals of the city center. Chemical analysis was performed targeting up to 217 micropollutants (pharmaceuticals, plasticizers, PFASs, flame retardants, hormones, pesticides). Bioanalysis was performed using six in-vitro bioassays for hormone receptor-mediated effects, xenobiotic metabolism pathways and oxidative stress response, respectively, all accompanied by cytotoxicity measurement. A total of 120 micropollutants were detected and displayed high variability along the river continuum with total concentration ranging from 0.25 to 78 μg L−1. Among them, 59 micropollutants were ubiquitous (detection frequency ≥ 80 %). An attenuation was observed in concentration and effect profiles towards the estuary. The urban canals were identified as major sources of micropollutants and bioactivity to the river, and one canal (Bến Nghé) exceeded the effect-based trigger values derived for estrogenicity and xenobiotic metabolism. Iceberg modelling apportioned the contribution of the quantified and the unknown chemicals to the measured effects. Diuron, metolachlor, chlorpyrifos, daidzein, genistein, climbazole, mebendazole and telmisartan were identified as main risk drivers of the oxidative stress response and xenobiotic metabolism pathway activation. Our study reinforced the need for improved wastewater management and deeper evaluations of the occurrence and fate of micropollutants in urbanized tropical estuarine environments.

Machine Learning Approach for Rapid Estimation of Five-Day Biochemical Oxygen Demand in Wastewater

Improperly managed wastewater effluent poses environmental and public health risks. BOD evaluation is complicated by wastewater treatment. Using key parameters to estimate BOD in wastewater can improve wastewater management and environmental monitoring. This study proposes a BOD determination method based on the Artificial Neural Networks (ANN) model to combine Chemical Oxygen Demand (COD), Suspended Solids (SS), Total Nitrogen (T-N), Ammonia Nitrogen (NH4-N), and Total Phosphorous (T-P) concentrations in wastewater. Twelve different transfer functions are investigated, including the common Hyperbolic Tangent Sigmoid (HTS), Log-sigmoid (LS), and Linear (Li) functions. This research evaluated 576,000 ANN models while considering the variable random number generator due to the ten alternative ANN configuration parameters. This study proposes a new approach to assessing water resources and wastewater facility performance. It also demonstrates ANN’s environmental and educational applications. Based on their RMSE index over the testing datasets and their configuration parameters, twenty ANN architectures are ranked. A BOD prediction equation written in Excel makes testing and applying in real-world applications easier. The developed and proposed ANN-LM 5-8-1 model depicting almost ideal performance metrics proved to be a reliable and helpful tool for scientists, researchers, engineers, and practitioners in water system monitoring and the design phase of wastewater treatment plants.

Blue economy, blue finance and ocean governance for achieving sustainable development goals

AbstractThis research paper is an attempt to define and analyse the concept of the blue economy (BE) and its implications for achieving Sustainable Development Goals (SDGs). This study covers aspects such as building a blue economy to achieve SDGs, the importance of a healthy ocean for current and future generations, maintaining the momentum to save the ocean, achievements of the United Nations (UN) conference on the Sustainable Blue Economy, and the highlights of the UN World Water Development Report 2020. This study specifically analyses the health effects and threats to biodiversity, adaptation and mitigation, improved wastewater management, prioritizing water, accessing climate funds, water and climate change, and the relationship between the blue economy and UN SDGs as well as identification of key stakeholders. This is achieved through a detailed literature review on the blue economy that identifies global organizations working on creating a blue economy, elements of the blue economy and current development efforts, United Nations Convention on the Law of the Sea, sustainability and equity, ocean governance, international law and frameworks, and improvement in governance frameworks among other issues. The methodology used attempted to develop a macro, comprehensive, and systematic aggregate database at the country level on macro parameters, namely blue economy, blue finance, BE‐SDGs linkages, water development, marine sector, SDGs data on SDG‐14 (life underwater), SDG‐6 (access to safe drinking water and sanitation), SDG‐3 (good health and well‐being), and optimal management of water resources through scientific techniques, such as building several small reservoirs instead of mega projects, develop small catchment dams and protect wetlands, soil management, micro catchment development, recharging of underground aquifers thus reducing the need for large dams, which has encountered challenges due to data limitations. The results of this research study emphasize broader stakeholder consultations at the global level to resolve the issues relating to blue economy, blue finance, and ocean governance. The most important conclusion and policy implications of the study are that international organizations including the United Nations, the Asian Development Bank, and the World Bank are working towards achieving the SDGs in general, and the blue economy, blue finance, and ocean governance in particular.

Stormwater Management in the City of Warsaw: A Review and Evaluation of Technical Solutions and Strategies to Improve the Capacity of the Combined Sewer System

Urban flooding is an increasingly common phenomenon around the world. The reasons are usually attributed to the insufficient capacity of the combined sewer system and its inability to adapt to the changing dynamics of rainfall. This is also the case in Warsaw (the capital of Poland), where the sewage system was designed in the 1960s. The aim of the article is to highlight possible hydrological solutions that would significantly improve Warsaw’s situation in terms of rainfall runoff. The article looks at some solutions that were previously mentioned in the literature and presents an assessment of the possible changes in land use/land cover on the hydrological processes and improvements in the general hydrological situation of Warsaw. In addition, the article points out the need to update the programme and spatial approach to the discharge of water from specific watersheds in Warsaw, as well as to establish a single manager for stormwater drainage in the city of Warsaw. An important issue is the restoration of natural retention basins in the city and the construction of artificial basins in places with frequent local flooding. The article emphasises the importance of building individual detention basins (as well as low-impact developments) for newly planned investments. Other important aspects are as follows: the construction of suitable underground or open channels, the need to disconnect Ursynów’s stormwater runoff from the catchment area of the Służewiecki Stream and to channel it along the southern bypass for Warsaw (S-2) to the dry lakes and ponds in Wilanów. Finally, the article discusses the application of Sustainable Drainage Systems (SuDS) and Real-Time Control (RTC) in urban drainage systems as a possible solution to improve wastewater management in urban areas.

Clarification of the Dynamic Autothermal Thermophilic Aerobic Digestion Process Using Metagenomic Analysis.

ABSTRACTThis study details a unique process of autothermal thermophilic aerobic digestion (ATAD) of human excreta useful in producing nitrogen-rich and pathogen-free organic fertilizer. The process was divided into initial, middle, and final phases, based on changes in temperature, dissolved oxygen (DO), and bacterial community structure. The aim of this study was to determine bacterial factors that would affect liquid fertilizer production in the process, using shotgun metagenomic analysis of each phase. Although the abundances of all 28 gene categories include 4 categories in SEED subsystems level 1 were similar to those in another type of wastewater treatment system, the abundances of 4 gene categories changed remarkably. Among them, a decrease in the abundance of the phage-related gene category and the presence of antibacterial substances in secondary metabolism may explain the change in bacterial community structure from the material to the initial phase. Increases in the abundances of two gene categories, phage-related and secondary metabolism, coincided with a decrease in alpha diversity from the material to the initial phase. A potential increase in the abundance of genes in the category of sporulation from the middle to the final phase was correlated with deterioration of growth conditions and stabilization processes. In addition, prompt consumption of short-chain fatty acids in the initial phase and unusually stable ammonia accumulation throughout the process could be explained by the presence/absence of related metabolic genes. In conclusion, the relationships between bacterial function and unique characteristics of ATAD were revealed; our findings support the enhancement of liquid fertilizer production from wastewater.IMPORTANCE Metagenome analysis was performed to determine the microbial dynamics of the unique autothermal thermophilic aerobic digestion process of human excreta, which includes initial, middle, and final phases. In this study, we revealed the details of functional genes related to physicochemical and bacterial characteristics in the ATAD process. Four gene categories showed increases and decreases during the digestion process. In addition, the unusual stable accumulation of ammonia and prompt consumption of short-chain fatty acids were explained by the absence or presence of related metabolic genes. In addition to revealing the relationships between bacteria and physicochemical properties, the results of this research may support improving wastewater management systems worldwide by using the ATAD process in liquid fertilizer production systems.

From wastewater to resource

Eighty percent of wastewater is left untreated or not reused, exacerbating the water quality challenge, especially in vulnerable communities. This Voices asks: how can we improve wastewater management and convert wastewater into a resource?

Constructed wetland for improved wastewater management and increased water use efficiency in resource scarce SAT villages: a case study from Kothapally village, in India

Evaluation a field-scale of constructed wetland (CW) for the treatment of rural wastewater (WW), in resource-scarce semi-arid tropic (SAT) villages, to provide improved wastewater management and increased water use efficiency, was the main objective of this study. A CW was commissioned in Kothapally village of Telangana to treat the wastewater generated from 100 households. The CW was vegetated with Typha latifolia and Canna indica. Average COD, sulfate and inorganic nitrogen removal efficiencies observed were 65%, 60% and 67% respectively, for the study period (one year). Removal efficiency for total coliform was consistently above 80%. The treated wastewater was stored in a farm pond and was utilized for irrigation in the nearby agricultural fields (0.6 ha). This perennial source of water, helped the nearby farmers to cultivate two additional crops, chickpea during rabi and sweetcorn during summer. The assured availability of water reduced their vulnerability to dry spells during the kharif by providing means for lifesaving irrigation. The biomass harvested from the constructed wetland was used as fodder for the livestock. A net additional income of Rs.70,000 (∼US$1,000) was realized by the farmers using the treated wastewater for cultivation. Similar constructed wetland-based wastewater management system can be scaled up across water scarce semi-arid tropics. Novelty statement Field-scale performance evaluation of constructed wetland based wastewater treatment in a semi-arid tropic village is scarce in the literature. The work presented gives a feasibility assessment for this technology critical for its wide-scale application to augment rural wastewater management in resource poor villages.