Explore the vast range of titles available.

Purpose Urbanization and industrial development intensify water utilization and wastewater generation. The efficiency of wastewater treatment systems varies and depends on system design and wastewater condition. The research aims to examine seven existing centralized municipal wastewater treatment plants (WWTPs) in Bangkok to discover which system configuration yields the best environmental and economic performance. The degree of environmental impact and operational costs from different system designs were investigated to help select future wastewater treatment systems. Methods Life cycle assessment (LCA) has been conducted to evaluate environmental impacts from centralized municipal wastewater treatment systems. Life cycle impact assessment method based on endpoint modeling (LIME) was applied, with three major potential environmental impact categories including eutrophication, global warming, and acidification. All seven centralized municipal WWTPs in Bangkok were investigated as case studies. The system configurations are classified into five types of activated sludge (AS) systems. The contribution of impacts from individual processes in each type of AS system was analyzed. The methodology covered major on-site and off-site operational processes excluding construction and maintenance phases. Average annual data were calculated to develop an inventory dataset. JEMAI-Pro software was utilized in this study to analyze the life cycle impact of the systems. Results and discussion The level of environmental impact from a WWTP depends on the configuration of the AS system. The highest potential environmental impact from a municipal WWTP is eutrophication, which is obviously affected by ammonium and phosphorous discharges into water bodies. The vertical loop reactor activated sludge (VLRAS) system yielded the best treatment performance among the five AS sub-systems. The consumption of electricity used to operate the system contributed significantly to global warming potential and correlated considerably with operating costs. Comparing among three system sizes, the large-scale WWTP revealed inefficient electricity consumption, whereas the medium plant provided better performance in chemical use and operating costs. Conclusions Centralized municipal WWTPs with capacities ranging from 10 to 350 × 10 3  m 3 /day were evaluated with respect to environmental performance and costs during the operating phase. Among all case studies, a medium-scale WWTP with a VLRAS system offered the best operating performance in terms of low environmental impact, resource consumption, and cost. To enhance WWTP management, it is vital to improve the efficiency of electricity consumption in primary and secondary treatment processes and increase wastewater collection efficiency to maximize the plant operating capacity and minimize overall environmental impacts.

Wastewater management has experienced different stages, including pollutant removal, resource recovery, and water nexus. Within these stages, anaerobic ammonia oxidation-based biotechnology can be incorporated for nitrogen removal, which can help achieve sustainable wastewater management, such as reclamation and ecologization of wastewater. Here, the physiology, metabolism, reaction kinetics and microbial interactions of anammox bacteria are discussed, and strategies to start-up the anammox system are presented. Anammox bacteria are slow growers with a high doubling time and a low reaction rate. Although most anammox bacteria grow autotrophically, some types can grow mixotrophically. The reaction stoichiometric coefficients can be affected by loading rates and other biological reactions. Microbial interactions also contribute to enhanced biological nitrogen removal and promote activities of anammox bacteria. The start-up of the anammox process is the key aspect for its practical application, which can be realized through seed selection, system stimulation, and biomass concentration enhancement.

Populations in urban centers of developing countries have increased very significantly during the post‐1960 period, primarily due to urbanization. Rates of population growth during this period simply overwhelmed their financial, institutional, and technical capacities to manage all types of basic services, including the provision of clean water and proper wastewater management. Surprisingly, issues of access to clean water and sanitation at major international forums of very senior policymakers were first raised during the United Nations Conference, in Vancouver, in 1976. It recommended that everyone should have access to clean water by 1990. Subsequently, Millennium Development Goals set the target that, by 2015, the number of people not having access to clean water should be reduced by half, compared to 1990. The United Nations claimed that this target was met in 2010. However, this is not true. Thereafter, the Sustainable Development Goals stipulated that everyone should have access to clean water by 2030. Current developments indicate that this goal is highly unlikely to be reached. This paper objectively reviews the progress of urban water security in developing countries from the post‐1960 period, analyses why international targets were missed in the past, and what can be done to ensure urban water security in developing countries in the future.

The paper is based on the use of evidence to scrutinise the effect of the Public-Private Partnership Act on the local public utility providers, where the context of the water and wastewater sector in Slovenia serves as an example. The Act affected the legal status of public enterprises, where solely public ownership was prescribed, and therefore demanded the reorganisation of existing public enterprises. The paper aims to evaluate the reorganisation process and the trend of remunicipalisation, the motives of reorganisation (political, pragmatic or transformative) and the advantages and disadvantages of the reorganisation process. A detailed, structured online questionnaire was designed and pretested for primary data collection to reach these aims. The questionnaire was sent to the Slovenian local public utility providers in water and wastewater management. The data was collated from 2018 to 2020. It was used in the analysis to provide evidence about the outcomes of the reorganisation process. The results show that new legislation contributed to increased public ownership in local public utility provision. The results also reveal that pragmatic motivating factors contributed to increased municipal buying out of private investors from (public) enterprises. The reorganisation process led municipalities into remunicipalisation, meaning that full municipal ownership and control increased.

Ubiquitous presence of cyanobacteria even under extreme conditions since millions of years is due to their ease in adaptability to these environments through various cellular and molecular modifications. Formation of biofilms has been found to be one of the effective modes of survival under harsh environmental conditions, with exopolysaccharides (EPS) contributing to the formation of these biofilms. Cyanobacterial EPS are unique heteropolysaccharides and being anionic in nature, they have the capabilities for excellent heavy metal adsorption and thus, play a vital role in conferring tolerance against heavy metal toxicity. EPS biosynthesis occurs through multiple pathways involving a multitude of genes. A comprehensive overview on these genes in cyanobacteria using Nostoc sp. strain PCC7120 as the model organism has been discussed in this review. The review also emphasizes on the contribution of EPS to heavy metal remediation and biofilm formation. In the age of developing eco-friendly approaches for environmental clean-up, this information would help engineer cyanobacteria as a potential green technology tool for bioremediation and waste water management.

Current wastewater management paradigms favor centralized solutions, as taught in traditional engineering schools, which imply high capital costs, long-range water transfer, long and disruptive construction and highly trained operators. On the other hand, small decentralized systems are seldom considered even though they require lower capital costs, less disruptive infrastructure construction and allow for the maintenance of a closer, more sustainable water cycle. This manuscript starts with an extensive review of the long history of wastewater systems, from the Greek antiquity to the modern era. The use of natural and physical systems in history and their evolution into modern technology is also analyzed. Finally, future trends are considered with emphasis on technological adaptation and sustainability of decentralized systems, with a view that lessons that can be learned from history and past practices. The manuscript aims to provide a critical overview of water and wastewater management in view of the oncoming challenges of this sector.

Environmental pollution and increasing water scarcity are key features of the urban landscape of India today. The extension of centralised sewerage networks cannot keep up with city growth, and alternative sanitation systems are needed for citywide inclusive sanitation (CWIS). The government of India mandated larger buildings to be equipped with small-scale wastewater treatment plants (SSTP). This resulted in the emergence of a large number of technology and service providers, and in the implementation of thousands of private SSTPs. However, this quick scaling up was not accompanied by the development of appropriate governance arrangements. As a result, a significant proportion of SSTPs underperform and do not meet the effluent standards. Through a systematic analysis of governance arrangements around SSTPs, this contribution analyses the scaling up process of small-scale wastewater management and reuse at building level in India, in particular in the state of Karnataka and the city of Bengaluru. This paper identifies the gaps in this multi-level, polycentric governance framework and investigates which arrangements are needed to enable the performance of SSTPs on the ground and to create the necessary synergies between the relevant governmental agencies, the private sector and civil society. The scaling up of SSTPs in India mainly followed a market governance approach within a governance environment that is traditionally very hierarchical. The authors argue that hybrid governance arrangements, blending hierarchical, market and network governance are needed to foster market regulation and stakeholder coordination, and increase the performance of the sector. They conclude that an efficient governance of SSS requires the creation of dedicated SSS units at state and city level, and the development of an online platform collating all databases, streamlining and supporting processes from establishment to monitoring, and allowing meaningful collaboration between stakeholders. Through the case study of India, this paper contributes to understand the governance arrangements necessary for the successful scaling up of decentralised sanitation systems, and how to fulfil the potential of alternative solutions for sustainable urban water management. It contributes to governance studies by substantiating the concept of hybrid governance approach and proposing concrete measures to make it work for such distributed systems.

Chronic and episodic water shortages are becoming common in many regions of the United States, and population growth in water-scarce regions further compounds the challenges. Increasingly, alternative water sources such as graywater-untreated wastewater that does not include water from the toilet but generally includes water from bathroom sinks, showers, bathtubs, clothes washers, and laundry sinks- and stormwater-water from rainfall or snow that can be measured downstream in a pipe, culvert, or stream shortly after the precipitation event-are being viewed as resources to supplement scarce water supplies rather than as waste to be discharged as rapidly as possible. Graywater and stormwater can serve a range of non-potable uses, including irrigation, toilet flushing, washing, and cooling, although treatment may be needed. Stormwater may also be used to recharge groundwater, which may ultimately be tapped for potable use. In addition to providing additional sources of local water supply, harvesting stormwater has many potential benefits, including energy savings, pollution prevention, and reducing the impacts of urban development on urban streams. Similarly, the reuse of graywater can enhance water supply reliability and extend the capacity of existing wastewater systems in growing cities. Despite the benefits of using local alternative water sources to address water demands, many questions remain that have limited the broader application of graywater and stormwater capture and use. In particular, limited information is available on the costs, benefits, and risks of these projects, and beyond the simplest applications many state and local public health agencies have not developed regulatory frameworks for full use of these local water resources. To address these issues, Using Graywater and Stormwater to Enhance Local Water Supplies analyzes the risks, costs, and benefits on various uses of graywater and stormwater. This report examines technical, economic, regulatory, and social issues associated with graywater and stormwater capture for a range of uses, including non-potable urban uses, irrigation, and groundwater recharge. Using Graywater and Stormwater to Enhance Local Water Supplies considers the quality and suitability of water for reuse, treatment and storage technologies, and human health and environmental risks of water reuse. The findings and recommendations of this report will be valuable for water managers, citizens of states under a current drought, and local and state health and environmental agencies.

High population growth, a lack of wastewater treatment plants and poor wastewater management are major challenges in wastewater management in Timor-Leste (East Timor). One of the approaches of the government of Timor-Leste is to separate wastewater into greywater and blackwater from domestic, commercial, residential, and industrial areas. Three methods were applied to obtain insight into the locations and discharge of grey- and blackwater to develop a cost-effective wastewater strategy: a field survey and data collection, interviews with over 130 participants from local authorities and communities, and the open-source mapping of locations of wastewater discharge. This research concluded that 47.7% of the grey wastewater is discharged into open sewers connected directly to the sea. Most communities discharge their wastewater directly due to the absence of wastewater management, policies and regulations, and lack of communities’ understanding of the possible health impacts of wastewater. The impact of poor wastewater management showed that most of the children in these communities have suffered from diarrhea (73.8%), and in the rainy season, there is a high possibility of infection with waterborne diseases. The literature review, field mapping, and interviews show that there is high demand for a cost-effective wastewater strategy for health improvement. Low-cost nature-based solutions such as constructed wetlands and bioswales can be implemented with local skills and materials to improve the wastewater situation and address other challenges such as biodiversity loss, heat stress, drought, and floodings. These installations are easier to rebuild than large-scale grey infrastructure given the multiple hazards that occur in Timor-Leste: landslides, earthquakes, strong wind, and pluvial and fluvial floodings, and they can serve as coastal protection.

The rapid expansion of shrimp aquaculture has led to the generation of nutrient-rich effluents, which contribute to environmental degradation if inadequately managed. This study evaluated the potential of Dunaliella salina for the reuse of shrimp aquaculture wastewater (SAW) in biofloc production systems under varying dilution levels (0%, 25%, and 50%) and the simultaneous production of high-value biomass. Growth kinetics were modeled using a four-parameter logistic model, and nutrient removal, biochemical composition, and fatty acid profile were assessed. D. salina exhibited substantial growth in undiluted SAW, achieving over 80% removal of total nitrogen and reducing the organic load, as measured by a chemical oxygen demand reduction of more than 79%. In SAW treatments, the protein content ranged from 24.7% to 26.3%, while the lipid content reached up to 67.1% in a 25% SAW dilution. Chlorophyll a and total carotenoids were measured at 5.3–7 µg/mL and 4.1–5.7 µg/mL, respectively, in SAW treatments. The polyunsaturated fatty acid content in undiluted SAW was 34.5%, with α-linolenic acid (C18:3n3) and linoleic acid (C18:2n6) comprising 12% and 7.5%, respectively. This study demonstrates the ability of D. salina to valorize shrimp aquaculture wastewater in biofloc systems into lipid-rich, bioactive biomass, supporting its use in integrated aquaculture biotechnology systems for sustainable wastewater management and bioproduct generation.