Centralized Wastewater Treatment Research Articles

Local residents' perception on factors affecting the willingness to pay for improved urban canal water: a case study in Can Tho city of Vietnam.

Urbanization and economic development cause water pollution in the inner-city canals and rivers globally. Bung Xang canal in Can Tho city of Vietnam is facing problems with water pollution due to the lack of centralized wastewater treatment plants and low public awareness on environmental protection. Perception of local residents was collected using structured questionnaires including both qualitative and quantitative information. Regression analysis was employed to evaluate the factors affecting the decision of respondents on the willingness to pay (WTP) to improve water quality in the Bung Xang canal. Knowledge about the environmental protection fee for domestic wastewater (10% of the VAT-excluded from the selling price of 1 m3 of tap water purchased), age of the respondents and their education levels affected the WTP positively, while respondents' perception on water quality affected the WTP negatively. There was 58.33% of the respondents showed the WTP for improved water quality in the canal. They agreed to pay a small fee of VND 10,000 to 15,000 (equivalent to USD 0.42-0.63)/month (1 US$= 23,700 VND). The result indicates that environmental education is the only way forward for a successful sustainable urban city.

Jilin city central wastewater treatment plant renovation design scheme

Jilin City is one of the top ten famous Chinese cities worth introducing to the world. To further improve the construction of urban infrastructure and meet the needs of the economic and social development of Jilin City, the Jilin City Government Joint Development and Reform Commission and the Ecological Environment Bureau decided to expand and renovate the former Jilin City wastewater treatment plant. This study designs a wastewater treatment plant by comprehensively considering the policy needs and the local basic background characteristics of Jilin to solve the wastewater overflow problem. The design modified the anaerobic tank and Carroussel oxidation ditch processes, which have more advantages than traditional treatment processes, mainly including better BOD, nitrogen and phosphorus removal efficiency, less power consumption, and lower operating costs. This treatment plant design contains two special characteristics: the design considers the overall plan and pipeline layout of the wastewater treatment plant, and the size data of each module are calculated through theoretical study conforming to the real case.

Analysis on Operation and Water Quality Characteristics of Centralized Wastewater Treatment Plants of Industrial Parks in Yellow River Basin, China

The Yellow River basin serves as an important economic belt and industrial base in China, featuring numerous industrial parks. However, alongside its economic significance, the basin struggles with significant water environmental challenges. This study analyzed the operational status, influent water quality, and energy consumption of 63 centralized wastewater treatment plants (WWTPs) from 54 major industrial parks in the Yellow River basin. The scale of these WWTPs was primarily within the range of 1 × 104~5 × 104 m3/d, with an average hydraulic loading rate of 53.8%. Aerobic treatment processes are predominant. The influent concentrations of chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP) in the WWTPs exhibited a right-skewed distribution. The BOD/COD ratio of the WWTPs fluctuated between 0.1 and 1.6, and 75% of the WWTPs showed a COD/TN ratio lower than eight. The average BOD5/TN was 2.7, and the probability of influent BOD5/TP > 20 was 84.6%. A significant linear correlation exists between the influent BOD and COD concentrations, while moderate linear relationships are also observed among NH3-N, TN and TP, emphasizing the importance of maintaining appropriate nitrogen and phosphorus levels for efficient pollutant removal. The average electricity consumption of WWTPs in the Yellow River basin in 2023 was 1.1 kWh/m3. It is important to upgrade these WWTPs and reduce their energy consumption. Further strengthening the construction of industrial wastewater collection and treatment facilities based on regional characteristics is recommended to promote the high-quality development of industrial wastewater treatment in the Yellow River basin.

The Best Solution for Centralized and Decentralized Wastewater Treatment in the Makkah Region in Saudi Arabia

The research establishes the best solution for centralized and decentralized wastewater treatment in the Makkah region in Saudi Arabia. The research used a thematic coding approach to identify literature materials on the research problem. The literature review indicated that wastewater treatment could be optimized by integrating multiple practices. The proposed solutions include creating awareness and optimizing safety standards, expanding the treatment plants and optimizing them, integrating treatment processes through centralized and decentralized wastewater treatment plants, using simple systems and technologies, expanding existing plants, optimizing performance, adopting cost-efficient strategies, and using the Right Technology, Control, and Integration Systems.

Microplastic occurrence and its potential role as a carrier for SARS-CoV-2 in health center wastewater treatment plant and surface water

This study investigated the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNAs on the surface of microplastics (MPs) collected from a hospital wastewater treatment plant (WWTP) and the Qara-sou river in Kermanshah, Iran. The MPs were characterized using stereo-, scanning electron-, and Fourier-transform infrared spectroscopies to determine their appearance, quantification, qualification, and morphology. The virus RNAs were extracted by rinsing the surface of the MPs with distilled water, followed by swapping and transferring the scratched material into viral transport medium. Identification was performed using SARS-CoV-2 molecular detection kits and real-time quantitative polymerase chain reaction (RT-qPCR). The most common type of MPs found in the wastewater acted as a vector for the virus RNA, whereas virus RNA was only identified in one sample of river water. These findings suggest that MPs can facilitate the spread of the virus through WWTPs and into receiving water bodies. Thus, research on MPs acting as carriers of COVID-19 should be emphasized as determining the presence of the coronavirus on the surface of MPs is crucial in determining a country's health strategies. Furthermore, this study shows that MPs have the potential to act as vectors for pathogens and create new microbial niches in aquatic environments.

Technical structure and influencing factors of nitrogen and phosphorus removal in constructed wetlands

Abstract Constructed wetlands purify water quality by synergistically removing nitrogen and phosphorus pollutants from water, among other pollutants such as organic matter through a physical, chemical, and biological composite remediation mechanism formed between plants, fillers, and microorganisms. Compared with large-scale centralized wastewater treatment systems with high cost and energy consumption, the construction and operation costs of artificial wetlands are relatively low, do not require large-scale equipment and high energy consumption treatment processes, and have the characteristics of green, environmental protection, and sustainability. Gradually, constructed wetlands are widely used to treat nitrogen and phosphorus substances in wastewater. Therefore, this article discusses in detail the role and interaction of the main technical structures (plants, microorganisms, and fillers) involved in nitrogen and phosphorus removal in constructed wetlands. At the same time, it analyses the impact of main environmental parameters (such as pH and temperature) and operating conditions (such as hydraulic load and hydraulic retention time, forced ventilation, influent carbon/nitrogen ratio, and feeding patterns) on nitrogen and phosphorus removal in wetland systems, and addresses the problems currently existing in relevant research, the future research directions are prospected in order to provide theoretical references for scholars’ research.

Emerging and legacy per- and polyfluoroalkyl substances (PFAS) in fluorochemical wastewater along full-scale treatment processes: Source, fate, and ecological risk

The increasing applications of emerging per- and polyfluoroalkyl substances (PFAS) have raised global concern. However, the release of emerging PFAS from the fluorochemical industry remains unclear. Herein, the occurrence of 48 emerging and legacy PFAS in wastewater from 10 fluorochemical manufacturers and mass flows of PFAS in a centralized wastewater treatment plant were investigated. Their distribution and ecological risk in neighboring riverine water were also evaluated. In wastewater from fluorochemical manufacturers, PFAS concentrations were in the range of 14,700–5200,000 ng/L and 2 H,2 H-perfluorooctanoic acid (6:2 FTCA), perfluorooctanoic acid (PFOA), N-ethyl perfluorooctane sulfonamide (N-EtFOSA), and 1 H,1 H,2 H,2 H-perfluorodecanesulfonate (8:2 FTS) were the major PFAS detected. Several PFAS displayed increased mass flows after wastewater treatment, especially PFOA and 6:2 FTCA. The mass flows of PFAS increased from − 20% to 233% after the activated sludge system but decreased by only 0–13% after the activated carbon filtration. In riverine water, PFAS concentrations were in the range of 5900–39,100 ng/L and 6:2 FTCA, 1 H,1 H,2 H,2 H-perfluorodecyl phosphate monoester (8:2 monoPAP), 1 H,1 H,2 H,2 H-perfluorooctyl phosphate monoester (6:2 monoPAP), PFOA, and perfluorohexanoic acid (PFHxA) were the major PFAS detected. PFOA and 6:2 FTCA exhibited comparable hazard quotients for ecological risk. Current wastewater treatment processes cannot fully remove various PFAS discharged by fluorochemical manufacturers, and further investigations on their risk are needed for better chemical management.

Heterogeneous application prospect and techno-economic analysis of hydrogen from wasted activated sludge: Using microbial electrolysis cell

The efficiency of hydrogen production from waste activated sludge (WAS) through combining anaerobic digestion and microbial electrolysis cell (AD-MEC) systems has been increasing. With advancements in materials science, the cost of MEC anode materials has decreased, making this technology potentially economically viable. By analyzing data from 3611 centralized wastewater treatment plants (WWTPs) in 276 prefecture-level cities in China, theoretical application scenarios and environmental benefits of hydrogen production in these WWTPs via AD-MEC were evaluated. Additionally, a theoretical economic model is constructed to validate the economic feasibility of AD-MEC technology. The key findings suggested that the theoretical potential for hydrogen production from WAS in China is 152,610.5 tons/year. The amount of CO2 emitted by natural gas, fuel diesel buses, or power electric public transportation could reduce approximately 1.51, 3.2, and 2.4 million tons/year, respectively, through utilizing hydrogen instead of the above energy sources. Due to the broader temperature adaptability of hydrogen fuel cells, this emission reduction effect was more pronounced in colder, high-latitude regions. Economic analysis revealed that, considering sludge reduction, the AD-MEC system could achieved a return on investment of 13%. This study demonstrated that with the rapid progression in urbanization, AD-MEC systems could contribute to reducing WAS treatment costs and providing clean hydrogen for carbon emission reductions in urban areas.

Investigation of Decentralized Wastewater Treatment System in Urban Wastewater Management: Case Study in Yangon, Myanmar

Urban wastewater management in rapidly growing cities presents a significant challenge. Traditional centralized systems are unable to keep pace with increasing urbanization and wastewater generation. This manuscript presents a case study conducted in Yangon, aimed at investigating the feasibility and potential benefits of approaching the decentralized wastewater treatment system (DEWATS) as an alternative solution. DEWATS and centralized wastewater treatment system (CWTS) cases were observed for performance, operational efficiency, and environmental benefits. Field studies, interviews with municipal personnel, and discussions with residents were also conducted. Residents using DEWATS in Yangon value its environmental advantages and are willing to invest in sustainability. Those who use centralized systems are concerned about high costs and unreliability. Results from sustainability assessments showed that DEWATS obtained higher total scores than CWTS. Based on Weighted Sum Methods in three sustainability scenarios, DEWATS ranked first and has been shown to be a sustainable solution for Yangon across environmental, social, economic, and technical aspects. This study provides an alternative strategy for urban planners and decision-makers to use DEWATS as an option for urban wastewater management. The evidence could support accelerating provision of wastewater treatment plants and encourage willingness to pay.

Sustainable application of electrocatalytic and photo-electrocatalytic oxidation systems for water and wastewater treatment: a review.

Wastewater treatment and reuse have risen as a solution to the water crisis plaguing the world. Global warming-induced climate change, population explosion and fast depletion of groundwater resources are going to exacerbate the present global water problems for the forthcoming future. In this scenario, advanced electrochemical oxidation process (EAOP) utilising electrocatalytic (EC) and photoelectrocatalytic (PEC) technologies have caught hold of the interest of the scientific community. The interest stems from the global water management plans to scale down centralised water and wastewater treatment systems to decentralised and semicentralised treatment systems for better usage efficiency and less resource wastage. In an age of rising water pollution caused by contaminants of emerging concern (CECs), EC and PEC systems were found to be capable of optimal mineralisation of these pollutants rendering them environmentally benign. The present review treads into the conventional electrochemical treatment systems to identify their drawbacks and analyses the scope of the EC and PEC to mitigate them. Probable electrode materials, potential catalysts and optimal operational conditions for such applications were also examined. The review also discusses the possible retrospective application of EC and PEC as point-of-use and point-of-entry treatment systems during the transition from conventional centralised systems to decentralised and semi-centralised water and wastewater treatment systems.

Phosphate Recovery from Urine-Equivalent Solutions for Fertilizer Production for Plant Growth.

This study presents a proof of concept for the recovery of phosphate from aqueous solutions with high phosphorus (PO4-P) initial contents to simulate the concentration of streams from decentralized wastewater systems. Solutions with ∼500 ppm phosphorus enable phosphate adsorption and recovery, in contrast to the highly diluted inlet streams (<10 ppm) from centralized wastewater treatment plants. In this work, Mg-Fe layered double hydroxide is used as a phosphate adsorbent, demonstrating its separation from aqueous streams, recovery, and use as a fertilizer following the principles of circular economy. We demonstrate that the mechanism of phosphate adsorption in this material is by a combination of surface complexation and electrostatic attraction. After the loss of crystallinity in the presence of water in the first cycle and its associated decrease in adsorption capacity, the Mg-Fe layered double hydroxide (LDH) is stable after consecutive adsorption/desorption cycles, where desorption solutions were reused to substantially increase the final phosphate concentration demonstrating the recyclability of the material in a semicontinuous process. Phosphate recovered in this way was used to complement phosphate-deficient plant growth medium, demonstrating its efficacy as a fertilizer and thereby promoting a circular and sustainable economy.

The potential of sweeping gas membrane distillation integrated with multistage bubble column dehumidifier in recovering potable water from wastewater contaminated with industrial metalworking fluids

Wastewater treatment is essential as freshwater becomes scarce due to increasing industrialization. However, the current centralized wastewater treatment technologies are suitable for large-scale applications. There is a pressing need to develop small-scale decentralized wastewater treatment techniques. Towards this goal, a new sweeping gas membrane distillation system (SGMD) integrated with a multistage bubble column dehumidifier (BCD) was designed, built and tested to treat metalworking fluid (MWF)-contaminated wastewater. The performance of the SGMD-BCD system was first optimized using deionized water experiments. The results showed that feed water temperature significantly affected permeate flux, while air and feed water mass flow rates of 10kg/hr and 90kg/hr were identified as optimum since permeate flux and gain output ratio were insignificant above these flow rates. The simulation results of the developed system-scale mathematical model revealed that multi-staging is a more preferable option for improving effectiveness compared to increasing the condensing area in a single-stage BCD. Additionally, in long-term experiments, about 35.5% and 47.7% drops in permeate flux were observed when the MWF concentration in wastewater increased from 5 to 25 wt% at feed water temperatures of 70°C and 80°C, respectively.

Method for ensuring the safety and effectiveness of wastewater treatment under centralized treatment mode by using a petrochemical park as case study

With the requirement of green development of industry and to achieve the synergistic effect of pollution reduction and carbon reduction in wastewater treatment, more and more industrial parks will treat wastewater by using centralized mode. How to effectively avoid risks including penetration, interference, dilution, and excessive emissions of pollutants discharge during the centralized wastewater treatment process has become an urgent problem to be solved. To ensure the safety and effectiveness of wastewater treatment, a method was established for industrial parks in this study by considering some factors such as the treatability of pollutants, the allowable pollutant discharge, the detection limit of the analysis method and the treatment load of the centralized wastewater treatment facility comprehensively. Taking a petrochemical park in East China as an example, the method was applied to identify 28 of 35 characteristic pollutants can be centrally treated. Benefit analysis shows the centralized wastewater treatment mode can not only ensure that the discharged wastewater meet requirements of emission limits, but also greatly save the cost of wastewater treatment for enterprises and help reduce electricity consumption as well as carbon emissions. Sufficient attention must be paid to the evaluation of the effectiveness and safety of centralized wastewater treatment in the future.

Industrial Wastewater Indirect Discharges in Integrated Pollution Prevention and Control Perspective: A Case Study of Prague

Wastewater discharge is one of the sources of environmental pollution. Wastewater pollution originates, inter alia, in industrial wastewater. After treatment, industrial wastewater can be discharged directly into the receiving water body or indirectly into a sewerage network terminated by the concluding stage of wastewater treatment. In the Czech Republic, indirect wastewater discharges are obeyed by the contractual relationship between the wastewater producer and the sewerage network operator. General limits for indirectly discharged wastewater are not set by any national legislation. The aim of this paper is a description of industrial wastewater discharged into the municipal sewerage system in Prague and possibilities of setting limits for installations undertaking the industrial activities listed in Annex I of the Integrated Prevention Act. The study showed that 72% of installations discharge industrial wastewater indirectly. The majority are energy plants that produce boiler blowdown wastewater. More than 80% of wastewater from studied installations is treated by one central wastewater treatment plant. The studied installations are equipped with a wastewater neutralization unit. However, despite the existence of the legislative framework to propose limits for studied installations, only two installations covered by BAT conclusions with relevant BAT-AELs for indirect discharges to the receiving water body were determined. Generally, a small percentage of installations can be limited by an integrated permit due to an inconsistent approach to the issue of indirect discharges from installations under the scope of the Integrated Prevention Act.

Analysis of Social Return on Investment for The Sekar Arum Domestic Wastewater Management System in Malang

The study focuses on the analysis of the Social Return on Investment (SROI) of the Sekar Arum Centralized Wastewater Treatment System (SPALD) in Malang, Indonesia. The research attempts to answer the main question regarding the economic, social, and environmental impacts produced by this program. The research methodology involved collecting both quantitative and qualitative data and consulting with stakeholders to understand their perceptions of the value and benefits of this initiative. The main findings suggest that investments in sanitation produce broad and multiplying benefits, including improved public health, reduced environmental pollution, and enhanced quality of life. The thesis delves into the significant implications of investing in sanitation and offers recommendations for increasing the effectiveness of the SPALD program. In conclusion, this thesis strengthens the understanding that investment in sanitation is a profitable and sustainable strategy that can help improve societal well-being and environmental health.

Urban Economic Efficiency, Environmental Factors, and Digital Finance: Impacts on Sustainable Development in Chinese Cities

This study investigates the potential of digital finance to mitigate the environmental impact of economic development. Utilizing panel data from 290 Chinese cities between 2011 and 2019, we employ a two-way fixed effects model to control for unobservable city characteristics and time-invariant macro factors. Our findings reveal that cities with higher proportions of value-added tax and secondary industries (mainly for manufacturing) tend to experience increased air pollution. Conversely, cities characterized by higher economic efficiency exhibit better air quality, underscoring the significance of prioritizing technology-intensive sectors during economic development. Pollution control technologies, such as centralized wastewater treatment systems and harmless treatment systems for household waste, also play positive roles. Moreover, technological and educational investments correlate with increased urban green coverage and lower air pollution, highlighting the pivotal role of technology development and residents’ literacy in fostering sustainable practices. Although we initially observed a positive association between the index of digital financial technology and air pollution, which could be attributed to the influence of economic growth, our study employs instrumental variable regression to unveil their true correlation. The results suggest the application of digital financial technology may enhance environmental awareness, contributing to the mitigation of air pollution.

Illuminated septic tank – A microalgae assisted onsite wastewater treatment system

To reduce the anthropogenic nutrient loading into natural waterways, onsite wastewater treatment is essential for households without access to municipal sewer systems. However, many conventional septic tanks significantly underperform the centralized wastewater treatment. In the present study, a novel illuminated septic tank inoculated with the consortium of microalga Chlorella vulgaris and aerobic bacteria was developed by modifying the conventional configuration. The inclusion of microalgae facilitated aeration inside the septic tank through photosynthetic oxygen evolution, and the microalgae-bacteria consortium enhanced the wastewater treatment performance. With the operation at 15 ℃ and a hydraulic retention time of 2.5 days, the lab-scale algae-assisted septic tank significantly decreased the concentrations of ammonium-nitrogen (NH4+-N), soluble phosphorus (P), total P, and total chemical oxygen demand by 54%, 65.2%, 78.5%, and 90.7% in the discharged effluent, respectively (p < 0.05), whereas the conventional septic tank without microalgae did not exhibit any treatment of NH4+-N or soluble P and the total P removal efficiency was lower by 50%. Meanwhile, the photosynthetic activity of microalgae altered the gas composition in the tank headspace by consuming carbon dioxide, emitting oxygen, and inhibiting the evolution of methane, which further benefited the aeration requirement and contributed to the mitigation of greenhouse gas emissions from septic systems.

Identification of Factors Influencing the Presence of Fecal Coliforms in Densely Populated Areas with Centralized Wastewater Treatment Systems

Introduction: Tegal Panggung is a high population density sub-district of 26,326 inhabitants/km2. Most residents utilize wells to meet their water demands, but fecal coliform bacteria were found in several wells at Tegal Panggung. This type of contamination source is typically from on-site wastewater treatments. However, wastewater from Tegal Panggung is treated at a centralized wastewater treatment plant. This study is aimed at identifying the factors leading to the presence of fecal coliform bacteria in Tegal Panggung. Methods: Factors reviewed in this study were the amount of waste, drainage, cattle pens, toilets, types of wells, and building density. Statistical methods and GIS were applied to determine the influence of the factors on the presence of fecal coliform and to map its distribution along with potential sources of pollution. The number of wells tested was 32, with a research period from September to October 2021. The statistical methods used are the Kolmogorov-Smirnov Normality Test, the Spearman Correlation Test, and the spatial analysis method, which was carried out using QGIS. The statistical tests were conducted to determine the correlation value between fecal coliform and pollutant. Results and Discussion: The study showed that only 40.62% met the standard requirements when there should be no fecal coliform contents in well water. Conclusion: Based on the Spearman Correlation Test, it can be deduced that the factors affecting the presence of fecal coliform within 10 meters radius are garbage and of 30 meters radius are toilets and building density.

Reverse Osmosis coupling Multi-Catalytic Ozonation (RO-MCO) in treating printing and dyeing wastewater and membrane concentrate: Removal performance and mechanism

In the face of high demand for reuse from printing and dyeing industries in centralized wastewater treatment of Jiangsu Province, reverse osmosis (RO) process is routinely used in wastewater recycling. However, the membrane concentrate is high in salinity, with high chromaticity and complex composition. Ozone oxidation, as an efficient and clean advanced oxidation process, is widely used but also suffers from several problems such as poor mass transfer and catalytic efficiency. In this paper, a novel aluminum-carbon based metal-doped composite ozone catalyst was designed, and RO coupling Multi-Catalytic Oxidation was constructed in treating biotreatment tail water. The optimal parameters of catalyst dosage of 0.5 g L−1, ozone concentration of 5 mg L−1 and 30% H2O2 dosage of 10 mg L−1 were obtained. After long-term operation experiments, the combined process has been proven to achieve safe discharge and recycling of the tail water, with low ecological risk to the external water environment.

Efisiensi Pengolahan Air Limbah Domestik pada IPAL Komunal Di Kabupaten Bone Bolango

Waste water needs to be managed properly based on its characteristics to reduce the levels of contaminants contained therein. Communal IPAL or Waste Water Treatment Plants (WWTP) is a centralized wastewater treatment system. Several Communal WWTPs in Bone Bolango Regency have been built, but monitoring is rarely carried out. The purpose of this research was to determine the processing efficiency of communal WWTPs in Kabila District (Dutohe Barat Village and Tanggilingo Village), and Tilongkabila District (Butu Village and Iloheluma Village). The parameters measured were Total Suspended Solid (TSS), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Coliform, Ammonia, and fatty oil tests from inlet and outlet water samples from WWTP. The values obtained are then compared with the quality standards based on the Indonesian National Standard (SNI) 6989.59:2008 concerning Water and Wastewater. The research method uses non-experimental with a quantitative descriptive approach. Sampling using a purposive sampling technique. Based on the results of observations, it was found that there were differences in the results of the efficiency of domestic wastewater treatment, namely the highest TSS removal efficiency in Butu Village (82.9); total coliform in all locations (0); the highest removal in efficiency values were in Iloheluma Village, namely BOD (100), Ammonia (86.95), COD (65.53) and fatty oil efficiency values (98.11) in Tanggilingo Village. The results of this research can be used as a reference for the Regional Government of Bone Bolango Regency to improve the Communal WWTP sustainably to overcome environmental pollution.