Evaluation of the application and operational performance of the modified multistage AO process in a sewage treatment plant

Recent concerns about excessive algal (Cladophora) growth in the nearshore area have prompted a comprehensive study of phosphorus concentrations and loads in the Milwaukee watershed (2000–2008). During this period, total phosphorus (TP) decreased slightly for Outer Harbor water monitoring Station 1 (OH-1) representing the confluence of the three rivers into the Outer Harbor; whereas TP remained the same or slightly increased for Outer Harbor water monitoring Station 2 (OH-2) near the Jones Island Water Reclamation Facility (WRF) outfall. Concentrations of TP at OH-2 (0.095±0.005 mg/L) are higher than at OH-1 (0.073±0.006 mg/L). Years with high rainfall and river discharge during May through June produce high daily and annual average TP loads. This appears to be caused by resuspension and erosion of sediments containing TP in the river beds. Jones Island WRF contributes 39,500 kg/year or less than 34% of the total load to the Harbor. An estimate of TP load to Lake Michigan from rivers is 76,500 kg/year (65.7%). Stepwise regression results show that total soluble phosphorus (TSP), total suspended solids (TSS), and biochemical oxygen demand (BOD), in that order, are important predictors of TP except for Station OH-2.

Rural decentralized domestic wastewater treatment (DDWT) facilities, as an alternative to centralized sewage treatment plants, have been rapidly developed in rural areas worldwide. However, the lack of performance evaluations and operational status assessments of these facilities poses a significant obstacle to advancements in rural domestic wastewater treatment strategies. In the present study, 30 rural DDWT facilities with AO (anoxic/oxic) and AAO (anaerobic/anoxic/oxic) processes were investigated. The results revealed that only two facilities reached the first A-grade discharge standards of China, and twelve facilities met the first B-grade discharge standards for all ten wastewater quality indicators. Low standard-achieving ratios for biochemical oxygen demand (BOD5) (63.3%), total nitrogen (TN) (60.0%), ammonia nitrogen (NH3-N) (63.3%), total phosphorus (TP) (30.0%), suspended solids (SS) (46.7%), and fecal coliforms (FC) (26.7%) were calculated. Thus, it is essential to improve the treatment efficiency for BOD5, TN, NH3-N, TP, SS, and FC for rural wastewater treatment facilities. In addition, the AAO process had a median weighted average removal efficiency of 82.02%, which was better than that of the AO process (72.48%). Minor equipment failure rates, i.e., less than 20%, did not affect the operation of the rural DDWT facilities, since most equipment in the DDWT facilities was backed up. Notably, problems in several areas, e.g., process design, equipment selection, construction, and especially operations, influencing treatment performance should be investigated and proactively addressed. These findings provide specific suggestions for improvements that could benefit the long-term operation and management of rural DDWT facilities.

The construction of municipal waste water treatment plants is carrying out actively all around the country due to the urgent requirement of the restoration of water pollution. Since 2007, Zhejiang province has taken the lead of possessing a waste water treatment plant in each county. This paper discusses and summarizes acquired achievements and effective measurements of some municipal waste water treatment plants of Zhejiang in cleaner production, in the aim of providing a meaningful reference to the other municipal waste water treatment plants of south China in cleaner production, since lots of waste water treatment plants will be coming into operation in the 12th 5 year plan period.

This paper proposes a pragmatic approach for rapid assessment of the weighted contribution of the main waste streams contributing to pollution of surface water bodies. A case study was conducted on Lake Burullus in Egypt. The lake suffers from pollution due to many human-based activities around the lake, such as domestic, industrial, agriculture, fish farming, and solid wastes. The weighted contribution of these activities was assessed in terms of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP). The results showed that the highest organic load is due to the domestic wastewater pollution component (63.2% of COD load), followed by fish aquaculture (35.4%). The highest TN (43.9%) and TP (58.3%) pollutant loads to Lake Burullus are due to the agricultural pollution component, followed by fish aquaculture with pollutant loads of 28.5% and 25.3%, respectively. The industrial wastewater pollution component has a very small effect on the pollution of Lake Burullus. The assessment of this study will help identify and magnify the key polluters and thus guide the decision-makers to prioritize investment planning for depollution intervention projects. For example, if the target is to reduce COD loads, investments must be directed toward the rehabilitation and expansion of wastewater treatment plants (WWTPs).

Sewage sludge (SS) with a moisture content of about 80 wt% is a byproduct of wastewater treatment. With the development of the urbanization process, this amount has been increasing with the construction and expansion of wastewater treatment plants. Containing complex organic matters as well as heavy metal and viruses, SS is not only a pollutant but also a wet resource.

On a deeper understanding of data-driven approaches in the current framework of wastewater treatment: looking inside the black-box

Biological and physical treatment in wastewater treatment plants appears to be one of the most important variables in water quality management and planning. This crucial characteristic, on the other hand, is difficult to quantify and takes a long time to obtain precise results. Scientists have sought to devise several solutions to address these issues. Artificial intelligence models are one technique to monitor the pollutant parameters more consistently and economically at treatment plants and regulate these pollution elements during processing. This study proposes using an adaptive network-based fuzzy inference system (ANFIS) model to regulate primary and biological wastewater treatment and used it to model the nonlinear interactions between influent pollutant factors and effluent variables in a wastewater treatment facility. Models for the prediction of removal efficiency of biological oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS) in a wastewater treatment plant were developed using ANFIS. Hydraulic retention time (HRT), temperature (T), and dissolved oxygen (DO) were input variables for BOD, TN, TP, and TSS models, as determined by linear correlation matrices between input and output variables. The findings reveal that the developed system is capable of accurately predicting and controlling outcomes. For BOD, TN, TP, and TSS, ANFIS was able to achieve minimum mean square errors of 0.1673, 0.0266, 0.0318, and 0.0523, respectively. The correlation coefficients for BOD, TN, TP, and TSS are all quite strong. In the wastewater treatment plant, ANFIS' prediction performance was satisfactory and the ANFIS model can be used to predict the efficiency of removing pollutants from wastewater.

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 inhabitants produce the sump waters and accumulate temporarily in the sumps. This is sewage that must be treated before it is discharged to surface waters. Slovak legislation does not allow the discharge of such waters into the soil. The possibilities of sump water treatment are given by the water management equipment of the given locality where sewage water is produced. The most common treatment method is transported at municipal wastewater treatment plants, which are, however, largely congested. In many cases, the sump water is no longer able to receive in WWTP. Another way is domestic wastewater treatment plants, and also they are wastewater treatment plants exclusively for sump waters. Sump waters have a predominantly high organic content and therefore their quality needs to be constantly monitored. The most important monitored characteristics of sump waters are COD (Chemical Oxygen Demand) and BOD5 (Biological Oxygen Demand). The high concentration of these substances in the sump water can adversely affect the processes at the municipal wastewater treatment plant. Due to the rapid development of rural settlements without a functioning sewerage system, it is necessary to intensify or adapt the existing wastewater treatment plants. However, many engineers see the solution to this problem in the construction of separate wastewater treatment plants for sump waters.

The history of wastewater treatment in Korea began in 1976 with construction of Chongke sewage treatment plant in the city of Seoul. At present, there are 48 large municipal sewage treatment plants for 42 cities with a total treatment capacity of 7,841,000 m3/d. This indicates that the population receiving sewage treatment is 42% of the total national population. The government is planning to extend the population receiving wastewater treatment to 73% by the year 1997. It turned out that activated sludge processes are the most popular type (39 out of 48 plants) for the treatment of municipal wastewater. The present lawful effluent criteria for BOD, COD, and SS from large municipal wastewater treatment plant are changing from 30 mg/l, 50 mg/l, and 70 mg/l, to 20 mg/l, 40 mg/l, and 20 mg/l, respectively, by the year 1996. Regulation of the total concentrations of nitrogen and phosphorus are also added as 60 mg/l and 8 mg/l, respectively. The enactment to control the nutrient concentrations in the lake and pond is inevitable for the protection of drinking water in South Korea.

Status of construction and operation of large wastewater treatment plants in South Korea

Advanced wastewater treatment processes and novel technologies are adopted to improve nutrient removal from wastewater so as to meet stringent discharge standards. Municipal wastewater treatment plants are one of the major contributors to the increase in the global greenhouse gas (GHG) emissions and therefore it is necessary to carry out intensive studies on quantification, assessment and characterization of GHG emissions in wastewater treatment plants, on the life cycle assessment from GHG emission prospective, and on the GHG mitigation strategies. Greenhouse Gas Emission and Mitigation in Municipal Wastewater Treatment Plants summarises the recent development in studies of greenhouse gases’ (CH4 and N2O) generation and emission in municipal wastewater treatment plants. It introduces the concepts of direct emission and indirect emission, and the mechanisms of GHG generations in wastewater treatment plants’ processing units. The book explicitly describes the techniques used to quantify direct GHG emissions in wastewater treatment plants and the protocol used by the Intergovernmental Panel on Climate Change (IPCC) to estimate GHG emission due to wastewater treatment in the national GHG inventory. Finally, the book explains the life cycle assessment (LCA) methodology on GHG emissions in consideration of the energy and chemical usage in municipal wastewater treatment plants. In addition, the strategies to mitigate GHG emissions are discussed. The book provides an overview for researchers, students, water professionals and policy makers on GHG emission and mitigation in municipal wastewater treatment plants and industrial wastewater treatment processes. It is a valuable resource for undergraduate and postgraduate students in the water, climate, and energy areas; for researchers in the relevant areas; and for professional reference by water professionals, government policy makers, and research institutes. ISBN: 9781780406305 (Print) ISBN: 9781780406312 (eBook) ISBN: 9781780409054 (ePUB)

Rapid urbanization, population growth, and other intensive human activities have greatly altered natural hydrological conditions and matter cycling, which are the main causes of water quality deterioration in North China’s rivers. With the help of a 15-year (2005–2019) dataset of river water quality (1043 records from nine sites), this study investigated the spatiotemporal water quality patterns in the Yongding River Basin (YRB) in North China using a new water quality index (WQI-DET), which has been customized for China’s water quality classification scheme. Our results showed that the river water quality of the YRB has significantly improved due to the decreased surface runoff and an abrupt change of WQI-DET was observed in 2011. The elimination of anoxic conditions and the mitigation of nitrogen and phosphorus resulting from the construction of wastewater treatment plants and the improvement of treatment capacity are the main reasons for the improvement in river water quality. We also found that eutrophication is still not completely eradicated because of the high concentrations of NH4 + and total phosphorus. Our study suggests that for rivers in which runoff has decreased sharply, the water quality could be improved significantly by wastewater treatment facilities. At present, for the YRB, more effort is needed to eliminate eutrophication and dried-up river sections and thereby finally improve the river ecosystem. We concluded that more attention and effort should be given to river hydrological conditions, specific river ecological characteristics, and the increasingly important non-point source pollutants during the design of river restoration measures in North China.

The statistics about construction, process, investment, treatment effect of 72 sewage treatment plants show that the plant scale of county sewage treatment plants are less than 50,000m?/d in Guangxi. The mainly treatment processes are SBR and its variants process, A2/O, Oxidation ditch. The sewage treatment plant's investment of unit total construction and operating costs are reduced with the treatment scale increases. While the treatment scales are below 10,000 m3/d, the investment of unit total construction is among 17,300-4,700 yuan/m3, but to scales in 10,000~20,000m?/d is 4,700-3,500 yuan/m3, and to scales 20,000 ~ 50,000 m3/d is about 3,500 yuan/m3. The average operating costs of scales below 20,000 m3/d and 20,000 ~ 50,000 m3/d is 0.48 and 0.36 yuan/m3, respectively. The pipe network actual investment is significantly lower than the municipal treatment plant construction investment. In 2010, the average load rate of the municipal treatment plant is only 60.8%, which is lower than national online average level. 96% of average wastewater treatment plant's efficiency reaches the standard, COD, BOD of the effluent are all reach the standards, but a few sewage treatment plants appear to ammonia nitrogen exceed standards for the less of technology, and shortage of carbon source.

Water scarcity is a global challenge faced by millions of people, and it has a negative impact on the ecosystem, public health, and financial stability. Water demand and supply management becomes critical, especially in areas with limited access to clean, safe water. Wastewater and water treatment infrastructure is essential for maintaining environmental integrity and protecting human health. However, water treatment plants in South Africa face various complex obstacles brought on by institutional setups, practical limitations, and environmental concerns, including water quality. This study investigated the institutional arrangements, operational challenges, and environmental concerns that water and wastewater treatment plants face in the Vhembe District Municipality, South Africa. A qualitative study was conducted in Limpopo province, where employees from 12 water and wastewater treatment plants were interviewed, and the data were analyzed thematically. The data were arranged into five major themes using thematic analysis: understanding water and wastewater treatment systems, educational and demographic profile, water quality assessment, operational performance and regulatory compliance, and water volume in waterworks plants. Staff attitudes, institutional and operational challenges, and the current condition of treatment plants were all comprehensively portrayed using Ostrom’s IAD Framework. It was found that workers generally understand water treatment processes, but inconsistencies and a lack of transparency in monitoring water quality were noted, with many parameters from SANS 241 not being tested consistently. A significant educational gap among workers was also observed. Insufficient capacity, load-shedding, limited resources, and inadequate infrastructure prevented treatment plants from meeting daily water needs, worsened by institutional and socio-economic factors. Similar challenges were noted in countries like China, Ethiopia, India, Pakistan, Malaysia, Brazil, and Libya. To enhance water management efficiency and compliance, the study recommends more training, standardized procedures, proactive maintenance, and stakeholder involvement.