Urban Sewage Treatment Plant Research Articles

Modified rare earth waste composite material for simultaneous denitrification and recovery of phosphate in water

Nitrogen and phosphorus discharged into water bodies with sewage are the main causes of water eutrophication.Currently,the adsorption method is a cost-effective and efficient denitrification and phosphorus removal technology. In this study, waste polishing powder, manganese dioxide and sepiolite are used as raw materials, and a novel adsorbent of Sep-pp-MnO2 is prepared through co-precipitation and redox methods for simultaneous removal of ammonia nitrogen and recovery of phosphate in water.The physicochemical properties of the adsorbent are characterised, and the adsorption performances and denitrification and phosphorus removal mechanisms are determined. Results showed that,at a temperature of 25°C and pH of 8, the maximum removal of ammonia nitrogen reaches 11.47 mg/g, while the adsorption capacity for phosphates is 14.93 mg/g. Adsorption mechanisms indicated that the removal mechanism of phosphate is ligand exchange, while the removal mechanism of ammonia nitrogen involves electrostatic attraction and oxidation to nitrogen. Recycling experiments showed that after five desorption cycles, the material could achieve a removal of 4.7 mg/g for ammonia nitrogen, an adsorption capacity of 8.25 mg/g for phosphate and a phosphate recovery rate of 55 % after desorption with 0.1 M NaOH solution. Municipal wastewater validation experiments demonstrated that when the dosage of Sep-pp-MnO2 was 4 g/L,Treated water met the Class B requirements of the comprehensive emission standard for pollutants from urban sewage treatment plants in China (GB18918–2002). This study explores a new method for efficient simultaneous nitrogen and phosphorus removal in water and provides a feasible idea for alleviating the shortage of phosphate rock resources.

TA and CTAB treatment synergistically enhance activated sludge dewatering by lowering proteins and boosting Zeta potential

Waste activated sludge (WAS) is produced by urban sewage treatment plants, which contains pathogenic microorganisms, chemical elements, wiht high moisture content (>99%). To mitigate environmental pollution and reduce the volume of WAS, sludge dewatering are widely needed. The main objective of this study is to investigate the improvement in sludge dewaterability through the combined efficacy of tannic acid (TA) and cetyltrimethylammonium bromide (CTAB). Significant reductions in Capillary Suction Time (CST), Specific Resistance to Filtration (SRF), and moisture content of vacuum-filtered sludge cake (WC) were observed as experimental findings demonstrated the combined use of TA and CTAB. Specifically, CST decreased from 78.6 s to 15 s, SRF reduced from 1.12×1013 m/kg to 2.23×1012 m/kg, and WC decreased from 97.98% to 74.80%. The levels of polysaccharides and proteins present in various layers of the extracellular polymeric substances (EPS) within the sludge were reduced due to the interaction and formation of protein complexes with TA and CTAB. Additionally, these additives neutralized surface with a negative electrical potential of EPS, decreasing repulsion among sediment particles. This led to a decrease in the Zeta potential, while the contact angle and particle size of the sludge increased. Additionally, the hydrophobicity of the sludge particles was enhanced. As a result, intracellular moisture was released by disrupting the sludge cells. The findings presented here may assist in the development of sustainable and productive strategies for the management of sludge, ultimately promoting environmental protection and the well-being of urban communities.

Experimental and statistical models moisture release of the mixture treated with reagents raw sludge and compacted active sludge

The technology of changing the resistivity of a mixture of raw sludge and compacted activated sludge taken after the sludge pumping station of urban sewage treatment plants by treating the sludge with aluminum sulfate and polyacrylamide (PAA) in doses from 0 to 300 mg/dm3 has been tested. The degree of influence of each reagent on the process of dehydration of the sediment under study has been established. It has been shown that PAA has about 2.0 times greater effect on the process of moisture loss than Al2(SO4)3 at reagent doses from 0 to 200 mg/dm3 and about 1.5 times – at doses from 100 to 300 mg/dm3. Mathematical models of the dependence of the change in the resistivity of the sediment on the amount of Al2(SO4)3 and PAA introduced into it are obtained. Mathematical models are also presented in graphical form (isolines). The optimal doses of coagulant and flocculant for chemical treatment of the studied sewage sludge were determined.

Physico-chemical characterization and possible uses of sludge processed from an urban sewage treatment plant

Nowadays, the challenge is to transform dehydrated sewage sludge resulting from wastewater treatment plants from waste into resource. Following this objective, the sludge was further dried and submitted to X-ray diffraction (XRD) and FTIR analysis. The sludge was first dried in ventilated and unventilated spaces at 50∘C and 100∘C, for 60 and 100 minutes (min) in each case. The final mass and evaporation degree of the sludge depends on the initial mass, ventilation type, drying time, and temperature. The ventilated drying space is preferred for temperature control, homogeneity, and higher evaporation degree. The influence of the drying process on the structure and behavior of the sewage sludge was emphasized through X-ray diffraction (XRD) and FTIR analysis. The XRD shows good structural properties of the sludge samples given by the reduction of the particle size through evaporation. According to FTIR, evaporation influences the depolymerization of the silicate network. The hydroxyl units and metallic ion modifiers can improve the sludge structure, but its intensity decreases through evaporation. With high content of solid substance, and good relation between the composition of the sludge and its structure and behavior, the dried sewage sludge can be used in: (i) agriculture, (ii) construction, (iii) the energy sector.

Reductive sequestration of Cr (VI) by phosphorylated nanoscale zerovalent iron

The cracked phosphorylated nanoscale zerovalent iron (p-nZVI) has a strong electron selectivity towards the reductive removal of many heavy metal ions in waters. However, the unintended environmental risk after interactions with impurities or wastewater are not involved. Therefore, in this study, the phosphate group was successfully adsorbed into p-nZVI, and the cracked p-nZVI was successfully prepared with an optimal P/Fe ratio of 0.5%. The dosages of p-nZVI and temperatures were positively correlated with the removal rates. The removal process of Cr(VI) was more suitable by the Langmuir isothermal model（R2 > 0.99). The process of Cr (VI) (10, 20 and 40 mg/L) removal more fitted the pseudo first-order reaction model, while the process of Cr (VI) (60, 80 mg/L) removal more fitted the pseudo second-order reaction model. The Cr (VI) removal rates gradually decreased when the pH was increased. Dissolved oxygen slowed nanoiron reaction rates. The order of inhibition on the reactivity towards Cr(VI) was SiO32− > SO42− > PO43− > NO3− > HCO3−.The facilitation followed the order of Cd2+>Cu2+>Mg2+>Mn2+>Ca2+. Ca2+ showed an inhibitory effect, but all other cations showed different degrees of facilitation. The promotion effect is relatively similar in presence of Mn2+ or Mg2+. HA had a significant inhibitory effect. Environmental friendly p-nZVI had a good effect in simulated groundwater, seawater, river water and secondary effluent of the urban sewage treatment plant. The main pathway to remove Cr (VI) was in situ reduction by p-nZVI. The improved adsorption and reduction effect of p-nZVI on heavy metal ions in water was due to the structural change and the phosphate group.

Current Situation and Prospect in Urban Sewage Treatment Plants

Sewage is the carrier of resources and energy, which contains great chemical energy and heat energy. The traditional sewage treatment process consumes energy, and the energy consumption is high. Under the background of carbon neutrality, China’s urban sewage treatment plants have achieved carbon neutrality operation in terms of energy self-sufficiency and reduction of greenhouse gas emissions. To explore the feasibility of carbon neutrality in sewage treatment plants, the cases of carbon neutrality in sewage treatment plants at domestic and abroad were analyzed. And the implementation approaches and main emission reduction processes to achieve carbon neutrality were summarized. The technical challenges and research directions of future sewage treatment plants in China from the perspective of carbon neutrality are proposed.

Unification of requirements for the use of reagents for the treatment of sewage sludge from urban sewage treatment plants

This paper describes the experience of unification of requirements for the use of natural and synthetic reagents at all stages of wastewater sludge treatment. The practical necessity of this study is due to the tightening of environmental requirements around the world and the increasingly active introduction of closed-loop technologies of the economy. To date, products from sewage sludge are unclaimed not only by construction and road enterprises, but also by municipalities, which could more actively use the soil for landscaping urban areas. The most promising in terms of results and costs is the use of reagents at all stages of wastewater sludge treatment. Their use makes it possible to significantly reduce the costs of such technological processes as dehydration and stabilization. Reagents are an indispensable component in modern approaches to composting and disinfection.

Current Situation, Development Trend and Challenges of Intelligent Dosing Control Technology for Chemical Phosphorus Removal in Urban Sewage Treatment Plants

Current Situation, Development Trend and Challenges of Intelligent Dosing Control Technology for Chemical Phosphorus Removal in Urban Sewage Treatment Plants

Detection of Inhibition Characteristics of Activated Sludge in Urban Sewage Treatment Plants by Landfill Leachate Based on Oxygen Uptake Rate (OUR)

Detection of Inhibition Characteristics of Activated Sludge in Urban Sewage Treatment Plants by Landfill Leachate Based on Oxygen Uptake Rate (OUR)

Research on the Management Countermeasures of Pollutant Discharge Permits in Urban Sewage Treatment Plant Based on the Improvement of Water Environment Quality

Research on the Management Countermeasures of Pollutant Discharge Permits in Urban Sewage Treatment Plant Based on the Improvement of Water Environment Quality

A research on the strengthening effect of sludge charcoal on activated sludge process in sewage treatment.

With the rapid development of urbanization, the number of urban sewage treatment plants is increasing, wastewater treatment volume is gradually becoming large, and correspondingly, the sludge production capacity has a rapid growth. As a new method of sludge disposal, sludge carbonization is characterized by low energy consumption, simple products, and wide resource utilization prospects, which is of great help to solve problems of current sludge disposal in China. The residual sludge from sewage plant was used as raw material in this study in order to investigate the physical and chemical properties of sludge charcoal after high temperature carbonization and explore the enhancement in the removal of pollutants including CODcr, NH3-N, TN, and TP during sewage treatment with the used sludge charcoal. The results show that the optimal dosing amount of sludge charcoal was 2g.L-1 when it was added into SBR equipment at one time, while the optimal dosing amount is 0.06g.L-1 when it was added into SBR equipment with each influent process. The enhanced removal effect of pollutants in sewage treatment process mainly depended on the physical adsorption and intensified bio-degradation of sludge charcoal, and activated sludge and sludge charcoal were synergistic in water treatment. The removal effect of pollutants is strengthened in the physical adsorption-bio-degradation-sludge charcoal reproduction-re-adsorption system. These suggested that sludge charcoal could be promising for the enhancement of pollutant removal in sewage through activated sludge process.

Investigating antimicrobial resistance determinants and micropollutants in urban sewage treatment plants of India: Occurrence, removal and ecotoxicological risk

Environmental contamination caused by emerging pollutants (EPs) and their associated ecological risk have received limited attention in India. Thus, this study aims to address this gap by investigating the occurrence and removal of antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs) and pharmaceutical and personal care products (PPCPs) in two sewage treatment plants (STPs) in New Delhi. The study also assessed the ecological risk associated with PPCPs in aquatic environments. Among the targeted ARB and ARGs, erythromycin resistant bacteria and ermB gene, respectively were the most ubiquitous pollutants in the influent of both STPs. In the final effluent, there was a reduction ranging from 0.8 log to 2.8 log units for most ARB, while removal of the majority of ARGs was less than 1 log unit. The secondary treatment demonstrated better removal of total ARG concentrations compared to the tertiary treatment methods employed in both STPs. Regarding PPCPs, metformin was quantified in both influent and effluent samples at a concentration exceeding 19,000 ng/L, indicating its persistence in wastewater. High concentrations of ARB, ARGs, and PPCPs were observed in undigested biosolids, while low to moderate removal of these pollutants was observed after anaerobic digestion. To assess the ecological risk, a risk quotient (RQ) assessment was conducted. The results revealed that compounds such as erythromycin, terbinafine, 17-α ethinylestradiol (EE2), 17-β estradiol (E2), diclofenac, triclosan, carbamazepine, and mefenamic acid exhibited high risks in the effluent. Additionally, EE2 and E2 showed higher risk levels in the digested biosolids, indicating potential risks to the aquatic ecosystem.

A Brief Analysis of the Problems and Countermeasures of Sewage Treatment Project in Urban Environmental Protection

With the development of urbanization in our country, the overall improvement of the economic level, all kinds of industrial wastewater as well as the urban household living sewage quantity is increasing, urban sewage treatment plant as industrial wastewater and domestic sewage end purification workshop, its operation has a significant role on water environment protection. This paper mainly explores the problems and countermeasures of sewage treatment projects under environmental protection, analyzes the main problems existing in China's sewage treatment projects under the current situation, and puts forward countermeasures for sewage treatment projects combined with specific problems.

Unveiling the Microbiome Landscape: A Metagenomic Study of Bacterial Diversity, Antibiotic Resistance, and Virulence Factors in the Sediments of the River Ganga, India.

The global rise in antibiotic resistance, fueled by indiscriminate antibiotic usage in medicine, aquaculture, agriculture, and the food industry, presents a significant public health challenge. Urban wastewater and sewage treatment plants have become key sources of antibiotic resistance proliferation. The present study focuses on the river Ganges in India, which is heavily impacted by human activities and serves as a potential hotspot for the spread of antibiotic resistance. We conducted a metagenomic analysis of sediment samples from six distinct locations along the river to assess the prevalence and diversity of antibiotic resistance genes (ARGs) within the microbial ecosystem. The metagenomic analysis revealed the predominance of Proteobacteria across regions of the river Ganges. The antimicrobial resistance (AMR) genes and virulence factors were determined by various databases. In addition to this, KEGG and COG analysis revealed important pathways related to AMR. The outcomes highlight noticeable regional differences in the prevalence of AMR genes. The findings suggest that enhancing health and sanitation infrastructure could play a crucial role in mitigating the global impact of AMR. This research contributes vital insights into the environmental aspects of antibiotic resistance, highlighting the importance of targeted public health interventions in the fight against AMR.

A novel carbon emission evaluation model for anaerobic-anoxic-oxic urban sewage treatment

The proposal of the dual carbon goal and the blue economy in China has sparked a keen interest in carbon emissions reduction from sewage treatment. Carbon accounting in urban sewage plants serves as the foundation for carbon emission reduction in sewage treatment. This paper re-evaluated carbon accounting in the operational processes for urban sewage treatment plants to develop a novel carbon emission evaluation model for anaerobic-anoxic-oxic treatment plants. The results show that the carbon emissions generated by non-carbon dioxide gases far exceed the carbon emissions from carbon dioxide alone. Moreover, the recycling of sewage leads to carbon emissions reduction that offsets the carbon emissions generated during the operation of the sewage plant. Also, the carbon emissions generated by sewage treatment plants are lower than those generated by untreated sewage. The findings and insights provided in this paper provide valuable references for carbon accounting and the implementation of low-carbon practices in urban sewage treatment plants.

Can regional environmental quality improve green innovation performance? an empirical analysis from China

Introduction: Green innovation is an important driving force for reducing pollution and achieving high-quality development. Environmental factors are important external variables that affect innovation and are crucial to innovation development. There is a close relationship between environmental quality and green innovation performance. This paper takes the single environmental factor and combination of environmental factors of environmental quality heterogeneity as the explanatory variables, the traffic scale, economic scale, industrial scale and consumption scale as the control variables, and the per capita GDP of each city as the threshold variable, and calculates the impact of the single environmental factor and combination of environmental quality factors on the green innovation performance of 286 cities in China under different per capita GDP thresholds.Methods: We used Data Envelopment Analysis (DEA) and Threshold Regression model to measure the relationship between environmental quality and green innovation.Results: 1) under different thresholds, a single environmental factor has different impacts on the comprehensive level of innovation drive in Chinese cities. Comparing the single environmental factor under different threshold values of per capita GDP, when the per capita GDP is low, attention should be paid to improving the centralized treatment rate of urban sewage treatment plants and the comprehensive utilization rate of general industrial solid waste; When the per capita GDP is high, the harmless treatment rate of domestic waste, the centralized treatment rate of sewage treatment plants, the green coverage rate of the built-up area, and the green area can all have different promotion effects on the driving capacity of cities along the line. 2) Under different thresholds, the elasticity coefficient of the total ecological environment, the total ecological environment has a relatively obvious promoting effect on the innovation-driven development of cities along the line, but this promoting effect shows a further weakening trend with the increase of per capita GDP.Conclusion: This study helps to explain environmental quality and green innovation, which is important for promoting sustainable economic development. The government should control environmental pollution and introduce laws and policies to ensure innovation.

LABORATORY STUDY ON THE SEDIMENTATION OF SURFACE WASTEWATER POLLUTANT COMPONENTS IN HISTORICAL PART OF SAMARA

The article discusses the existing drainage systems in Samara, the proposed project for the reconstruction of storm collector outlets located within the boundaries of the historical part of Samara.
 One of the factors of reservoir pollution (of Volga and Samara rivers) is untreated surface wastewater. The article specifies the outlets in the historical part of the city pernicious for the water reservoir.
 The study on the sedimentation of pollutant components contained in surface wastewater disposed from the historical part of Samara was held.
 As a result of the research, it was found that due to treatment facilities and storage tanks construction, as well as wastewater pumping into the household sewerage system, surface wastewater pumping will reduce the anthropogenic impact on the reservoir.
 It will also contribute to some extent to household waste dilution and increase the hydraulic load on urban sewage treatment plants.
 The water bodies of the water area of Samara are experiencing anthropogenic pressure, including due to untreated surface wastewater.
 The qualitative indicators of surface wastewater of a large industrial center have been studied on the example of the urban district of Samara. A list of negative indicators for water bodies has been determined; their maximal, average and minimal value ranges have been specified. It was revealed that the presented data will not have a negative impact on the centralized water disposal systems of settlements and urban districts.

Impact of urban underground sewage treatment plants on surrounding housing prices: Case study of Beijing, China

Currently, the enhancement of the surrounding house prices and land value by underground construction of urban sewage treatment plants (USTP) is mainly limited to the qualitative level, lacking quantitative evaluation methods. Analysing the impacts of USTP on the surrounding housing prices, an above-ground sewage treatment plant (ASTP) and a USTP in Beijing are considered research objects, with the housing price data collected and processed utilising geographic information and big data technology. Using the difference-in-difference (DID) model, the impact of urban sewage treatment plants (STP) on the surrounding housing prices is quantitatively analysed. Analysing the differences in house prices, growth volume and growth rate before and after the underground construction of urban STPs makes it clear that the USTP has a positive promoting effect on the surrounding house prices within 0–1 km; however, ASTP negatively inhibits house prices of the same size. Given the ASTP inhibition, analysis of reconstruction in the underground mode on the surrounding housing prices and the value of the released land resources makes it clear that its economic value is much greater than the investment in itself and the operating costs. In addition, it was verified that the underground reconstruction of ASTPs in large cities could significantly improve the economic value of the surrounding areas.

Isolation and characterization of novel lytic bacteriophages that infect multi drug resistant clinical strains of Escherichia coli.

The pathogenic strains of Escherichia coli (E. coli) are frequent cause of urinary tract infections including catheter-associated, soft tissue infections and sepsis. The growing antibiotic resistance in E. coli is a major health concern. Bacteriophages are specific for their bacterial host, thus providing a novel and effective alternatives. This study focuses on isolation of bacteriophages from urban sewage treatment plants. Initially 50 different bacteriophages have been isolated against non-resistant reference E. coli strain and fifty multidrug resistant clinical isolates of extraintestinal infections. Out of which only thirty-one lytic phages which gave clear plaques were further analysed for different physico-chemical aspects such as thermal inactivation, pH, effect oforganic solvents and detergents. Two bacteriophages, ASEC2201 and ASEC2202, were selected for their ability to withstand temperature fluctuation from -20 to 62 °C and a pH range from 4 to 10. They also showed good survival (40-94%) in the presence of organic solvents like ethanol, acetone, DMSO and chloroform or ability to form plaques even after the treatment with detergents like SDS, CTAB and sarkosyl. Both efficiently killed reference strain and 40-44% of multidrug resistant clinical isolates of E. coli. Later ASEC2201 and ASEC2202 were subjected to morphological characterisation through transmission electron microscopy, which revealed them to be tailed phages. The genomic analysis confirmed them to be Escherichia phages which belonged to family Drexlerviridae of Caudovirales.

Research Progress of Sewage Treatment Technology in Small and Medium Sized Towns

A / O process, oxidation ditch process and other leading technologies used in China's cities, Europe and the United States and other developed countries have been proved to be effective water pollution control technologies. They have their own advantages and disadvantages, and their applicability is also different. However, for small and medium-sized urban sewage treatment plants, these methods may not be suitable. Therefore, for small and medium-sized urban sewage treatment plants, we should consider the problems of technology, management, investment and operation. Therefore, we should look for more convenient, simple operation, low investment and operation cost methods that are more suitable for small towns. In this paper, several common sewage treatment processes are compared to determine the type of sewage treatment process in small and medium-sized towns.