Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making sys...Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making system to propose a sewage treatment mode and scheme suitable for local conditions.By considering the village spatial layout and terrain factors,a decision tree model of residential density and terrain type was constructed with accuracies of 76.47%and 96.00%,respectively.Combined with binary classification probability unit regression,an appropriate sewage treatment mode for the village was determined with 87.00%accuracy.The Analytic Hierarchy Process(AHP),combined with the Technique for Order Preference(TOPSIS)by Similarity to an Ideal Solution model,formed the basis for optimal treatment process selection under different emission standards.Verification was conducted in 542 villages across three counties of the Inner Mongolia Autonomous Region,focusing on the standard effluent effect(0.3773),low investment cost(0.3196),and high standard effluent effect(0.5115)to determine the best treatment process for the same emission standard under different needs.The annual environmental and carbon emission benefits of sewage treatment in these villages were estimated.This model matches village density,geographic feature,and social development level,and provides scientific support and a theoretical basis for rural sewage treatment decision-making.展开更多
This study investigates the innovative reuse of sewage sludge with eco-friendly alkaline solutes to improve clayey soil without conventional cementitious binders.The unconfined compressive strength(UCS)was the main cr...This study investigates the innovative reuse of sewage sludge with eco-friendly alkaline solutes to improve clayey soil without conventional cementitious binders.The unconfined compressive strength(UCS)was the main criterion to assess the quality and effectiveness of the proposed solutions,as this test was performed to measure the strength of the stabilized clay by varying binders’dosages and curing times.Moreover,the direct shear test(DST)was used to investigate the Mohr-Coulomb parameters of the treated soil.Microstructure observations of the natural and treated soil were conducted using scanning electron microscope(SEM),energy-dispersive spectroscopy(EDS),and FTIR.Furthermore,toxicity characteristic leaching procedure(TCLP)tests were performed on the treated soil to investigate the leachability of metals.According to the results,using 2.5%of sewage sludge activated by NaOH and Na_(2)SiO_(3)increases the UCS values from 176 kPa to 1.46 MPa after 7 d and 56 d of curing,respectively.The results of the DST indicate that sewage sludge as a precursor increases cohesion and enhances frictional resistance,thereby improving the Mohr-Coulomb parameters of the stabilized soil.The SEM micrographs show that alkali-activated sewage sludge increases the integrity and reduces the cavity volumes in the stabilized soil.Moreover,TCLP tests revealed that the solubility of metals in the treated soil alkaliactivated by sewage sludge significantly decreased.This study suggests that using sewage sludge can replace cement and lime in ground improvement,improve the circular economy,and reduce the carbon footprint of construction projects.展开更多
Sewage sludge(SS)and SS impregnated with activating agents(ZnCl_(2) and KOH)were pyrolyzed in a fixed-bed reactor to produce gaseous fuel and activated char.The effects of heating rate,pyrolysis temperature and activa...Sewage sludge(SS)and SS impregnated with activating agents(ZnCl_(2) and KOH)were pyrolyzed in a fixed-bed reactor to produce gaseous fuel and activated char.The effects of heating rate,pyrolysis temperature and activator type on gas yields,pore structure and adsorption properties of activated char were systematically studied.The results demonstrated that increasing the pyrolysis temperature from 450℃ to 850℃ propo rtionally enhanced H_(2) and CO yields from the rapid pyrolysis of SS,while CH_(4) yield showed minimal variation between 650℃ and 850℃.ZnCl_(2) notably increased the CO yield,reaching71.9 ml·g^(-1)at 850℃,but caused a marked reduction in CH_(4) yield under the tested conditions.Similarly,KOH promoted CO yield at 750℃ and 850℃,with minimal impact on CH_(4) production.Both activators facilitated higher H_(2) yields in the range of 450-550℃,while the maximum H_(2) yield(109.8 ml·g^(-1))was observed at 850℃ in the absence of activator.The activated char derived from ZnCl_(2)-assisted pyrolysis exhibited well-developed micro-and mesopore structures,with specific surface areas ranging from 188.2 to 54.1 m^(2)·g^(-1)across pyrolysis temperatures of 450-850℃.When evaluated as adsorbents for methylene blue removal,activated char with greater specific surface area and total pore volume exhibited superior adsorption capacity.The adsorption process was well-described by the pseudo-second-order kinetic model.展开更多
We read with great interest the investigations conducted by Pourakbar et al.(2024)on the“Stabilization of clay soil using alkali-activated sewage sludge.”The authors have investigated the feasibility of utilizing al...We read with great interest the investigations conducted by Pourakbar et al.(2024)on the“Stabilization of clay soil using alkali-activated sewage sludge.”The authors have investigated the feasibility of utilizing alkali-activated sewage sludge(AASS)as a binder for stabilizing the clayey soil.Sewage sludge(SS)in varying proportions of 1.5%,2%,2.5%,3.5%,and 4.5%was utilized to prepare geopolymer binders using sodium and potassium-based alkali activators.Furthermore,unconfined compressive strength(UCS)and direct shear tests were conducted to examine the strength development of clayey soil stabilized with AASS.While the study presented some intriguing results,we have identified critical concerns regarding(i)the selection of SS as a precursor for alkali activation,(ii)technical inconsistencies associated with the compaction characteristics and microstructural analysis,and(iii)the feasibility of the proposed methodology for practical applications.Through our discussion,we seek to highlight these issues and provide constructive feedback to advance the understanding of alkali activation processes and their implications for soil stabilization.展开更多
Discharge from sewage treatment plants can deteriorate river water quality due to improper management or insufficient levels of treatment.To address these challenges,constructed wetland systems(CWSs)have been widely u...Discharge from sewage treatment plants can deteriorate river water quality due to improper management or insufficient levels of treatment.To address these challenges,constructed wetland systems(CWSs)have been widely used as a sustainable and effective solution for wastewater management.This study provides an overview of the conceptual design for a CWS to treat the discharge from the Papan Regional Sewage Treatment Plant(RSTP).The design influent for the CWS was determined,and the proposed sizing was based on simulation results to achieve the targeted concentrations consistent with Water Quality Index(WQI)Class II.The MUSIC-X software was used in this study to simulate pollutant removal performance,hydraulic behavior,and effluent quality under various flow conditions.The model was set up using site-specific inflow parameters,targeted effluent concentrations,and wetland configuration inputs,including surface area,depth,vegetation zones,and retention times.This study introduces an innovative approach by adopting the paddy field concept as the geometrical design of a multi-cell CWS,covering a total surface area of 1,250,000m^(2)and divided into two sections(Wetland 1 and Wetland 2),with different planting plots separated by a gabion wall.The innovation lies in reimagining abandoned mining ponds as functional wetland zones,while using a paddy field-inspired grid layout to enhance hydraulic control,pollutant removal,and land efficiency.This approach transforms degraded land into an eco-engineered,cost-effective,and scalable wastewater treatment system-a novel model for tropical developing regions.展开更多
This article focuses on the optimization of water supply and drainage systems,involving theories such as hydraulic models of pipeline systems and multi-objective collaborative optimization.It introduces the system dyn...This article focuses on the optimization of water supply and drainage systems,involving theories such as hydraulic models of pipeline systems and multi-objective collaborative optimization.It introduces the system dynamics model of sewage treatment facility expansion.Elaborating on detection technology,construction of an intelligent operation and maintenance system,and factors to be considered for sewage plant expansion,it emphasizes the importance of collaborative development and verifies benefits through the PSR model.展开更多
[ Objective] This study was to improve the biomass of Navicula tenera, and thus to provide reference for achieving the industrial production of Navicula tenera. [Method] The feasibility of using sewage to cultivate Na...[ Objective] This study was to improve the biomass of Navicula tenera, and thus to provide reference for achieving the industrial production of Navicula tenera. [Method] The feasibility of using sewage to cultivate Navicula tenera was preliminarily investigated based on the consideration of regional characteristics; and a series of culture conditions including the nutrient source of nitrogen（N）, phosphorus（P）, iron（Fe）, silicon（ Si ） and the salinity in medium for culturing Navicula tenera, were optimized by single factor test and orthogonal design.[Result] The optimized conditions for cultivating Navicula tenera using sewage are as follows： the water from Xiaoerlou Artificial Lake of Nanjing University of Technology as basic solvent; 360 mg/L urea; 150 mg/L N2HPO4 · 12H2O; 50 mg/L ferric citrate; 2 000 mg/L Na2SiO3 · 9H2O; 2.0 mol/L salinity. Navicula tenera was strongly adaptive to sewage and could well uptake the nutrient sources in the sewage. Under the optimized conditions, the culture cost decreased, and meanwhile the biomass of Navicula tenera reached 4. 766 g/L which is 3.57 multiples over original medium and 1.9 multiples over optimized medium No. 1.[ Conclusion] This study laid a foundation for the combination of culturing Navicula tenera in large scale and sewage treatment.展开更多
Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants （WWTPs） and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentratio...Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants （WWTPs） and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentrations in the sludge were determined. Metal speciation was also studied. The results showed that sewage sludge had high organic carbon, and was rich in such nutrients as N and P. The concentrations of Mn, Zn, and Cu were the highest, followed by Ni, Pb, and Cr, Cd had the lowest concentration. In addition, the concentrations of the aforementioned heavy metals in the sludge samples were higher than those recorded in the background data for crop soils. With the exception of Cu and Cd from site S1, and Ni from sites S1, $2, and $5, all other metal concentrations conformed to permissible levels prescribed by the national application standard of acid soil in China （GB 18918--2002）. The results of the BCR sequential extraction showed that the concentrations of Mn and Zn were predominant in acid-soluble/exchangeable and reducible fractions. Cu was principally distributed in oxidizable and residual fractions, whereas Cr was present in oxidizable and residual fractions, Pb was found in the state of residual fractions, and the distribution of Ni and Cd did not show significant characteristics.展开更多
With the development of rural economy, pollutions of rural sewage are in- creasingly serious. This paper introduces the characteristics of rural domestic sewage and the rural sewage treatment situation, and according ...With the development of rural economy, pollutions of rural sewage are in- creasingly serious. This paper introduces the characteristics of rural domestic sewage and the rural sewage treatment situation, and according to the problems of funds, management, process selection, policy and weak awareness of environmental protection in the rural domestic sewage treatment, puts forward relevant countermea- sures to ensure long-term operation of sewage treatment system, and achieve the purpose of improving rural water environment and protect the ecological environment in rural areas.展开更多
Aiming to resolve the problem that conventional sewage source heat pump systems cannot satisfy heat peak loads of buildings,a new idea that the freezing latent heat is exacted as the auxiliary heat source at the peak ...Aiming to resolve the problem that conventional sewage source heat pump systems cannot satisfy heat peak loads of buildings,a new idea that the freezing latent heat is exacted as the auxiliary heat source at the peak heat load is proposed.First,on the basis of sewage characteristics,a freezing latent heat exchanger is developed to safely eliminate ice,continuously extract heat and remove sewage soft-dirt.A reasonable form of the urban sewage source heat pump system with freezing latent heat collection is presented.Then,the feasibility of the system is theoretically analyzed.The calculation results under typical operating conditions show that the heating ability of the new system is higher than that of the conventional one and the ratio of these two highest heating rates is between 4.5 and 8.7,which proves that the new system has great application potential in cold regions.展开更多
[Objection] The aim was to study application of channels constructed wetland in treatment of domestic sewages in new countryside. [Method] Supported by construction of new rural areas project in China, we surveyed on ...[Objection] The aim was to study application of channels constructed wetland in treatment of domestic sewages in new countryside. [Method] Supported by construction of new rural areas project in China, we surveyed on new rural areas in Gannan, Jiangxi Province, summarized source, characteristics and treatment of domestic sewage in countryside, and designed channels constructed wetland for sewage treatment. [Result] The technique is proven effective in sewage treatment. After the technique was conducted for a trial run for four months, removal rates of COD, TP and TN averaged 73.07%, 73.25% and 72.36%, respectively. After contin- uous sampling for six times, effluent COD was analyzed 20-35 mg/L, TP was 0.60- 1.19 mg/L and TN was 6.88-11.21 mg/L, better than that of Standard 1B ruled by Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant. [Conclusion] Thanks for low investment, channels constructed wetland can be built by trans- formation of bottom land, proving a good way for treatment of diffuse pollution source and control of water non-point pollution.展开更多
Increase of sewage sludge(SS)has led to the construction of more incineration plants,exacerbating to the production of SS incineration residues.However,few studies have considered the mass balance of elements in large...Increase of sewage sludge(SS)has led to the construction of more incineration plants,exacerbating to the production of SS incineration residues.However,few studies have considered the mass balance of elements in large-scale SS incineration plants,affecting the residues treatment and utilization.In this study,flow analysis was conducted for major and trace elements in the SS,the fly ash(sewage sludge ash,SSA)and bottom ash from two large-scale SS incineration plants.The elemental characteristics were compared with those of coal fly ash(CFA),and air pollution control residues from municipal solid waste incineration(MSWIA),as well as related criteria.The results showed that the most abundant major element in SSA was Si,ranging from 120 to 240 g/kg,followed by Al(76–348 g/kg),Ca(26–113 g/kg),Fe(35–80 g/kg),and P(26–104 g/kg),and the trace elements were mainly Zn,Ba,Cu,and Mn.Not all the major elements were derived from SS.Most trace elements in the SS incineration residues accounted for 82.4%–127%of those from SS,indicating that SS was the main source of trace elements.The partitioning of heavy metals in the SS incineration residues showed that electrostatic precipitator ash or cyclone ash with high production rates were the major pollutant sinks.The differences in some major and trace elements could be indicators to differentiate SSA from CFA and MSWIA.Compared with related land criteria,the pollutants in SSA should not be ignored during disposal and utilization.展开更多
Nowadays,rural domestic sewage has had serious effects on the natural environment in rural areas such as the body of water and soil.In order to ensure rural water security and good health condition of farmers,it is ur...Nowadays,rural domestic sewage has had serious effects on the natural environment in rural areas such as the body of water and soil.In order to ensure rural water security and good health condition of farmers,it is urgent to treat the rural sewage.The theoretical principle,characteristics,deficiencies and application status of some decentralized disposal technologies for domestic sewage are introduced,which include high rate algal pond technology,subsurface infiltration treatment system,earthworm eco-filter,constructed wetland treatment technology and membrane bioreactor technology,so as to provide references for the rural sewage treatment.展开更多
In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town ...In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town of Zhenjiang. The specific research object is the runoff of the outfall of rainwater-sewage confluence in the area. On the basis of detecting and analyzing the water yield and water quality of the runoff of rainwater-sewage confluence a combined technology which contains four independent continuous processes for lowering pollution load was developed and system equipment was established and put into operation. The processing effects of the project were monitored and analyzed.The results show that the pollution control project of outfall runoff is efficient which decreases the pollution load including chemical oxygen demand COD total phosphorus TP suspended solids SS and ammonia-nitrogen NH3-N .As a result the water environment of the ancient canal is protected.展开更多
A pilot test is carried out to treat Beijing suburb campus sewage by using integrated constructed wetland system, which combines three systems that are multi-level complex constructed wetland system, buried integratio...A pilot test is carried out to treat Beijing suburb campus sewage by using integrated constructed wetland system, which combines three systems that are multi-level complex constructed wetland system, buried integration pretreatment system and wetland landscape system. Results show that the integrated system has a good pollutant removal efficiency: COD is mainly removed in the integration pretreatment system with an average removal rate of 96.87%; as NH4-N, TN and TP are mainly removed in the multi-level complex constructed wetland system, the average concentrations in effluent of COD, NH4-N, TN and TP are 45.58, 19.51, 31.9 and 1.49 mg/L, respectively; the Wetland landscape system also plays a role of depth processing, as the average concentrations in effluent of COD, NH4-N and TP are 13.33, 0.34 and 0.53 mg/L, respectively.展开更多
Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies...Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies on rural domestic sewage treatment from the governance techniques and modes of governance subjects and research perspectives, in order to provide reference for the implementation of rural revitalization strategy and rural domestic sewage treatment research and action implementation.展开更多
At present, there are still many problems in the specific treatment of industrial sewage in our country. In order to enhance the treatment quality of industrial sewage, relevant sewage treatment units should pay atten...At present, there are still many problems in the specific treatment of industrial sewage in our country. In order to enhance the treatment quality of industrial sewage, relevant sewage treatment units should pay attention to improving the treatment level of environmental engineering sewage, strengthening the standardization of sewage treatment market system and strengthening the innovation of sewage management form. Based on the characteristics of industrial wastewater treatment, reasonable and effective treatment strategies are applied to effectively improve the wastewater treatment technology, which is helpful to improve the quality of wastewater treatment. This paper makes an in-depth exploration and analysis of the common problems in industrial sewage treatment for reference.展开更多
In order to understand the current situation of urban sewage treatment and pipe network construction and operation, find out the foundation, find out the sticking point, control the source and stop the pollution, help...In order to understand the current situation of urban sewage treatment and pipe network construction and operation, find out the foundation, find out the sticking point, control the source and stop the pollution, help the water pollution prevention and control, and promote the sustainable development of water environment, this paper investigates the current situation of urban sewage treatment and pipe network construction and operation in Qiannan Prefecture.展开更多
The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis （DGGE） of nested polymerase chain reaction （ne...The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis （DGGE） of nested polymerase chain reaction （nested PCR） amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated sludge samples were amplified using the extracted genomic DNA before the PCR products were loaded on the same DGGE gel for bacterial community analysis. Ammonia-oxidizing bacterial and actinomycetic community analysis were also carried out to investigate the relationship between specific population structures and system or sludge performance. The two plants demonstrated a similarity in bacterial community structures of raw sewage and activated sludge, but they had different effluent populations. Many dominant bacterial populations of raw sewage did not appear in the activated sludge samples, suggesting that the dominant bacterial populations in raw sewage might not play an important role during wastewater treatment. Although the two plants had different sludge properties in terms of settleability and foam forming ability, they demonstrated similar actinomycetic community structures. For activated sludge with bad settling performance, the treated water presented a similar DGGE pattern with that of activated sludge, indicating the nonselective washout of bacteria from the system. The plant with better ammonium removal efficiency showed higher ammonia-oxidizing bacteria species richness. Analysis of sequencing results showed that the major populations in raw sewage were uncultured bacterium, while in activated sludge the predominant populations were beta proteobacteria.展开更多
Low organic matter content and high heavy metal levels severely inhibit the anaerobic digestion(AD) of sewage sludge. In this study, the effect of added manganese oxidemodified biochar composite(MBC) on methane produc...Low organic matter content and high heavy metal levels severely inhibit the anaerobic digestion(AD) of sewage sludge. In this study, the effect of added manganese oxidemodified biochar composite(MBC) on methane production and heavy metal fractionation during sewage sludge AD was examined. The MBC could increase the buffering capacity,enhance the methane production and degradation of intermediate acids, buffer the pH of the culture, and stabilize the sewage sludge AD process. The application of MBC positively impacted methane production and the cumulative methane yield increased up to 121.97%,as compared with the control. The MBC addition can improve metal stabilization in the digestate. An optimum MBC dose of 2.36 g was recommended, which would produce up to 121.1 L/kg volatile solids of methane. After the AD process, even though most of the metals accumulated in the residual solids, they could be transformation from the bio-available fractions to a more stable fraction. The total organic-and sulfide-bound and residual fraction content at a 3 g dose of MBC that is 0.12 g/g dry matter were 51.06% and 35.11% higher than the control, respectively. The results indicated that the application of MBC could improve the performance of AD and promote stabilization of heavy metals in sewage sludge post the AD process.展开更多
基金supported by the Central Government Guiding Local Science and Technology Development Fund Project(No.2024SZY0343)the Joint Research Program for Ecological Conservation and High Quality Development of the Yellow River Basin(No.2022-YRUC-01-050205)+2 种基金the Higher Education Scientific Research Project of Inner Mongolia Autonomous Region(No.NJZZ23078)the project of Inner Mongolia"Prairie Talents"Engineering Innovation Entrepreneurship Talent Team,the Major Projects of Erdos Science and Technology(No.2022EEDSKJZDZX015)the Innovation Team of the Inner Mongolia Academy of Science and Technology(No.CXTD2023-01-016).
文摘Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making system to propose a sewage treatment mode and scheme suitable for local conditions.By considering the village spatial layout and terrain factors,a decision tree model of residential density and terrain type was constructed with accuracies of 76.47%and 96.00%,respectively.Combined with binary classification probability unit regression,an appropriate sewage treatment mode for the village was determined with 87.00%accuracy.The Analytic Hierarchy Process(AHP),combined with the Technique for Order Preference(TOPSIS)by Similarity to an Ideal Solution model,formed the basis for optimal treatment process selection under different emission standards.Verification was conducted in 542 villages across three counties of the Inner Mongolia Autonomous Region,focusing on the standard effluent effect(0.3773),low investment cost(0.3196),and high standard effluent effect(0.5115)to determine the best treatment process for the same emission standard under different needs.The annual environmental and carbon emission benefits of sewage treatment in these villages were estimated.This model matches village density,geographic feature,and social development level,and provides scientific support and a theoretical basis for rural sewage treatment decision-making.
文摘This study investigates the innovative reuse of sewage sludge with eco-friendly alkaline solutes to improve clayey soil without conventional cementitious binders.The unconfined compressive strength(UCS)was the main criterion to assess the quality and effectiveness of the proposed solutions,as this test was performed to measure the strength of the stabilized clay by varying binders’dosages and curing times.Moreover,the direct shear test(DST)was used to investigate the Mohr-Coulomb parameters of the treated soil.Microstructure observations of the natural and treated soil were conducted using scanning electron microscope(SEM),energy-dispersive spectroscopy(EDS),and FTIR.Furthermore,toxicity characteristic leaching procedure(TCLP)tests were performed on the treated soil to investigate the leachability of metals.According to the results,using 2.5%of sewage sludge activated by NaOH and Na_(2)SiO_(3)increases the UCS values from 176 kPa to 1.46 MPa after 7 d and 56 d of curing,respectively.The results of the DST indicate that sewage sludge as a precursor increases cohesion and enhances frictional resistance,thereby improving the Mohr-Coulomb parameters of the stabilized soil.The SEM micrographs show that alkali-activated sewage sludge increases the integrity and reduces the cavity volumes in the stabilized soil.Moreover,TCLP tests revealed that the solubility of metals in the treated soil alkaliactivated by sewage sludge significantly decreased.This study suggests that using sewage sludge can replace cement and lime in ground improvement,improve the circular economy,and reduce the carbon footprint of construction projects.
基金financially supported by the National Natural Science Foundation of China(U21A2062)National innovative training program for college students of China(202410792014)。
文摘Sewage sludge(SS)and SS impregnated with activating agents(ZnCl_(2) and KOH)were pyrolyzed in a fixed-bed reactor to produce gaseous fuel and activated char.The effects of heating rate,pyrolysis temperature and activator type on gas yields,pore structure and adsorption properties of activated char were systematically studied.The results demonstrated that increasing the pyrolysis temperature from 450℃ to 850℃ propo rtionally enhanced H_(2) and CO yields from the rapid pyrolysis of SS,while CH_(4) yield showed minimal variation between 650℃ and 850℃.ZnCl_(2) notably increased the CO yield,reaching71.9 ml·g^(-1)at 850℃,but caused a marked reduction in CH_(4) yield under the tested conditions.Similarly,KOH promoted CO yield at 750℃ and 850℃,with minimal impact on CH_(4) production.Both activators facilitated higher H_(2) yields in the range of 450-550℃,while the maximum H_(2) yield(109.8 ml·g^(-1))was observed at 850℃ in the absence of activator.The activated char derived from ZnCl_(2)-assisted pyrolysis exhibited well-developed micro-and mesopore structures,with specific surface areas ranging from 188.2 to 54.1 m^(2)·g^(-1)across pyrolysis temperatures of 450-850℃.When evaluated as adsorbents for methylene blue removal,activated char with greater specific surface area and total pore volume exhibited superior adsorption capacity.The adsorption process was well-described by the pseudo-second-order kinetic model.
文摘We read with great interest the investigations conducted by Pourakbar et al.(2024)on the“Stabilization of clay soil using alkali-activated sewage sludge.”The authors have investigated the feasibility of utilizing alkali-activated sewage sludge(AASS)as a binder for stabilizing the clayey soil.Sewage sludge(SS)in varying proportions of 1.5%,2%,2.5%,3.5%,and 4.5%was utilized to prepare geopolymer binders using sodium and potassium-based alkali activators.Furthermore,unconfined compressive strength(UCS)and direct shear tests were conducted to examine the strength development of clayey soil stabilized with AASS.While the study presented some intriguing results,we have identified critical concerns regarding(i)the selection of SS as a precursor for alkali activation,(ii)technical inconsistencies associated with the compaction characteristics and microstructural analysis,and(iii)the feasibility of the proposed methodology for practical applications.Through our discussion,we seek to highlight these issues and provide constructive feedback to advance the understanding of alkali activation processes and their implications for soil stabilization.
基金Higher Institution Centre of Excellence Program(HICoE),Grant/Award Number:A305-LRAKH001-0004403901-0000。
文摘Discharge from sewage treatment plants can deteriorate river water quality due to improper management or insufficient levels of treatment.To address these challenges,constructed wetland systems(CWSs)have been widely used as a sustainable and effective solution for wastewater management.This study provides an overview of the conceptual design for a CWS to treat the discharge from the Papan Regional Sewage Treatment Plant(RSTP).The design influent for the CWS was determined,and the proposed sizing was based on simulation results to achieve the targeted concentrations consistent with Water Quality Index(WQI)Class II.The MUSIC-X software was used in this study to simulate pollutant removal performance,hydraulic behavior,and effluent quality under various flow conditions.The model was set up using site-specific inflow parameters,targeted effluent concentrations,and wetland configuration inputs,including surface area,depth,vegetation zones,and retention times.This study introduces an innovative approach by adopting the paddy field concept as the geometrical design of a multi-cell CWS,covering a total surface area of 1,250,000m^(2)and divided into two sections(Wetland 1 and Wetland 2),with different planting plots separated by a gabion wall.The innovation lies in reimagining abandoned mining ponds as functional wetland zones,while using a paddy field-inspired grid layout to enhance hydraulic control,pollutant removal,and land efficiency.This approach transforms degraded land into an eco-engineered,cost-effective,and scalable wastewater treatment system-a novel model for tropical developing regions.
文摘This article focuses on the optimization of water supply and drainage systems,involving theories such as hydraulic models of pipeline systems and multi-objective collaborative optimization.It introduces the system dynamics model of sewage treatment facility expansion.Elaborating on detection technology,construction of an intelligent operation and maintenance system,and factors to be considered for sewage plant expansion,it emphasizes the importance of collaborative development and verifies benefits through the PSR model.
基金Supported by National Basic Research Program of China(973 Pro-gram)(2003CB71600)~~
文摘[ Objective] This study was to improve the biomass of Navicula tenera, and thus to provide reference for achieving the industrial production of Navicula tenera. [Method] The feasibility of using sewage to cultivate Navicula tenera was preliminarily investigated based on the consideration of regional characteristics; and a series of culture conditions including the nutrient source of nitrogen（N）, phosphorus（P）, iron（Fe）, silicon（ Si ） and the salinity in medium for culturing Navicula tenera, were optimized by single factor test and orthogonal design.[Result] The optimized conditions for cultivating Navicula tenera using sewage are as follows： the water from Xiaoerlou Artificial Lake of Nanjing University of Technology as basic solvent; 360 mg/L urea; 150 mg/L N2HPO4 · 12H2O; 50 mg/L ferric citrate; 2 000 mg/L Na2SiO3 · 9H2O; 2.0 mol/L salinity. Navicula tenera was strongly adaptive to sewage and could well uptake the nutrient sources in the sewage. Under the optimized conditions, the culture cost decreased, and meanwhile the biomass of Navicula tenera reached 4. 766 g/L which is 3.57 multiples over original medium and 1.9 multiples over optimized medium No. 1.[ Conclusion] This study laid a foundation for the combination of culturing Navicula tenera in large scale and sewage treatment.
基金Project(51308132) supported by the National Natural Science Foundation of ChinaProject(2012B050300023) supported by the Scientific and Technological Planning Project of Guangdong Province,China+1 种基金Project(LYM11059) supported by the Foundation for Distinguished Young Talents in Higher Education of Guangdong,ChinaProjects(2011B090400161,2011B090400144) supported by the Cooperation Foundation for Industry,University and Research Institute,Guangdong Province and Ministry of Education of China
文摘Dewatered municipal sludge samples were collected from five municipal wastewater treatment plants （WWTPs） and one industrial WWTP in Guangzhou, China. A number of agricultural parameters and total metal concentrations in the sludge were determined. Metal speciation was also studied. The results showed that sewage sludge had high organic carbon, and was rich in such nutrients as N and P. The concentrations of Mn, Zn, and Cu were the highest, followed by Ni, Pb, and Cr, Cd had the lowest concentration. In addition, the concentrations of the aforementioned heavy metals in the sludge samples were higher than those recorded in the background data for crop soils. With the exception of Cu and Cd from site S1, and Ni from sites S1, $2, and $5, all other metal concentrations conformed to permissible levels prescribed by the national application standard of acid soil in China （GB 18918--2002）. The results of the BCR sequential extraction showed that the concentrations of Mn and Zn were predominant in acid-soluble/exchangeable and reducible fractions. Cu was principally distributed in oxidizable and residual fractions, whereas Cr was present in oxidizable and residual fractions, Pb was found in the state of residual fractions, and the distribution of Ni and Cd did not show significant characteristics.
文摘With the development of rural economy, pollutions of rural sewage are in- creasingly serious. This paper introduces the characteristics of rural domestic sewage and the rural sewage treatment situation, and according to the problems of funds, management, process selection, policy and weak awareness of environmental protection in the rural domestic sewage treatment, puts forward relevant countermea- sures to ensure long-term operation of sewage treatment system, and achieve the purpose of improving rural water environment and protect the ecological environment in rural areas.
基金The National Key Technology R&D Program of Chinaduring the 11th Five-Year Plan Period(No.2008BAJ12B05-05)the Research Foundation of Education Bureau of Heilongjiang Province,China(No.11551114)the China Postdoctoral Science Foundation(No.20100471438).
文摘Aiming to resolve the problem that conventional sewage source heat pump systems cannot satisfy heat peak loads of buildings,a new idea that the freezing latent heat is exacted as the auxiliary heat source at the peak heat load is proposed.First,on the basis of sewage characteristics,a freezing latent heat exchanger is developed to safely eliminate ice,continuously extract heat and remove sewage soft-dirt.A reasonable form of the urban sewage source heat pump system with freezing latent heat collection is presented.Then,the feasibility of the system is theoretically analyzed.The calculation results under typical operating conditions show that the heating ability of the new system is higher than that of the conventional one and the ratio of these two highest heating rates is between 4.5 and 8.7,which proves that the new system has great application potential in cold regions.
基金Supported by Project of the National Eleventh-Five Year Research Program of China(2008BAD96B04)~~
文摘[Objection] The aim was to study application of channels constructed wetland in treatment of domestic sewages in new countryside. [Method] Supported by construction of new rural areas project in China, we surveyed on new rural areas in Gannan, Jiangxi Province, summarized source, characteristics and treatment of domestic sewage in countryside, and designed channels constructed wetland for sewage treatment. [Result] The technique is proven effective in sewage treatment. After the technique was conducted for a trial run for four months, removal rates of COD, TP and TN averaged 73.07%, 73.25% and 72.36%, respectively. After contin- uous sampling for six times, effluent COD was analyzed 20-35 mg/L, TP was 0.60- 1.19 mg/L and TN was 6.88-11.21 mg/L, better than that of Standard 1B ruled by Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant. [Conclusion] Thanks for low investment, channels constructed wetland can be built by trans- formation of bottom land, proving a good way for treatment of diffuse pollution source and control of water non-point pollution.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No.2017ZX07202005)National Natural Science Foundation of China(No.21577102)。
文摘Increase of sewage sludge(SS)has led to the construction of more incineration plants,exacerbating to the production of SS incineration residues.However,few studies have considered the mass balance of elements in large-scale SS incineration plants,affecting the residues treatment and utilization.In this study,flow analysis was conducted for major and trace elements in the SS,the fly ash(sewage sludge ash,SSA)and bottom ash from two large-scale SS incineration plants.The elemental characteristics were compared with those of coal fly ash(CFA),and air pollution control residues from municipal solid waste incineration(MSWIA),as well as related criteria.The results showed that the most abundant major element in SSA was Si,ranging from 120 to 240 g/kg,followed by Al(76–348 g/kg),Ca(26–113 g/kg),Fe(35–80 g/kg),and P(26–104 g/kg),and the trace elements were mainly Zn,Ba,Cu,and Mn.Not all the major elements were derived from SS.Most trace elements in the SS incineration residues accounted for 82.4%–127%of those from SS,indicating that SS was the main source of trace elements.The partitioning of heavy metals in the SS incineration residues showed that electrostatic precipitator ash or cyclone ash with high production rates were the major pollutant sinks.The differences in some major and trace elements could be indicators to differentiate SSA from CFA and MSWIA.Compared with related land criteria,the pollutants in SSA should not be ignored during disposal and utilization.
基金Supported by Major Science and Technology Project of State Water Pollution Control and Governance(2008ZX07208-005)
文摘Nowadays,rural domestic sewage has had serious effects on the natural environment in rural areas such as the body of water and soil.In order to ensure rural water security and good health condition of farmers,it is urgent to treat the rural sewage.The theoretical principle,characteristics,deficiencies and application status of some decentralized disposal technologies for domestic sewage are introduced,which include high rate algal pond technology,subsurface infiltration treatment system,earthworm eco-filter,constructed wetland treatment technology and membrane bioreactor technology,so as to provide references for the rural sewage treatment.
基金The National Science and Technology Major Project of China(No.2008ZX07317-001)
文摘In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town of Zhenjiang. The specific research object is the runoff of the outfall of rainwater-sewage confluence in the area. On the basis of detecting and analyzing the water yield and water quality of the runoff of rainwater-sewage confluence a combined technology which contains four independent continuous processes for lowering pollution load was developed and system equipment was established and put into operation. The processing effects of the project were monitored and analyzed.The results show that the pollution control project of outfall runoff is efficient which decreases the pollution load including chemical oxygen demand COD total phosphorus TP suspended solids SS and ammonia-nitrogen NH3-N .As a result the water environment of the ancient canal is protected.
基金Supported by Subtopic of New Countryside Sewage Comprehensive Treatment Demonstration Project of Beijing Science and Technology Plans (D07040600770701-8 D08040600580803) ~~
文摘A pilot test is carried out to treat Beijing suburb campus sewage by using integrated constructed wetland system, which combines three systems that are multi-level complex constructed wetland system, buried integration pretreatment system and wetland landscape system. Results show that the integrated system has a good pollutant removal efficiency: COD is mainly removed in the integration pretreatment system with an average removal rate of 96.87%; as NH4-N, TN and TP are mainly removed in the multi-level complex constructed wetland system, the average concentrations in effluent of COD, NH4-N, TN and TP are 45.58, 19.51, 31.9 and 1.49 mg/L, respectively; the Wetland landscape system also plays a role of depth processing, as the average concentrations in effluent of COD, NH4-N and TP are 13.33, 0.34 and 0.53 mg/L, respectively.
文摘Rural domestic sewage treatment is an important part of the rural revitalization strategy and a key action to build a livable, livable and beautiful countryside. This paper composes and summarizes the relevant studies on rural domestic sewage treatment from the governance techniques and modes of governance subjects and research perspectives, in order to provide reference for the implementation of rural revitalization strategy and rural domestic sewage treatment research and action implementation.
文摘At present, there are still many problems in the specific treatment of industrial sewage in our country. In order to enhance the treatment quality of industrial sewage, relevant sewage treatment units should pay attention to improving the treatment level of environmental engineering sewage, strengthening the standardization of sewage treatment market system and strengthening the innovation of sewage management form. Based on the characteristics of industrial wastewater treatment, reasonable and effective treatment strategies are applied to effectively improve the wastewater treatment technology, which is helpful to improve the quality of wastewater treatment. This paper makes an in-depth exploration and analysis of the common problems in industrial sewage treatment for reference.
文摘In order to understand the current situation of urban sewage treatment and pipe network construction and operation, find out the foundation, find out the sticking point, control the source and stop the pollution, help the water pollution prevention and control, and promote the sustainable development of water environment, this paper investigates the current situation of urban sewage treatment and pipe network construction and operation in Qiannan Prefecture.
基金Project supported by the National Natural Science Foundation of China (No. 20510076, 50238050).
文摘The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis （DGGE） of nested polymerase chain reaction （nested PCR） amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated sludge samples were amplified using the extracted genomic DNA before the PCR products were loaded on the same DGGE gel for bacterial community analysis. Ammonia-oxidizing bacterial and actinomycetic community analysis were also carried out to investigate the relationship between specific population structures and system or sludge performance. The two plants demonstrated a similarity in bacterial community structures of raw sewage and activated sludge, but they had different effluent populations. Many dominant bacterial populations of raw sewage did not appear in the activated sludge samples, suggesting that the dominant bacterial populations in raw sewage might not play an important role during wastewater treatment. Although the two plants had different sludge properties in terms of settleability and foam forming ability, they demonstrated similar actinomycetic community structures. For activated sludge with bad settling performance, the treated water presented a similar DGGE pattern with that of activated sludge, indicating the nonselective washout of bacteria from the system. The plant with better ammonium removal efficiency showed higher ammonia-oxidizing bacteria species richness. Analysis of sequencing results showed that the major populations in raw sewage were uncultured bacterium, while in activated sludge the predominant populations were beta proteobacteria.
基金supported by the Foundation of National Special Item on Water Resource and Environment (No.2014ZX07303003 and 2017ZX07603003)
文摘Low organic matter content and high heavy metal levels severely inhibit the anaerobic digestion(AD) of sewage sludge. In this study, the effect of added manganese oxidemodified biochar composite(MBC) on methane production and heavy metal fractionation during sewage sludge AD was examined. The MBC could increase the buffering capacity,enhance the methane production and degradation of intermediate acids, buffer the pH of the culture, and stabilize the sewage sludge AD process. The application of MBC positively impacted methane production and the cumulative methane yield increased up to 121.97%,as compared with the control. The MBC addition can improve metal stabilization in the digestate. An optimum MBC dose of 2.36 g was recommended, which would produce up to 121.1 L/kg volatile solids of methane. After the AD process, even though most of the metals accumulated in the residual solids, they could be transformation from the bio-available fractions to a more stable fraction. The total organic-and sulfide-bound and residual fraction content at a 3 g dose of MBC that is 0.12 g/g dry matter were 51.06% and 35.11% higher than the control, respectively. The results indicated that the application of MBC could improve the performance of AD and promote stabilization of heavy metals in sewage sludge post the AD process.
