The problem of effluent total nitrogen(TN)at most of the wastewater treatment plants(WWTPs)in China is important for meeting the related water quality standards,even under the condition of high energy consumption.To a...The problem of effluent total nitrogen(TN)at most of the wastewater treatment plants(WWTPs)in China is important for meeting the related water quality standards,even under the condition of high energy consumption.To achieve better prediction and control of effluent TN concentration,an efficient prediction model,based on controllable operation parameters,was constructed in a sequencing batch reactor process.Compared with previous models,this model has two main characteristics:①Superficial gas velocity and anoxic time are controllable operation parameters and are selected as the main input parameters instead of dissolved oxygen to improve the model controllability,and②the model prediction accuracy is improved on the basis of a feedforward neural network(FFNN)with algorithm optimization.The results demonstrated that the FFNN model was efficiently optimized by scaled conjugate gradient,and the performance was excellent compared with other models in terms of the correlation coefficient(R).The optimized FFNN model could provide an accurate prediction of effluent TN based on influent water parameters and key control parameters.This study revealed the possible application of the optimized FFNN model for the efficient removal of pollutants and lower energy consumption at most of the WWTPs.展开更多
Soil phosphomonoesterase plays a critical role in controlling phosphorus(P) cycling for crop nutrition,especially in P-deficient soils.A 6-year field experiment was conducted to evaluate soil phosphomonoesterase activ...Soil phosphomonoesterase plays a critical role in controlling phosphorus(P) cycling for crop nutrition,especially in P-deficient soils.A 6-year field experiment was conducted to evaluate soil phosphomonoesterase activities,kinetics and thermodynamics during rice growth stages after consistent swine manure application,to understand the impacts of swine manure amendment rates on soil chemical and enzymatic properties,and to investigate the correlations between soil enzymatic and chemical variables.The experiment was set out in a randomized complete block design with three replicates and five treatments including three swine manure rates(26,39,and 52 kg P ha^(-1),representing low,middle,and high application rates,respectively) and two controls(no-fertilizer and superphosphate at 26 kg P ha^(-1)).The results indicated that the grain yield and soil chemical properties were significantly improved with the application of P-based swine manure from 0 to 39 kg P ha^(-1);however,the differences between the 39(M_(39)) and 52 kg P ha^(-1) treatments(M_(52)) were not significant.The enzymatic property analysis indicated that acid phosphomonoesterase was the predominant phosphomonoesterase in the tested soil.The M_(39) and M_(52) treatments had relatively high initial velocity(V_0),maximal velocity(V_(max)),and activation grade(lgN_a) but low Michaelis constant(K_m),temperature coefficient(Q_(10)),activation energy(E_a),and activation enthalpy(ΔH),implying that the M_(39) and M_(52) treatments could stimulate the enzyme-catalyzed reactions more easily than all other treatments.The correlation analysis showed that the distribution of soil phosphomonoesterase activities mainly followed the distributions of total C and total N.Based on these results,39 kg P ha^(-1) could be recommended as the most appropriate rate of swine manure amendment.展开更多
To develop a cost-effective combined phytoremediation and biological process, a combined perennial ryegrass/artificial aquatic mat biofilm reactor was used to treat synthetic wastewater. Influent ammonium loading, ref...To develop a cost-effective combined phytoremediation and biological process, a combined perennial ryegrass/artificial aquatic mat biofilm reactor was used to treat synthetic wastewater. Influent ammonium loading, reflux ratio, hydraulic retention time (HRT) and temperature all had significant effects on the treatment efficiency. The results indicated that the effluent concentration of ammonium increased with increasing influent ammonium loading. The reactor temperature played an important role in the nitrification process. The ammonium removal efficiency significantly decreased from 80% to 30%-50% when the reactor temperatttre dropped to below 10℃. In addition, the optimal nitrogen removal condition was a reflux ratio of 2. The nitrate and ammonium concentration of the effluent were consistent with the HRT of the combined system. The chemical oxygen demand (COD) removal efficiency was at a high level during the whole experiment, being almost 80% after the start-up, and then mostly above 90%. The direct uptake of N by the perennial ryegrass accounted for 18.17% of the total N removal by the whole system. The perennial ryegrass absorption was a significant contributor to nitrogen removal in the combined system. The result'illustrated that the combined perennial ryegrass/artificial aquatic mat biofilm reactor demonstrated good performance in ammonium, total N and COD removal.展开更多
This study was designed to evaluate whether the decentralized rural kitchen waste(KW)composting technologies used in China can be widely applied.To this end,we completed a techno-economic analysis of three typical typ...This study was designed to evaluate whether the decentralized rural kitchen waste(KW)composting technologies used in China can be widely applied.To this end,we completed a techno-economic analysis of three typical types of KW compositing,namely solar-assisted(SAC),bio-enhanced(BEC),and heat-dewatering composting(HDC).These evaluations revealed that all three technologies produce composting products that meet China’s organic fertilizer standard and that both SAC and BEC are economically self-sustaining and generate net profits(18824.94 and 17791.52 US$/a)and positive net present values(32133.11 and 25035.93 US$).Subsequent sensitivity analysis demonstrated that the KW-handling subsidy plays a critical role in making decentralized composting economically attractive.Based on these analyses,we believe that reducing the coverage area of SAC,reducing the operating cost of BEC and HDC,upgrading composting products,and strengthening secondary pollution control would aid in supporting the technological improvement of these processes.Moreover,providing appropriate subsidies and promulgating specific standards and policies for KW fertilizer are key strategies for decentralized rural KW composting management.展开更多
In ecosystem engineering research,the contribution of microbial cooperation to ecosystem function has been emphasized.Fungi are one of the predominant decomposers in composting,but thus far,less attention has been giv...In ecosystem engineering research,the contribution of microbial cooperation to ecosystem function has been emphasized.Fungi are one of the predominant decomposers in composting,but thus far,less attention has been given to fungal than to bacterial cooperation.Therefore,network and cohesion analyses were combined to reveal the correlation between fungal cooperation and organic matter(OM)degradation in ten composting piles.Positive cohesion,reflecting the cooperation degree,was positively linked to the degradation rate of OM.From the community perspective,core species(i.e.,Candida tropicalis,Issatchenkia orientails,Kazachstania exigua,and Dipodascus australiensis)with high occurrence frequency and abundance were the key in regulating positive cohesion.These species were highly relevant to functional genera associated with OM degradation in both fungal and bacterial domains.Therefore,focusing on these core fungal species might be an appropriate strategy for targeted regulation of functional microbes and promotion of degradation rates.展开更多
基金This work was funded by the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07201003)the National Natural Science Foundation of China(51961125101)the Science and Technology Project of Zhejiang Province(2018C03003).
文摘The problem of effluent total nitrogen(TN)at most of the wastewater treatment plants(WWTPs)in China is important for meeting the related water quality standards,even under the condition of high energy consumption.To achieve better prediction and control of effluent TN concentration,an efficient prediction model,based on controllable operation parameters,was constructed in a sequencing batch reactor process.Compared with previous models,this model has two main characteristics:①Superficial gas velocity and anoxic time are controllable operation parameters and are selected as the main input parameters instead of dissolved oxygen to improve the model controllability,and②the model prediction accuracy is improved on the basis of a feedforward neural network(FFNN)with algorithm optimization.The results demonstrated that the FFNN model was efficiently optimized by scaled conjugate gradient,and the performance was excellent compared with other models in terms of the correlation coefficient(R).The optimized FFNN model could provide an accurate prediction of effluent TN based on influent water parameters and key control parameters.This study revealed the possible application of the optimized FFNN model for the efficient removal of pollutants and lower energy consumption at most of the WWTPs.
基金supported by the National Natural Science Foundation of China(Nos.21077088,41271314and 51008107)
文摘Soil phosphomonoesterase plays a critical role in controlling phosphorus(P) cycling for crop nutrition,especially in P-deficient soils.A 6-year field experiment was conducted to evaluate soil phosphomonoesterase activities,kinetics and thermodynamics during rice growth stages after consistent swine manure application,to understand the impacts of swine manure amendment rates on soil chemical and enzymatic properties,and to investigate the correlations between soil enzymatic and chemical variables.The experiment was set out in a randomized complete block design with three replicates and five treatments including three swine manure rates(26,39,and 52 kg P ha^(-1),representing low,middle,and high application rates,respectively) and two controls(no-fertilizer and superphosphate at 26 kg P ha^(-1)).The results indicated that the grain yield and soil chemical properties were significantly improved with the application of P-based swine manure from 0 to 39 kg P ha^(-1);however,the differences between the 39(M_(39)) and 52 kg P ha^(-1) treatments(M_(52)) were not significant.The enzymatic property analysis indicated that acid phosphomonoesterase was the predominant phosphomonoesterase in the tested soil.The M_(39) and M_(52) treatments had relatively high initial velocity(V_0),maximal velocity(V_(max)),and activation grade(lgN_a) but low Michaelis constant(K_m),temperature coefficient(Q_(10)),activation energy(E_a),and activation enthalpy(ΔH),implying that the M_(39) and M_(52) treatments could stimulate the enzyme-catalyzed reactions more easily than all other treatments.The correlation analysis showed that the distribution of soil phosphomonoesterase activities mainly followed the distributions of total C and total N.Based on these results,39 kg P ha^(-1) could be recommended as the most appropriate rate of swine manure amendment.
基金supported by the China National Critical Project for Science and Technology on Water Pollution Prevention and Control (No. 2008ZX07101-006)
文摘To develop a cost-effective combined phytoremediation and biological process, a combined perennial ryegrass/artificial aquatic mat biofilm reactor was used to treat synthetic wastewater. Influent ammonium loading, reflux ratio, hydraulic retention time (HRT) and temperature all had significant effects on the treatment efficiency. The results indicated that the effluent concentration of ammonium increased with increasing influent ammonium loading. The reactor temperature played an important role in the nitrification process. The ammonium removal efficiency significantly decreased from 80% to 30%-50% when the reactor temperatttre dropped to below 10℃. In addition, the optimal nitrogen removal condition was a reflux ratio of 2. The nitrate and ammonium concentration of the effluent were consistent with the HRT of the combined system. The chemical oxygen demand (COD) removal efficiency was at a high level during the whole experiment, being almost 80% after the start-up, and then mostly above 90%. The direct uptake of N by the perennial ryegrass accounted for 18.17% of the total N removal by the whole system. The perennial ryegrass absorption was a significant contributor to nitrogen removal in the combined system. The result'illustrated that the combined perennial ryegrass/artificial aquatic mat biofilm reactor demonstrated good performance in ammonium, total N and COD removal.
基金This work was financially supported by the Zhejiang Province Key Research and Development Project(Nos.2019C03006 and 2021C03024).
文摘This study was designed to evaluate whether the decentralized rural kitchen waste(KW)composting technologies used in China can be widely applied.To this end,we completed a techno-economic analysis of three typical types of KW compositing,namely solar-assisted(SAC),bio-enhanced(BEC),and heat-dewatering composting(HDC).These evaluations revealed that all three technologies produce composting products that meet China’s organic fertilizer standard and that both SAC and BEC are economically self-sustaining and generate net profits(18824.94 and 17791.52 US$/a)and positive net present values(32133.11 and 25035.93 US$).Subsequent sensitivity analysis demonstrated that the KW-handling subsidy plays a critical role in making decentralized composting economically attractive.Based on these analyses,we believe that reducing the coverage area of SAC,reducing the operating cost of BEC and HDC,upgrading composting products,and strengthening secondary pollution control would aid in supporting the technological improvement of these processes.Moreover,providing appropriate subsidies and promulgating specific standards and policies for KW fertilizer are key strategies for decentralized rural KW composting management.
基金financially supported by the National Key R&D Program of China[2019YFC1905003]the Open Project of State Key Laboratory of Urban Water Resource and Environment[ES202118]。
文摘In ecosystem engineering research,the contribution of microbial cooperation to ecosystem function has been emphasized.Fungi are one of the predominant decomposers in composting,but thus far,less attention has been given to fungal than to bacterial cooperation.Therefore,network and cohesion analyses were combined to reveal the correlation between fungal cooperation and organic matter(OM)degradation in ten composting piles.Positive cohesion,reflecting the cooperation degree,was positively linked to the degradation rate of OM.From the community perspective,core species(i.e.,Candida tropicalis,Issatchenkia orientails,Kazachstania exigua,and Dipodascus australiensis)with high occurrence frequency and abundance were the key in regulating positive cohesion.These species were highly relevant to functional genera associated with OM degradation in both fungal and bacterial domains.Therefore,focusing on these core fungal species might be an appropriate strategy for targeted regulation of functional microbes and promotion of degradation rates.