[ Objective] The study aims at discussing the feasibility of urban sewage sludge applied to desertification forestland. [ Method] Through the simulated leaching test, the effects of sewage sludge application on the co...[ Objective] The study aims at discussing the feasibility of urban sewage sludge applied to desertification forestland. [ Method] Through the simulated leaching test, the effects of sewage sludge application on the content of nutrients and heavy metals in aeolian sandy soil were ana- lyzed. [ Result] After the simulated leaching with sewage sludge, the contents of total nitrogen （TN）, total phosphorus （TP）, available nitrogen （AN） and available phosphorus （AP） in each layer of aeolian sandy soil increased significantly, and the increase in 0 -20 cm soil was more signifi- cant than that in 20 -40 and 40 -60 cm soil. Meanwhile, the content of each heavy metal in 0 -20 cm soil rose significantly, while the increase was small in 40 -60 cm soil. In addition, after the application of sewage sludge, the Nemrew Index of aeolian sandy soil was 0.67, lower than the na- tional soil quality standard of forestland （0.70）, and the short-time application of sewage sludge to sandy soil did not cause serious pollution. How- ever, if sewage sludge has been applied to aeolian sandy soil for a long term, the potential hazard of heavy metals （especially Cd） caused by loneterm accumulation should be paid more attention to.展开更多
Along with the development and progress of environmental protection management,it is necessary to pay full attention to the disposal of excess sludge in the process of urban sewage treatment plant management.It is nec...Along with the development and progress of environmental protection management,it is necessary to pay full attention to the disposal of excess sludge in the process of urban sewage treatment plant management.It is necessary to ensure effective integration of management mechanisms and management paths.To a certain extent,it can improve the actual efficiency of digestion and treatment work and lay a foundation for the optimal operation of environmental protection management.In this paper,the treatment of excess sludge in a sewage treatment plant is studied.The method and results of anaerobic digestion test of excess sludge in a sewage treatment plant are discussed for reference only.展开更多
Agricultural soils in semi-arid regions have frequently been degraded due to adverse climatic conditions,organic matter depletion,and poor farming practices.To enhance soil quality,this study examines the reuse of sew...Agricultural soils in semi-arid regions have frequently been degraded due to adverse climatic conditions,organic matter depletion,and poor farming practices.To enhance soil quality,this study examines the reuse of sewage sludge(SS)as an available source of organic matter in a typical Mediterranean sandy-loam soil.Accordingly,we studied the cumulative effect of two annual applications of 40,80 and 120 tons of sludge per ha on soil quality in absence of vegetation.The dose-dependent improvement of organic matter content was the most significant event that reflected sludge application rates,and consequently influenced other soil properties.Accordingly,soil structural stability increased by 13.3%,28.8%and 59.4%for treatments SS-40,SS-80 and SS-120 respectively as compared to unamended control.Structural stability improvement was also confirmed by the dose-dependent variation of other edaphic factors including calcium content,the microbial quotient as well as Welt and C:N ratios.These param-eters are involved in cementing soil aggregates by cation bridging,the formation of microbial mucilage,and clay-humic complexes.Soil magnetic susceptibility(SMS)was measured in situ as a possible rapid tool to evaluate soil condition.SMS showed significant correlation with sludge dose and stability amelioration testifying to the aggregation role that can play Al2O3 and particularly Fe2O3 minerals added by the hematite-rich sludge.Besides,analytical results and field observations revealed no trends of soil salinization or acidification by excessive sludge amounts.By avoiding the rhizosphere effect,outcomes could reflect the resilience and intrinsic capacity of the soil to cope with excessive sludge loads.展开更多
文摘[ Objective] The study aims at discussing the feasibility of urban sewage sludge applied to desertification forestland. [ Method] Through the simulated leaching test, the effects of sewage sludge application on the content of nutrients and heavy metals in aeolian sandy soil were ana- lyzed. [ Result] After the simulated leaching with sewage sludge, the contents of total nitrogen （TN）, total phosphorus （TP）, available nitrogen （AN） and available phosphorus （AP） in each layer of aeolian sandy soil increased significantly, and the increase in 0 -20 cm soil was more signifi- cant than that in 20 -40 and 40 -60 cm soil. Meanwhile, the content of each heavy metal in 0 -20 cm soil rose significantly, while the increase was small in 40 -60 cm soil. In addition, after the application of sewage sludge, the Nemrew Index of aeolian sandy soil was 0.67, lower than the na- tional soil quality standard of forestland （0.70）, and the short-time application of sewage sludge to sandy soil did not cause serious pollution. How- ever, if sewage sludge has been applied to aeolian sandy soil for a long term, the potential hazard of heavy metals （especially Cd） caused by loneterm accumulation should be paid more attention to.
文摘Along with the development and progress of environmental protection management,it is necessary to pay full attention to the disposal of excess sludge in the process of urban sewage treatment plant management.It is necessary to ensure effective integration of management mechanisms and management paths.To a certain extent,it can improve the actual efficiency of digestion and treatment work and lay a foundation for the optimal operation of environmental protection management.In this paper,the treatment of excess sludge in a sewage treatment plant is studied.The method and results of anaerobic digestion test of excess sludge in a sewage treatment plant are discussed for reference only.
基金This study was financially supported by a research grant from the Tunisian Ministry of Higher Education and Scientific ResearchThe authors would like to thank the National Sanitation Utility(ONAS)for providing urban sewage sludgeThe technical support of Rym Ghrib is hereby acknowledged.
文摘Agricultural soils in semi-arid regions have frequently been degraded due to adverse climatic conditions,organic matter depletion,and poor farming practices.To enhance soil quality,this study examines the reuse of sewage sludge(SS)as an available source of organic matter in a typical Mediterranean sandy-loam soil.Accordingly,we studied the cumulative effect of two annual applications of 40,80 and 120 tons of sludge per ha on soil quality in absence of vegetation.The dose-dependent improvement of organic matter content was the most significant event that reflected sludge application rates,and consequently influenced other soil properties.Accordingly,soil structural stability increased by 13.3%,28.8%and 59.4%for treatments SS-40,SS-80 and SS-120 respectively as compared to unamended control.Structural stability improvement was also confirmed by the dose-dependent variation of other edaphic factors including calcium content,the microbial quotient as well as Welt and C:N ratios.These param-eters are involved in cementing soil aggregates by cation bridging,the formation of microbial mucilage,and clay-humic complexes.Soil magnetic susceptibility(SMS)was measured in situ as a possible rapid tool to evaluate soil condition.SMS showed significant correlation with sludge dose and stability amelioration testifying to the aggregation role that can play Al2O3 and particularly Fe2O3 minerals added by the hematite-rich sludge.Besides,analytical results and field observations revealed no trends of soil salinization or acidification by excessive sludge amounts.By avoiding the rhizosphere effect,outcomes could reflect the resilience and intrinsic capacity of the soil to cope with excessive sludge loads.
