Every day,human beings produce excreta all over the world,and the sludge that accumulates in waste disposal systems is referred to as the‘faecal sludge(FS)’.FS can cause serious environmental pollution in urban area...Every day,human beings produce excreta all over the world,and the sludge that accumulates in waste disposal systems is referred to as the‘faecal sludge(FS)’.FS can cause serious environmental pollution in urban areas if it cannot be disposed of properly.A complete FS management system must include onsite sanitation technologies,FS collection and transport,a treatment plant,and resource recovery or disposal of the treatment end-products.Focusing on the treatment and reuse/disposal step of a FS complete service chain,this research presents two cases of FS treatment in Beijing.In Case 1,FS biogas plant adopts anaerobic digestion(AD)to treat FS,and the digestate can be used as biofertilizer in the surrounding greenhouse.In Case 2,several technologies including solid-liquid separation,dewatering,pyrolysis,AD and co-composting are integrated to find innovative solutions for FS treatment.A comprehensive assessment including the aspects of technology,economy and environment is conducted for further SWOT(Strengths,Weaknesses,Opportunities and Threats)analysis.Then,critical strategies are developed,which include(1)selecting project site for optimized transportation,maximum waste reuse,minimum environmental impact and convenient final effluent disposal;(2)planning technical options at a feasible study stage,considering resource recovery,secondary pollution prevention and fire protection;(3)exploring market channels for by-products sale to increase profitability;(4)guaranteeing engineering quality and service life for the purpose of sustainable operation;(5)minimizing health risks to persons exposed to the untreated FS;and(6)providing necessary training for hygiene protection.The cases in Beijing can provide valuable lessons for urban areas in developing countries and the strategies can provide a reference for stakeholders and decision-makers who intend to develop FS treatment projects.展开更多
Dry-toilet collected matter （DCM） from traditional dry-toilet pits are a potential health and ecological risk in suburban areas. In this study, the characteristics of metals in DCMs from suburban areas of Ulaanbaata...Dry-toilet collected matter （DCM） from traditional dry-toilet pits are a potential health and ecological risk in suburban areas. In this study, the characteristics of metals in DCMs from suburban areas of Ulaanbaatar were surveyed. The results indicate that DCMs contain a high percentage of organic matter and nutrients, while heavy metals are at low levels, which shows good agricultural potential. The concentration ranges of Cr, Cu, Hg, Ni, Pb, and Zn were 11±5, 46±9, 0.08±0.05, 9±3, 17±9, and 338±86mg·kg^-1, respectively. The concentration of Cd was below 0.5 mg.kgl, and a high positive relation was shown between chromium and nickel concentrations. The heavy metals in DCMs were safe for land application but Zn in DCMs was close to the effects range median （ERM）, which is toxic in some cases, such as amphipod bioassays. Because it is mandatory to treat DCMs to reduce pathogens, in the case of heavy metal enrichment and agricultural reuse, composting or pyrolysis are better choices than incinera- tion. Compared with global soil background values, the heavy metals in DCMs showed a low level of ecological risk, but a medium level when compared with Mongolian soil background values. The ecological risk of six heavy metals was in the descending order Hg 〉 Cu 〉 Zn 〉 Pb 〉 Ni 〉 Cr and the contribution rate of Hg exceeded 60%.展开更多
基金National Key Research and Development Plan(2016YFE0115600)Fundamental Research Funds for the Central Universities(TW201704)The authors would like to take this opportunity to express our sincere appreciation for the support of National Environment and Energy International Science and Technology Cooperation Base and Reinvent the Toilet Challenge-China Regional Program(Global Development Grant Number OPP1051913).
文摘Every day,human beings produce excreta all over the world,and the sludge that accumulates in waste disposal systems is referred to as the‘faecal sludge(FS)’.FS can cause serious environmental pollution in urban areas if it cannot be disposed of properly.A complete FS management system must include onsite sanitation technologies,FS collection and transport,a treatment plant,and resource recovery or disposal of the treatment end-products.Focusing on the treatment and reuse/disposal step of a FS complete service chain,this research presents two cases of FS treatment in Beijing.In Case 1,FS biogas plant adopts anaerobic digestion(AD)to treat FS,and the digestate can be used as biofertilizer in the surrounding greenhouse.In Case 2,several technologies including solid-liquid separation,dewatering,pyrolysis,AD and co-composting are integrated to find innovative solutions for FS treatment.A comprehensive assessment including the aspects of technology,economy and environment is conducted for further SWOT(Strengths,Weaknesses,Opportunities and Threats)analysis.Then,critical strategies are developed,which include(1)selecting project site for optimized transportation,maximum waste reuse,minimum environmental impact and convenient final effluent disposal;(2)planning technical options at a feasible study stage,considering resource recovery,secondary pollution prevention and fire protection;(3)exploring market channels for by-products sale to increase profitability;(4)guaranteeing engineering quality and service life for the purpose of sustainable operation;(5)minimizing health risks to persons exposed to the untreated FS;and(6)providing necessary training for hygiene protection.The cases in Beijing can provide valuable lessons for urban areas in developing countries and the strategies can provide a reference for stakeholders and decision-makers who intend to develop FS treatment projects.
文摘Dry-toilet collected matter （DCM） from traditional dry-toilet pits are a potential health and ecological risk in suburban areas. In this study, the characteristics of metals in DCMs from suburban areas of Ulaanbaatar were surveyed. The results indicate that DCMs contain a high percentage of organic matter and nutrients, while heavy metals are at low levels, which shows good agricultural potential. The concentration ranges of Cr, Cu, Hg, Ni, Pb, and Zn were 11±5, 46±9, 0.08±0.05, 9±3, 17±9, and 338±86mg·kg^-1, respectively. The concentration of Cd was below 0.5 mg.kgl, and a high positive relation was shown between chromium and nickel concentrations. The heavy metals in DCMs were safe for land application but Zn in DCMs was close to the effects range median （ERM）, which is toxic in some cases, such as amphipod bioassays. Because it is mandatory to treat DCMs to reduce pathogens, in the case of heavy metal enrichment and agricultural reuse, composting or pyrolysis are better choices than incinera- tion. Compared with global soil background values, the heavy metals in DCMs showed a low level of ecological risk, but a medium level when compared with Mongolian soil background values. The ecological risk of six heavy metals was in the descending order Hg 〉 Cu 〉 Zn 〉 Pb 〉 Ni 〉 Cr and the contribution rate of Hg exceeded 60%.
