Composting and compost application in China

The current situation of municipal solid waste (MSW) and sewage sludge production (in terms of volume as well as composition) in China is introduced. Composting and compost application in China are reviewed. In China, the production of municipal solid waste and sewage sludge is changing rapidly along with economic development. Composting is mainly applied for treating MSW, about 20% of the total amount of MSW being disposed. MSW composting is mainly co-composted with night soil or sewage sludge. Compost is used in agriculture, forestry and horticulture. Compost application is the key factor influencing the composting development in China. To promote composting and compost application in China, a state-wide survey on the production, composition and physical and chemical properties of MSW and sewage sludge should be carried out. More effort should be made to develop low cost and high efficient composting technologies according to China's conditions. The environmental impact of compost application should also be given more attention.     

Municipal solid waste generation in Kathmandu, Nepal

Waste stream characteristics must be understood to tackle waste management problems in Kathmandu Metropolitan City (KMC), Nepal. Three-stage stratified cluster sampling was used to evaluate solid waste data collected from 336 households in KMC. This information was combined with data collected regarding waste from restaurants, hotels, schools and streets. The study found that 497.3 g capita(-1) day(-1) of solid waste was generated from households and 48.5, 113.3 and 26.1 kg facility(-1) day(-1) of waste was generated from restaurants, hotels and schools, respectively. Street litter measured 69.3 metric tons day(-1). The average municipal solid waste generation rate was 523.8 metric tons day(-1) or 0.66 kg capita(-1) day(-1) as compared to the 320 metric tons day(-1) reported by the city. The coefficient of correlation between the number of people and the amount of waste produced was 0.94. Key household waste constituents included 71% organic wastes, 12% plastics, 7.5% paper and paper products, 5% dirt and construction debris and 1% hazardous wastes. Although the waste composition varied depending on the source, the composition analysis of waste from restaurants, hotels, schools and streets showed a high percentage of organic wastes. These numbers suggest a greater potential for recovery of organic wastes via composting and there is an opportunity for recycling. Because there is no previous inquiry of this scale in reporting comprehensive municipal solid waste generation in Nepal, this study can be treated as a baseline for other Nepalese municipalities.     

Anaerobic treatment with methane recovery of agricultural and village wastes

To provide more efficient utilization of village wastes and agricultural residues and eliminate pollution from current practices anaerobic treatment of such wastes with methane recovery is proposed. This paper describes studies to determine the performance of anaerobic composting for such wastes.Composting of three waste types was investigated: (a) agricultural residues, (b) Village solid waste and 1:1 mixture of (a) and (b). Three 150 gallon reactors with periodic leachate recycling were used for anaerobic composting while three 50 gallon reactors produced an aerobic compost from the same wastes. Reactors were maintained for six months simulating the time between growing seasons. Volatile solids destruction ranged from 10.3 to 38.7%. Biogas production was ranged from 1350 to 1420 1 per k of volatile solids destroyed with a methane content of 55 to 70%. Leachate was monitored throughout for: pH, alkalinity, total and ammonia nitrogen, COD, TOC, total solids, volatile solids and four metals. MPN data was collected for various bacterial groups (total plate count, anaerobic cellulose decomposers, and anaerobic acid producers) to monitor increases and declines in the leachate bacterial population. Physical and chemical testing provided comparisons between finished anaerobic compost and aerobic compost from the same three waste samples.     

城市垃圾和污水脱水污泥、排水管污泥混合堆肥工艺研究

城市垃圾和污水脱水污染、排水管污泥已成为现代城市污染的主要总是。由于这些废弃物中有机物质的含量较高,因此可以利用堆肥的方法来进行处理,使其转化为农田的有机肥料,本文用城市生活垃圾和污水处理厂污泥、排水管污泥混合进行堆肥的研究。     

A CLOSED WATER REUSE SYSTEM FOR POWER PLANT COOLING AND DIGESTER HEATING1

ABSTRACT: A model consisting of closed water reuse and productive use of various types of wastes for energy generation is presented. The sewage after treatment would be used as the cooling water for power plants, and the condenser discharge therefrom be used as heating water for sludge digesters. The water is then purified for municipal water supply for continuous use. The advantages of this system are that water resources and energy are conserved while various types of wastes including waste heat are controlled. With a preliminary system analysis, it appears that the design for power plant based on the total heating value of wastes and digester capacity based on sewage sludge generation is feasible in terms of acquisition and full utilization of various types of wastes as generated in a single metropolitan area. The system as shown in this design is in balance among various factors such as the generation rate of municipal refuse, municipal sewage, waste heat in the condenser discharge, and raw sewage sludge.     

Improvement of soil quality after "alperujo" compost application to two contaminated soils characterised by differing heavy metal solubility

Reclamation of trace element polluted soils often requires the improvement of the soil quality by using appropriate organic amendments. Low quality compost from municipal solid waste has been tested for reclamation of soils, but these materials can provide high amounts of heavy metals. Therefore, a high-quality compost, with low levels of heavy metals, produced from the main by-product of the Spanish olive oil extraction industry ("alperujo") was evaluated for remediation of soils affected by a pyritic mine sludge. Two contaminated soils were selected from the same area: they were characterised by differing pH values (4.6 and 7.3) and total metal concentrations, which greatly affected the fractionation of the metals. Compost was applied to soil at two rates (equivalent to 48 and 72 Tm ha(-1)) and compared with an inorganic fertiliser treatment. Compost acted as an available nutrient source (C, N and P) and showed a low mineralisation rate, suggesting a slow release of nutrients and thus favouring long term soil fertility. In addition, the liming effect of the compost led to a significant reduction of toxicity for soil microorganisms in the acidic soil and immobilisation of soil heavy metals (especially Mn and Zn), resulting in a clear increase in both soil microbial biomass and nitrification. Such positive effects were clearly greater than those provoked by the mineral fertiliser even at the lowest compost application rate, which indicates that this type of compost can be very useful for bioremediation programmes (reclamation and revegetation of polluted soils) based on phytostabilisation strategies.     

浅析含油污泥处理中石油烃控制指标

石油烃含量是含油污泥处理中必不可少的重要控制指标。文章分析了含油污泥中石油烃组成及主要污染控制要求,介绍了国内外含油污泥处置对石油烃含量的控制现状;依据危险废物鉴别标准的相关规定,以及对原油中芳香族化合物及其多环芳烃含量的研究成果,对采用石油烃指标进行危险废物鉴别做了推论计算。结果认为:含油污泥等固体废物及其处理残余物的石油烃含量≤0.25%,不属于危险废物;石油烃含量介于0.25%～1.7%时,其是否属于危险废物,最终需要进行危险废物鉴别而确定;石油烃含量1.7%,则属于危险废物。     

采油作业“三废”控制技术研究与应用

针对采油作业产生的废酸、固废、废水处理成本高、技术不成熟等问题,研发改性废酸降压增注、深部调剖技术;高比重污泥悬浮研磨后的固废处理技术;低耗水打塞、原井液+CaCl2压井、原井液处理再利用技术,减少了"三废"的产生,解决了"三废"环保处理费高等问题,消除了环保隐患,实现了清洁生产,环境效益显著。     

Comparison of heavy metals content in compost against vermicompost of organic solid waste: Past and present

Disposal of the municipal organic solid waste is a serious problem worldwide. Composting is one of the most preferred methods of solid waste management practice, principally due to the high percentage of organic material in the waste composition. Composting has advantages over land-filling and incineration in Mauritius because of lower operational costs, less environmental pollution, beneficial use of the end product, high humidity and organic content of household waste. Vermicomposting is a comparatively enhanced method in composting, and involves the stabilization of organic solid waste through earthworm consumption that converts the waste into earthworm castings. In both composting and vermicomposting processes, the presence of heavy metals and different toxics substances limits its land use without processing. The production and application of compost potentially contaminate the environment with heavy metals. There is a high-degree of consensus in the past and present literatures that composting increases metal concentrations but whether similar changes in metal concentration and availability occur during vermicomposting has not been fully resolved. This review deals with various total metal contents present in composting compared to that present in vermicomposting of organic solid wastes from past and present years.     

生活垃圾与市政污泥R-SACT混合堆肥技术

由于生活垃圾与市政污泥的各自特点具有互补性，使堆肥技术应用于二者混合物料处置成为可能。根据R—SACT工艺的流程、特点，通过实验研究得到温度、含水率、pH、C／N、通风量、配比等工艺参数结论，并且给出了典型项目的技术经济分析。最后通过技术、经济和社会三个层面说明了该技术是适合中国国情的固废处置技术。     

Environmental fate of triasulfuron in soils amended with municipal waste compost

The amendment of soil with compost may significantly influence the mobility and persistence of pesticides and thus affect their environmental fate. Factors like adsorption, kinetics, and rate of degradation of pesticides could be altered in amended soils. The aim of this study was to determine the effects of the addition of compost made from source-separated municipal waste and green waste, on the fate of triasulfuron [(2-(2-chloroethoxy)-N-[[4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]benzenesulfonamide], a sulfonylurea herbicide used in postemergence treatment of cereals. Two native soils with low organic matter content were used. A series of analyses was performed to evaluate the adsorption and degradation of the herbicide in soil and in solution after the addition of compost and compost-extracted organic fractions, namely humic acids (HA), fulvic acids (FA), and hydrophobic dissolved organic matter (HoDOM). Results have shown that the adsorption of triasulfuron to soil increases in the presence of compost, and that the HA and HoDOM fractions are mainly responsible for this increase. Hydrophobic dissolved organic matter applied to the soils underwent sorption reactions with the soils, and in the sorbed state, served to increase the adsorption capacity of the soil for triasulfuron. The rate of hydrolysis of triasulfuron in solution was significantly higher at acidic pH and the presence of organic matter fractions extracted from compost also slightly increased the rate of hydrolysis. The rate of degradation in amended and nonamended soils is explained by a two-stage degradation kinetics. During the initial phase, although triasulfuron degradation was rapid with a half-life of approximately 30 d, the presence of compost and HoDOM was found to slightly reduce the rate of degradation with respect to that in nonamended soil.     

城市生活垃圾的堆肥研究

城市生活垃圾经动态式堆肥翻堆机处理制成腐熟堆肥，并最终试制成有机复混颗粒肥，二者先后在茶树、数种花卉作物和数种叶菜类蔬菜上进行田间试验，证明有较好的肥效，且成本较低廉，在农业生产上有实际应用的价值。从环境保护角度上看：这种方法是将城市生活垃圾转化为资源化、无害化的一项有意义的举措。     

Health-care waste management in India.

Health-care waste management in India is receiving greater attention due to recent regulations (the Biomedical Wastes (Management & Handling) Rules, 1998). The prevailing situation is analysed covering various issues like quantities and proportion of different constituents of wastes, handling, treatment and disposal methods in various health-care units (HCUs). The waste generation rate ranges between 0.5 and 2.0 kg bed-1 day-1. It is estimated that annually about 0.33 million tonnes of waste are generated in India. The solid waste from the hospitals consists of bandages, linen and other infectious waste (30-35%), plastics (7-10%), disposable syringes (0.3-0.5%), glass (3-5%) and other general wastes including food (40-45%). In general, the wastes are collected in a mixed form, transported and disposed of along with municipal solid wastes. At many places, authorities are failing to install appropriate systems for a variety of reasons, such as non-availability of appropriate technologies, inadequate financial resources and absence of professional training on waste management. Hazards associated with health-care waste management and shortcomings in the existing system are identified. The rules for management and handling of biomedical wastes are summarised, giving the categories of different wastes, suggested storage containers including colour-coding and treatment options. Existing and proposed systems of health-care waste management are described. A waste-management plan for health-care establishments is also proposed, which includes institutional arrangements, appropriate technologies, operational plans, financial management and the drawing up of appropriate staff training programmes.     

施用污泥堆肥对滩涂土壤理化性质的影响

污泥堆肥中富含有机质营养成分，可改良土壤，同时要防止重金属和病原菌等可能引起的污染。为评价污泥堆肥作为土壤改良基质的可能性，本试验系统进行了上海曲阳水质净化厂污泥堆肥／滩涂土混配土的理化性质分析。研究结果表明，污泥堆肥与滩涂土混配后，土壤pH、电导率、阳离子交换量等理化指标得到改善；营养得到补充，肥力提高明显；混配土中未见病原菌污染问题，污泥堆肥施加比例控制在30％（干重计）以内时，也不存在重金属污染风险，混配土可以满足农用要求。     

Compost, manure, and gypsum application to timothy/red clover forage

Some of the most fertile agricultural land in Atlantic Canada includes dykelands, which were developed from rich salt marshes along the Bay of Fundy through the construction of dykes. A 2-yr field experiment was conducted on dykeland soil to evaluate the effect of fertility treatments: source-separated municipal solid waste (SS-MSW) compost, solid manure, commercial fertilizer, and gypsum on (1) timothy/red clover forage productivity, (2) N, S, and other nutrients uptake, and (3) residual NO(3)-N and NH(4)-N in the soil profile. All fertility treatments increased dry matter yields from the two cuts each year relative to the control. Residual soil NO(3)-N and NH(4)-N concentrations in the fall of the second year decreased with depth, and beyond 20-cm depth were lower than 1 mg kg(-1). Gypsum application equivalent to 40 kg S ha(-1) increased dry matter yields and N uptake by forage, and increased soil Mehlich 3-extractable S, tissue S, and uptake of S, Ca, P, Cu, Fe, and Mn relative to the control. High rates of compost can provide sufficient N, S, and perhaps other nutrients to a perennial forage system under the cool wet climate of Atlantic Canada with no heavy metal enrichment of forage. However, the chemical N provided greater total N uptake than organic sources, except the high rate of compost, suggesting that the N availability from organic sources was not well synchronized with forage N demand. Municipal solid waste compost may also increase soil and forage tissue Na, which might be of concern.     

Phosphorus sorption and availability in soils amended with animal manures and sewage sludge

Soils that receive large applications of animal wastes and sewage sludge are vulnerable to releasing environmentally significant concentrations of dissolved P available to subsurface flow owing to the gradual saturation of the soil's P sorption capacity. This study evaluated P sorption (calculated from Langmuir isotherms) and availability of P (as CaCl2-P and resin P) in soils incubated for 20 d with poultry litter, poultry manure, cattle slurry, municipal sewage sludge, or KH2PO4, added on a P-equivalent basis (100 mg P kg(-1)). All the P sources had a marked negative effect on P sorption and a positive effect on P availability in all soils. In the cattle slurry- and KH2PO4-treated soils, the decreases in P sorption maximum (19-66%) and binding energy (25-89%) were consistently larger than the corresponding decreases (7-41% and 11-30%) in poultry litter-, poultry manure-, and sewage sludge-treated soils. The effects of cattle slurry and KH2PO4 on P availability were, in most cases, larger than those of the other P sources. In the poultry litter, poultry manure, and sewage sludge treatments, the increase in soil solution P was inversely related (R2 = 0.75) to the input of Ca from these relatively high Ca (13.5-42 g kg(-1)) sources. Correlation analyses implied that the magnitude of the changes in P sorption and availability was not related to the water-extractable P content of the P sources. Future research on the sustainable application of organic wastes to agricultural soils needs to consider the non-P- as well as P-containing components of the waste.     

Alternative treatment for septic tank sludge: co-digestion with municipal solid waste in bioreactor landfill simulators

Co-disposal of septic tank sludge had a positive effect on the municipal solid waste (MSW) stabilisation process in Bioreactor Landfill simulators. Co-disposal experiments were carried out using the Bioreactor Landfill approach aiming to solve the environmental problems caused by indiscriminate and inadequate disposal of MSW and especially of septic tank sludge. The simulator receiving septic tank sludge exhibited a 200 days shorter lag-phase as compared to the 350 days required by the control simulator to start the exponential biogas production. Additionally, the simulator with septic sludge apparently retained more moisture (>60% w/w), which enhanced the overall conversion of organic matter hence increasing the biogas production (0.60 m3 biogas kg(-1)VS(converted)) and removal efficiency of 60% for VS from the simulator. Alkaline pH values (pH>8.5) did not inhibit the biogas production; moreover it contributed to reduce partially the negative effects of NH(4)(+) (>2 g L(-1)) due to NH(3) volatilisation thus reducing the nitrogen content of the residues. Associated risks and hazards with septage disposal were practically eliminated as total coliform and faecal coliform contents were reduced by 99% and 100%, respectively at the end of the experiment. These results indicate that co-disposal has two direct benefits, including the safe and environmentally sound disposal of septic tank sludge and an improvement of the overall performance of the Bioreactor Landfill by increasing moisture retention and supplying a more acclimatised bacterial population.     

兰炭生产过程中固体废物的产生与利用现状分析

在对国内兰炭生产工艺流程应用及现状介绍的基础上,概括总结了旧式低温干馏阶段和现阶段兰炭生产过程中固体废物的产生节点、种类、性质和主要处置方式。结果表明,旧式低温干馏阶段,兰炭生产过程中产生的固体废物主要包括煤筛分破碎工序产生的末煤和煤矸石、筛焦工序产生的焦粉、焦油冷却收集系统产生的焦油渣等;现阶段,兰炭生产过程中产生的固体废物主要包括煤筛分破碎工序产生的末煤和煤矸石以及破碎过程中经除尘器收集的煤尘、筛焦工序产生的焦粉、废水处理污泥、焦油冷却收集系统产生的焦油渣、脱硫工序产生的脱硫残液等。其中末煤、煤矸石、煤尘、焦粉作为一般工业固废全部综合利用,废水污泥、焦油渣、脱硫残液主要掺入原料煤中自行消化处置。     

Reclamation of wastes contaminated by copper,lead, and zinc

Waste materials containing toxic levels of copper, lead, and zinc, such as mine and smelter wastes, present difficult conditions for the establishment of vegetation. This article reviews the many attempts which have been made to reclaim these wastes. Inert wastes from mining and quarrying operations, such as slate quarry waste and certain colliery shales, seem to be good materials for reclaiming wastes contaminated by copper, lead, and zinc. Organic wastes, such as sewage sludge and domestic refuse, may provide only a temporary visual improvement and stabilization of the toxic materials.Nontolerant plant materials may often be planted directly on modern waste materials, which are less toxic than they were in the past. However, tolerant plant materials are needed for revegetating waste materials produced by early and more primitive extraction methods.     

Use of wastewater and compost extracts as nutrient sources for growing nursery and turfgrass species

Nutrient salts present in liquid by-products following waste treatment are lost resources if not effectively recycled, and can cause environmental problems if improperly disposed. This research compared the growth response and mineral nutrient status of two nursery and two turfgrass species, hydroponically supplied with nutritive by-product extracts derived from anaerobically digested municipal solid waste (MSW) and aerobically composted organic wastes from the mushroom and MSW industries. Forsythia (Forsythia x intermedia 'Lynwood') and weigela (Weigela florida 'Red Prince'), and creeping bentgrass (Agrostis palustris Huds.) and Kentucky bluegrass (Poa pratensis L.), were grown in nutrient solutions/extracts prepared from: (i) half-strength Hoagland's #2 solution (HH; control), (ii) Plant Products liquid fertilizer (PP; g kg(-1): 180 N; 39 P; 224 K), (iii) spent mushroom compost (SMC), (iv) MSW compost (GMC), and (v) intra-process wastewater from the anaerobic digestion of MSW (ADW). Additional nutrient solutions (SMC-A, GMC-A, and ADW-A) were prepared by amending the original solutions with N, P, and/or K to concentrations in HH (mg L(-1): 105 N; 15 P; 118 K). Plants receiving the SMC-A extract grew best or at least as well as those in HH, PP, and the amended GMC-A and ADW-A solutions. This study indicated that, with proper amendments of N, P, K and other nutrients, water-soluble constituents derived from organic waste treatment have potential for use as supplemental nutrient sources for plant production.