生活垃圾的不同组分对堆肥腐熟度的影响

依托北京市南宫堆肥厂,研究了生活垃圾的不同物理组分对高温发酵阶段的堆肥腐熟度的影响。结果表明：从EC、Ed/E6、C／N、GI等指标来看,植物性垃圾对堆肥的腐熟度起主导性作用;纸类和木竹类也对堆肥的腐熟度有一定的促进作用。在8d的高温发酵阶段,以上类别的原垃圾均可以得到较充分的降解,基本达到了高温期间对腐熟度指标的要求。因此在堆肥的原料中适当增加植物性垃圾,如厨余垃圾的比例,可加快垃圾堆肥的腐熟速度。     

北京市生活垃圾堆肥适宜性的判别分析

分2-3次随机采集北京市城八区的5个垃圾转运站及宣武区、丰台区8个功能区共48个生活垃圾样品，分别测定垃圾的有机质含量、含水率、密度、pH和C／N指标，用Fisher判别法初步评价48个垃圾样品堆肥的适宜性并建立堆肥适宜性的判别函数。用小武基和马家楼转运站筛分后粒径15～60mm的垃圾堆肥适宜性的判别函数进行检验，准确率达100％，8周堆肥的腐熟度指标变化验证了判别函数。通过判别函数推出决定垃圾堆肥的主要因素为垃圾的含水率和C／N。     

生活垃圾生物稳定化处理效果研究

以广州市番禺区猛涌村生活垃圾为研究对象,采用生物稳定化技术,通过12d高温发酵,12d后熟化,12d最终熟化的堆肥方式来处理研究,结果表明：温度能达到60℃至少10d以上,使堆肥无害化;水分在堆肥结束时为29．7％,pH为7．87,水溶性碳（wsc）为4．45g／kg,堆肥腐熟度好。浸提液NH3-N浓度为15．1mg／L,是峰值（93．8mg／L）的16．1％;COD浓度1770mg／L,为峰值（16266mg／L）的10．9％,生活垃圾污染潜力大大消减,稳定性提高。筛分后的堆肥产品,总养分含量（N＋P20,＋K：0）超过4％。     

造纸污泥交替好氧厌氧堆肥中氮素的形态转变研究

通过交替式好氧厌氧堆肥处理造纸污泥试验,研究氮素的变化规律.结果表明:堆肥初始的中高温期,主要是堆体中的有机氮转化为氨氮;之后的降温期和腐熟期是硝态氮形成的主要阶段;总氮在整个堆肥阶段呈上升趋势.无机氮(NH3-N,NO-3-N)可以直接被作物吸收,是污泥堆肥中的主要氮素形态,因此减少堆肥初期氨氮的挥发,增加腐熟阶段NO-3-N的形成,以及降低滤液中无机氮的流失是提高造纸污泥堆肥肥效的关键.     

强制通风堆肥技术处理农村生活垃圾的可行性研究

对北京市海淀区北部新区农村生活垃圾中的有机成分进行3组不同物料配比的堆肥试验,在堆肥周期内对堆体的理化性质、腐熟度指标与控制参数进行了研究.结果表明:农村生活垃圾中的有机成分含水率偏高,不利于直接堆肥.采用强制通风静态好氧堆肥,堆肥过程中温度、含水率、体积、pH、电导率、碳氮比的变化与一般堆肥过程各参数的变化规律相似,...     

城市污泥反应器堆肥实验

采用强制通风好氧静态方式对城市污泥进行堆肥实验,结果表明:通过调节城市污泥水分和C/N,经过好氧反应器堆肥处理,污泥有机质发生降解,TN、TP和TK含量都呈上升趋势,VS和有机碳分别达到60%和30%的稳定状态,种子发芽指数达到100%左右,有效杀灭病原菌,实现城市污泥无害化、稳定化和减量化的要求.腐熟的污泥堆肥成为高价值的农用产品.     

灰色关联分析法在堆肥腐熟度评价中的应用

堆肥腐熟度的评价指标很多,但以单个指标评价腐熟度显然是不够全面的.而采用多个指标的综合性评价必须要有一定的评价标准,目前我国尚缺乏统一的评价标准.以美国加利福尼亚州堆肥质量委员会(CCQC)提出的腐熟度评价标准为依据,参考国内堆肥腐熟度评价方法,制定出一套新的堆肥腐熟度评价标准.并通过灰色关联分析法综合性地判别堆肥腐熟度.     

共填埋技术改善垃圾渗沥液水质特性研究

基于生活垃圾/深度脱水污泥夹心式共填埋的工程实践,考察了该技术对填埋渗沥液水质特性的影响。以化学需氧量(CODCr)、生化需氧量(BOD5)、可生化性(B/C)、氨氮(NH3-N)、总磷(TP)和p H为评价指标,对共填埋作业阶段、封场阶段填埋库区的渗沥液进行采样监测。结果显示:生活垃圾/深度脱水污泥夹心式共填埋可有效降解有机物,封场稳定后渗沥液CODCr水平在3 000 mg/L以下,去除率达95.5%;渗沥液可生化性较好,监测后期B/C维持在0.3以上;监测后期NH3-N和TP浓度分别为1 700 mg/L和28 mg/L,较生活垃圾和污泥单独填埋渗沥液低;共填埋渗沥液p H水平呈中性,利于后续生物处理。     

大港污水污泥兼性厌氧堆肥用于绿地的可行性研究

以天津市大港区污水处理厂的剩余污泥为研究对象,利用兼性厌氧堆肥装置,研究了污泥堆肥前后温度、含水率、有机质、氮、磷、钾以及pH等指标的变化。结果表明：采用污泥与锯末的体积比为1∶1的堆肥,控制初始含水率为65%左右,可顺利实现升温。堆肥15d后,物料的含水率、有机质明显降低;总氮、总磷及总钾的含量有不同程度的增加,符合绿地施用的要求。经计算得出由N决定的污泥堆肥年施用量为32.77t/hm2。     

污水污泥与垃圾无害化处理利用研究

本文对城市污水污泥与生活垃圾以不同配比进行高温堆制的试验研究。结果表明:各种配比的堆肥均达到了国家高温堆肥卫生评价标准,其中以污水污泥与煤气户垃圾以1:1的配比堆制效果最好;与此同时堆肥中的硝态氮、铵态氮、速效磷、速效钾等营养成份提高,成为适于农田施用的优质肥料。以此达到城市固体废弃物无害化、资源化的目的。     

Prevalence of asbestos in composted waste from 26 communities in the United States

Composting of yard waste, sewage sludge and municipal solid waste (MSW) for subsequent application to soils in agricultural, horticultural and recreational areas is being promoted nationwide. Since asbestos is a common contaminant in sewage sludge, an analytical survey was conducted for the presence of asbestos in composts collected from 26 communities nationwide resulting from sludge as well as yard waste and municipal solid waste. Asbestos was detected in 12 of the 26 composts or 46%. Asbestos was most consistently present in compost resulting from source material containing MSW and to a lesser extent sewage sludge rather than yard waste. The possible origins of asbestos in the compost source material, the mechanisms by which humans may be exposed, and the health significance are discussed.     

Survey of toxicants and nutrients in composted waste materials

Currently, there is much activity in composting yard wastes (leaves, twigs, grass), sewage sludge and portions of municipal solid wastes (MSW) in the United States. The resultant compost is typically applied to agricultural or recreational land. A nationwide analytical survey was therefore conducted of 21 toxic and nutrient elements, polychlorinated biphenyls (PCBs) and gamma emission in 26 composts sampled nationwide in 1991. Those composts produced solely from sludge or MSW tended to be higher in metals such as Cd, Cu, Hg, and Zn as compared to totally yard waste compost. Molybdenum, P and Se were higher in composted sewage sludge and Na and Pb in composted MSW than in yard waste compost. PCBs and gamma emission were low or not detectable in most compost samples. Shards of metal and glass found particularly in MSW-containing composts would detract from its application especially in recreational areas. References dealing with the reactions of metals in composts and environmental effects of compost application to land are cited.     

Effects of Composting Process and Fly Ash Amendment on Phytotoxicity of Sewage Sludge

With the increasingly growing global production of sewage sludge, evaluation of its applicability in agriculture and land restoration is essential. This study assessed the potential effects of composting process and fly ash amendment on soil-ameliorating properties of sewage sludge. The metal availability and phytotoxicity of ash-amended sludge compost (AS, mature sewage sludge compost mixed with fresh lagoon ash) and sludge-ash co-compost (SA, co-composted mixture of sewage sludge and lagoon ash) were compared. The results of this work suggested that both composts favored the applicability of sewage sludge for land application by reducing Cd, Cu, Pb, and Zn availability. The SA co-compost stimulated seed germination at ash amendment rates of ≤10%, whereas various treatments of AS compost inhibited germination at an extract dilution of 50%. Amendment of lagoon ash before or after sludge composting increased electrical conductivity (EC) and volatilization of NH₄-N, but lowered availability of PO₄-P. Together with the results of phytotoxicity, an optimal ash amendment rate of 5% for AS and 10% for SA were most desirable. Alkaline amendment prior to sludge composting was recommended, because it could be more effective in reducing soluble and plant-available metal concentrations through the composting process. Received: 1 October 1999/Accepted: 31 May 2000     

某大型医院污水处理净化效果

目的了解膜生物反应池和次氯酸钠消毒对医院污水的净化效果.方法于2005年5月,检测天津医科大学总医院污水处理站的污水处理效果.在污水经膜生物反应池处理前后及次氯酸钠消毒后分别取水样测定pH值、悬浮物、CODCr、BOD5,氨氮、粪大肠菌群及余氯.结果经膜生物反应池处理后,悬浮物、CODCr、BOD5、氨氮、粪大肠菌群的去除率分别为82.25%,80.25%,75.52%,75.84%,96.75%;经次氯酸钠消毒后,水中粪大肠菌群的去除率为99.96%,余氯为3.4mg/L.结论膜生物反应器结合次氯酸钠消毒的方法对医院污水有很好的净化效果,达到GB 8978-1996《污水综合排放标准》二级标准.     

Nitrogen and carbon flows between the caecum, blood and rumen in sheep given chopped lucerne (Medicago sativa) hay

1. Experiments involving 15N and 14C tracers were made in sheep consuming 800 g air-dry chopped lucerne (Medicago sativa) hay/d and providing 20.4 g N/d to study N and C flows within the caecal digesta and between the caecum, blood and rumen. 2. Continuous infusions of 15N tracers were made into the caecal ammonia, blood urea and rumen NH3 pools. The concentration and enrichment of caecal digesta NH3-N, caecal microbial N, caecal digesta non-urea, non-ammonia-N (NU-NAN), faecal NU-NAN, blood urea-N, rumen digesta NH3-N and rumen bacterial N were estimated at intervals during the infusions. A three-pool open-compartment model was solved to estimate N flows between the caecal digesta NH3-N, blood urea-N and rumen digesta NH3-N pools. 3. The rate of irreversible loss from the caecal digesta NH3-N pool was 2.17 (SE 0.623) g N/d. On average 0.9 (SE 0.56) g N/d of caecal digesta NH3-N was derived from blood urea and 0.1 (SE 0.08) g caecal digesta NH3-N/d was apparently derived from the fermentation of undigested rumen microbes in the caecum. The amount of NH3-N produced by proteolysis and deamination of dietary and endogenous N was 1.1 (SE 0.13) g/d. 4. There was net incorporation of 0.56 (SE 0.306) g caecal digesta NH3-N/d into caecal microbes. The microbial N synthesized de novo in the caecum was not determined, but 2.9 (SE 0.52) g microbial N/d of both rumen and caecal origin flowed out of the caecum and constituted 0.48 of the NU-NAN flow. The majority (mean 0.83 (SE 0.044] of this microbial N was excreted in faeces. 5. On average 1.8 (SE 0.80) g caecal digesta NH3-N/d were absorbed. Of this NH3-N, 0.92 (SE 0.054) was converted to blood urea, contributing 0.10 (SE 0.031) of blood urea-N. Only 0.012 (SE 0.0041) of rumen digesta NH3-N and 0.005 (SE 0.0009) of rumen bacterial N were derived from caecal digesta NH3-N. 6. Infusions of 14C tracers were made into the caecal digesta bicarbonate, blood bicarbonate, rumen digesta bicarbonate and blood urea pools, and samples were obtained at intervals to determine the specific radioactivity of each pool. A four-pool open-compartment model was solved to estimate C flows between these pools. 7. The rate of irreversible loss of blood urea estimated with [14C]urea (17.1 (SE 1.18) g N/d) was greater (P less than 0.01) than that estimated with [15N]urea (14.0 (SE 0.87) g N/d).(ABSTRACT TRUNCATED AT 400 WORDS)     

Composition of toxicants and other constituents in yard or sludge composts from the same community as a function of time-of-waste-collection

Samples of yard waste compost and sewage sludge compost were analyzed for toxic and nutrient elements and PCBs to assess variations in their concentrations as a function of the time of delivery of the initial organic material to the same composting site. In general, the variations in composition found were remarkably small. Generally, the samples of sludge compost were higher in Ca, Cd, Cu, Fe, Hg, Mo, Na, P, Pb, S, Se, Zn, and PCBs than those of the yard waste compost. The latter was higher in Cr, Ni, K, Mg, and Si. Possible factors affecting compost composition are discussed.     

A novel challenge test incorporating irradiation (60Co) of compost sub-samples to validate thermal lethality towards pathogenic bacteria

Maturing compost heaps normally attaining temperatures ranging from 55 to 65 degrees C is generally regarded to conform to recommended biological risks and sanitation standards for composts stipulated by either EU or US-EPA. Composted products derived from animal sources are further required by EU biohazard safety regulatory legislation that such composts either attain 70 degrees C for over 3h during maturation or via treatment at 70 degrees C for 1h before being considered for dispensation on land. The setting of the upper limit of thermal lethality at 70 degrees C/1h for achieving biosecurity of the animal waste composted products (e.g. pelleted fertilizer formulations) is not properly substantiated by specific validation tests, comprising a 'wipe-out' step (usually via autoclaving) followed by inoculation of a prescribed bacterium, exposure to 70 degrees C/1h and the lethality determined. Pelleted formulations of composts are not amenable for wet methods (autoclaving) for wipe-out sterilization step as this is detrimental to the pellet and compromises sample integrity. This study describes a laboratory method involving the employment of ((60)Co) irradiation 'wipe-out' step to: (a) compost sub-samples drawn from compost formulation heaps and (b) pelleted products derived from composted animal products while determining the thermal lethality of a given time/temperature (70 degrees C/1h) treatment process and by challenging the irradiated sample (not just with one bacterium but), out with 10 potential food-poisoning organisms from the bacterial genera (Campylobacter, Escherichia, Listeria, Salmonella, Yersinia) frequently detected in pig and poultry farm wastes. This challenge test on compost sub-samples can be a useful intervention ploy for 'inspection and validation' technique for composters during the compost maturity process, whose attainment of temperatures of 55-65 degrees C is presumed sufficient for attainment of sanitation. Stringent measures are further required by law for composted products arising from rural industrialists producing pelleted fertilizers from re-composted animal agriculture wastes comprising pig slurry solids, poultry litter and spent mushroom compost, which carry residual food-borne pathogens with implications to the food chain including humans. Environmentally, sustainable means of recycling farm wastes require that final composted products are free of pathogens in compliance with environmental safety legislation before their release to the market. This test developed provides a science-based risk characterization tool for sustainably managing environmental safety by 'validating' thermal lethality of a given composting process or their derivatives achieved without compromising the sample integrity or ambiguity attached to microbiological validation involving steam sterilization or autoclaving procedures and helps audit the resurgent bacterial populations from surviving non-pathogenic organisms in the end-products of animal waste compost formulations.