Degradation of DEHP,PAHs and LAS in Source Separated MSW and Sewage Sludge During Composting

The efficiency of composting to remove the pollutants DEHP, PAHs and LAS from organic waste products was investigated. Source separated MSW and sewage sludge, respectively, were composted at temperatures ranging from 35 to 70°C using a laboratory-scale reactor composting system. At regular intervals, compost samples were taken from the reactors for chemical analysis. DEHP disappeared rapidly during composting of MSW; 96 to 99% of the initial content was degraded within 25 days of composting regardless of process temperature. In sewage sludge, the highest degradation of 91% was reached at a composting temperature of 65°C. LAS degradation in sewage sludge was fastest at 55°C, but at both process temperatures tested 99% of the initial content had been removed within 25 days. Degradation of PAHs was less complete. However, in all composting experiments, with MSW as well as sewage sludge, the final PAH concentration was less than in the starting material. Further experiments suggested that less than 0.1% of the pollutants had evaporated. Thus, composting proved to be a promising technique to promote degradation of organic pollutants — especially DEHP and LAS — in MSW and sewage sludge.     

Composting of Rhododendron and Bilberry Wastes To Contain Spread of Exotic Plant Pathogens Phytophthora kernoviae and Phytophthora ramorum

Plant material infected with the exotic pathogens Phytophthora kernoviae and Phytophthora ramorum, particularly of the invasive and highly susceptible Rhododendron ponticum, can pose a risk to indigenous host flora in Britain. Areas of infected bilberry (Vaccinium myrtillus) can also threaten surrounding non-infected heathland. Composting was examined as a more environmentally acceptable method of disposal of infected plant material than burning. Three types of low cost composting systems were developed and tested on shredded rhododendron and chopped bilberry wastes: permanent and mobile insulated bays, and insulated cargo containers, located at six different sites. In addition to temperature-time profiles of the composting wastes, the discoloration of the waxy leaves of R. ponticum and Portugal laurel (Prunus lusitanica) was developed as a potential indicator of the sanitising effect of the composting process. The relationship between the mean compost temperature and the percentage of green area of leaves positioned in the compost enabled the sanitising effect of a composting process to be immediately assessed. Mean compost temperatures and exposure times achieved in shredded rhododendron or chopped bilberry wastes in the majority of the compost in the insulated composting systems were above those needed to reduce P. ramorum and P. kernoviae to below detectable limits, and to eliminate any green colour in the indicator leaves. The exception was in the corners of the systems that contained >4 m³ waste, and in the outer surfaces at one site where the volume of waste was only 2.9 m³. Temperature-time profiles of the composts and positioned indicator leaves demonstrated that the main pathogen survival risk was in the corners of the insulated composting systems; pathogen survival risk could be minimised by positioning the corner material into the centre of the composting system during sequential refilling.     

Occurrence,Degradation and Fate of Pesticides During Composting

This paper reviews the findings of research reported in the currently available literature regarding the occurrence and transformations of pesticides through the composting process and the use of compost. Part I summarizes the composting process, pesticides and mechanisms of pesticide degradation. Part II reviews research studies concerning the occurrence and fate of pesticides during composting. Investigations of pesticide residues in composting feedstocks and finished compost detected few of the target pesticides. The compounds that were found occurred at low concentrations. The majority of the compounds detected were insecticides in the organochlorine category, including chemicals that have been banned from use in the U.S. for many years. Generally, organophosphate and carbamate insecticides and most herbicides were rarely detected. Comparisons of pesticide concentrations before and after composting also showed organochlorine compounds to be most resistant to biodegradation during composting. With some exceptions, pesticides in other categories decomposed moderately well to very well. Studies that followed the mechanisms of degradation indicate that mineralization accounts for only a small portion of pesticide disappearance. Other prominent fates include partial degradation to secondary compounds, adsorption, humification, and volatilization. In general the research results suggest that the pattern of pesticide degradation during composting is similar to the degradation observed in soils. With a few important distinctions, composting can be considered a biologically active soil environment in which degradation is accelerated. However, as some studies noted, composting does not always speed the degradation of all pesticides. The nature of the pesticide, specific composting conditions and procedures, the microbial communities present, and the duration of composting affect the extent and the mechanisms of degradation.     

Fatty Acid Formation during Composting of Separately Collected Organic Household Wastes

? Recent studies indicate that fatty acids are formed in significant concentrations during the composting of organic household residuals. Their presence may be one major reason for depressed germination and seedling development that often result following application of compost. Experimental results in Sweden indicate that at least five to six months should elapse before low levels of fatty acids for cropping are reached in the composts. Further research on fatty acid formation is recommended.     

Evolution of Biochemical Parameters During Composting of Urban Wastes

An experiment was performed for evaluating the most suitable biochemical parameters to measure dynamics of substrate transformation during composting of the organic fraction derived from preselected urban wastes and wood bark mixture. Changes of chemical (organic C, hydrosoluble sugars, total and mineral N, humified fraction, volatile acids and phenolic compounds) and biochemical (microbial respiration, biomass C, qCO₂, dehydrogenase, catalase, urease activities, FDA, and BIF) parameters were monitored for 120 days. Limited changes in organic C, total nitrogen, and humification characteristics were observed during composting. Dehydrogenase and catalase activities, BIF and FDA showed small changes during composting. Urease activity and, with some limitations regarding the early stages of composting, microbial respiration and qCO₂, were found to be the most suitable parameters to measure dynamics of substrate transformation during composting of preselected urban wastes.     

Effluents from Anaerobic Digestion of Organic Wastes: Treatment by Chemical and Electrochemical Processes

The treatment of effluent from anaerobic digestion of organic wastes was carried out using chemical and electrochemical processes, namely, chemical coagulation (CC) with lime, electrocoagulation (EC) with iron consumable electrodes, and electrochemical oxidation (EO) with a boron-doped diamond anode, at different experimental conditions. In the CC assays, the highest chemical oxygen demand (COD) removal, 50%, was achieved for a lime concentration of 70 g L^?1 after 2 h experiment. Under the experimental conditions studied, EC promoted COD removals of 80% after 5 h and EO led to COD removals of 43% after 6 h electrolysis, being this last removal increased to 60% when chloride was added to the effluent. A combined EC+EO treatment was also performed, utilizing the most favorable experimental conditions obtained in the individual processes, and global removals of 95% in COD and 44% in ammonia nitrogen were attained after 5 h of EC followed by 6 h of EO. These results proved that the combined process can be an efficient alternative in the treatment of effluents from anaerobic digestion of organic wastes with the characteristics of the studied effluent.     

餐厨垃圾与麦秸混合堆肥中碳素物质变化规律研究

餐厨垃圾堆肥是实现营养物质资源良性循环的重要途径,为了研究不同季节环境条件下餐厨垃圾与小麦秸秆混合高温好氧堆肥过程中碳素物质变化规律,试验设定了具有中原地区季节代表性的3种环境温度在15、25、35℃条件下分别进行了为期21d的堆肥。结果表明,餐厨垃圾和麦秸混合堆肥在25。C和35℃条件下,堆体温度能满足堆肥产品无害化要求,而15℃时不能满足;35℃条件下的pH值在前期下降幅度最多,15℃条件下pH值则始终保持在6．0以下;在25℃和35℃条件下,TOC含量明显比15℃条件下下降幅度大,堆肥物料中的糖类物质很容易被微生物分解,经过10d95％以上的糖类物质就被分解,粗纤维降解率均达到60％以上,而在15℃条件下到堆肥结束时,仍有30％多的糖类没有被分解,粗纤维也只分解了27．57％。     

Literature Review: Occurrence,Degradation and Fate of Pesticides During Composting: Part II: Occurrence and Fate of Pesticides in Compost and Composting Systems

This paper reviews the findings of research reported in the currently available literature regarding the occurrence and transformations of pesticides through the composting process and the use of compost. Part I summarizes the composting process, pesticides and mechanisms of pesticide degradation. Part II reviews research studies concerning the occurrence and fate of pesticides during composting. Investigations of pesticide residues in composting feedstocks and finished compost detected few of the target pesticides. The compounds that were found occurred at low concentrations. The majority of the compounds detected were insecticides in the organochlorine category, including chemicals that have been banned from use in the U.S. for many years. Generally, organophosphate and carbamate insecticides and most herbicides were rarely detected. Comparisons of pesticide concentrations before and after composting also showed organochlorine compounds to be most resistant to biodegradation during composting. With some exceptions, pesticides in other categories decomposed moderately well to very well. Studies that followed the mechanisms of degradation indicate that mineralization accounts for only a small portion of pesticide disappearance. Other prominent fates include partial degradation to secondary compounds, adsorption, humification, and volatilization. In general the research results suggest that the pattern of pesticide degradation during composting is similar to the degradatiion observed in soils. With a few important distinctions, composting can be considered a biologically active soil environment in which degradation is accelerated. However, as some studies noted, composting does not always speed the degradation of all pesticides. The nature of the pesticide, specific composting conditions and procedures, the microbial communities present, and the duration of composting affect the extent and the mechanisms of degradation.     

Fate of Fusarium graminearum and Other Fusarium Species During Composting Of Beef Cattle Feedlot Manure

Fusarium head blight, caused by Fusarium graminearum, could potentially become a major concern for the cereal industry in Alberta, Canada. Infested feed grain in feedlot manure may act as a means of spreading the disease when manure is land applied. The ability of manure composting to eradicate the pathogen on infested grain (wheat, barley, corn) was evaluated. F. graminearum and other Fusarium spp. were rapidly eradicated from infested grains buried in compost windrows with no recovery after 2 d where windrow temperature attained 51°C. Under cooler windrow conditions (11.9 to 17.5°C), recovery of F. graminearum reached zero on Day 9 for corn (Zea mays L.), Day 14 for wheat (Triticum aestivum L.) and Day 22 for barley (Hordeum vulgare L.), showing that factors in addition to compost temperature may play a role in pathogen elimination. Composting represents an effective strategy in mitigating the dissemination of F. graminearum via manure should land application occur on fields that are subsequently used for grain production.     

Assessment of Biogas use as an Energy Source from Anaerobic Digestion of Brewery Wastewater

Energy recovery from a crossflow ultrafiltration (UF) membraneunit employed in order to improve the performance of an anaerobic contact digester for the treatment of brewery wastewater was assessed. The performance of the pilot-scale anaerobic UF membrane system was studied for over 15 months. At steady-state conditions, an organic loading rate of 28.5 kg COD m^-3 d^-1, a hydraulic retention time of 4.2 days and overall COD and BOD removal efficiencies of 99% and almost 100% were achieved, respectively. Percent methane in biogas was found to be in a range of 67–79% with the corresponding methane yield of 0.28–0.35 m³ CH₄ kg^-1 COD_removed. The potential energy recovery from the system treating brewery wastewater at an OLR of 28.5 kg COD m^-3 d^-1 was 87 MJ d^-1 which would enable to maintain all energy requirements of the feed pump, mixing and heating of the reactor contents. In addition to this, 71% of the energy requirement for recirculating the reactor content through the membranes would also be recovered.     

剩余污泥厌氧消化过程重金属形态转化及生物有效性分析

为研究污泥厌氧消化过程中物理化学性质的变化对典型重金属形态转化的影响,对其农用的可行性及生物有效性进行评估,对取自某城市污水处理厂的剩余污泥进行了序批式厌氧消化实验,在试验过程中测定了污泥理化学性质,采用Tessier分步提取法提取了污泥样品中的典型重金属,并采用电感耦合等离子发射光谱仪（ICP-OES）测定各形态重金属含量及总量。结果表明,厌氧消化过程中重金属的形态发生了显著变化,由不稳定态向比较稳定的残渣态和有机结合态转变,某些重金属形态与污泥理化性质如pH、碱度、VS/TS及氨氮显著相关。厌氧消化可以有效地降低污泥中重金属的潜在迁移能力和生物有效性,经厌氧消化后污泥可以更好地进行土地利用。     

The Use of Bacillus Licheniformis HA1 To Accelerate Composting of Organic Wastes

The effect of Bacillus licheniformis HA1 cell density on the acceleration of organic waste composting was tested in a bench-scale composting system utilizing a process limit temperature of 60°C. Variables measured during composting were CO₂ evolution rate, conversion of substrate carbon and pH. When an initial cell density of 2.0×10⁴ cfu/g-dry solid was used, the strain HA1 increased in number and prevented the decrease in pH during the early stage of composting. This resulted in enhanced populations of other thermophiles and increased the rate of organic matter decomposition. By contrast, no effect was observed at a lower cell density of HA1. It was found that the minimum cell density of HA1 to accelerate organic decomposition was around 10⁴-10⁵ cfu/g dry solid of raw material.     

城市生活垃圾高温厌氧转化生物质能研究

城市生活垃圾的处理与处置问题已成为研究热点,在国内外已有的研究基础上,对城市生活垃圾高温厌氧(批量)发酵实验进行一些初步探索,研究了在55℃的高温条件下累积产气量与消化时间的关系,C/N与产气量的关系;消化过程中pH值变化的关系,并研究了垃圾高温发酵实验过程中沼气中的CH₄和CO₂的含量变化,其中甲烷含量可达75.3%.实验结果表明,城市生活垃圾高温消化的降解效果较好,产气量较高,启动时间短.     

沼气发酵系统在生态农业中的地位和作用

沼气发酵系统是生态农业系统能量和物质转化运行中起着一定枢纽作用的环节，它能够有效地回收农业废弃物的能量和物质。开展沼气综合利用，能够促进农村生态环境的良性循环，改善农村环境卫生条件。     

Use of a Rotating-Drum Pilot Plant To Model the Composting of Household Waste On an Industrial Scale

Any expert appraisal of municipal solid waste composting plants requires the evaluation of each piece of equipment in the processing sequence. However, the in situ study of working rotating drums is limited or impossible in composting plants, in particular for safety reasons. A laboratory pilot system (1.5 m length and 0.8 m diameter) with a rotating drum was developed. We compared its output with that of a rotary drum composting reactor in a working installation in Landerneau (France), both using similar municipal solid waste input. We were thus able to confirm the double function of the composting set up: microbiological degradation and size reduction of the municipal solid waste. Although the second function remains difficult to reproduce owing to the dimensions of the drums, extending the residence time in the laboratory led to fuller degradation of the organic matter. As the ash content remained constant, the weight loss at 550°C for material at the input and at the output of the rotating drum allowed evaluation of the organic matter losses and thus assessment of the plant's yield. The accuracy of this evaluation remains closely linked to the error involved in measurement of the ash. The daily losses of organic matter were about 3.3% dry wt. for the industrial plant and about 1.5% in the laboratory.     

曝气距离对植物源废弃物气流膜好氧发酵效率的影响

利用工厂化气流膜堆肥方式,探究了距离风机不同位置对堆体中废弃尾菜配伍蘑菇渣和醋糟发酵效率的影响.试验将尾菜、醋糟和蘑菇渣按照鲜重比1:1:3混合均匀后,放入气流膜发酵槽中,覆盖戈尔膜,底部曝气发酵30 d,以靠近风机一侧的终点为0点,分别于距离风机1.5、4.5、9.0、13.5、16.5 m处取样,测定了堆肥过程中距...     

废弃烤烟茎秆与鸡粪堆肥化利用的研究

采用特制的堆肥箱,对废弃烤烟茎秆与鸡粪的堆肥化利用进行了研究。结果表明,烤烟茎秆＋鸡粪（处理A）混合堆肥处理的堆温保持在50℃以上的时间为10d,而烤烟茎秆＋碳酸氢铵（处理B）处理的仅为2d。堆肥30d时,处理A的碳素含量基本趋于稳定,C／N为15．8;处理B的碳素含量仍不稳定,C／N为23．5;处理A的铵态氮与硝态氮的比值为0．43,处理B的达0．60。堆肥20d时,处理A堆料浸出液浸种后的种子发芽指数比处理B的高15个百分点,差异达极显著水平。堆肥50d时,两处理的种子发芽指数差异不明显,种子发芽率均达到100％。烤烟茎秆与鸡粪堆肥成品的有机质和总养分（N、P2O5、K2O）含量、重金属（As,Hg,Ph,Cd,Cr）含量控制标准等完全达到有机肥质量的要求。     

添加剂在猪粪堆肥过程中的作用研究

添加剂是指为了加快堆肥进程和提高堆肥产品质量,在堆肥物料中加入的微生物、有机或无机物质。本文通过室内培养与室外堆肥试验,研究不同添加剂对猪粪发酵过程中臭味及氮素损失的影响。结果表明,使用本研究中所采用的添加剂与发酵工艺,可以减少猪粪发酵中氨的挥发、氮素损失与猪粪的恶臭。75%含水量的猪粪经过20d的发酵,可达基本腐熟程度。添加剂可以优化堆肥过程的环境条件,提高微生物活性;加快堆肥的腐熟;减少氮素损失,保持养分含量;调节堆肥中各种营养元素的含量,提高堆肥质量。     

Temperature and Chemical Changes During Composting of Broiler Litter

Composting broiler litter (a mixture of manure, bedding material, and wasted feed) with commonly available high-C substrates may be a viable alternative to reduce current land disposal practices for litter. Broiler litter with wood shavings as a bedding material and broiler litter with peanut hulls as a bedding material were composted with wheat straw, peanut hulls, pine bark and paper mill sludge in 0.33 m³ batch reactors. Litters and C substrates were mixed to achieve C:N ratios of approximately 30:1. Dry weight, total N, total C, temperature, electrical conductivity and pH were determined at regular intervals. Maximum temperatures peaked near 70°C within 2.25 d after mixing peanut hulls with litter and within 2.58 d for pine bark and litter. Composts made from paper mill sludge approached 50°C within 3.71 d. Wheat straw composts never exceeded 40°C which could present potential health problems associated with pathogenic microorganisms. Mass loss and C:N ratio gradually declined and stabilized approximately 84 d after mixing. Mass loss averaged 73 percent for wheat straw compost, 33 percent for peanut hull composts, and 16 percent for the other mixes. Wheat straw compost C:N ratios stabilized near 14:1 and other mixes remained above 20:1, indicating N limited conditions for complete composting. Compost pH was 5.8 after 84 d from pine bark composted with wood shaving litter and was significantly lower than pH from paper mill sludge compost with an average pH of 6.9 but similar to all other compost mixes (pH 6.7). Electrical conductivity ranged from 0.35 S m^?1 for paper mill sludge composted with wood shaving litter to 0.91 S m^?1 from wheat straw composted with peanut hull litter. Composting temperature varied considerably among C sources and all required at least 72 d of curing to stabilize the C:N ratio. Composts made from wheat straw were most effective for waste reduction but temperatures were below the 50°C level generally considered necessary to kill pathogens.     

不同来源农业废弃物堆肥进程与产品肥效研究

评价不同来源农业废弃物的堆肥效率与产品肥效,为高品质有机肥生产提供依据.采用室外堆肥的试验方法,选取6种动物源粪便与7种植物源农业废弃物为原料,设置13个堆肥处理,比较不同堆肥原料堆肥过程中温度、pH、C/N、腐殖酸、养分等指标差异及其堆肥产品对小白菜生长的影响.结果表明,动物源和植物源材料质量比7:3,C/N为25:...