Environmental assessment of two home composts with high and low gaseous emissions of the composting process

A Life Cycle Assessment (LCA) of two home composts with low and high gaseous emissions of the composting process is presented. The study focused on the gaseous emissions of the composting process. Gaseous emissions of methane, nitrous oxides, ammonia and volatic organic compounds of the composting process were experimentally measured in field real trials. The results showed that the differences in gaseous emissions between the two home composts were 4.5, 5.8 and 52 for methane, nitrous oxides and ammonia, respectively. Higher emissions of nitrous oxides and methane affected significantly the category of global warming potential, while higher emissions of ammonia affected mainly the categories of acidification potential, eutrophication potential and photochemical oxidation. The differences found in the compost emissions were attributable to the composting production management (quality and composition of waste stream, frequency mixing of waste, humidity and temperature monitoring, among others) as well as weather conditions (temperature and humidity).     

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.     

不同腐熟度猪粪、奶牛粪在小白菜和香瓜上施用的农学效应研究

进行猪粪和奶牛粪自然高温堆肥发酵,分别在15、25、35、50 d取样,获得了不同腐熟程度堆肥产物,分别进行了小白菜和香瓜种子发芽与田间应用试验,以期获得不同腐熟堆肥在蔬菜上施用的农学效应,旨在从堆肥农田施用的农学效应角度,为制订堆肥腐熟度标准提供科学依据。结果表明：牛粪堆肥过程中的最高温度高于猪粪,且高温期也长于猪粪;两种处理在35d有机碳含量均显著降低,全氮含量为先降低后升高趋势;两种堆肥在35d后,均达到无害化标准。不同腐熟程度堆肥对小白菜株高和主根长及香瓜苗重和主根长均没有明显抑制作用,对小白菜和香瓜出苗率、根系活力及小白菜单株鲜重和生物产量影响较大,尤其是猪粪腐熟25d,奶牛粪腐熟15d的堆肥表现出显著抑制作用。将堆肥理化参数与小白菜、香瓜生长指标进行相关分析表明：pH值、全氮含量和C/N这3种指标均与小白菜和香瓜各项生物性状无显著相关性;有机碳和DOC与各项生物性状指标均表现出显著或极显著相关性;铵/硝与小白菜和香瓜的GI和根系活力均表现极显著或显著的相关性,其结果与现行的堆肥腐熟度指标并不一致。因此,在制订堆肥腐熟度标准时,应关注堆肥产物农田施用后不同作物所表现出的不同农学效应。     

The maturity tests during the composting of municipal solid wastes

This study investigated at first the evolution of co-composting process of municipal solid waste and sewage sludge under Tunisian pedo-climatic conditions.Results showed that the temperature profiles established in the system revealed three classical steps, the mesophilic phase during the first 25 days, the thermophilic phase between 30 and 130 days and the cooling phase began after the 14th week in the two windrows W1 (100% of municipal solid wastes) and W2 (60% of municipal solid wastes and 40% of dried sewage sludge). Potential toxic heavy metal content appeared generally more important in W2 than W1, and both finished products of compost obtained in this study satisfied most parts of the recommended norms of agronomical use. The presence or absence of nitrifying activity allowed determining that the compost W1 was more mature than the compost W2.Composting cannot only transform waste by reducing its harmful effect but also corrects when added to soil, the deficit in organic matter. The nature of the raw material used in composting may affect the quality of the final product. There is a significant need for the amendment of soils by compost. The quality of the amendment may have a significant impact on environment.     

施入城市生活垃圾堆肥对玉米植株重金属分布及土壤养分的影响

以玉米为供试作物,研究施入生活垃圾堆肥对土壤和玉米各器官重金属分布规律及对土壤养分的影响。结果表明：连续3年施肥,土壤速效养分的含量明显增加;土壤重金属呈现累积,但含量远远低于二级土壤标准（GB 15618—1995）;植株中重金属含量表现为根部〉茎秆〉叶片〉籽粒,Cd在植株根部富集,但未大量向其他部位转移,玉米植株地上部分重金属含量明显低于饲料卫生标准（GB 13078—2001）。由此推断,在短期内（3年）,年施入60 000 kg·hm^-2的垃圾堆肥能提高土壤肥力,且暂时不会引起土壤重金属污染,也不影响玉米植株的饲用;使用多年后应及时监测,以保证安全性。     

Persistent organic pollutants in the environment: chlordane residues in compost

The half-lives of some persistent organic pollutants (POPs) in environmental compartments such as soil and air can be as long as decades. In spite of the hydrophobicity of many POPs, the literature contains reports of their uptake by, and translocation through, a variety of plants. Both these observations prompt the investigation of whether a vegetation-based environmental compartment such as compost contains significant residues of POPs. Previous reports imply that residues of technical chlordane will be found in compost. Due to its physicochemical properties, technical chlordane provides insights into the fate of POPs in the environment, which are not accessible through determinations of other pollutants in this group. Accordingly, we undertook the first comprehensive examination of technical chlordane residues in a variety of composts, specifically, 13 commercial and 39 municipal compost products, to both characterize and quantify the magnitude of this point source of contamination. Using chiral gas chromatography interfaced to ion trap mass spectrometry, the concentration and the compositional and enantiomeric profiles of chlordane components were determined. Of the 13 commercial products, 9 contained detectable chlordane concentrations, ranging from 4.7 to 292 microg/kg (dry wt.), while all 39 municipal products contained chlordane residues ranging from 13.9 to 415 microg/kg (dry wt.). The residue concentrations and profiles suggest possible feedstock sources for the chlordane in the finished compost product. The data also support the conclusion that some composts contribute to anthropogenic cycling of POPs through the biosphere.     

城市生活垃圾堆肥处理工程技术发展探讨

文章分析了我国城市生活垃圾堆肥陷入滞销困境多年的原因，指出摆脱这一困境的技术途径是要大幅度提高堆肥品质。而要实现这一目标，首先必须引进先进的堆肥翻堆技术，缩短腐熟时间，提高腐熟度；其次是应用气流密度分选系统对粗堆肥进行精分选。     

Modeling carbon and nitrogen transformations for adjustment of compost application with nitrogen uptake by wheat

Environmentally sound management of the use of composts in agriculture relies on matching the rate of release of available N from compost-amended soils to the crop demand. To develop such management it is necessary to (i) characterize the properties of composts that control their rates of decomposition and release of N and (ii) determine the optimal amount of composts that should be applied annually to wheat (Triticum aestivum L.). Carbon and N mineralization were measured under controlled conditions to determine compost decomposition rate parameters, and the NCSOIL model was used to derive the organic wastes parameters that control the rates of N and C transformations in the soil. We also characterized the effect of a drying period to estimate the effects of the dry season on C and N dynamics in the soil. The optimized compost parameters were then used to predict mineral N concentration dynamics in a soil-wheat system after successive annual applications of compost. Sewage sludge compost (SSC) and cattle manure compost (CMC) mineralization characteristics showed similar partitioning into two components of differing ease of decomposition. The labile component accounted for 16 to 20% of total C and 11 to 14% of total N, and it decomposed at a rate of 2.4 x 10(-2) d(-1), whereas the resistant pool had a decomposition rate constant of 1.2 to 1.4 x 10(-4) d(-1). The main differences between the two composts resulted from their total C and N and inorganic N contents, which were determined analytically. The long-term effect of a drying period on C and N mineralization was negligible. Use of these optimization results in a simulation of compost mineralization under a wheat crop, with a modified plant-effect version of the NCSOIL model, enabled us to evaluate the effects of the following factors on the C and N dynamics in soil: (i) soil temperature, (ii) mineral N uptake by plants, and (iii) release of very labile organic C in root exudates. This labile organic C enhanced N immobilization following application, and so decreased the N available for uptake by plants.     

Solubility of phosphorus and heavy metals in potting media amended with yard waste-biosolids compost

The potential risk of surface and ground water contamination by phosphorus (P) and heavy metals leached from compost-based containerized media has become an environmental concern. Solubility and fractionation of P and heavy metals were evaluated in media containing 0, 25, 50, 75, or 100% compost derived from biosolids and yard trimmings for potential impacts on the environment. As compost proportion in peat-based media increased from 0 to 100%, concentrations of total P, Cd, Cu, Ni, Pb, Zn, and Mn in the media increased whereas concentrations of total Co and Cr decreased. Except for Cu, all heavy metals in the water-soluble fraction decreased with increasing compost proportion in the media, because of higher Fe, Al, and Ca concentrations and pH values of the composts than the peat. When the media pH is controlled and maintained at normal range of plant growth (5.5-6.5), leaching of the heavy metals is minimal. Incorporation of compost to the peat-based media also decreased the proportion of total P that was water-soluble. However, concentrations of bioavailable inorganic phosphorus (NaHCO3-IP), readily mineralizable organic phosphorus (NaHCO3-OP), potentially bioavailable inorganic phosphorus (NaOH-IP), and potentially bioavailable organic phosphorus (NaOH-OP) were still higher in the media amended with compost because of higher total P concentration in the compost. Further study is needed to verify if less or no topdressing of chemical P fertilizer should be applied to the compost-amended media to minimize P effect on the environment when compost-amended potting media are used for nursery or greenhouse crop production systems.     

Nitrogen, phosphorus, and potassium uptake by wheat and their distribution in soil following successive, annual compost applications

The overall objective of the present study was to determine the loading limits of composts that should be applied annually to irrigated wheat. We conducted a container experiment in a greenhouse during four years. It included eight treatments: sewage sludge compost (SSC) and cattle manure compost (CMC), each applied annually to a sandy soil, at rates equivalent to 3, 6, and 12 kg m(-2), and two controls, one fertilized and one unfertilized. Total dry matter (DM), grain production, and the amount of N, P, and K taken up by plants increased with increasing compost rate. Nitrogen uptake by the plants of the fertilized control was much higher than by the plants of the highest compost rate. Phosphorus and K uptake by the plants amended with the highest compost rate was much higher than by the fertilized control plants. Inorganic N quantity in the soil increased with increasing compost rate and with successive applications. The net N mineralization during the first year of wheat growth was very low, less than 3.5% of the applied organic N under all compost application rates. The contribution of the organic N mineralization increased during the second and third years. Most of the N increase in the compost treatment was found in the upper layer of 0 to 15 cm, whereas in the fertilized treatment N accumulated from the surface to the bottom of the container, 0 to 55 cm. The successive application of high rates of composts resulted in P and K accumulation in the soil profile.     

University of Benin water supply system: Microbiological and physico-chemical assessments

The microbiological and physico-chemical characteristics of the drinking water supplied by the Central Borehole at the University of Benin, Ugbowo Campus were investigated. The investigation entailed assessment of the pH, turbidity, total suspended solids, total dissolved solids, dissolved oxygen, temperature, salinity, conductivity, nitrate, nitrite, phosphate, sulphate, chloride, N-nitroso compounds, cadmium, chromium, nickel, lead, zinc, manganese, iron, coliform count, BOD₅ and COD of the water at the Central Borehole and at ten residential quarters. The assessment indicated that the water was fit for drinking and other domestic applications. Results were also compared with WHO, EU and Nigeria FEPA standards. The results showed that the pH values of the water (5.01–5.86) and total coliform count (1–2/100 ml) expressed as MPN were outside the limits set by the WHO, EU and FEPA. The data also showed that the other water quality parameters assessed were within WHO, EU and FEPA permissible limits. The results of ANOVA showed that significant changes occurred during distribution.     

不同菌剂处理下猪粪和牛粪堆肥前期性质变化

以猪粪和牛粪为堆肥原料,设计了人工接种MixF-3菌剂堆肥、添加灭活菌剂堆肥和自然堆肥3个处理进行堆肥前期实验,探讨堆肥9d过程中温度、水分、有机碳、全氮和微生物量碳等参数的变化。结果表明,按1L/t接种MixF-3混合菌剂堆肥温度升温快,猪粪堆肥第48h和第84h时温度分别达到66℃和71.5℃,牛粪堆肥第48h时温度达69℃,明显高于灭活菌剂处理组和CK对照组。随着堆肥的进行,各处理组水分含量缓慢下降,牛粪比猪粪含水量略高。人工接种菌剂的猪粪和牛粪堆肥处理组中pH变化幅度小,有机碳碳含量的下降幅度比灭活组和自然堆肥组大,分别下降15.64%和11.25%,全氮含量缓慢升高但变化不大,人工接种牛粪比猪粪处理组中堆肥全氮含量升幅高;在猪粪和牛粪堆肥中人工接种菌剂微生物量碳降幅最小,分别为9537μg/g和3212μg/g,表明在猪粪和牛粪堆肥原料中添加MixF-3复合菌剂有利于微生物繁殖生长,同时拓宽了菌剂使用的单一性,更具有普遍性意义。     

Defining acceptable conditions in wilderness

The limits of acceptable change (LAC) planning framework recognizes that forest managers must decide what indicators of wilderness conditions best represent resource naturalness and high-quality visitor experiences and how much change from the pristine is acceptable for each indicator. Visitor opinions on the aspects of the wilderness that have great impact on their experience can provide valuable input to selection of indicators. Cohutta, Georgia; Caney Creek, Arkansas; Upland Island, Texas; and Rattlesnake, Montana, wilderness visitors have high shared agreement that littering and damage to trees in campsites, noise, and seeing wildlife are very important influences on wilderness experiences. Camping within sight or sound of other people influences experience quality more than do encounters on the trails. Visitors’ standards of acceptable conditions within wilderness vary considerably, suggesting a potential need to manage different zones within wilderness for different clientele groups and experiences. Standards across wildernesses, however, are remarkably similar.     

Composting of vinasse and cotton gin waste by using two different systems

Two composts were obtained by co-composting of a concentrated depotassified beet vinasse and cotton gin waste using two different aeration systems: static aerated pile (forced aeration provided by a blower whom operated in the positive mode) and windrow (turned pile). The composting mixtures were cotton gin trash (55%) and vinasse (45%) (dry weight). In static pile, the total amount of vinasse was added at the beginning of the process whereas, in windrow two additions of vinasse were performed. Differences in temperature changes between both composting systems were found: a faster increase of temperature in the windrow (54 °C at 7 days) than in the static pile (45 °C at 21 days) was observed. Probably in the static pile system, the compaction of the substrates made difficult the correct distribution of the air inside the pile. Moreover, after the second addition of vinasse a new thermophilic phase was started in windrow. The different aeration systems and the way of addition of vinasse could cause differences in organic matter (OM) degradation and in weight (22.6% for the static pile and 26.7% for the windrow) and gas losses during the process. Nevertheless, the composts obtained by the two systems had a high fertilizer value (25.1 g kg⁻¹ N; 3.2 g kg⁻¹ P₂O₅; 21.4 g kg⁻¹ K₂O; C/N8) for compost obtained in static pile and (16.2 g kg⁻¹ N; 3.4 g kg⁻¹ P₂O₅; 16.1 g kg⁻¹ K₂O; C/N 12) for compost obtained in the windrow). A high degree of stability was reached in the final composts. Composting of vinasse with cotton gin waste serves two objectives, disposal of wastes and recycling of waste components.     

我国《土壤环境质量标准》中重金属污染相关问题探讨

我国《土壤环境质量标准》（GB 15168—1995）的颁布促进了土壤资源的保护、管理与监督,但由于时间跨度过长社会发展较快,已经不能满足目前实际应用的需要。本文概述了发达国家关于土壤重金属污染的相关指导值/筛选值,并总结了我国现行土壤环境质量标准实施以来存在的问题及近年来的研究进展,对我国《土壤环境质量标准》的修订进行了探讨。     

Metals in vineyard soils of the Penedès area (NE Spain) after compost application

The application of organic wastes to improve soil physical characteristics in mechanized vineyards planted after land levelling is becoming a common practice in Mediterranean areas. It may be useful as an additional source of organic matter and nutrients, but these wastes could also have negative effects due to their metal content. The aim of the study was to evaluate the influence of compost application on soil metal contents in mechanized vineyard soils of the Spanish Mediterranean area, where this practice is repeated every three years. The study was carried out in a ten-year-old vineyard where the main soil type is Typic Calcixerept. Composted cattle manure was applied in alternate rows, at a rate of 40 Mgha(-1) dry-weight. Nine sampling points were located along the slopes of two plots: a levelled plot prepared for mechanization with large soil disturbance movements within the plot, and a plot of undisturbed soil. At each location, soil samples were taken in both treated and untreated soils. Total concentrations (digestion with aqua regia) and the extractable DTPA (Diethylene-triaminepentacetic)-CaCl2-TEA (Triethanolamine) fractions of Cu, Zn and Mn were analyzed in each sample. For Cu and Zn, the initial concentration was higher in the undisturbed plot. In both cases, total Cu and total Zn were positively affected by manure input and the concentration in treated soils was significantly higher than in untreated soil. For Mn, the initial concentration was higher in disturbed soils than in undisturbed ones, and although in both scenarios the concentrations increased with manure, no significant differences were found between treated and untreated soils. The extractable fraction also increased in treated versus untreated soils, although for Cu and Mn the extractable/total metal ratio was similar in treated and untreated soils. After one compost application, total metal contents increased significantly, particularly for Zn. Most of those metals are accumulated in the soil, due to the soil characteristics.     

Effect of biosolids processing on lead bioavailability in an urban soil

The potential for biosolids products to reduce Pb availability in soil was tested on a high Pb urban soil with biosolids from a treatment plant that used different processing technologies. High Fe biosolids compost and high Fe + lime biosolids compost from other treatment plants were also tested. Amendments were added to a Pb-contaminated soil (2000 mg kg(-1) Pb) at 100 g kg(-1) soil and incubated for 30 d. Reductions in Pb bioavailability were evaluated with both in vivo and in vitro procedures. The in vivo study entailed feeding a mixture of the Pb-contaminated soil and AIN93G Basal Mix to weanling rats. Three variations of an in vitro procedure were performed as well as conventional soil extracts [diethylenetriaminepentaacetic acid (DTPA) and Ca(NO3)2] and sequential extraction. Addition of the high Fe compost reduced the bioavailability of soil Pb (in both in vivo and in vitro studies) by 37 and 43%, respectively. Three of the four compost materials tested reduced Pb bioavailability more than 20%. The rapid in vitro (pH 2.3) data had the best correlation with the in vivo bone results (R = 0.9). In the sequential extract, changes in partitioning of Pb to Fe and Mn oxide fractions appeared to reflect the changes in in vivo Pb bioavailability. Conventional extracts showed no changes in metal availability. These results indicate that addition of 100 g kg(-1) of high Fe and Mn biosolids composts effectively reduced Pb availability in a high Pb urban soil.     

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.     

生活生产类产品VOCs含量限值法规与标准研究

本文对国内生活生产类产品VOCs含量限值的国家标准、地方标准、行业标准以及中国香港、欧美等发达地区精细化的生活生产类产品VOCs含量限值法规和标准做了比较全面的综述,并从产品限值种类以及限值要求两个方面进行了对比研究和分析,提出了我国生产生活类产品VOCs 含量限值法规标准制定建议。笔者认为,应借鉴发达国家成功的生活生产类产品VOCs含量限值法规及标准制定经验,从做好标准和产品技术要求衔接、建立区域协同制定标准模式、结合经济因素或环境空气质量,分步推进相关标准制定和发布等方面入手,建立符合实际国情的产品种类较为全面、标准要求较高的生产生活类产品VOCs含量限值法规与标准体系,尤其是生活消费品方面,减少直接与人体接触的生活消费品VOCs排放。