Composting for the Treatment of Cattle Wastes

? Livestock farming in England and Wales is estimated to produce an annual figure of 200 million tons of animal excreta, half generated by the dairy cattle industry. In the United Kingdom, the structure of the cattle industry has shifted from large numbers of small dairy farms to fewer but larger units. The national average herd size increased from 26 to 42 and finally to 64 animals in 1965, 1975 and 1985, respectively. The latest census revealed that currently there were 2.44 million dairy cows and 9.45 million other cattle and calves in the United Kingdom (total 11.89 million), third place after France (21.50 million) and Germany (19.51 million) in the EEC countries.     

Composting of Crucifer Wastes Using Geotextile Covers

Composting trials were undertaken in 1994 – 996 in Ste. Anne de Bellevue, Quebec, to study the feasibility of using crucifer or carrot residues with sawdust or straw for composting. Geotextile covers were tested for their influence on different parameters of the composting process. Two complete composting cycles from fall to summer were monitored. Measurements were taken for compost temperature, moisture, and leachate. Chemical analyses were performed on compost samples. Phytotoxicity tests were done with compost leachate samples. The results indicated that temperatures of covered compost (CC) decreased more slowly during late fall and early winter than non-covered compost (NC). In addition, CC did not freeze to as great a depth during the winter, and warmed earlier and faster than NC in the spring. The moisture content of CC was significantly lower than in NC at the end of both composting cycles. CC had a higher mineral content than NC in both cycles, and the levels of total N, P, K and NO₃ were significantly higher for CC in the second cycle. The carbon/nitrogen (C/N) ratio of CC decreased earlier and reached a lower level at the end of the composting cycle. The quantity of leachate from CC was significantly reduced compared to NC in the second cycle. Compost leachate in both treatments showed a high level of phytotoxicity at the beginning of the composting cycle. However, there was no evidence that compost covers influenced the phytotoxicity in leachate throughout the composting cycle. The use of covers could translate into economic or environmental benefits for most composting operations.     

The Fate of Plant Pathogens and Seeds During Anaerobic Digestion and Aerobic Composting of Source Separated Household Wastes

Anaerobic digestion is becoming a more common method for treatment of organic wastes. Little is known, however, about the effects of this process on the fate of plant pathogens and seeds. Therefore, the fates of the plant pathogens Plasmodiophora brassicae, Heterodera schachtii, Meloidogyne incognita, Ralstonia solanacearum, tobacco mosaic virus (TMV) and tomato seeds were followed during anaerobic digestion of source separated household wastes. With the exception of TMV, all test organisms were destroyed to below detectable limits within one day of anaerobic digestion at 52°C. Two days of anaerobic digestion did not reduce the concentration of TMV. However, two days of anaerobic digestion followed by 19 days of high temperature composting at 58°C reduced the concentration of infectious TMV particles by a factor of almost three orders. Anaerobic digestion followed by 12 days of composting at 68°C was even more effective. Although TMV concentrations were not eliminated entirely, we conclude that short-term high temperature anaerobic digestion followed by high temperature composting is a highly efficient process for the eradication of detrimental agents from solid wastes.     

Emission of Volatile Organic Compounds during Composting of Poultry Litter

The objective of this study was to identify and quantify volatile organic compounds (VOCs) produced during composting of poultry litter. The VOCs produced from in-vessel composting with a controlled aeration system were tested using the F-ITR method by VOC analyzer. Alkanes and alkylated benzenes were emitted in the highest amounts from poultry litter, while aldehydes, terpenes, ketones were emitted in much lesser amounts. Studies showed that VOCs generation was the greatest early during the composting process and greatly reduced thereafter. Composting temperatures were found to affect VOCs. All VOCs were least with the high temperatures generated during composting.     

Cobiogasification of Wastepaper Products with Separately Collected Municipal Solid Waste

? The treatment of soiled hygiene papers (HYP), such as diapers and sanitary napkins, added at a concentration of 10 percent (w/w) to separately collected municipal biowaste was tested at Biotechnishce Abfallverwertung (BTA)'s three stage mesophilic biogas plant in Munich. The study aimed to establish the feasibility of cobiogasification of hygiene papers and biowaste. Parameters measured were: Efficiency of plastics and inerts separation; Mass balances; Organic and inorganic dry residues; COD; C:N ratio; Heavy metal content; Bacterial counts; Fiber analysis of suspension; Residues; Effluent for hemicellulose, cellulose and lignin; Biogas yield; and Quality. In the conditioning stage, the hygiene papers (HYP) (10 percent) were completely suspended with municipal solid waste. The dry materials balance of the conditioning unit resulted in an increase of 1.5 percent of the screenings, corresponding exactly to the amount of the added plastics. Heavy metal contents in the residues were well below limits established by German compost quality guidelines. Plate counts of the sums of Enterobacteriae and Salmonellae revealed that addition of soiled HYPs does not increase risk of contamination. Fermentation process and yield did not differ from control; biogas contained about 70-75 percent methane and most organic pollutants measured were undetectable.     

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.     

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％。     

Mineralizable Nitrogen of Organic Wastes and Soil Chemical Changes under Laboratory Conditions

This study looks at the ability of organic wastes from different sources to efficiently promote chemical attributes and enhance nitrogen (N) concentrations in an Oxisol Ustox with a sandy texture. This experiment was performed in a randomized design using wastes from pulp mill sludge, petrochemical complex, sewage treatment plant, dairy factory sewage treatment plant, and pulp fruit industry, on 10 different days. Results showed that addition of the wastes to the soil amended their chemical attributes. The different characteristics of the organic wastes seem to have influenced the N mineralization rates during the 112 days. There was a close relationship between the N mineralization and organic waste C/N ratio: blank soil (SP) (Nma = 3.17) < Treated pulp mill sludge (PMS) (Nma = 30.49, C/N 63.6:1) < Organic compost from the fruit pulp industry (FPW) (Nma = 67.6, C/N 11.9:1) < Treated urban sewage sludge (USS) (Nma = 76.22, C/N 7.2:1) = Petrochemical complex sludge (PS) (Nma = 84.0, C/N 7.7:1) < Treated dairy industry sewage sludge (DSS) (Nma = 102.17, C/N 8.4:1).     

Assessment of Fulvic Acid-Like Fractions during Tannery Waste Composting

Changes in the structural composition of fulvic acids were followed during composting of tannery solid waste after neutralization of its acidity by ammonium or by lime. Different techniques (elemental analysis, Fourier transform infrared (FTIR), ¹³C-NMR spectroscopy) were applied. During both trials of composting, a decrease of carbon and increase of oxygen occurred, which originated from strong microbial oxidation and preservation of some structures during composting. In fact, Nuclear Magnetic Resonance (NMR) spectra showed the preservation of anomeric or tannin structures around 105 ppm. The infrared (IR) spectral data showed a decrease in the intensity of COO^? group bands (1623 and 1399.5 cm^?1); this is correlated with a decrease of fulvic acid levels. The variations observed in NMR spectra could be explained by the involvement of COO^? groups of certain structures in polycondensing to form humic acids. The fulvic acids remain composed of less polycondensed structures with a –COOH extremity, as supported by a decrease of the C/H ratio. In contrast, in the trial with addition of ammonia a slight increase in N content occurred, a decrease in absorbance in the 1730–1000 cm^?1 regions compared to the absorbance around 3400 cm^?1, and a strong decrease of carboxyl carbon in the ¹³C-NMR spectra.     

Composting of Source-Separated Household Organics At Different Oxygen Levels: Gaining an Understanding of the Emission Dynamics

Source-separated household organics were composted in a reactor at three oxygen levels, 16%, 2.5% and 1% in the compost gas. Short-chained fatty acids were initially present in the compost material, and were also produced during the mesophilic phase at all three oxygen levels. This indicated that partial anaerobic conditions existed. No NH₃ emissions occurred during the mesophilic phase due to acidic conditions. Composting at 2.5% and 1% O₂ concentrations prolonged the mesophilic phase and reduced the microbial activity as compared to 16% O₂. This led to delayed and decreased emissions of NH₃. Nitrous oxide was not formed during thermophilic conditions. Methane, which was measured at 2.5% and 1% O₂, was only found during thermophilic conditions. The emission of methane indicates that anaerobic conditions occurred during the thermophilic phase. The main reactions regulating pH during composting were outlined involving the ion species VFA, NH₄⁺/NH₃ and CO₂/HCO₃^?/CO₃^2?.     

Effects of Application of Organic and Inorganic Wastes for Restoration of Sulphur-Mine Soil

In situ remediation with waste material is an inexpensive method to reduce contaminant availability in polluted soil. The experiments were done to investigate the effects of possible in situ application of two different amendments: inorganic material (marble sludge) and organic material (horticultural waste compost) on chemical and biological properties of abandoned metalliferous mine wastes. The results show that the application of inorganic material raises the pH above neutrality and the combination of inorganic and organic material would produce the highest ratio of biological activity. The reductions of available Zn, Pb and As in lime, organic and lime/organic amendments were favoured by incubation time. However, available Cd content increased after 275?days of incubation, except the treatment with inorganic amendment. This work denoted that the application of lime with organic amendments has a better effect than the lime alone because the addition of both amendments improves both soil chemical and biological properties.     

Efficiency of Organic Compost from Agri-Industrial Wastes as Fertilizer for Corn and Wheat

Favorable effects of organic wastes on soil characteristics are capable of permitting a sustainable agriculture. This experiment was conducted to evaluate the effects of organic compost from two agri-industrial wastes on soil fertility and productivity of corn and wheat in Astorga County, northwestern Paraná, Brazil. The organic compost had components from the gelatin industry, which uses bovine chips and shavings by-products from the tannery industry and by-products (filter cake and plant straws) from the sugarcane industry. The experimental design was randomized complete block with eight treatments and four replications. Only the wheat had increased productivity, and there was no response to doses above 25 t ha^?1. Not all levels of organic compost affected the soil electrical conductivity.     

Quantitative Measurement of Organic Carbon in Mine Wastes: Methods Comparison for Inorganic Carbon Removal and Organic Carbon Recovery

The present study aims to evaluate carbon recovery and analytical precision of two methods based on dry combustion for organic carbon (OC) quantification in base metal mine tailings: (1) IC subtraction method (inorganic C(IC) measured and subtracted from total C) and (2) direct OC quantification after acid pretreatment. Results showed IC subtraction method effectively hydrolyzed a range of IC minerals [calcium carbonate (CaCO₃), magnesium carbonate (MgCO₃), dolomite, magnesite, calcite] with satisfactory IC (as CO₂ released) recovery (87–103 percent). In the direct OC quantification method, 5 M hydrochloric acid (HCl) pretreatment resulted in a satisfactory recovery (76–92 percent) of most organic compounds [ethylenediaminetetraacetic acid (EDTA), cellulose, plant litter, and charcoal], except for water-soluble OC (sucrose, 40 percent recovery). The precision of both methods declined when C levels were <5 g kg^?1 with RSD (Relative Standard Deviation) > 10 percent. The OC values in test samples of base metal mine tailings were comparable between the two methods. However, IC subtraction method is not applicable for tailings with low OC levels (<5 g kg^?1) until the precision is substantially improved. Moreover, compared to the IC subtraction method, OC values are significantly lower in direct OC quantification method for tailings with high OC levels.     

农业有机废弃物对黑土腐殖质元素组成的影响

以循环农业为指导,选取5种具有代表性的农业有机废弃物(秸秆、牛粪、鸡粪、菌渣、树叶)与化肥配施进行腐解培养还田试验,以不施肥(CK)和单施化肥(NPK)作为对照,系统的研究了3a后它们对黑土腐殖质胡敏酸(HA)、富里酸(FA)和胡敏素(HM)元素组成的影响。结果表明,与CK相比,NPK处理并没有对黑土腐殖质元素组成产生明显影响。不同种类有机废弃物与化肥配施可显著提高HA的N、H和O元素含量,降低C元素含量,其中牛粪与化肥配施处理结果不同;5种配施处理均降低了HA的缩合度,且有利于HA中含氮基团的形成。配施处理提高了FA的C和N元素含量,降低O元素含量,但FA的缩合度几乎不变,其中,牛粪和菌渣与化肥配施处理对FA的元素组成影响具有相似性。无论单施化肥还是配施处理,HA的[O]/[C]原子个数比均小于FA,说明FA中含有较多的烷氧基和羧基。配施处理使HMi的H元素含量降低,而O元素含量升高,且各处理之间差异显著;同时提高了HMc的芳香度,使其结构变复杂,以鸡粪与化肥配施作用最为显著。由此可见,有机废弃物与化肥配合施用均对黑土腐殖质元素组成产生了一定的影响,显著优于单施化肥,具有良好的培肥效果,其中以牛粪和秸秆与化肥配施较好,菌渣、树叶及鸡粪与化肥配施次之。     

Regional Inventory of Organic Industrial Wastes: Case Study in New Brunswick,Canada

? This study was undertaken to investigate the possibility of composting organic industrial wastes which are currently being generated in the Canadian province of New Brunswick. Four types of this waste stream were identified: Fish wastes; Agricultural wastes; Pulp and paper and sawmill wastes; and Food processing wastes. Other objectives of this study were to establish valid cost estimates of selected solid waste composting approaches and to address the potential of a value-added compost product.

In the past 20 years, fish landings in the province averaged approximately 136,000 metric tons annually. Processing in fish transformation plants leads to fresh and pickled fish wastes that must be either discarded by dumping or processed into usable byproducts.

Animal manure is the principal waste currently being generated by the agricultural industry with 1,333,000 metric tons of manure produced in 1986. There are also approximately 90,000 metric tons of potato culls produced by the potato industry per year. Most of these agricultural wastes are presently being used or applied on land.

The forest industry is the biggest in New Brunswick and as such produces the largest amount of industrial wastes. Wood residues are generated in two sectors of the forest industry: Logging and Wood Processing organizations.

The food processing industry is a diversified enterprise processing items such as fruit products, vegetable products and meat products. Potato processing companies produce one of the most significant vegetable wastes of the province, with about 50,000 metric tons of wastes annually.     

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.     

Oxygen and CO2 Profiles and Methane Formation During the Maturation Phase of Composting

Several different composts were examined both at bench-scale and on-site. The samples were taken from full-scale windrow composting plants at different stages of maturation. Oxygen, carbon dioxide and methane profiles within the material matrix for each sample were monitored and values for specific oxygen uptake rate (SOUR), moisture content (MC), and volatile solids (VS) were also determined. Methane was detected inside some of the composting piles (with values higher than 10% by volume) and in one of the bench-scale systems (with values up to 0.9% by volume) but never within the upper 0.20 meters of material. The profiles indicated that the methane was probably oxidized within the mass and consequently methane release during the maturation stage of the composting process was probably not common.     

Characterization of Organic Matter in Compost Produced with Municipal Solid Wastes: An Italian Approach

Stabilization of the organic matter of a static pile of compost from municipal solid wastes (MSW) under a forced-pressure ventilation composting system was followed for 55 days during winter season. The materials were analyzed according to the official methodologies required by Italian regulations regarding the quality of composts from MSW. The stabilization process of the organic matter was monitored using both the degree of humification (DH), i.e. the ratio between the humified fractions (HA + FA) and the total extractable carbon (TEC), and the electrofocusing technique (EF). The DH increased steadily in compost during stabilization process and converged asymptotically at the end of the period of composting. The EF analyses of the organic extracts of compost from MSW showed a definite trend in the humification process and confirmed the actual evolution of the organic matter composted.     

基于微生物电解池利用有机废弃物产氢研究进展

微生物电解池(Microbial electrolysis cell,MEC)技术作为一种新兴技术,实现了利用有机废水、农林废弃物、活性污泥等废物同步酶解发酵产氢的目的,有效提高了资源的综合利用效率。本文主要介绍了MEC产氢的工作原理,分析了MEC利用有机废弃物产氢过程中的影响因素。