Evaluation of Organic Wastes for Composting

Management of organic wastes is essential to reduce environmental pollution and increase resources of plane nutrients for crop production. This study was undertaken to evaluate major organic wastes produced in northwestern Pakistan for characteristics that are useful for composting. Organic wastes such as manures, municipal wastes (MW), crop residues, fruit/vegetable wastes, and yard wastes contained large reserves of nutrients. Manures had high nitrogen (N) and crop residues had low N. Crop residues were relatively dry (7–12% moisture); MW, poultry manure, sheep manure, leaves, and city garbage were moderately moist (27–47% moisture), whereas cattle manure (CM), fruit and vegetable wastes, and grass clippings were wet (62–89% moisture). The compost developed from mixing MW with CM matured early and had low C/N ratio compared with either source alone. These results suggested that MW could be converted into compost when mixed with CM. The inoculation of wastes with effective microbes (EM) was ineffective in expediting the process of composting.     

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.     

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.     

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.     

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.     

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.     

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.     

有机废物沼气发酵的综述

本文阐述了有机废物厌氧处理的生物化学、微生物学、氢分压对沼气发酵的影响及其起动等厌氧消化处理有机废物的重要问题。结合实验结果,对世界先进国家在厌氧处理有机废物的理论和实践进行概括。它将对我国在此领域进一步提高理论、科研和实际应用能力达到世界先进水平很有益处。     

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:...     

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％。     

The Effects of Different Organic Wastes on Mineral Element Content in Organic Strawberry Cultivation

In this article, five different organic waste effects on mineral uptake in growing organic strawberries was investigated. In the experiment, the impacts of different organic wastes, such as hazelnut husk (H), hazelnut husk compost (HC), rice hull (R), rice hull compost (RC), and farmyard manure on mineral element contents of strawberry cultivars ‘Camarosa’ and ‘Sweet Charlie’ were investigated. The harvesting of the plants was performed at the beginning of resting, fluorescence, and at the end of the harvest throughout the experiment in order to examine the impacts of organic wastes on mineral element contents, which were detected in the leaf samples extracted from these harvests. In this experiment, it was observed that the applications H Compost and H yielded better results than farmyard manure and other wastes regarding mineral element content. In the research, when examined pull up dates, N, P, Mg, Fe, and Mn contents were adequate, but K, Ca, and Zn contents were found to be insufficient in strawberry leaves.     

Bioremediation of Acid Mine Drainage Using Acidic Soil and Organic Wastes for Promoting Sulphate-Reducing Bacteria Activity on a Column Reactor

Acid mine drainage (AMD) is a serious environmental problem resulting from extensive sulphide mining activities. The old copper mine of S. Domingos in Southeast Portugal is an example of such a situation. The abandoned open-pit from the mining operations resulted in the creation of a large pit lake with acidic water (pH～2) and high contents of sulphate and heavy metals. Sulphate-reducing biological processes have been studied as a remediation technology for this problem. A new application based on a simple and semi-continuous process for the treatment of S. Domingos AMD has been presented herein. Experiments using bench scale fixed-bed column bioreactors were carried out to evaluate the efficiency of the process. Sewage, anaerobic sludge and soil from the mining area were tested as solid matrices and/or inocula, as well as sources of complex organic substrates. The addition of lactose as a supplementary carbon source, easily available at zero cost or at negative cost in the effluents of the local cheese industries, was also tested. The data obtained indicate that it is possible to use the matrices tested for the production of sulphide by sulphate reduction, and that the regular addition of lactose is effective. Results showed that the process is efficient for the precipitation of the main dissolved metals, for the reduction in the sulphate content and, most importantly, for the neutralization of the AMD. Moreover, the use of soil as solid support also showed the possibility of using this process for the decontamination of both waters and soils.     

Physico-Chemical Evaluation of Organic Wastes Compost-Based Substrates for Eucalyptus Seedlings Growth

Eucalyptus growth was evaluated in five compost-based substrates formulated with different proportions of sewage sludge, coffee husk, peat, chicken manure, cattle manure, pine bark, sawdust, and coconut fiber, compared to two commercial substrates (CS). Organic wastes compost-based substrates (OWS) and CS were characterized regarding the available contents of macro and micronutrients, sodium (Na⁺), pH, electrical conductivity (EC), and bulk density (BD). Substrate attributes and eucalyptus biomass production were submitted to principal component analysis (PCA) to detect patterns of clustering. The different proportions of organic wastes influenced the physico-chemical characteristics of OWS and, consequently, the eucalyptus biomass production. The highest biomass was observed in one of the CS that is rich in available boron (B) and calcium (Ca), less concentrated in most of the nutrients and with low EC and Na⁺ contents. The PCA allowed the verification that B availability was the attribute that explained most of the variation in eucalyptus biomass production.     

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.     

Enhanced Biodegradation of Used Engine Oil in Soil Amended with Organic Wastes

Three organic wastes (banana skin (BS), brewery spent grain (BSG), and spent mushroom compost (SMC)) were used for bioremediation of soil spiked with used engine oil to determine the potential of these organic wastes in enhancing biodegradation of used oil in soil. The rates of biodegradation of the oil were studied for a period of 84 days under laboratory conditions. Hydrocarbon-utilizing bacterial counts were high in all the organic waste-amended soil ranging between 10.2?×?10⁶ and 80.5?×?10⁶?CFU/g compared to unamended control soil throughout the 84 days of study. Oil-contaminated soil amended with BSG showed the highest reduction in total petroleum hydrocarbon with net loss of 26.76% in 84 days compared to other treatments. First-order kinetic model revealed that BSG was the best of the three organic wastes used with biodegradation rate constant of 0.3163 day^?1 and half-life of 2.19 days. The results obtained demonstrated the potential of organic wastes for oil bioremediation in the order BSG?>?BS?>?SMC.     

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.     

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).     

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.     

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?.