Abstract: Information on compost organic matter stability is necessary to anticipate the effects of compost application on soil properties. Such information will soon be required by French legislation. The main objectives of the present work were: (1) to study the influence of the composting process and the composted waste on the kinetics of stabilization of organic matter during the composting process; (2) to validate physicochemical indicators of compost stabilization and also rapid tests used by the compost producers on the composting plants in order to be able to follow compost stabilization during the process. Ten compost windrows were sampled after 3, 4 and 6 months of composting at plants where green wastes (GW), biowastes (BIO), sludge (SG) or municipal solid wastes (MSW) were composted. In some plants, the composting process was accelerated by enforced aeration. The stability of the organic matter was assessed by laboratory incubations during which organic matter mineralization was followed. Maturity tests...

Abstract: For the last two decades, carcass disposal by burial is being replaced with alternatives such as composting. Improper animal mortality disposal may generate various environmental and health hazards such as odor nuisance (resulting from the anaerobic breakdown of proteins) that can reduce the quality of life and decrease property values. Pathogens, which may still be present in the decomposed material, are capable of spreading diseases in soil, plants, animals and humans. The potential leaching of harmful nitrogen and sulfur compounds from animal mortalities to ground water is another concern. To control these side effects, compost facility operators need to know and understand the science and guidelines of carcass composting. While basic principles of carcass composting are similar to those for composting of organic materials, its management issues, including appropriate composting methods for large or small scale carcass composting, quantities and types of carbon sources, composting time, odor and leachate control, and equipment requirements differ from composting of organics. The purpose of this study is to review the previous works related to carcass composting and provide information on recent advances in small and large-scale carcass composting enabling higher decomposition rates, minimum usage of carbon source materials, easier and shorter management control strategies and reduced land requirement while producing a useful end product and avoiding negative impact on public safety and environmental parameters.

Abstract: The changes in the different organic matter (OM) fractions of lignocellulosic wastes during composting were studied and related to OM humification parameters and compost maturation degree. For this purpose, four mixtures of lignocellulosic materials (lemon tree prunings, cotton waste, brewery waste, olive husk, olive leaves and the solid fraction of olive mill wastewater) were composted in a static pile system with forced ventilation. The evolution of the parameters humic acid to NaOH-extractable organic carbon proportion or PAH (HAC/EXC × 100), humic to fulvic acid ratio (HAC/FAC), cation exchange capacity to total organic carbon ratio (CEC/TOC), and water-soluble organic carbon to organic nitrogen ratio (HOC/Organic-N), clearly reflected the increase in the degree of humification and stability of the OM during the composting process in all four mixtures. The concentration of water-soluble carbohydrates was significantly correlated with PAH, HAC/FAC and the HOC/Organic-N ratio in only two mixtures along ...

Abstract: A field study was conducted to assess the benefits, with respect to soil physical properties and soil organic matter fractions of utilizing composts from a diversity of sources in perennial forage production. A mixed forage (timothy-red clover (Trifolium pratense L.) and monocrop timothy (Phleum pratense L.) sward were fertilized annually with ammonium nitrate (AN) at up to 150kg and 300 N ha−1 yr−1, respectively, from 1998-2001. Organic amendments, applied at up to 600 kg N ha−1 yr−1 in the first two years only, included composts derived from crop residue (CSC), dairy manure (DMC) or sewage sludge (SSLC), plus liquid dairy manure (DM), and supplied C to soil at 4.6 and 9.2 (CSC), 10.9 (SSLC), 10.0 (DMC) 2.9 (DM) Mg C ha−1. Soil samples (0-5cm; 5-10cm;10-15cm) were recovered in 2000 and 2001. Improvements in soil physical properties (soil bulk density and water content) were obtained for compost treatments alone. Composts alone influenced soil C:N ratio and substantially increased soil organic carbon (SOC...

Abstract: A two-year field experiment (2001 and 2003) was carried out in a Mediterranean environment to study the effects of municipal solid waste (MSW) compost application compared with mineral nitrogen (N) fertilization on the agronomic performance and N utilization of a tomato crop, in rotation with durum wheat The research was conducted in the south of Italy where five N treatments and two soil tillage depths (40-45 cm and 10-15 cm) were compared The N treatments were: MSW compost at 140 kg ha−1 (Ncom); mineral N fertilizer at 140 kg ha−1 (Nmin); MSW compost combined with mineral N fertilizer (Nmix) (70 kg ha−1 as organic N plus 70 kg ha−1 as mineral N); mineral N fertilizer at 70 kg ha−1 combined with two applications of foliar fertilizer (Nfito) (3 kg ha−1 as hydrolyzed proteins), and an untreated control (Contr) During cropping cycles, growth parameters and plant N status (SPAD readings and petiole nitrate content) were determined; at harvest the marketable, overripe, green fruit, total yield, yield compo

Abstract: Biotoilet is a composting toilet that uses sawdust as a matrix for bioconversion of human excreta into compost and is managed with the aim of accelerating decomposition, optimizing efficiency, and minimizing any potential environmental problems. Understanding how the moisture content affects the biodegradation rates of feces is a key factor for setting criteria for the proper design and operation of the biotoilet. A research project in this respect was conducted in laboratory-scale composting reactors. Results showed that composting is characterized by different biological responses of microorganisms depending on the moisture content under which the process is conducted. Low moisture contents ( 64%) cause both aerobic and anaerobic decomposition. Higher reductions in parameters such as total solids (TS), volatile solids (VS), and chemical oxygen demand (COD), and higher oxygen utilization rates were obtained at moisture contents ne...

Abstract: Two composts were prepared from olive press cake (OPC) repeatedly turned and moistened with either olive mill wastewater (OPC+OMW) or water (OPC+W). When phytotoxicity was drastically reduced and the pH of the composts had reached 8.6 and 7.55 respectively, elemental sulfur was added at 0.9% of dry weight to the OPC+OMW compost and at five different doses (0.1 – 1.0% of dry wt) to the OPC+W compost. During the following six months, an exponential pH decline was observed in both compost materials. The pH reached a final value of 5.8 in the OPC+OMW compost whereas a pH decline related to the amount of added sulfur was observed in the OPC+W compost (final values from 6.8 to 4.3). Over 80% of the pH decline occurred during the first two months following the sulfur addition. Sulfur was applied following the stabilization of the material in the case of OPC+W. No phytotoxic effects of the final products were observed at sulfur application doses up to 0.5% of dry compost weight, but a significant germination inde...

Abstract: Experiments were conducted on calcareous and sandy soils to investigate the effects of organic amendments for vegetable production on groundwater nitrogen (N) concentration in south Florida. The treatments consisted of applying yard and food residuals compost, biosolids compost, a cocompost of the municipal solid waste and biosolids, and inorganic fertilizer. Nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), and total N concentrations were collected for a period of two years for both soils. Statistical analysis results revealed that for the three species tested, there were no significant differences among treatments. NO3-N concentrations for all treatments remained less than the maximum contamination level (10 mg/L). NO3-N transport to groundwater was higher in calcareous soil (mean=5.3 mg/L) than in sandy soil (mean=0.6 mg/L). NH4-N concentrations ranged from 0 to 13.6 mg/L throughout the experiment. Calcareous soil had lower NH4-N concentrations (mean=0.1 mg/L) than sandy soils (mean=0.7 mg/L). Total...

Abstract: Despite the commercialization of a variety of different composting systems, the design and operation of composting systems to minimize the cost of producing compost remains a major goal. Evaluation of how system design and management affects the time required to stabilize compost is critical to optimizing the process. In this study, analytical equations relating biological and physical factors and compost temperature, moisture, oxygen level and decomposition rates for aerobic composting are developed. The study focused on the effects of intermittent aeration on the composting operation. A multi-parameter kinetic model in conjunction with heat and mass balance equations were used to predict and optimize the performance of composting systems. Equations evaluating airflow and on/off fan cycle times on composting temperature, oxygen and moisture were developed. Kinetic data from pilot scale experiments using three different feedstocks: municipal solid waste, biosolids/woodchips, and grass/leaves/brush were us...

Abstract: Heavy metals are toxic and persistent pollutants that may be present in organic waste materials used as soil amendments. Following accumulation in amended soil, crop plants could assimilate these pollutants in sufficient concentrations to pose a threat to humans consumers. The Federal Clean Water Act and additional state regulations set minimum standards for heavy metals in organic amendments. Cumulative amounts of heavy metal pollutants that may be added to soils through amendments are regulated through national and state environmental protection agencies and the Federal Food and Drug Administration regulate maximum tolerances of heavy metal contaminants in food. The objective of the research was to study the effects of long-term organic amendment application on the accumulation of heavy metal pollutants in soil and subsequent contamination in pepper fruits. Organic amendments were applied yearly to replicate large plots during 1996 to 2000. Controls received no amendments. Different organic amendments were applied every year to simulate grower organic amendment availability throughout long-term application. Although higher levels of extractable Cd, Cu, Ni, Pb, and Zn were observed from amended soils during 1996 to 2000, all were within acceptable levels. Furthermore, no accumulation of Cd, Cu, Pb, and Ni was observed in pepper fruit. Therefore, long-term application of organic amendments made from waste materials with pollutant content below maximum acceptable levels under state and federal regulations should be suitable for vegetable production.

Abstract: The sludge residue from olive oil mill wastewater (OMW) evaporated in natural conditions in an open-air lagoon was cocomposted with tree cuttings (TC) in two mixtures, 48% of OMW sludge + 52% of TC (M1, C/N ratio, 30), and 58% of OMW sludge + 42% of TC (M2, C/N ratio, 26). The evolution and modification of properties occurring in the OMW sludge-TC mixtures at different stages of the composting process were evaluated by chemical analyses, including pH, electrical conductivity and contents of total organic C, total N, total extractable C and humified C fractions. Further, HAs were isolated from the mixtures by a conventional procedure based on alkaline extraction, acidic precipitation to pH 1, purification by repeated alkaline dissolutions and acidic precipitations, water washing, dialysis, and final freeze-drying. The HAs obtained were analyzed for elemental (C, H, N, S, O) and acidic functional group (carboxylic and phenolic) composition, and by ultraviolet/visible, Fourier transform infrared, fluorescenc...

Abstract: Seedlings of 'Candid Charm' cauliflower (Brassica oleracea L. Botrytis group) were grown in six different media comprised of varying proportions of a commercial peat-lite mix (PL) and a 50% yard trimmings -50% biosolids compost. A control of 100% PL was compared to treatments of PL:compost at 80%:20%, 60%:40%, 40%:60%, and 20%:80%) respectively by volume, and 100% compost. The experiment was performed twice. Electrical conductivity of the medium increased with increasing compost additions, while the carbon:nitrogen ratio was greatly decreased. Increasing proportions of compost blended with PL inconsistently affected medium pH. Seedling emergence was delayed when compost comprised the majority of the medium, but stands were not reduced except with 100% compost. Decreases in seedling height and dry weight began to occur in the 60% PL, 40% compost treatment and were more pronounced with higher amounts of compost. Seedlings grown in 80% PL, 20% compost were similar to those grown in 100% PL with one exception: the compost blend resulted in an increased seedling N concentration. While we cannot conclude that a 20% replacement rate is ideal, the 80% PL, 20% compost medium was horticulturally acceptable as an alternative to 100% PL for cauliflower transplant production.

Abstract: About 25 m3 of a poplar bark-poultry dung mixture were composted in a covered place with natural ventilation, air entering the lower part and going out through four shafts in the upper part. The gaseous emissions were measured and analyzed. The first heap (initial C/N of 28) was monitored for one month, then turned and more dung added. The second heap (initial C/N of 8) was monitored for seven months with two intermediate turnings. For the whole experiment, N losses were estimated at 61-74% of initial N, of which 62% was lost as NH3 (38-46% of initial N) and 1% as N2O (0.6-0.7% of initial N). N-NOx losses were 1000 times lower than N-N3 H3 losses. N2O and NOx were found only at the end of the periods before the piles were turned. As for carbon, C-CO2 emissions were estimated at 45-55% of initial C content, the ratio of CH4 to CO2 in the effluent air was 1 to 100 on average, with significant variations. The global warming potential of CH and N O was estimated at respectively 25% and 50% of total CO2 emissi...

Abstract: Assessment of phytosanitary risks associated with application of composts in agriculture generally has focused on the sanitation (self-heating) phase during composting when most plant pathogens are inactivated due to lethal temperatures. However, a few plant pathogens are heat resistant and they may survive a properly monitored and controlled composting process. To assess the phytosanitary risks associated with compost utilization, several additional factors need to be considered which all relate to a tracing-and-tracking principle. It includes the composition of the original waste and several aspects related to compost utilization. The following parameters are considered to be key-factors: 1) the proportion of host biomass relative to the total quantity of biowaste, 2) the proportion of host infected with a pathogen, 3) the density of infected host material, 4) the proportion of propagules of a pathogen that survived the process, and 5) the threshold density of a pathogen in soil above which disease of the host is expected to develop. While the first two parameters may be rather easy to estimate and information on survival of many plant pathogens can be obtained from the literature, little knowledge exists on the density of the pathogens in host materials or on threshold values. This applies particularly to virus diseases. The phytosanitary risk of several types of plant pathogens is discussed in some detail in this paper. Recommendations are given for testing of a composting process for phytohygienic safety.

Abstract: The wine industry in Catalonia (Spain) plays an important role in the economy of the region. In this framework, Miguel Torres S.A. is a well known company specializing in production of high-quality wines and brandy, which possesses its own vineyard. Two of the main solid wastes produced in this kind of industry are: stalk (waste from grape harvesting which is only produced during September and October) and wine sludge from the biological wastewater treatment plant which is steadily generated. A composting process was proposed to treat these two organic wastes for recycling its organic matter content to the vineyard crops. Experiments at laboratory-scale in static composting systems did not show positive results for different stalk:sludge mixtures due to the high moisture content of both wastes. Field composting experiments with windrow methods showed that the thermophilic range of composting could be achieved for a 2:1 stalk:sludge volumetric ratio resulting in a complete sanitation of the material with t...

Abstract: A laboratory-scale bioreactor was used to investigate the influence of inoculum size on the composting process of tomato remains-wood shavings mixture. Urea (as a nitrogen source) was added to correct the initial C: N ratio (30: 1). The average temperature in each bioreactor was strongly influenced by the size of inoculum. Maximum temperature of each mixture correlated with the reduction of Volatile solids (VS), total carbon (TC) and Total Kjeldahl Nitrogen (TKN). Volatile solids losses were in the range of 16.9-44.7 %, while total carbon losses were in the range of 9.4-28.4 % and TKN losses were in the range of 3.4-25.4 %. Neither the nitrogen nor the moisture content were limiting factors as the C: N ratio remained in the range of 28: 1 to 29: 1 and the moisture content remained within the optimum ranged of 57-61%. Carbon availability appeared to be the limiting factor in these set of experiments. Since wood shavings, which made 65% of the total mixture, contain no bioavailable carbon, another bulking a...

Abstract: Spatial differences in the physical and chemical characteristics of composted organic matter are strongly influenced by the composting method. We examined a traditional turned windrow (TW) treatment and two static passively aerated treatments (uncovered (SPA-U) and covered (SPA-C)) to determine spatial and temporal differences within and between treatments during composting of an animal waste-straw mixture. Temperature, moisture content, pH, respiration rate, C:N, mineral nitrogen and 15N were measured at three depths over a period of 176 days. All treatments met composting temperature criteria established by US EPA regulation 503. Covering piles for a short period elevated temperatures and may enhance thermal destruction of pathogens on and near the surface layer. The final C:N ratio was similar (10-11) between treatments and total C loss ranged from 40-45%. Total N concentrations increased about 20% during composting and there was no measurable loss of nitrogen from any treatments. SPA treatments tended...

Abstract: The compostability of degradable polyethylene under open windrow composting conditions is explored within this paper. Areas for consideration were the use of, and impacts of, degradable polyethylene sacks on the composting process and the quality of the finished compost product. These factors were investigated through tracking the polyethylene's weight loss over the composting process; the amount of polymer residue and chemical contaminants in the finished compost product; the windrow temperature profiles and a bioassay to establish plant growth and germination levels using the final compost product. Statistical analysis of the windrow temperature profiles has led to the development of a model, which can help to predict the expected trends in the temperature profiles of open compost windrows where the organic waste is kerbside collected using a degradable polyethylene sack.

Abstract: Liners of angelonia ‘Pink’ (Angelonia angustifolia Benth.), shooting star (Pseuderanthemum laxiflorum), coreopsis ‘Early Sunrise’ (Coreopsis grandiflorum Hogg ex Sweet.), and scutellaria ‘Purple Fountains’ (Scutellaria costaricana H. Wendl.) were transplanted into containers filled with, by volume, 1) 100% compost; 2) 60% compost, 25% vermiculite, 15% perlite; 3) 30% compost, 30% sphagnum peat, 25% vermiculite, 15% perlite; 4) 0% compost, 60% sphagnum peat, 25% vermiculite, 15% perlite. Two compost products were evaluated: SW, a 1:1 by volume mixture of partially composted seaweed and partially composted yard trimmings and SYT, a 1:1 by weight mixture of biosolids compost and yard trimmings compost. There was no difference in angelonia shoot dry mass among the different percentages of SW compost but angelonia plants grown in 0 and 30% SYT had greater shoot dry mass than plants grown in 60 or 100% SYT. Shoot dry mass of shooting star plants increased as the percentage of SYT compost increased from 0 to 30 ...

Abstract: Indigenous soil microorganisms contribute to disease suppression in cropping systems by reducing and competing with pathogen populations, thereby limiting disease severity. Various communities of indigenous microorganisms in any particular soil have adapted to the specific environmental conditions. If the soil around the plant roots could be altered to favor the indigenous soil microorganisms relative to the plant pathogen, the survival and proliferation of indigenous soil microorganisms, and thus effectiveness of biological control, may be increased. Wood chip-poiyacrylarnide (PAM) cores were used to alter the soil environment in a greenhouse study to favor indigenous soil microorganisms in vegetable and manure compost to reduce Verticillium dahliae infection of potato (Solarium tuberosum L.) plants. Potato plants growing in soils amended with vegetable compost-wood chip-PAM cores had significantly lower visible (V vi,) and isolation (V.so) dahliae infection rates than control soils and soils with dairy or vegetable compost alone. Soils amended with wood chip-PAM-dairy compost cores had significantly lower IC and isolation V. than control soils and soils with dairy compost. Soils with wood chip-PAM cores ana soils with wooirchipPAM-vegetable compost had greater microbial biomass/ Verticillium dahliae biomass (MB/ VB) ratios in soil than control soils or in soils amended with compost alone. MB / VB ratios in wood chip-PAM cores and wood chip- PAM-vegetable compost were greater than in wood chip-PAM-dairy compost cores. V correlated in a quadratic relationship with the MB /VB ratio (r 2=0.76). As MB /VB ratio increased Although field studies with several crops and economic evaluations are necessary, this greenhouse study provides evidence that a wood chip-PAM or wood chip- PAM-vegetable compost soil amendment may be a viable method to control some soil diseases in high value crops.

Abstract: The objective of this study was to evaluate the effects of a soil conditioner, prepared from food wastes, on soil microbial activity, soil nutrient levels, and melon (Cucumis melo reticulata) growth and yield. Food waste, generated from a residence dining hall, was fermented with and without a microbial inoculant for 20 days. The resulting soil conditioners were incorporated into soil (Mexico silt loam) by tilling to a 15-cm depth using a rotary tiller. Melon seedlings were transplanted three weeks after soil amendment. Soil nutrient levels and microbial activity were monitored periodically during the growing season to detect effects of the soil conditioners on soils and plant growth. Fruit weight per plant was significantly (P≤0.05) increased with the microbially-inoculated soil conditioner compared to the control in both years, but was not different from the non-inoculated soil conditioner in 2000 or the fertilizer treatment in 2001. Soil conditioners produced from food wastes inoculated with selected m...

Abstract: The experimental trials on dead animal composting have been carried out on a poultry farm, using cereal straw and solid hen manure. Other farm wastes such as cardboard and nonmarketable eggs were also included in the last three trials. Eight trials have been conducted on a real-life scale, in the open air and at different times of year using a simple pile system. The pile was moistened with water or with liquid hen manure from a nearby manure lagoon, as necessary. The ratios straw/hen manure and (straw + hen manure)/dead poultry used in the different piles ranged between 4/1 and 5/1 for the first one and 8/1 and 2/1 for the second one. In all trials two clearly different stages were observed. A primary stage where high temperatures (53-66 °C) within the curing pile were reached and the poultry mortalities were completely degraded while straw was only partially degraded. No turnings were made in this stage. The secondary stage used a standard dynamic pile system with turnings and watering. A device was fit...

Abstract: Manure in coldwater aquaculture production systems is typically settled in quiescent zones created within raceways to concentrate it prior to being pumped to storage in off-line settling basins. As the water passes through the off-line settling basins, the solids settle out and the excess water is discharged to surface water. Since the basins are not frequently emptied, the organic solids mineralize and nutrients flow out of the basins with the surface water discharge. A system was tested to remove solids from settling basins frequently and treat by mesophilic composting. Two carbon (C) sources (wheat straw or oak sawdust) were evaluated. Manure was applied to beds of carbon sources at a rate of about 1cm of arctic char manure (8% solids) every 10 days using a vacuum tank spreader modified for side discharge over the plots. The open and porous structure of wheat straw resulted in several advantages over the oak sawdust; there was not runoff during application even during freezing winter temperatures when the oak sawdust compost was frozen solid, aerobic conditions were maintained with lower amounts of C, and decomposition rates were higher resulting in less time needed to reach stability (about 90d vs. 140d). Inorganic nitrogen (N) increased as the organic matter decomposed with either C source. Mineralization and nitrification rates were higher with wheat straw. Water-extractable P decreased as the organic matter from both C sources decomposed. Land requirements are about 0.001 ha to compost the manure for each 1 Mg Arctic char produced annually, but could be significantly higher for the wheat straw since experimental loading rates were limited by the reduced capacity of the oak sawdust compost. A layered mesophilic compost system may be a viable manure management system to store and treat manure and replace long-term storage in off-line settling basins for fish farmers. In this system, solids would continue to be settled in the off-line settling basins but pumped onto straw nearby for storage and stabilization on land thereby minimizing discharge of nutrients to surface water.

Abstract: To study the carbon mineralization of pruning waste compost, four samples originated from pruning waste, leaves and grass clippings were collected each from a different pilot pile at different stage of the composting process: initial nondecomposed material (C1); two-months old at the end of the biooxidative stage (C2); seven months old during the curing phase (C3) and 12 months old at the end of the curing phase (C4). The CO2-C evolution was measured during 56 days of aerobic incubation. The proportion mineralized from the different composts (% of compost TOC) during the incubation period were: 4.54, 2.43, 1.71 and 1.60 for C1, C2, C3 y C4, respectively. Regardless of compost age, C mineralization occurred in two phases: a first rapid phase (corresponding to the decomposition of the most labile products by microorganisms) and a second, slower phase, during which the most resistant organic products mineralized. During the first stage, the model was fitted to a first-order equation, whereas in the second ph...

Abstract: The potential of Community Level Physiological Profiles (CLPPs) as a compost maturity test is significant, given the sensitivity and the simplicity of the assay. Nevertheless, application of the technique to compost requires more methodological work because of the fast changes in physicochemical and microbiological properties and the dependence of the rate of color development on the inoculum density. The aim of this work was to investigate the reliability of a new approach to standardize inoculum density and the effects of different data interpretation and storage conditions on CLPPs of compost samples with different degree of stabilization. Compost samples (fresh, air dried, frozen and air dried-rewetted) with different degree of stabilization were extracted with a two-batch procedure and then inoculated on Biolog Ecoplates. Standardization of inoculum density was performed according to microbial biomass content determined by substrate induced respiration (SIR) on fresh samples. Microplates were incubat...

Abstract: The purpose of this research was to investigate the compostability of waste residuals from a strawboard manufacturing facility. Phase 1 used bench-scale reactors to compost various recipes using three feedstock materials (straw, process unders, and livestock lagoon sludge) at different moisture levels for a nine-week period. Water addition and the addition of unders to tbe compost mixture increased degradability. The livestock lagoon waste did not significantly improve degradability. Phase 2 focused on tbe straw feedstock, investigating tbe effects of straw particle size using four unsbredded:shredded straw ratios (by volume): 100:0; 67:33; 33:67; and 0:100. The recipes were composted in 140 L rigid plastic containers for a period of 180 days at a moisture content of 70% (wet basis). Volatile solids (VS) and lignocellulose degradation was greatest for recipes containing both shredded and unsbredded straw, with tbe recipe containing 67% shredded straw performing the best (35%. VS removal). Pure unshredded and shredded straw bad VS reductions of 29%- and 26%, respectively. Total volume reductions ranged from 80 to 90%. Hemicellulose was completely degraded for all recipes by day 95. By day 180 cellulose content had decreased from 3.75 to 0.75 g/g ash for all four recipes. By day 180, lignin degradation was greatest for recipes containing botb shredded and unsbredded straw (reduction from 1.0 to 0.4 g/g ash) while lignin content decreased from 1.0 to 0.6 g/g ash for the other recipes. It was concluded that recipes containing a mixture of sbredded and unshredded straw provided better composting conditions.

Abstract: High concentrations of atmospheric ammonia (NH3) can impact poultry and human health. During composting inside high-rise, caged layer facilities, high concentrations of NH3 are produced due to low carbon to nitrogen ratios of composting materials and the confined building environment. This study characterized the spatial and temporal variability of NH3 during in-house composting as a preliminary step to identifying control measures. Boric acid solutions and gas sensors were used to measure NH3 in 2 m × 7.5 m grid patterns for three high-rise laying hen structures during composting. Spatial variability was evident in all buildings, with areas of higher NH3 concentration near the center of buildings away from ventilation fans. Ammonia concentrations in the composting area frequently exceeded human health standards for 8-hour and 10-minute exposure periods of 25 and 35 μL L−1, respectively. Ammonia concentrations were lower in cage areas of high-rise structures due to the negative pressure ventilation system...

Abstract: Municipal solid waste (MSW) has for decades been processed into compost. Community collection of residential trash of various degrees of separation followed by some form of presorting, tumbling or batch processing along with aerated static or mechanical-turned windrowing are typical in the industry. A significant portion of MSW is plastic or synthetic material including woven polyester and polyethylene materials that may easily reduce into fine fragments. European studies in the 1980's indicated significant contamination as a result of mixing and grinding which caused metals and glass to become reduced and enter the fine compost fraction. The results of these early studies provided impetus towards source separation, nongrinding of initial MSW and later introduction of novel biodegradable plastics and natural polymers to replace plastic content for collection of household organics. The present study was conducted using several mixed waste compost streams from archived lab samples taken recently from across...

Abstract: Composting inside high-rise, caged layer facilities can produce atmospheric ammonia (NH3) concentrations exceeding standards for human and poultry health. Control measures that reduce NH3 volatilization are necessary for in-house composting to be sustainable. Due to differences specific to in-house composting — low carbon to nitrogen ratios of composting material, continuous manure addition, and frequent turning — it is not known whether NH3 control measures used previously for poultry manure will work. The objectives of this study were to evaluate various amendment and process controls on NH3 produced during simulated in-house composting in the lab, and to evaluate select chemical control measures during composting inside a high-rise layer facility. Ten amendments (aluminum sulfate; chloride salts of aluminum, calcium, magnesium, and potassium; gypsum; sodium bisulfate; zeolite (clinoptilolite); straw; and cellulose) and four process controls (moisture; temperature; turning frequency; and particle size) ...