Yard Waste Composting with Heat Recovery

? The feasibility of yard waste composting in a closed continuous reactor with heat recovery has been investigated. Results obtained in this research are reported and discussed. In the system, the recovered energy (heat) can be transformed by a heat pump in hot water both for domestic and for residential heating. The organic fertilizer produced can be used in horticulture.     

Economic Analysis of Composting Crab Processing Waste

A study of composting crab processing waste (CPW) was performed to identify a cost-effective alternative to landfilling. If CPW could be economically recycled into a useful value-added product, the waste would not have to go to landfills, and could be sold commercially to the landscaping and nursery industries. Economic models of three systems were constructed and analyses performed using a variety of investment and operating costs. To ensure robust model analysis, several factors of the cost components were varied. The equivalent-uniform-annual-costs were used to compare the alternatives, Ag-Bag, windrowing, and landfilling the waste. Profit analysis was also performed for each of the proposed systems. The average annual cost for the processes of Ag-Bag 1, Ag-Bag 2, and windrowing was $62,903, $73,796, and $53,533 respectively. While none of the methods analyzed were profitable, windrowing results in the smallest loss of $?0.066/kg ($?63.08/ton) for all economic models considered, followed by Ag-Bag 1 with an average loss of $?0.107/kg ($?100.18/ton) and Ag-Bag 2 with an average loss of $?0.117/kg ($?109.80/ton). Although having the least loss, windrowing has drawbacks such as offensive odors. A sensitivity analysis to determine how much additional throughput would have to be utilized to create a profit was performed. This analysis found that the windrow system is the only system capable of ever garnering a profit, with a total throughput exceeding 1,003 tons/year. Under current market conditions, composting CPW by one of the systems described herein is not feasible.     

Composting Food Processing Waste in the European Economic Community

For more than half a century, large food processing companies, faced with mounting solid waste disposal problems, have opted for landfilling. Other options, concentrating on utilization, are now being increasingly explored. Energy recovery (ethanol and methanol) and fodder production from food processing residuals in some cases are valid solutions. Of the many alternatives to food recovery waste disposal, composting seems to be an effective method. Managed properly, research has shown that composting can produce a nutrient-rich soil amendment; odors can be controlled during the transformation process and in the final product. The process is competitive and cost-effective environmentally, completes the biological chain and returns to the soil what has been taken from it. For these reasons, composting seems to be the best candidate to solve problems connected with food factory waste disposal.     

园林废弃物堆肥红外光谱特性分析

以添加不同外源物质的园林废弃物为研究对象,采用近红外光谱分析方法跟踪测定不同堆肥阶段园林废弃物堆体中近红外光谱变化,结合堆体温度变化,探讨外源添加剂对堆肥物质结构转化影响。结果表明:单独添加腐殖酸处理(FZS)、复合添加EM菌剂和腐殖酸处理(EM+FZS)、复合添加京圃园菌剂和腐殖酸处理(JPY+FZS)以及无添加处理(CK)堆体物质转化机制相同,即随着堆肥进行,蛋白质,碳水化合物,脂肪类物质不断减少,物质芳构化程度提高,外源添加剂不影响堆肥物质转化顺序。不同外源添加剂处理红外光谱特征峰吸收频率位置基本一致,但特征峰吸收强度有所变化,说明不同外源添加剂堆肥物质中含有相似的官能团,但官能团数量与物质结构不同,外源添加剂对堆肥分解速率,分解程度以及堆肥产物芳化度均有影响。京圃园菌剂与腐殖酸复合施用(JPY+FZS)能够显著加速物质转化进程,提高堆肥产品芳化程度,更适宜应用于园林废弃物堆肥。     

Recycling of Remediated Soil for Effective Composting Of Diesel-Contaminated Soil

Soil contaminated with diesel oil was remediated by the addition of remediated soil. Several mix ratios of contaminated soil to remediated soil were tested. Judging from TPH degradation rate and biochemical parameters, the optimum mix ratio (wet weight basis) was 1:1. In this mix ratio, the first order degradation rate constant of diesel oil based on TPH was 0.099/day. Degradation rate of TPH and total amount of CO₂ evolved in this condition were two times larger than those of contaminated soil without adding remediated soil. The addition of remediated soil was a very effective treatment option to facilitate the degradation rate of diesel oil in contaminated soil.     

Management of Cassava Starch Factory Solid Waste (Thippi) through Composting to a Nutrient-Rich Organic Manure

In India, cassava cultivation is confined in South India. In Tamil Nadu, tubers are used as raw material for starch and sago industry. About 8–10 large-scale starch factories and 150–200 small-scale starch and sago production units are generating nearly 40–60 tonnes of solid waste (thippi) per annum creating serious environmental pollution. A study undertaken to manage it through composting to a nutrient-rich organic manure revealed thippi as acidic with low major and micronutrient concentration, high water-holding capacity, good porosity, low bulk density, high starch, fiber, low protein, and cyanide. Composting of thippi with different combinations of raw materials, microbial cultures, and earthworms indicated that thippi enriched with gliricida and cassava leaves and composted with earthworm had the highest nutrient concentration with narrow carbon to nitrogen (C:N) ratio. The mean concentrations of N, phosphorus (P), potassium (K) calcium (Ca) and magnesium (Mg), iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in thippi compost were 1.32, 3.82, 0.40, 2.18, 0.96, 1.11, 0.08%, 11.23, and 89.93 mg/kg, respectively, which is 3.5, 49,7, 32.5, 8, 185, 100, 2.5, and 12 times than thippi. Thippi compost had low bulk density, starch, without fiber and cyanide but high protein suggesting this protocol as a possible alternative for the management of thippi.     

A Kinetic Model of the Yard Waste Composting Process

A new kinetic concept was applied to the yard waste composting process. Yard waste mixtures with different fractions of grass clippings were composted in pilot-scale vessels. Ammonia emissions were highest with high fractions of grass clippings. Calculation of reaction rate constants was based on heat and materials balances. Although the compost mass ratios (a dimensionless number that describes how far the process has advanced) of the mixtures after composting were similar, their chemical and biological analyses reveal differences. A first order reaction model is presented that can be used for plant design. The effects of temperature and particle size on process kinetics need to be investigated further.     

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 Food Waste and Waste Paper with Top soils for Nitrogen Catching

Abstract

Food waste, waste paper and different topsoils were composted in different experiments. The composts were characterised by high contents of N, P, S, Na and K in the food waste, of Mg in the soil, and of Ca in paper and soils. The nitrogen catching was between 50 and 70% of the input. The lowest amounts were caught in the composts with sandy soils, the highest in a clay soil with high ignition loss.     

Intermittent Aeration for In-vessel Composting Of Crab Processing Waste

A crab processing waste/wood shaving mixture was composted in-vessel with four intermittent aeration strategies. The composting process was monitored to assess the efficacy of the aeration methods. Temperature, moisture content and volatile solids of the compost were monitored along with the interstitial oxygen concentration. There was no significant difference in temperature profiles between constant frequency aeration and temperature feedback controlled aeration methods. An increased frequency of aeration resulted in significantly more drying than the less frequent aeration using the same total air volume. Results indicated that air volume could be reduced after the first five days of composting, and the in-vessel composting retention time could be reduced to 15 to 17 days for odor and vermin/vector problems prevention.     

Windrow Composting of Waste Paint Sludge Containing Melamine Resins

ABSTRACT

Melamine resins (MR), widely used in various industries, are thermosetting plastics that have hard and durable properties. These resins can be introduced into the environment as components of waste products or via industrial effluents. It is important to seek environmentally friendly means to recycle, remove, or degrade melamine resins before they are released to the environment. Waste paint sludge containing MR has been shown to be efficiently composted under bench-scale conditions. In this study, the impacts of C/N ratios on windrow composting of waste paint sludge containing MR were evaluated. As composting proceeded, temperature, concentrations of MR and melamine degradation products (i.e., ammeline, ammelide, and cyanuric acid) were determined. After 98 days of composting, 87.5, 83.3, 80.9, and 70.1% of the initial MR were degraded under the treatments with C/N ratios of 30, 33, 35, and 37, respectively. Degradation of MR was enhanced by relatively low C/N ratios. Significant amounts of plant nutrients were found in the final composts, while heavy metals were well below values considered to be of concern regarding surface water quality or crop production. We conclude that adjusting C/N ratio to approximately 30 in the initial mixtures with oat and hay straws can increase the degradation of MR and its derivatives during windrow composting of waste paint sludge containing MR and produce a good quality compost product.     

Impact of Composting Food Waste with Green Waste on Greenhouse Gas Emissions from Compost Windrows

Windrow composting of green waste as an alternative to green waste disposal in landfills requires an understanding of the impacts on greenhouse gas (GHG) emissions and the development of effective and efficient management strategies to reduce these emissions. The addition of food waste to green waste compost operations is becoming more common, but its effect on GHG emissions is less understood. As more food waste diversion occurs as a result of recent implementation of climate smart policies in California, more information is needed to address the sustainability of composting different combinations of waste types. We monitored GHG emissions from compost windrows comprised of green waste alone and a green/food waste mixture (green waste : food waste = 9:1, by wet weight) at the University of California, Davis Student Farm in 2016 using a modified, open, flow-through chamber technique. When comparing total emissions of nitrous oxide (N₂O) and methane (CH₄), the green/food waste mixture produced 110?kg CO₂ eq./ton DM (dry matter, std error = 12.2), which were slightly lower than emissions produced by the green waste alone (152?kg CO₂ eq./ton DM, std error = 15.9). Methane was a large contributor to global warming potential (GWP) of both composting treatments, suggesting that management practices that optimize porosity and air flow in compost piles are promising in reducing emissions from both green waste and green/food waste mixtures.     

Composting Olive Mill Waste and Sheep Manure For Orchard Use

An industrial-scale composting plant has been designed for producing organic fertilizers from olive mill waste using the windrow pile system. Materials to be composted, two phase olive mill waste (TPOMW) and sheep litter (SL), were characterized and made into three piles consisting of different proportions of each. Throughout the composting process, temperature (T), moisture (M), organic matter (OM), total organic carbon (C_org), total nitrogen (NT), germination index (GI), pH and electrical conductivity (EC) were monitored. The potential agronomic value of the final composts was ascertained by analyzing the bulk density, OM and Corg concentration, pH, EC, macro and micronutrient content (N, P, K, Ca, Mg, Fe, Cu, Mn, Zn, B), the concentration of humic and fulvic acids and inorganic nitrogen (NH₄⁺,NO₂^?,NO₃^?). Each compost was applied to an area of one hectare within a six year-old olive plantation. Four months after application, the soils showed an increased OM concentration and cationic exchange capacity (CEC).     

Composting of Yard Waste and Wastewater Treatment Plant Sludge Mixtures

Composting of yard waste and sludge/yard waste mixtures was investigated during laboratory and field testing. A strong correlation between moisture content and windrow peak temperatures was observed. Odors were detected at cocomposting windrows when temperatures exceeded 54°C. The sludge to yard waste mixture ratio was found to affect resulting compost particle size and, consequently, oxygen transport. Compost quality was excellent, with pesticides below detection level and low concentrations of heavy metals.     

Recycling of Spent Mushroom Substrates by Aerobic Composting to Produce Novel Horticultural Substrates

The mushroom industry in the United Kingdom, the country's second largest user of horticultural peat, considers it important to examine alternative materials. Reflecting this objective, a series of trial were conducted to examine whether SMS could hygienically and rapidly be recomposted and reused as a peat alternative for mushroom casing. Alternative horticultural uses of recomposted SMS, such as greenhouse crop substrates, also were considered. Analyses were conducted on leaching, physical and chemical factors, mushroom yields, disease generation, and the economics of different approaches.     

竹炭添加对厨余垃圾好氧堆肥过程的影响

为了探讨竹炭对厨余垃圾好氧堆肥过程的影响,向厨余垃圾添加稻草调节堆肥原料初始含水率为70%后,分别添加0%和5%的竹炭(竹炭与堆肥原料湿基比)进行为期15 d的好氧堆肥,研究了堆肥过程中堆体温度、厨余垃圾和稻草有机物降解率及堆肥腐熟程度的变化。结果表明:竹炭的添加增加了厨余垃圾好氧堆肥高温(> 55℃)持续时间,且高温阶段的前4天,添加5%竹炭堆体温度都明显高于对照;竹炭的添加提高了堆肥过程中有机物的降解率,堆肥结束时,与添加5%竹炭堆体其厨余垃圾和稻草的有机物降解率分别比对照提高了20.6%和29.2%,表征腐熟化程度的SUVA254和SUVA280值分别提高了15.6%和12.4%。以上结果表明,竹炭的添加促进了厨余垃圾堆肥过程有机物的降解,提高了堆肥产品的腐熟程度。     

Optimization of Medlar Pruning Waste Composting Process by Cattle Manure Addition

In this study, medlar pruning waste (MPW) was composted with and without cattle manure (CM). Two piles were prepared: one contained only MPW (pile 1) and one contained MPW augmented with CM (pile 2). Both piles were composted in an enclosed composting vessel with passive aeration and aeration by turning. During the composting process, temperature, pH, electrical conductivity (EC), organic matter (OM), OM losses, total organic carbon (C_org), total nitrogen (N_T), C_org/N_T ratio, and germination index (GI) were measured. Pile 2 produced a faster increase of the temperature and had a longer thermophilic phase than pile 1. However, the rate of OM degradation was faster in pile 1 than in the pile containing CM (pile 2). The addition of CM also resulted in an increased pH and salt content. In both piles, C/N ratio decreased throughout the process, presumably as a result of the faster organic carbon degradation compared to N mineralization. However, only pile 2 had a final C/N ratio <20, the limit accepted for compost by the Spanish legislation on fertilizer. Also, both composts had GI > 50 percent, indicating an absence of phytotoxicity.     

垃圾好氧堆肥渗滤液与填埋场渗滤液的比较

通过以配制的城市垃圾和实验室堆肥装置,通过12d的堆肥,研究好氧堆肥渗滤液的成分,将其与新填埋渗滤液、成熟填埋渗滤液以及世界卫生组织标准（1984年）进行详细的比较。结果表明：堆肥渗滤液呈碱性,大于新填埋场和成熟填埋场渗滤液的pH;COD、NH4^＋ -N和BOD5等参数对比说明了一次堆肥过程较新填埋场发酵过程成熟,但没有成熟填埋场发酵更彻底;堆肥渗滤液是一种有机营养的废水,同时富含大量的微生物。     

废弃烤烟茎秆与鸡粪堆肥化利用的研究

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