Small-Scale Composting of Horse Manure Mixed with Wood Shavings

There is an increased interest in composting manure on small horse farms (1-5 horses). It is known that simple backyard, food waste composters do not efficiently reduce pathogens due to their small scale. However, it was not clear if small-scale manure composting on horse farms could ensure pathogen reduction during all seasons. Furthermore, because of potential human health concerns, the release of Aspergillus fumigatus on small horse farms was of interest. The objective of this study was to evaluate pathogen reduction in a simple shed composter and the release of Aspergillus fumigatus emissions from fall to spring under typical farm operational conditions. Horse manure mixed with wood shavings (bedding) was composted for 4-8 weeks in the fall, winter, early spring and late spring. Fecal streptococci and eggs of strongyles, which are a major recognized health concern for horses, were used as pathogen indicator organisms. Temperatures increased in all composting piles during all seasons, but tended to be higher in warmer weather. After 4 weeks, the fecal streptococci reduction was about 10- to 100-fold and, after 8 weeks, about 100- to 1000-fold. There was some effect of season on fecal streptococci levels, with the higher composting temperatures appearing to provide greater reductions. Strongyle eggs in this study were very low and were reduced over time. Levels of viable A. fumigatus spores during turning ranged from 12-2084 CFU m^?3, while background levels ranged between 6 - 300 CFU m^?3. Overall, this study indicates that composting horse manure mixed with wood shavings reduces pathogens. A. fumigatus levels are elevated during turning, but the levels are lower than those found at sewage sludge/municipal solid waste composting facilities or inside barns.     

End Product Quality and Agronomic Performance of Compost

Washington State University produces a manure-based compost of high pH (>8) and low N content (1 percent) by windrow composting campus wastes. Annual production at the four-acre facility is 18-20,000 cubic yards. In the interest of producing compost of higher N content and lower pH, ten experimental piles were constructed to investigate the effects of different feedstocks on the composting process, end quality and agronomic performance. Biosolids and manure were compared at two rates of bedding both with and without coal ash. Compost temperature and inorganic N content during 96 days of active composting are reported along with end product nutrient analysis and metal concentration. The composts behaved differently based on the N feedstock and level of bedding in the mix. Compost quality was influenced by the characteristics of the feedstocks. Applying the composts to an eroded hilltop (50 Mg/ha) increased winter wheat yield, but there were no differences among the ten composts.     

A Comparison of Different Bulking Agents for the Composting of Fish Offal

An experiment comparing the effectiveness of three different bulking agents in the composting of fish processing wastes was carried out using small-scale composters operated at ambient temperatures. Fish offal was mixed with each of peat moss, sawdust and wood shavings in a 5:1 ratio by weight. The mixed materials were left undisturbed in the composters for an initial 55 days. They were then mixed and reloaded into their respective composters for a further 95 days of composting. Temperatures were monitored throughout the experiment, while serial physical and chemical analyses of the compost materials were initiated after the mixing. Headspace-gas chromatography was also used to determine the levels of phytotoxic organic acids and phenol. All the compost piles reached thermophilic temperature levels (40–70°C). Due to insufficient pile mass, temperatures over 55°C were not sustained for a sufficient length of time to satisfy the EPA requirements for pathogen reduction. The temperature profiles suggest that ambient temperatures near the freezing point can significantly influence the temperature of compost piles with volumes of 63 liters or less. The results reaffirm the potential of composting as a viable option for utilizing fish processing wastes and the suitability of peat moss, sawdust, and wood shavings as bulking materials. The physical and chemical qualities of the 150-day old composts were comparable to other seafood compost products. Peat moss gave the best results in terms of nitrogen conservation, but is the most expensive option. Monitoring the concentrations of phytotoxic organic acids and phenol using headspace-gas chromatography proved to be a useful method for establishing compost maturity.     

Assessing How the Ratio of Barley Mash to Wood Chips in Compost Affects Rates of Microbial Processing and Subsequent Vegetable Yield

The composting of food waste coupled with urban agriculture presents an opportunity to increase nutrient recycling in urban ecosystems. One potential constraint limiting the expansion of aerobic food waste composting is the availability of carbon-rich recalcitrant materials, such as wood chips. We measured the differences in nutrient retention throughout the compost life cycle for different mixtures of barley mash to wood chips, to assess whether composting using proportionally less wood chips would lead to higher nutrient recycling rates. Nine compost piles (1 m³) were constructed at varying ratios barley mash to wood chips, ranging from 10:90 to 90:10. During the composting process, the 50:50 mixture maintained internal temperatures above 55°C for 30 days, with drop-offs as mixtures diverged in either direction. Food waste content was positively related to internal moisture and CO₂, and negatively related to internal O₂, throughout the ensuing 3 months. The finished compost was used in raised-bed garden plots during the following summer. Yields of arugula and tomatoes increased with compost barley mash content, saturating at high levels. Across all treatments, <5% of N and <2% of P were recycled from barley mash into new vegetable production. Although the maximum amount of nutrients was recycled using high barley mash compost, these treatments also had lower nutrient recycling efficiency compared to intermediate mixtures. These results indicate that the use of wood chips in composting increases the efficiency nutrient retention from food waste and in turn enhances nutrient recycling in urban environments.     

Recycling of Two-Phase Olive-Mill Cake “Alperujo” by Co-composting with Animal Manures

The use of poultry manure or goat/sheep manure in the co-composting of the two-phase olive-mill cake “alperujo” (ALP) with olive leaf (OL) is compared by studying organic-matter mineralization and humification processes during composting and the characteristics of the end products. For this, two different piles (P1 and P2) were prepared using ALP with OL mixed with poultry manure (PM) and goat/sheep manure (GSM), respectively, and composted by the turned windrow composting system. Throughout the composting process, a number of parameters were monitored, such as 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 the germination index (GI). In both piles, the temperature exceeded 55 °C for more than 2 weeks, which ensured maximum pathogen reduction. Organic-matter losses followed a first-order kinetic equation in both piles. The final composts presented a stabilized OM and absence of phytotoxins, as observed in the evolution and final values of the C_org/N_t ratio (C_org/N_t < 20) and the germination index (GI > 50 percent). Therefore, composting can be considered as an efficient treatment to recycle this type of waste, obtaining composts with suitable properties that can be safely used in agriculture.     

The Effect of Different C/N Ratios on the Composting of Pig Manure and Edible Fungus Residue with Rice Bran

The aim of this study was to determine the effects of initial C/N ratio (16.3, 19.1, 24.1, and 29.6) on decomposition rate and nitrogen loss during the composting of pig manure and edible fungus residue with rice bran. The results showed that all composting piles reached a temperature greater than 55°C for at least 7 days (which meets the requirements for destroying pathogens), and the maturity times of composts with low initial C/N ratios were shorter than in composts with high initial C/N ratios. The nitrogen loss in the composting pile with initial C/N of 16.3 was significantly higher than the other treatments. Furthermore, the statistics analysis showed that the initial C/N ratios of the composts, which varied from 16.3 to 29.6, had a significant negative linear correlation with the loss of total organic matter (R = ?0.9661) and loss of total nitrogen (R = ?0.9365). Therefore, for treating more agricultural wastes and achieving high-quality final product as well as the reduction of nitrogen losses, this study recommends that initial C/N ratios ranging from 20 to 25 are suitable for composting pig manure and edible fungus residue.

Highlight:

Various agricultural wastes can be successfully composted with initial C/N ratios 16:1–30:1.

Nitrogen loss had a significant linear negative correlation with the initial C/N ratio.

Compost with a low C/N ratio was beneficial to dispose of more pig manure since reducing the addition of carbon materials.     

木质纤维降解复合菌剂促进堆肥腐熟研究

利用工厂化高温好氧堆肥方式,探究了具有高效降解木质纤维能力的微生物复合菌剂分别对纯秸秆和秸秆畜禽粪污混合物堆肥效率的影响。以纯秸秆和猪粪秸秆混合物为原料,设置空白对照、单菌处理和复合菌处理,评估堆肥过程中不同堆体温度、含水量、pH、有机质含量、发芽指数和养分等理化指标的变化对堆体腐熟效率的影响。结果表明,无论何种堆肥原料,相比空白和单菌处理,复合菌处理堆体均升温速率最快,高温期温度最高,后熟期降温最快。堆肥过程中,各处理p H无显著差异,变化趋势基本一致;各处理发芽指数(GI)不断提高,纯秸秆和秸秆粪污混合物为原料的接复合菌处理均在第25天高于接单菌处理,至堆肥结束时,接复合菌处理的发芽指数分别为93.45%和98.67%;随堆肥的进行,各处理有机质含量均处于下降趋势,至堆肥结束时,所有处理的有机质含量均高于450 g/kg;各处理的全氮、全磷、全钾含量在堆肥结束时比堆肥初始均有所增加,至堆肥结束时,以纯秸秆和秸秆粪污混合物为原料的接复合菌处理的总氮和总磷含量均显著高于其他处理。综上,相比于不添加外源菌和添加单一菌株,高效木质纤维降解复合菌剂的添加,能够有效促进堆肥的腐熟,提高堆肥效率。     

立式筒仓反应器堆肥技术工艺优化研究

反应器堆肥技术作为一种新型快速堆肥方式逐渐被人们所认可，该技术包括反应器堆肥处理和陈化两个阶段，但反应器堆肥时长和通气方式等工艺参数对堆肥全过程的影响尚不清楚。因此，本研究立足生产中的实际问题，利用12 m³立式堆肥反应器，开展了反应器堆肥工艺优化调控试验，以鸡粪和锯末为原料，分别研究了连续供气和间歇供气（风机开3 min，关7 min）两种供气方式下，反应器处理周期对堆肥有机质降解率、产品含水率、氮素损失和运行成本的影响。研究结果表明：反应器堆肥10 d比2 d的处理物料有机质降解率分别增加60.7%（间歇）和66.2%（连续），产品含水率分别降低41.2%（间歇）和40.7%（连续）。反应器堆肥阶段是物料降解的主要阶段，利用反应器堆肥的时长越长，堆肥产品生产时间越短；但运行成本的增加也对反应器堆肥时长造成了限制，同时增加反应器堆肥时长也会增加堆肥物料的氮素损失，其中连续供气反应器堆肥10 d比2 d氮素损失增加17.5%。连续供气方式可提高堆肥效率，较间歇供气处理堆肥周期平均缩短32.1%，产品全氮含量平均提高7.4%，虽然反应器堆肥阶段每日能耗较间歇供气高20.2%，但堆肥周期的缩短使全程连续供气平均运行成本降低16.5%。其中，连续供气下反应器中处理6 d、8 d和10 d，堆肥产品理化性质无显著差异。综合考虑堆肥效率、产品和经济，本试验建议选择“连续供气方式+反应器内堆肥8 d”处理，既可提高反应器堆肥处理效率，在实际生产中又具有较高的经济效益潜力。     

添加菌糠对鸡粪-烟末堆肥腐熟度及污染气体排放的影响

为探索鸡粪-烟末混合堆肥体系合适的菌糠投入量,减轻堆肥过程中污染气体的排放,通过35 d的堆肥试验,设置3个菌糠投入量[0(CK)、5%、10%],研究鸡粪-烟末堆肥条件下添加菌糠对堆肥腐熟度和污染气体排放的影响。结果表明,堆肥处理堆体温度均能在55℃持续8 d以上,达无害化标准。与CK相比,添加5%、10%菌糠处理堆肥产品对作物生长无毒害作用,腐熟度得到有效改善,但均未达到腐熟标准;添加5%菌糠处理总有机碳(TOC)损失降低了2.39个百分点,总氮(TN)损失降低了8.92个百分点;添加10%菌糠处理TOC损失增加了0.27个百分点,但TN损失降低了11.89个百分点。综合考虑堆肥腐熟度、碳氮损失和环境效应,添加菌糠作为膨松剂能够提升堆肥腐熟度并减少污染气体排放,更有利于农业废弃物肥料化的可持续发展。     

菌剂DF-1对啤酒厂污泥与鸡粪堆肥的影响

为了探讨功能性菌剂对堆肥化进程的影响,并为加快啤酒厂污泥与鸡粪堆肥化进程和减少臭气提供理论依据,将自制菌剂DF-1接种至啤酒厂污泥与鸡粪的堆体中,以不接种堆体为参照,测定了堆肥化过程中各参数的变化及菌剂DF-1中优势微生物变化情况。结果显示：两个堆体废气中NH3浓度均呈现先上升后下降的变化趋势,H2S浓度则呈现持续下降的变化情形;不接种堆体NH3浓度至堆肥腐熟期仍为0.39 mmol/m3,而接种堆体第10天为1.25 mmol/m3,此后无法检出;不接种堆体中H2S浓度在堆肥第22天仍为0.7 mg/L;而接种菌剂堆体第10天为0.48 mg/L,此后无法检出。接种菌剂DF-1不但能降低堆体水分含量,而且其堆体腐熟期TN含量高于未接种菌剂DF-1的堆体,说明接种菌剂后不但能有效减少臭气,而且有利于堆肥产品后期烘干制粒和优质高效有机肥的产生。菌剂DF-1中优势菌种乳酸乳球菌、热带假丝酵母及绿色木霉在堆肥过程中存在交替演变。     

微生物菌剂对猪粪堆肥过程中堆肥理化性质和优势细菌群落的影响

  【目的】  掌握猪粪堆肥过程中微生物群落的演替规律与理化指标的相互关系,对提高猪粪堆肥营养品质和加速堆肥进程具有重要的意义。  【方法】  以猪粪和玉米秸秆 (质量比6∶1) 混合物为堆肥原料,耐高温菌剂主要含Acinetobacter pittii、Bacillus subtilis subsp. Stercoris和Bacillus altitudinis。堆体设接种菌剂 (MI) 和未接种 (对照,CK) 两个处理。常规监测堆肥温度和理化指标值,于堆肥开始后第4、12、24和32天采集样品,以16S rRNA高通量测序技术研究堆肥细菌群落的变化。用堆肥第4、12、24和32天采集的新鲜样品制备浸提液,进行紫花苜蓿种子发芽试验。堆肥结束时,测定全氮、全磷和全钾含量,并探讨微生物菌剂对堆肥理化指标和细菌群落演替的影响。  【结果】  接种微生物菌剂可使堆肥高温期提前2天出现,并且能延长高温期2天。堆肥浸提液的促生试验发现,在堆肥24天后紫花苜蓿种子发芽指数 (GI) 大于80%,且MI对幼苗主根的促生能力大于CK (P < 0.05)。随着发酵过程的进行,堆体体积不断缩小,CK和MI中全钾 (TK) 和全磷 (TP) 含量一直呈增加趋势,在堆肥第32天,CK和MI的全磷含量分别为2.28%和2.63%,处理间差异显著 (P < 0.05),而全钾含量分别为1.81%和1.86%,全氮含量分别为2.65%和2.63%,pH分别为8.72和8.78,处理间差异均不显著。在整个堆肥过程中,MI和CK的pH变化范围分别为8.40～8.95和8.61～8.93;CK和MI中总有机碳 (TOC) 的降解速率在堆肥的4～12和24～32天均表现为MI大于CK,CK和MI的碳氮比 (C/N) 分别为13.28和15.26,差异显著 (P < 0.05)。堆肥过程中在门水平上占据主导地位的细菌群落主要包括 Proteobacteria、Actinobacteria、Firmicutes和Bacteroidetes,在堆肥的高温期 (堆肥24天),堆体CK和MI中Firmicutes的相对丰富度分别为17.4%和59.8%;在堆肥的升温期、高温期和腐熟期,优势门水平细菌群落Proteobacteria、Firmicutes和Actinobacteria依次演替,且MI堆体中细菌群落的相对丰度均大于CK。属水平优势细菌为Acinetobacter、Lysinibacillus、Solibacillus、Pseudomonas和Flavobacterium,添加微生物菌剂可使Acinetobacter的丰度在堆肥第4天增加21.41%,此外,添加复合微生物可使堆肥第12天的Shannon和Observed species指数增加。相关性分析表明,温度、全N (TN)、TP、TK、TOC及GI与堆体中细菌组成具有显著相关性,而pH和细菌的相关性不显著。  【结论】  在堆体内接种微生物菌剂可显著提高并维持堆肥过程中优势门、属细菌群落的丰度,进而促进堆体升温并延长高温时期,缩短堆肥腐熟周期,加快总有机碳的分解,最终提高堆肥产品中有效磷的含量。复合微生物菌剂在堆肥升温期起主要作用的为Acinetobacter pittii,高温期为Bacillus subtilis subsp. Stercoris和Bacillus altitudinis,我们建议筛选耐高温细菌时应集中在厚壁菌门的芽孢杆菌属。     

Changes in Chemical,Physical and Biological Properties Of Passively-Aerated Cocomposted Poultry Litter And Municipal Solid Waste Compost

Cocomposting of poultry litter with municipal solid waste compost (MSW) was evaluated as a means to stabilize nitrogen and phosphorus in poultry litter and to produce a stable organic soil amendment. Four passively aerated compost piles were established by mixing fixed weight ratios of MSW and composted poultry litter (21:1, 6:1, 3:1, 1:1); moisture was adjusted to 50 percent by weight at pile establishment. These ratios represented a range of initial C:N (26-12) and C:P (150-50) ratios. Composting process parameters monitored over eight months included temperature, oxygen and moisture contents, pH, electrical conductivity, C:N:P ratios, microbial respiration and diversity. Initial feedstock ratios had no significant effect on temperature in the thermophilic phase of composting. After one year of composting, microbial respiration in 21:1 and 6:1 mixtures was high relative to 3:1 and 1:1 mixtures suggesting slow maturation in piles with high MSW content. Salmonella sp. and coliform organisms were detectable for up to 47 days. Results suggest that MSW has potential as a carbon feedstock for poultry litter composting when used in moderate amounts.     

Compost Production from Olive Tree Pruning Wastes Enriched with Phosphate Rock

Olive production is increasing very fast in the last 20 years in Al-Jouf region, northern region of the Kingdom of Saudi Arabia. There are now more than 5 million olive trees in the productive stage. A huge amount of waste is produced annually from this sector, including pruning waste of olive trees and solid waste from olive oil mills of three-phase system. The waste of olive used to produce compost could be of safe disposal technique. Disposal of such waste is expensive and it causes some environmental hazards. Rock phosphate (RP), which is available in the same region, can be used to improve the nutrient value of the produced compost. In this experiment olive pruning waste was composted alone and in a mixture with different RP in two different ratios, namely 5% and 10%, on the dry weight basis of olive waste. Compost processing took place on plies for 8 months. Temperature and moisture were monitored daily while periodical samples were taken from all piles for testing pH, EC, C/N, and germination index. Composts in all treatments reached the theomorphic phase, which killed weed seeds and pathogens. The produced compost from all treatments fulfilled the requirements of maturity according to the California Compost Quality Council after 8 months of composting. In addition, the RP enhanced composting efficiency and improved the quality of the produced compost. Compost parameters met the standard requirements for the compost that was suitable for agriculture purposes with average values of pH ranging from (7.02–7.65) and EC (2.20–3.94 dS m^?1). Nutrient concentrations in the produced compost were N (1.28–1.79%), P (0.23–2.15%), and K (2.59–4.22%).     

Composting Wet Olive Husks with a Starter Based on Oil-Depleted Husks Enhances Compost Humification

Wet olive husks represent an environmental problem in Mediterranean areas but also a potential resource as recyclable organic matter. In the present work, we describe the composting of wet olive husks, using mechanically turned piles without forced ventilation, carried out to study the effects of partially composted oil-depleted husks as a starter for wet husks degradation. At the beginning of the composting process, protease and dehydrogenase activity, along with the microbial respiration, were higher in the piles with the starter, demonstrating a higher microbial activity in comparison with the piles without the starter. At the end of the process, the compost with the starter showed a deeper humification and a lower content of total organic carbon with respect to the compost without the starter, indicating a higher level of biodegradation and organic matter evolution. The main outcome of this research includes the possibility to: (a) detoxify and de-odorize a bad-smelling waste into an hygienically safe product; (b) produce a green, mature, humified compost useful to restore soil fertility and texture in intensive and organic agriculture.     

Comparison of Cassava Distillery Residues and Straw as Bulking Agents for Full-scale Sewage Sludge Composting

To solve problems of bulking agents shortage for sewage sludge (SS) composting and of disposal of cassava distillery residues (CDR) in the alcohol industry, the effects of using CDR instead of maize straw as bulking agents were investigated at full scale in Rizhao, China. This was done by comparing CDR-added and straw-added piles. Both CDR and straw promoted sanitation achievement of SS composts. CDR was effective at increasing fermentation temperature, whereas straw was superior in maintaining the thermophilic phase. The free air space (FAS) of matrices provided by CDR or straw were sufficient (>30%) for fermentation, and showed rising trends during composting. Extensive mass reduction was also accomplished in composting even after considering the weight of added straw or CDR. Compared with straw-added piles, CDR-added piles showed less average FAS (51.42%), water removal (49.68%), and organic matter (OM) loss (21.51%), but greater volume reduction (16.34%). The time-dependence of OM loss varied between the CDR-added (which followed zero-order kinetics) and straw-added (first-order kinetics) piles. After fermentation, the composts were phytotoxin-free in both treatments. The CDR-added piles had lower EC (2,221 μS cm^?1) and C/N (13.29) than straw-added piles. A smaller germination index (73.59%) for CDR-added piles, combined with higher pH (7.33) and oxygen consumption rate (4.33 mL L^?1 min^?1), suggests that SS composting with CDR requires a longer time to reach maturity than with straw. However, CDR can be used instead of maize straw as a bulking agent for full-scale SS composting.     

Compost Recipe Development and Weed Seed Viability Evaluation with Cranberry Leaves

A small-pile demonstration study was conducted to evaluate the possibility of composting cranberry leaves on commercial cranberry farms in Southeastern Massachusetts. The recipe ratios tested were: 20:0:0 (cranberry leaves only), 10:10:2, and 10:10:1 (leaves:horse manure and bedding:fish hydrolysate). Both mixed recipes generated thermophilic temperatures (between 43-66°C for at least 20 d), conditions known to destroy many plant pathogens and weed seeds. Analysis of leaf samples indicated that all three recipes were more acidic than most other types of compost (values below pH 6). Nitrogen levels were at or below the low-end (0.45-0.75% N) of the typical level seen with most compost (1% N). The final C:N ratios (22:1 to 38:1) were within the acceptable range for many uses. The mixed piles attained thermophilic temperatures for sufficient duration to prevent germination of the seven species of weeds tested. Leaf residue levels for eight common cranberry pesticides were also determined. The insecticide, chlorpyrifos, and the metabolite of the herbicide dichlobenil, BAM (2,6-dichlorobenzamide), were detected at levels below food tolerance and slightly above the food tolerance threshold, respectively. These levels were within a range that would allow the pursuit of commercial development of the compost since ingestion is not an anticipated end-product use. The data from this preliminary demonstration study would suggest that the composted product would be acceptable for use on-farm as well as for distribution to other off-farm sites, but additional replicated research studies are warranted.     

Application of respiration and FDA hydrolysis measurements for estimating microbial activity during composting processes

Olive-tree leaves (OL) were mixed with olive press cake (OPC) and extracted olive press cake (EPC) at 1:1 dw/dw ratios to prepare two composting mixtures (OL+OPC and OL+EPC). Both CO₂–C evolution and fluorescein diacetate (FDA) hydrolysis, determined as estimates of the microbial activity during composting, were related to temperature fluctuations in the compost piles, showing greater values at the temperature peaks, compared to the end, of each thermophilic phase. This, however, was only shown after handling and incubating samples at the temperatures of the compost mixtures at the sampling times and not at a low standard temperature. Incubating samples from thermophilic phases at low standard temperatures resulted in underestimation of the microbial activity occurring during composting. The effect of incubation temperature was less dramatic for FDA hydrolysis compared to CO₂–C evolution measurements, probably reflecting the reduced dependence of enzymes involved in FDA hydrolysis on the respective temperatures. However, FDA hydrolysis was a less sensitive indicator of microbial activity, probably due to extracellular cleavage of fluorescein by persistent esterases, at lowered microbial activity phases. Total microbial biomass, estimated by the fumigation–extraction method, was not consistently related to temperature fluctuations during composting and showed a clear increase at the end of composting, probably resulting from a large slow-growing mycelial community colonising the end products. Since high temperatures did not induce significant non-microbial CO₂–C release and FDA degradation, we propose the performance of microbial activity measurements during thermophilic composting phases at the actual temperatures evolving in the composts.     

生物过滤法去除死猪堆肥排放臭气效果的中试

为研究生物过滤法去除死猪堆肥发酵处理过程产生臭气以及挥发性有机物(volatile organic compounds,VOCs)的可行性,开展了死猪和猪粪混合堆肥试验,分析了死猪堆肥过程臭气浓度特性和VOCs组分特征,对生物过滤法去除臭气中VOCs的工艺关键参数-停留时间进行优化试验。死猪堆肥过程中排放VOCs种类达37种,其中主要致臭组分为三甲胺、二甲基硫、二甲基二硫、二甲基三硫;以腐熟猪粪堆肥作为滤料(添加3%活性污泥),在停留时间为30~100 s的条件下,生物过滤法对死猪堆肥排放臭气去除率达90%以上;停留时间60~100 s的条件下对VOCs中主要致臭组分的去除效率达82.2%~100%,生物过滤法去除死猪堆肥过程臭气浓度和VOCs的优化停留时间为60 s。研究结果能为死猪堆肥发酵过程排放臭气的处理和控制技术进一步研发提供科学依据。     

风干预处理对堆肥腐熟度及臭气排放量的影响

该研究以风干猪粪堆肥为处理,以新鲜猪粪堆肥为对照,在秸秆调理相同C/N基础上,对两个处理腐熟度和臭气排放进行比较分析。从温度、p H值、电导率和发芽率来看,利用新鲜猪粪和风干猪粪堆肥所得的产品均能达到腐熟和无害化标准;在硫化氢、羰基硫、二硫化碳、甲硫醚、乙硫醚、二甲二硫、甲硫醇和乙硫醇几种含硫臭气中,甲硫醚和二甲二硫占96%以上;风干猪粪堆肥比新鲜猪粪堆肥少排放71.09%的氨气,66.11%的甲硫醚和9.66%的二甲二硫。在不考虑风干环节存在的问题条件下,与新鲜猪粪堆肥相比,风干猪粪堆肥堆肥时间短,在堆肥品质提高的基础上,堆肥产品产量增加60%。通过降低水分和体积风干猪粪运输成本降低1/3,且对环境影响小,是远距离资源化处理畜禽粪便的较好途径。     

In-Vessel Cocomposting of Green Waste With Biosolids and Paper Waste

In comparison to traditional windrow composting, in-vessel composting techniques often represent more effective waste management options due to the reduced production of bioaerosols and leachate and the potential for better process control. Chemical processes occurring during the cocomposting of three common wastes (green waste, biosolids and paper processing waste) were studied using the forced aeration, static pile, in-vessel EcoPOD® composting system. Since no turning of the compost occurs within the static piles, spatial differences in the vessel were also monitored. These measurements revealed significant spatial gradients in temperature; however, this did not result in spatial differences in nutrients within the composting vessel. Significant differences in soluble N production were observed during the composting process following the series: green plus paper waste < green waste < green waste plus biosolids. After the active compost phase was over, and the compost was removed from the vessel and matured outside, we demonstrated that covering the compost was essential to preserve compost quality. Our study clearly shows that cocomposting of common waste feedstocks can be used to successfully manipulate the chemistry of the final compost making it suitable for multiple end uses. In addition, our study demonstrated that careful management of the compost maturing phase is also required to maximise quality and minimize pollution.