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1.
Vicia faba, in a pot experiment with sandy and clayey soils under greenhouse conditions, was checked for growth response to different amendments with coal alkaline fly ash or cocomposted fly ash mixed with lignocellulosic residues. Soil microbial populations, pH and electrical conductivity as well as heavy metal uptake by plants were monitored. At rates of five and ten percent (on a dry matter basis) in both soils, neither fly ash alone nor cocomposted fly ash exerted any negative effect. Plant biomass production was not influenced in either clayey or sandy soil. Alkaline fly ash did not promote microbial growth when applied alone to the soils. However, cocomposted fly ash generally increased bacterial and actinomycetes counts in both soils. Fungi were not affected by ash. Due to the increase of soil pH by alkaline fly ash or cocomposted fly ash, plant uptake of heavy metals was depressed in the sandy soil. Heavy metal mobility did not cause change in the clayey soil where a high buffering capacity mitigated the effects of fly ash amendments.  相似文献   

2.
Heavy metal contents in the culture substrate and in the mushroom, Agaricus bisporus, grown in composts mixed with municipal waste and sewage The addition of increasing quantities of municipal waste compost to conventional horse manure compost resulted in a proportional increase in the heavy metal content of the mixture. The increases ranged between 250% (zinc) and 900% (mercury). Ninety-four to ninety-nine percent of the heavy metals in municipal waste compost are bound in compounds from which they can not be extracted using CaCl2 solution. The amounts extractable from horse manure compost with CaCl22 solution are from 1.5 (zinc)- to 33 (mercury)-times higher. The influences of the increasing quantities of heavy metals in municipal waste — horse manure composts are demonstrable in the content of these metals in harvested mushroom. This, in turn, corresponds to the availability of the metals. The relative enrichment is greatest with mercury, and least with cadmium. The quantities found in mushrooms, with the exception of mercury, fall within the normal range detected in vegetable crops.  相似文献   

3.
Soil‐quality parameters, such as soil organic matter (SOM) and plant‐available nutrient contents, microbial properties, aggregate stability, and the amounts of heavy metals were carried out in arable soils of different rotation schedules applied with a total of 50 Mg dry mass ha–1 biowaste compost relative to an untreated control. This was investigated during a 10 y period from 1994 to 2004. Overall, soil‐quality parameters studied appeared to be promoted by biowaste‐compost application. This was evidenced for example by a remarkable increase of SOM and total N content of ≈ 15%–20% relative to the control. Subsequently, amounts of soil microbial biomass and alkaline phosphatase activity were significantly increased as well. In addition, biowaste‐compost application revealed an increase of plant‐available P and K contents and aggregate stability in soil. There was, however, no treatment effect for net N‐mineralization rates. Moreover, in soils of maize and sugar beet rotation schedule a slight decrease was found. Heavy‐metal contents of Pb and Zn were significantly increased in all compost‐treated soils, whereas no significant increase of Cd and Cu contents was measured. However, the investigated amounts were far below of the limits of the German Biowaste Ordinance. It is finally recommended, that biowaste compost may sustain and improve soil quality in agriculture when N nutrition will be considered.  相似文献   

4.
利用牧草与沼渣栽培毛木耳及其残渣改良土壤效果   总被引：3，自引：0，他引：3  
以不同比例牧草与沼渣替代木屑栽培毛木耳对其产量、品质及氨基酸含量影响各异。30%草粉 +30%沼渣替代木屑效果较好,生物效率为107.5%,产量比对照高82.2%,粗蛋白、氨基酸、粗脂肪、可溶性糖含量分别比对照高3.7%、1.75%、0.13%、0.37%;以50%草粉或沼渣替代木屑其毛木耳产量分别比对照高55.1%和61.0%。山地果园连续3年施用5t/hm2沼渣、5t/hm2菌渣和5t/hm2鲜草处理区与对照相比,其红壤中腐殖酸碳含量分 别提高22.9%、26.5%和16.5%;红壤中团粒结构依次提高78.5%、79.9%和69.3%,改良土壤效果较好。  相似文献   

5.
A comparative study was run during 13 months on two biowaste definitions involving both lab tests and field surveys. A narrow biowaste definition, allowing only biogenic wastes (kitchen and garden waste) and referred to as ‘Biowaste,’ was compared to a broad biowaste definition, referred to as ‘Biowaste Plus’ and including man-made products, such as nonrecyclable wastepaper and diapers. Two similar test areas, each with about 425 inhabitants, were defined in a semiurban area north of Antwerp. During the entire test period, the amount of curbside waste (i.e., biowaste and restwaste or ‘grey waste’), was continuously measured and analyzed regularly (twice per season) for composition. At the start, middle and end of the test, the population of each test area was surveyed. Bench-scale aerobic composting experiments were run to evaluate the influence of both biowaste definitions on the composting process and the compost end product.

The introduction of source separated waste collection resulted in an overall landfill diversion rate of 43 percent for the (narrow) ‘Biowaste’ definition and 46 percent for the (broad) ‘Biowaste Plus’ definition. The contamination of biowaste with restwaste was low for both definitions (about three percent). Assuming that the collection and the appropriate disposal of organics could be improved to 95 percent efficiency (compared to about 60 percent currently), the landfill diversion rate could be increased to 59 percent for the ‘Biowaste’ and 74 percent for the ‘Biowaste Plus’ definition. Whereas the average sorting efficiency of separately collected organics was about 61 percent; 49 percent for nonrecyclable paper; and as low as 20 percent for certain categories of nonrecyclable paper (e.g., nonrecyclable cardboard packages). Apparently more education or a better systém of recognition and identification is needed to improve the collection efficiency of man-made compostables. Indeed, for easily recognizable products such as diapers, the sorting efficiency was as high as 70 percent.

The acceptance and goodwill of the population was significantly higher for the ‘Biowaste Plus’ definition, especially in the summer months. The yearly, overall composition of the total curbside waste (biowaste and restwaste combined) was 17 percent kitchen organics, 47 percent yard waste, four percent recyclable paper, 13 percent nonrecyclable paper and 19 percent noncompostables. It must be mentioned that glass, paper and large yard waste were collected separately by a voluntary bring-system. Biowaste Plus typically contained 16.0 percent paper (of which 2.9 percent was recyclable) versus 2.0 percent for Biowaste (0.3 percent recyclable).

The ‘Biowaste Plus’ definition resulted in improvements for the aerobic composting process due to easier moisture control, better aeration and a more tempered pH evolution. A significant difference was seen for NH3 and corresponding odor emission, both being much lower with ‘Biowaste Plus.’ The quality of the compost produced was similar and acceptable for both biowaste definitions, according to existing standards (VLACO in Flanders and RAL in Germany).  相似文献   

6.
Growth of Impatiens wallerana Hook. ‘Accent Red’ was evaluated in three composted urban waste materials (composted biosolids and yard trash (SYT): 20 percent biosolids/sewage sludge, 44 percent yard trimmings, and 36 percent mixed paper; composted refuse fuel residues with biosolids and yard trash (RYT): 74 percent refuse-derived fuel residuals, 10 percent biosolids/sewage sludge, and 16 percent yard trimmings; and composted municipal solid waste (MSW): 100 percent municipal solid waste). Treatments consisted of 100 percent composted waste and media in which the composted wastes were combined with control medium components at 60 percent, 30 percent, or 0 percent composted waste, by volume. Shoot dry mass of plants grown in SYT increased as the percentage of SYT in the medium increased, while shoot dry mass of plants grown in MSW linearly decreased from 1.24 g to 0.15 g. There were no significant differences in shoot dry mass of plants grown in different percentages of RYT. Initial medium soluble salt concentrations in MSW media were more than double concentrations measured in SYT and RYT media. Soluble salt concentrations in both the 100 percent and 60 percent MSW media exceeded 1.75 dS.m?1, while the soluble salt concentrations in 100 percent SYT and 100 percent RYT were 0.50 dS.m?1 and 0.61 dS.m?1, respectively. The C:N ratios in 100 percent SYT and RYT were 17 and 15, respectively, while 100 percent MSW had a C:N ratio of 29. The relatively higher level of compost maturity as indicated by lower C:N and soluble salt concentrations contributed to superior growth of impatiens plants in 100 percent SYT and RYT compared to 100 percent MSW.  相似文献   

7.
Background, Aim and Scope   Phytoremediation is a remediation method which uses plants to remove, contain or detoxify environmental contaminants. Phytoremediation has successfully been applied for the removal of fresh hydrocarbon contamination, but removal of aged hydrocarbons has proven more difficult. Biodegradation of hydrocarbons in the subsurface can be enhanced by the presence of plant roots, i.e. the rhizosphere effect. Phytostabilization reduces heavy metal availability via immobilization in the rhizosphere. Soils contaminated by both hydrocarbons and heavy metals are abundant and may be difficult to treat. Heavy metal toxicity can inhibit the activity of hydrocarbon-degrading microorganisms and decrease the metabolic diversity of soil bacteria. In this experiment, weathered hydrocarbon- and heavy metal- contaminated soil was treated using phytoremediation in a 39- month field study in attempts to achieve both hydrocarbon removal and heavy metal stabilization. Materials and Methods: A combination of hydrocarbon degradation and heavy metal stabilization was evaluated in a field-scale phytoremediation study of weathered contaminants. Soil had been contaminated over several years with hydrocarbons (11400±4300 mg kg dry soil)-1 and heavy metals from bus maintenance activities and was geologically characterized as till. Concentrations of soil copper, lead and zinc were 170±50 mgkg-1, 1100±1500 mg kg-1 and 390±340 mg kg-1, respectively. The effect of contaminants, plant species and soil amendment (NPK fertilizer or biowaste compost) on metabolic activity of soil microbiota was determined. Phytostabilization performance was investigated by analyses of metal concentrations in plants, soil and site leachate as well as acute toxicity to Vibrio fischeri and Enchtraeus albidus. Results: Over 39 months hydrocarbon concentrations did not decrease significantly (P=0.05) in non-amended soil, although 30% of initial hydrocarbon concentrations were removed by the last four months of study. In soil amended with NPK fertilizer and municipal biowaste compost, 65 % and 60 % of hydrocarbons were removed, respectively. The soil contained metabolically diverse bacteria, measured as carbon source utilization and extracellular enzymatic activities. Compost addition resulted in a slight increase in enzymatic activities. Diesel fuel utilization potential in Biolog MT2 plates inoculated with a soil suspension was enhanced by both compost and NPK compared to non-amended soil. Soil toxicity to V. fischeri and E. albidus was low. The leachate was not toxic to V. fischeri. Pine (Pinus sylvestris), poplar (Populus deltoides x Wettsteinii), grasses and clover (Trifolium repens) survived to varying degrees in the contaminated soil. All plants suffered from phytotoxicity symptoms and some trees died during the study period. Plants formed a dense cover over the compost-amended soil, whereas non-amended soil had areas devoid of vegetation throughout the study. Vegetation coverage in the NPK-amended quarter was about 50 % after the first four months of study, but increased gradually to 100 %. Heavy metals did not accumulate in plant tissue. Discussion: Removal of hydrocarbons from weathered unfertilized hydrocarbon-contaminated soil was not statistically significant despite the presence of a viable hydrocarbon-degrading microbial community. This effect is attributed to soil heterogeneity and low bioavailability of hydrocarbons. Hydrocarbon concentrations were not reduced to the desired level, i.e., 1500 mg hydrocarbons (kg of dry soil)-1, in any treatment. . The presence of clay minerals and organic matter within the compost may have limited heavy metal transfer to leachate and plant tissue. Conclusions: Weathered hydrocarbons were partly decomposed in soil fertilized with NPK fertilizer or biowaste compost, but not from unfertilized soil. The active hydrocarbon-degrading microbiota and low toxicity of soil to V. fischeri and E. albidus indicates low availability of contaminants to microorganisms. Despite high heavy metal concentrations, the soil contained metabolically diverse bacteria, measured as carbon source utilization and extracellular enzymatic activities. Heavy metals did not accumulate in test plants. Pine and poplar suffered from phytotoxicity symptoms in the soil and could not enhance hydrocarbon removal in compost-amended soil. Compost addition combined with a grass and legume crop is suggested for stabilization of combined hydrocarbon- and metal-contaminated soil. Recommendations and Perspectives: Both compost and NPK fertilizers can be used to enhance phytoremediation of soil contaminated with weathered hydrocarbons in the presence of heavy metals; however, compost addition is recommended since it enables greater vegetative coverage. This in turn may decrease heavy metal mobility. Phytoremediation can be used for remediation of soil contaminated with weathered hydrocarbons in the presence of heavy metals. However, phytoremediation of weathered contaminants requires extended periods of time; thus, other remediation methods should be considered in the event of soil contamination posing an immediate public health and/or environmental threat.  相似文献   

8.
A 4-year field study was carried out to investigate the effects of three types of biowastes application on PCB accumulation in agricultural soils. This study was based on the experiments designed for four soils in two areas of Palencia province (Spain) (Cerrato and Tierra de Campos) for non irrigated and irrigated land after applying biowaste. The amounts of the three different types of biowastes added were determined according to the fertilization needs of nitrogen for the crop. The concentrations of PCBs in soils were determined before and after biowaste application. The three biowaste treatments raise the concentration of PCBs in the soil, sewage sludge compost (SC) treatment produced the main increase in PCBs concentration, followed by municipal solid waste compost (MC) treatment and the dehydrated sewage sludge (SD) treatment. The values of biowaste treated areas were 3.7-11.5 times higher than the respective values of the non treated areas. Changes observed in the congener distribution also suggest the influence of the biowaste on the soil. The biowaste used had an average PCBs concentration of 63.16 ng g?1 with a range from 34.08 ng g?1 to 118.93 ng g?1, which are values below the EEC recommended limit (800 ng g?1). In the soils without treatment was found an average concentration 0.206 ng g?1 of PCBs, typical of areas with low levels of environmental pollution.  相似文献   

9.
Advanced treatment of residues from anaerobic digestion of leftovers and kitchen waste originating from an industrial waste treatment plant was carried out by means of cocomposting in order to reveal potential synergistic effects. After a retention time of two weeks in the anaerobic reactor, microbial activity of the residues remained high. The biogas produced is of use in combined heat and power generation. Lab-scale experiments in the liquid phase have demonstrated “cracking” of the anaerobic stabilized organic matter under aerobic conditions. The advanced aerobic treatment of residues from anaerobic digestion by means of cocomposting leads to high quality composts. The addition of output material to biowaste from the separated bin collection may improve the formation of humic substances. Extractable humic acids are considered to represent a reliable parameter in describing high quality composts. Thus, the improvement of humic acid formation by means of composting is a goal to be achieved. Process control was performed by assessing parameters such as loss of ignition, total organic carbon, nitrogen and humic acid content as well as by modern analytic methods like FT-IR spectroscopy and thermogravimetry.  相似文献   

10.
Overused soil resources and the build-up of organic residues from industrial processes have resulted in increased risk of environmental contamination. Recycling of organic residues from industry by incorporation into agricultural soil, can provide valuable organic amendment as well as supply nutrients to crops. The effect of applying organic amendments to an agricultural sandy soil on the nitrogen nutrition of wheat (Triticum aestivum L.) and residual effects on the growth of a following maize crop (Zea mays, L.), were assessed under semi-controlled environmental conditions and were compared to nitrogen mineralization prediction obtained from an aerobic incubation. Six different organic residues (composted municipal solid waste, secondary pulp-mill sludge, hornmeal, poultry manure, the solid phase from pig slurry and composted pig manure) were added to a Cambic arenosol, incubated or used in pot experiments, to evaluate and try to predict the availability to crop plants of nitrogen released from these materials. Poultry manure was the most effective amendment in making nitrogen available and enhancing nitrogen uptake by wheat plants resulting in greater dry matter yield. The dried solid phase from pig slurry and hornmeal were also beneficial to wheat growth. There was a greater recovery of nitrogen (N), from organic materials studied, by a maize crop. Poultry manure was the residue that provided a greater residual effect on N supply to maize.  相似文献   

11.
NaOH处理玉米秸秆厌氧生物气化试验研究   总被引：30，自引：2，他引：28  
提出通过NaOH化学处理以改善玉米秸秆的可生物消化性能、提高玉米秸秆厌氧消化产气量的方法。NaOH添加量为玉米秸秆干物质的8%。对未处理和经NaOH处理的玉米秸秆进行了厌氧消化对比试验研究,厌氧消化负荷率为35,50,65和80 g/L。分析并比较了两者在不同负荷率下的日产气量、累积产气量、单位TS和VS产气量等。结果显示,与未处理玉米秸相比,NaOH处理过的玉米秸的干物质消化率和产气量明显提高,在35,50,65,80 g/L负荷率下,产气量分别提高了13.1%,39.8%,48.3%和47.8%,单位TS、VS的产气率分别提高了13.1%～48.3%、23%～61.3%;两种玉米秸分别在35和65 g/L负荷率下获得了最高单位TS产气量。NaOH化学处理使玉米秸细胞壁结构和化学成分发生了明显的变化,分别有53.2%、46.9%和66.6%的木质素、纤维素和半纤维素被分解,其中1/2～2/3被转化成了易被厌氧菌利用的可溶性物质,这是产气量提高的主要原因之一。研究结果对提高玉米秸的产气效率、实现大规模应用具有重要指导意义。  相似文献   

12.
Greenhouse experiments with alfalfa (Medicago sativa L. cv. ‘Apollo') were performed to evaluate the effect of varied nutrient solution concentrations of S on the yield, nodulation, dinitrogen fixation, N and S concentration, and the partitioning of N and S into shoots and roots.

Sulfur treatments consisted of four levels (0, 1, 2.5, and 25 mg S/L) of added S. The experimental design was a randomized complete block, with three replications. Seeds were inoculated with commercial inoculum, planted in plastic containers of acid‐washed sand, and irrigated with nutrient solution for one minute, at 2 h intervals.

Sulfur application increased the yield of all treatments. The results demonstrated that the addition of 2.5 mg S/L to the nutrient solution, besides providing the highest total dry matter yield (12 g/72 plants), showed the highest percent yield increase (19%), acetylene reduction rate (0.426 umole ethylene/mg nodule dry wt/h), total N content (306 mg/72 plants), percent recovery of S (3.8%), and percent increase in N due to dinitrogen fixation (32%).

N:S ratios obtained were different for shoots and roots, with S application decreasing the N:S ratios. The N:S ratios of 16:1 (shoots), and 9:1 (roots) obtained in the 2.5 mg S/L treatment were found to be adequate for normal growth and development.

These data indicated that the 2.5 mg S/L treatment (2.7 mg total S/L) was optimal for alfalfa seedling development.  相似文献   


13.
Abstract

Out‐wintering pads are a cattle housing system, consisting of a layer of timber residue over an artificially drained surface. Residues from out‐wintering pads that require management include liquid effluent and spent timber residue (timber soiled with manure). In Ireland, the current management strategy for these materials is to apply them to grassland for the production of silage. The main objective of this study was to determine the dry‐matter yield and nitrogen (N) response of first and residual cut silage to spent timber residue at three rates (10, 30 and 50 t ha?1). No silage yield or N response was observed from application of spent timber residue. A secondary objective was to determine the impact of dry timber residue (i.e., not soiled with manure) on silage yield and N response for first, second, and third cut silage. A significant negative response was observed for first cut silage yield in response to dry timber residue. However, no effect was observed for the second and third cut silage yield.  相似文献   

14.
传统沼气工程的气肥联产工艺中,厌氧发酵产气与好氧发酵产肥互相独立,产气和产肥周期均较长、有机肥品质差,影响工程的高效运行。为缩短发酵周期、提高产气效率和有机肥品质,该研究将猪粪、鸡粪和秸秆混合进行15和30 d的干法厌氧发酵,将得到的沼渣添加秸秆辅料混合,分别设置65%和70%的发酵物料初始含水率进行15 d的高温好氧发酵,对比分析了不同厌氧-好氧发酵组合对产气和产肥的影响。结果表明:厌氧发酵阶段,混合物料的日产气率自发酵开始后逐渐上升,并在第8天达到最高峰,至第15天降至峰值的50%以下,此时累积产气量达到30 d发酵周期的71%,平均容积产气率达到1.91 m~3/(m~3?d),比发酵30 d平均容积产气率高41.5%。好氧发酵阶段,各处理组碳元素含量持续下降,氮元素含量先下降后增加,所得发酵产物均达到腐熟标准。采用15 d厌氧发酵所获得的沼渣进行好氧发酵,所得发酵产物的电导率、腐殖化程度和发芽指数均优于采用30 d厌氧发酵所获得的沼渣进行好氧发酵所得的发酵产物,同时总有机碳和总氮含量也较其分别提高了6.0%～21.7%和3.0%～10.2%,不同好氧发酵物料初始含水率对发酵产物的品质影响较不明显。因此,采用厌氧、好氧发酵周期均为15 d的组合,可缩短发酵周期、大幅提高产气效率和发酵产物的碳氮营养元素含量,有利于提高沼气工程运行效率和经济效益。  相似文献   

15.
为了阐明在东北高寒区连年施用沼渣对玉米产量、效益和土壤肥力的影响,于2013年5月至2014年10月在黑龙江省海林市海林农场的玉米试验田进行了沼渣和化肥配施的田间试验。结果表明:连续2年的施用沼渣以及沼渣与化肥配施均能够增加玉米产量,而施用45 000kg/hm~2的沼渣增产幅度最大,全量施用600kg/hm~2化肥的玉米产量小幅减少。施用1t沼渣可替代135.25kg尿素、180.18kg磷酸二铵和107.09kg硫酸钾,产生956.72元的直接经济效益。施用沼渣的各处理与不施肥处理相比,经济效益均显著增加,7 500kg/hm~2沼渣+450kg/hm~2化肥的处理经济效益最高,平均可达到18 066.2元/hm~2。沼渣单施及沼渣与化肥配施后表层土壤pH可提高0.02~0.28个单位,有机质可增加0.14~2.84g/kg,可在一定程度上增加表层土壤中养分的含量。因此,在东北高寒区实际生产中可以考虑合理的配施沼渣替代化肥,实现对沼渣的高效化和经济化的利用。  相似文献   

16.
氮磷钾配施沼气肥对早稻产量和品质的影响   总被引：2，自引：0，他引：2  
通过田间试验研究沼气肥对土壤供氮能力以及早稻产量及其构成因素、品质性状、稻田主要病虫害的影响。结果表明:增施沼气肥可显著提高早稻的有效穗数和实粒数,显著提高产量。在等量氮磷钾下,与常规施肥相比增产17.81%。等量沼气肥下,沼气肥与常规施肥中减少20%氮和33%钾用量西施处理比与常规施肥配施处理略有减产,仅增产4.24%,但比常规施肥处理增产13.03%。施用沼气肥对早稻稻米碾米品质和外观品质影响不明显,但稻米的食味品质和营养品质明显改善。施用沼气肥还可以减轻水稻主要病虫害的发生和危害。  相似文献   

17.
Managing municipal solid waste (MSW) compost for agricultural use requires an understanding of waste stream components and how they affect the value of the finished product. We evaluated the influence of disposable diaper content in MSW compost because of the recent concern of the environmental impact of this product. To determine the potential effect of disposable diapers on MSW compost, the ‘normal’ concentration of soiled, disposable diapers in a waste stream was raised from 2 percent to 8 percent. Previous observations indicated that the diapers disassociated during in-vessel digestion and most of the components could not be distinguished from the primary compost. The objective of this study was to examine the effect of additional diapers on the agricultural value of mature MSW compost. Loamy sand and silt loam soils were amended with MSW compost at a rate of 20 percent. Comparisons between the two composts and their interactions with soil type were made on the basis of water retention characteristics; germination and emergence of corn, soybean, radish and lettuce; and yield and element uptake by corn and lettuce at two moisture regimes. Differences between the compost amended soils suggested that the primary benefits of additional diapers were increased nutrient availability and soil water retention, and the foremost concerns were excess total soluble salts and boron.  相似文献   

18.
A major input in intensive organic agriculture is nutrient-rich liquid fertilizers. Guano and other fowl manure are frequently digested in water extracts, and the supernatant is supplied as fertilizer. The resultant manure biowaste (MBW) is commonly disposed of to the environment, posing potential pollution and health risks. The study aims were to determine two types of fowl MBWs for their chemical properties before and after lime treatment and to test their reuse potential as soil amendment. Guano and layer manure were digested, and the residues?? chemical properties were analyzed before and after lime treatment. MBWs were then air-dried and used as a soil amendment in a parsley-growing experiment. The lime-treated MBW composition met the European standards for high-quality biowaste compost. Both digested and lime-treated MBWs had residual nitrogen, 3% and 1% in guano and layer manure, respectively. Parsley grown in soil amended with layer MBW had 100% survival, high yield, and good crop quality compared with controls. Plants grown with soil amended with guano biowaste exhibited lower yield and only 50% survival. These findings indicate that the current practice of disposing guano biowaste to the environment may pollute soil and water bodies, while the land spread of lime-treated layer MBW is safe and may improve soil fertility.  相似文献   

19.
猪粪中温半干法连续厌氧发酵产气性能   总被引：2，自引：1，他引：1  
为改善猪粪在连续型沼气工程中的容积产气效率和降低其进出料过程的热损失,该研究拟采用高浓度和小体积喂料方式进行,将新鲜猪粪分别稀释成总固体质量分数(total solid,TS)为10%、12%和14%3个水平,通过逐级缩短水力停留时间(hydraulic retention time,HRT)(HRT:25 d→20 d→18.5 d)的方式来改变各组反应器的负荷。试验结果表明,当HRT:25 d时,各组平均日产气量均表现最高,约为460 m L/g,此阶段可获得85%以上的沼气转化效率;当HRT:20d时,各组均获得最大容积产气率,最高达到2.29 L/(L·d)(TS:14%);当HRT下降至18.5 d时,各组产气量均呈下降趋势,表明有机负荷已超出反应器的最大转化能力。通过综合原料产气转化效率和容积产气效率2个指标,发现进料TS为14%和HRT为25 d为较优组合条件。该研究可为在实际沼气工程中如何协调进料浓度和HRT的关系提供参考。  相似文献   

20.
畜禽养殖使用饲料中普遍添加了含有重金属的添加剂,畜禽对重金属的利用率低,绝大部分残留于粪便中,对生态环境和人类健康存在潜在风险。调查分析了太湖流域西岸区域养猪场饲料、猪粪和沼气化的沼渣和沼液9种重金属（Cr,Mn,Co,Ni,Cu,Zn,As,Cd,Pb）,研究结果表明,猪饲料和猪粪中Cu,Zn,Pb,Cd和As重金属均超标严重,猪大小不同,使得猪饲料和猪粪中重金属含量差异较大。沼液中Cu,Zn,As含量分别为3.37,34.49,0.36 mg/L,均严重超标,沼渣中Cu,Zn,Pb,Cd和Ni,分别达到1 348.20,10 525.03,1 254.45,57.36和1 043.99 mg/kg,均也严重超标,沼气化工程后除了Pb,Cd和Co外,其他6种重金属可溶态含量都增大,因此沼肥均不宜直接施用农田,需通过相应处理实现沼肥安全农用。  相似文献   

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