施用沼肥对设施土壤固氮菌影响的研究

以有机质含量相同的猪粪、沼渣为基肥,以N,P,K含量相同的化肥与沼液为追肥,以L402番茄为供试作物,采用二裂式区组设计的方法.研究了沼肥、猪粪、化肥等不同施肥组合对设施土壤固氮菌动态变化的影响.试验结果表明:随着番茄生育期的推进,各施肥处理土壤自生固氮菌的数量逐渐增加,基施沼渣比基施猪粪有利于促进土壤自生固氮菌的生长;从番茄苗期到成熟期,追施化肥土壤自生固氮菌数量多于追施沼液土壤,猪粪与化肥配合施用、沼渣与沼液配合施用分别较猪粪与沼液配合施用、沼渣与化肥配合施用能更好地促进土壤自生同氮菌的繁殖.     

沼肥对保护地番茄生长发育及其产量的影响

采用二裂式区组设计的方法，以番茄为供试作物，以沼肥（沼液、沼渣）、猪粪和化肥为肥料，研究了不同施肥措施对番茄生长发育及其产量的影响。结果表明：与施用化肥相比，施用沼液的番茄植株平均株高及根系体积有所增加，番茄产量略有降低；与施用猪粪相比，施用沼渣可促进植株茎秆的健壮生长及根系发育，番茄产量提高20．8％；与沼渣和化肥配合施用相比，沼渣与沼液配合施用促进了番茄植株的生长发育，其植株生长稳健，根系发达，而且番茄产量增加；与猪粪和化肥配合施用相比，猪粪与沼液配合施用促进了番茄植株的生长发育，其株高较高、茎秆粗壮、根系发达，但番茄产量下降。     

基于LCA方法沼渣沼液生产利用过程的环境影响分析

采用生命周期评价(LCA)方法,以1 t沼渣沼液为功能单位,评估了北京市延庆县某大型沼气工程的沼渣沼液在生产利用过程中产生的环境影响,并与化肥生产利用全过程产生的环境影响进行了对比分析。结果表明:在整个生产利用过程中,沼渣沼液环境影响综合指数为-13.949×10-3,化肥的环境影响综合指数为5.219×10-3。沼渣沼液作为有机肥用于农业生产,对全球变暖、环境酸化、富营养化、光化学氧化和能量消耗等方面的负面作用小于化肥,但在人类毒性和土壤毒性方面的负面作用比化肥大。     

沼渣底施对黄瓜生长及土壤微生物数量的影响

采用盆栽试验,研究了沼渣肥用量对黄瓜不同生育时期生长情况和土壤中细菌、真菌两种微生物数量的影响。结果表明,不同添加量的沼渣肥都能够显著促进黄瓜生长,其中以5.0%沼渣的综合应用效果最好,该处理对黄瓜收获期的根重、地上部重、植株干重、株高、叶数和茎粗分别比未施肥对照组高130.51%,141.87%,72.88%,26.70%,39.32%和35.11%。沼渣肥的施用也显著改变了土壤中微生物的数量,使土壤中细菌数量增加、真菌数量降低,对生育前期土壤微生物的数量影响很大,随着生育期的延长而逐渐降低。土壤中微生物含量与黄瓜生物量相关性分析表明,土壤细菌数与黄瓜生物量成正相关,土壤真菌数量与黄瓜生物量成负相关。田间试验表明,施用沼渣比常规处理产量增加8.3%,比空白对照增产19.2%。     

施用沼肥对生菜生长特性及品质影响的研究

通过沼肥与化肥的混合施用,试验研究了沼肥对生菜生长特性及其品质的影响,目的是为沼气的综合利用提供理论依据和技术支持.试验结果表明：施用沼肥能有效提高生菜产量,改善生菜的植物学性状和营养品质,特别是在喷施沼液的情况下,当沼渣与化肥配比为8：2时,生菜产量最高,品质最优.     

沼液沼渣的综合利用技术

沼液和沼渣总称为沼肥,是生物质经过沼气池厌氧发酵的产物。沼液中含有丰富的氮、磷、钾、钠、等营养元素。沼渣是由部分未分解的原料和新生的微生物菌体组成,分为三部分：一是有机质、腐殖酸,对改良土壤起着主要作用;二是氮、磷、钾等元素,满足作物生长需要;三是未腐熟原料,施入农田继续发酵,释放肥分。如何让农民更好地、最大限度地用好沼气,充分发挥出沼液、沼渣综合利用的经济效益,就必须掌握沼液、沼渣的综合利用关键技术,下面就其主要技术介绍如下。     

沼肥中重金属含量初步研究

采用青饲料和配合饲料饲喂生猪,对所产生的猪粪进行沼气发酵,测试和分析沼肥中主要重金属的含量,初步探索出沼肥中重金属含量的变化趋势.分析数据表明:配合饲料沼渣中砷、镉、铬的含量远高于青饲料沼渣,两者沼液中汞、铅的含量呈显著性差异.     

花生施用沼肥的技术研究

沼肥是沼气池的副产物，它包括沼液和沼渣2部分。沼液中含有氮、磷、钾、钙、铁等18种元素、多种活性酶和生长素。沼液用于浸种，可提高种子的发芽率，增加作物的产量。沼渣由未分解的原料固形物及微生物菌体组成。沼渣营养丰富，尤其是腐殖酸含量很高．可达10％～24％，腐殖酸对土壤改良有重要作用，其土壤改良功效十分明显。沼肥应用于作物生产，可以节约化肥的施用量，减轻对环境的污染，可以广泛地应用于无公害农作物产品的生产。     

沼液对土壤有机质含量和肥效的影响

试验研究了施用沼液对土壤改良及土壤有机质含量和肥效的影响.试验分为8个组,每组设4个重复;土壤处理分为灭菌和不灭菌2部分;青菜种植分为施用沼液与不施用沼液2部分.试验结果表明:施用沼液能够显著增加土壤有机质、氨态氮、速效钾、速效磷的含量,有利于调节土壤pH值.施用沼液对土壤有显著的改良效果.     

沸石对猪粪沼气发酵特性及沼渣、沼液中重金属Zn的影响

为减少重金属污染,以猪粪为发酵原料,采用厌氧发酵技术进行试验。结果表明:添加沸石对沼气发酵产气量、甲烷含量影响不大;厌氧发酵后,添加沸石组重金属Zn的89.88%存在于沼渣中,10.12%存在于沼液中;Zn总量下降了32.41%,下降幅度高于空白对照组;厌氧发酵后,沼渣、沼液中的重金属形态都以残渣态为主,添加沸石组的沼渣、沼液中残渣态的比例高于空白对照组;厌氧发酵后,空白组沼渣中重金属Zn的有效态含量占32.63%,添加沸石组重金属Zn的有效态含量占29.12%。添加沸石有利于降低重金属Zn的生物有效性,因此,建议在厌氧发酵过程中添加重金属钝化剂,以此减少沼肥回田后重金属污染的风险。     

川渝养殖场沼气工程运行状况与沼液生物学特性研究

为探索沼气工程运行状况、沼液理化性质及微生物群落结构差异,对川渝9个养殖场沼气工程进行调查与采样分析,利用16S rRNA基因扩增子高通量测序技术研究沼液中微生物群落组成及多样性。结果表明,川渝地区养殖场沼气工程以处理养殖场废水为主,不以产能为目的,总氮(TN)、总磷(TP)、NH+4和化学需氧量(CODCr)等理化指标在猪场和牛场沼液之间无显著差异。14个沼液样品中厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)、变形菌门(Proteobacteria)、互养菌门(Synergistetes)和疣微菌门(Verrucomicrobia)是主导微生物,这5大类细菌占细菌克隆总数的84%以上。猪场沼气工程Proteobacteria相对丰度在45.0%~69.3%之间,显著高于牛场,而牛场沼液中Firmicutes及Bacteroidetes占主要优势,两者相对丰度之和的平均值为58.4%。沼液中古菌以甲烷微菌纲(Methanomicrobia)、甲烷杆菌纲(Methanobacteria)占优,且Methanomicrobia丰度在2类养殖场间存在显著差异;猪场沼液中Methanosaeta占绝对优势,达到84.1%~94.4%,而Methanosarcina丰度极少。进一步分析,结果显示,沼液铵磷比与Firmicutes相对丰度、丰富度指数(Chao1)及多样性指数(Shannon)都存在显著的相关性。沼液中群落主坐标分析及聚类分析均可准确辨识猪场沼气工程、运行状况良好及运行状况欠佳的牛场沼气工程,可为养殖场粪污治理效果评价提供科学依据。     

沼气微氧发酵过程硫转化及微生物群落

以水稻秸秆与猪粪为原料,探究微氧发酵过程中S元素的转化与微生物群落特征以及通氧量的影响。结果表明,厌氧发酵过程中原料的S元素约有65.7%转化为H2S进入沼气,19.0%进入发酵后的沼液,15.3%残留在沼渣中。微氧条件下,沼液中S2-的浓度(100 mg/L)远低于厌氧条件的250 mg/L,约71.8%的S元素转化为H2S然后被氧化成为S单质和少量SO42-。H2S去除效率随通氧量的增大而增大,当通氧量为11.85 L/m3沼气时,约96%的H2S被氧化脱除。根据高通量测序结果,与厌氧发酵相比,在微氧条件下,沼液中微生物多样性仅有轻微变化,比较稳定;硫氧化菌明显增多,而产甲烷菌无明显变化。较高浓度硫氧化菌的存在,有利于沼气中H2S的及时转化,可减轻H2S对产甲烷菌活性的抑制,从而促进厌氧发酵的进行。     

Evaluation of biogas production from different biomass wastes with/without hydrothermal pretreatment

Municipal biomass waste is regarded as new available energy source, although it could cause serious environmental pollution. Generally, biogas recovery by anaerobic digestion was seen as an ideal way to treat biomass waste. Different types of biomass waste have different biogas production potential. In this paper, cow manure, pig manure, municipal sewage sludge, fruit/vegetable waste, and food waste were chosen as typical municipal biomass waste. In addition, hydrothermal pretreatment was used to accelerate digestion and increase biogas production. Biochemical methane potential (BMP) test was used to evaluate biogas production for raw biomass and hydrothermal treated waste. Raw materials of fruit/vegetable and food waste show higher methane production than that of cow manure, pig manure, and municipal sewage sludge. After hydrothermal pretreatment at typical condition (170 °C at 1 h), the biogas production of pig manure, cow manure, fruit/vegetable waste, and municipal sewage sludge increased by 7.8, 13.3, 18.5, and 67.8% respectively. While, for treated food waste, the biogas decrease by 3.4%. The methane yield of pig manure, fruit/vegetable waste, and municipal sewage sludge increased by 14.6, 16.1, and 65.8%, respectively. While, for treated cow manure and food waste, the methane decrease by 6.9% and 7.5%.     

How can we improve biomethane production per unit of feedstock in biogas plants?

Biogas production is one of the number of tools that may be used to alleviate the problems of global warming, energy security and waste management. Biogas plants can be difficult to sustain from a financial perspective. The facilities must be financially optimized through use of substrates with high biogas potential, low water content and low retention requirement. This research carried out in laboratory scale batch digesters assessed the biogas potential of energy crops (maize and grass silage) and solid manure fractions from manure separation units. The ultimate methane productivity in terms of volatile solids (VS) was determined as 330, 161, 230, 236, 361 L/kg VS from raw pig slurry, filter pressed manure fiber (FPMF), chemically precipitated manure fiber (CPMF), maize silage and grass silage respectively. Methane productivity based on mass (L/kg substrate) was significantly higher in FPMF (55 L/kg substrate), maize silage (68 L/kg substrate) and grass silage (45–124 L/kg substrate (depending on dry solids of feedstock)) as in comparison to raw pig slurry (10 L/kg substrate). The use of these materials as co-substrates with raw pig slurry will increase significantly the biomethane yield per unit feedstock in the biogas plant.     

苇沟大型猪场猪粪沼渣在黄瓜栽培上的应用

用絮凝后的猪粪沼渣和沼水在黄瓜栽培上应用试验结果表明，用沼渣作基肥效稍优于等量Ｎ，Ｐ，Ｋ化肥，用沼水作追肥肥效明显低于等Ｎ化肥。沼渣中所含的Ｃａ，Ｆｅ，Ｃｕ，Ｍｇ，Ｍｎ，Ｚｎ，Ｍｏ等元素与黄瓜植株中所含的元素种类基本一致，长期应用沼渣可保持土壤肥力平衡，应用絮凝沼渣与化肥混合配成的复肥作基肥后，瓜中许多元素的含量低于其他处理，此现象可能与沼渣絮凝剂和加工工艺有关。     

Anaerobic Digesters: From Waste to Energy Crops as an Alternative Energy Source

Abstract

The main objective of the present study is to investigate the integrated organic waste-anaerobic digester-energy crop production system as a eco-agricultural system and to use anaerobically digested cattle slurry as fertilizer for safflower production. The value of slurry as fertilizer for growing safflower was compared with commercial organic and chemical fertilizers. According to the results of this study, higher yields were obtained from the application of anaerobically digested cattle slurry as fertilizer than the applications of commercial organic and chemical fertilizers such as aerobically digested cattle fertilizer, composted poultry fertilizer and compose fertilizer. Recycling of organic wastes by this system can decrease input of chemical fertilizer and use of fossil fuels. Also, it can improve soil texture. In conclusion, this system that combined organic waste, biogas production and energy crop production as an eco-agricultural system will play an important role in improving residential sanitation and economical development in rural areas.     

Pig slurry as fertilizer on willow plantation

The aim of this study is to investigate the effect of the use of pig slurry as fertilizer on the productivity of a willow plantation, while evaluating the risk of a negative impact on the environment. We evaluated plant response to increasing slurry amounts and compared this response to the effect of mineral fertilization. We also verified the impact of slurry on soil nutritional content as well as on nitrate and phosphorus concentrations in the soil. Although slurry nitrogen was less efficient than mineral fertilizer, the results of our study show that slurry constitutes an effective fertilizer for willow plantations. In fact, yields over two years on plots that received increasing amounts of slurry were on the order of 30.0-32.9 t/ha. We observed an increase in soil levels of nitrates, copper and zinc as a function of increasing slurry amounts. These levels actually decreased during the second growing season, possibly due to uptake by the willows. Springtime concentrations of water in lysimeters indicated that the maximum quantity of slurry tested was accompanied by a certain risk of nitrates leaching into the soil.     

Can slurry biogas systems be cost effective without subsidy in Mexico?

Biogas from pig slurry in Mexico has potential to produce 21 PJ per year, equivalent to 3.5% of natural gas consumption in 2013. In this paper, three different scenarios are analysed: mono-digestion of pig slurry in a finisher farm (scenario 1); co-digestion of pig slurry and elephant grass in a finisher farm in situ (scenario 2) and co-digestion of pig slurry and elephant grass in centralised biogas plants (scenario 3). The digesters proposed are anaerobic high density polyurethane (HDPE) covered lagoons. HDPE centralised plants can have capital costs 5 times cheaper than European biogas plants. The economics of utilisation of biogas for electricity generation and as biomethane (a natural gas substitute) were investigated. Economic evaluations for on-site slurry digestion (Scenario 1) and on-site co-digestion of elephant grass and pig slurry (Scenario 2) showed potential for profitability with tariffs less than $US 0.12/kWh_e. For centralised systems (Scenario 3) tariffs of $US 0.161/kWh_e to $US 0.195/kWh_e are required. Slurry transportation, energy use and harvest and ensiling account for 65% of the operational costs in centralised plants (Scenario 3). Biomethane production could compete with natural gas if a subsidy of 4.5 c/L diesel (1 m³ of biomethane) equivalent was available.