【作者】 朱凤香；

【导师】 冯明光；

【作者基本信息】 浙江大学 ， 微生物学， 2012， 博士

【摘要】 猪粪规模化生猪产业的副产物,量大面广,既是有机肥的重要来源,又是不可忽视的环境污染源。围绕利用蝇蛆对鲜猪粪进行生物脱水的主题,本研究较系统地考查了蝇蛆生物脱水堆肥过程中蝇蛆产量、蝇蛆品质、堆肥样品的理化性质、酶活、植物毒性及低分子有机物质等指标的动态变化,形成了利用鲜猪粪快速生产饲用蝇蛆和合格有机肥的二步堆酵技术。主要结果摘要如下：初孵蝇蛆(家蝇Musca domestica一龄幼虫)与麦麸组成的接种体(每克含蛆约2000头),按0.25%-1.5%的重量比接种到平堆于水泥池(2.4×2.3×0.2m)中的200kg鲜猪粪中,每接种量处理三次重复,常温堆酵7天后收获蝇蛆。结果表明,0.5%接种量处理的蝇蛆产量最高,达鲜猪粪重量的11.5%。收获蝇蛆的蛋白质含量为54.62%,蛋氨酸MET含量为1.23%,赖氨酸LYS含量为4.16%,重金属含量As≤10mg/kg, Pb≤10mg/kg, Hg≤0.5mg/kg, Cd≤2.0mg/kg, Cr≤8.0mg/kg,均符合国家鱼粉标准GB13078-2001和GB/T19164-2003三级品的相应要求。经蝇蛆处理的粪渣呈小颗粒状,含水率由初始的72.3%降至56.3%,符合堆酵生产有机肥的含水率要求(50%-60%)。将上述优化的蝇蛆接种量用于扩大的二步堆酵试验中,鲜猪粪总量为1.8吨,分装于三个大水泥池(7.3×2.3×0.2m)中,常温堆酵7天后收获蝇蛆193kg,即鲜猪粪总重量的10.7%,与接种量试验中的蝇蛆产量相近。蝇蛆收获后,所有粪渣堆成长4.5m、宽2.2m、高0.8m的峰堆,并设无蝇蛆处理的相应粪堆作为对照,进行为期12周的第二步堆酵。整个堆酵期间,定期取样测定各种理化、酶活和生物指标,以考查温度、pH、含水率、水溶性碳、总氮、过氧化氢酶、多酚氧化酶、脱氢酶、碱性磷酸酶、脲酶、硝酸还原酶、亚硝酸还原酶、转化酶活性和发芽指数随堆肥过程的动态变化。结果表明,第一步为期一周的蝇蛆处理能有效降低猪粪含水率,第6天后含水率降至50-60%之间；堆肥快速升温,第10天堆温上升至50℃以上,连续9天保持平均温度55℃左右,而对照在第17天的温度才上升至50℃。与对照相比,蝇蛆处理的粪堆最终水溶性碳损失为35%,总氮损失16%。用定期抽取的堆肥样品进行大白菜和黄瓜种子的发芽试验,结果表明,蝇蛆处理样品的大白菜和黄瓜发芽指数分别在第10天和第25天达到71.4%和86.5%,其熟化比对照提早20天左右。在测定的酶活指标中,过氧化氢酶活更有堆肥腐熟的指标意义。为了研究堆肥过程中低分子有机物质随堆肥时间的变化情况,探索出顶空固相微萃取(HS-SPME)的优化条件为：CAR/PDMS萃取头,萃取温度60℃,萃取时间30min。堆酵过程中被检测到的化学物质有87种,而且大部分低分子有机物质在堆酵22天后已检测不出,此后苯环类和烷类等有害物质的含量却增大。因此,基于蝇蛆处理的鲜猪粪二步堆酵的时间应控制在22-25天,如此生产的堆肥中吡啶和吲哚类物质含量较高而具有一定的抗病促生长作用。更多还原

【Abstract】 A burst of pig industry in China has brought about a huge amount of manure that is not only a reservoir of pathogens, parasites and weed seeds but also a favorable substrate for breeding the larvae (maggots) of the housefly Musca domestica. This study sought to develop a two-stage composting technology for the use of fresh pig manure in the production of maggots as feed supplement and organic fertilizer. The objective was to maximize maggot production in the first stage and accelerate the composting to maturity in the second stage by monitoring changes in temperature, moisture, pH, phytotoxicity, microbial enzyme activities, and low-molecular organic substances. Harvested maggots were also evaluated for the quality of their feed-purpose application in terms of the contents of nutrients and heavy metal ion. The results are summarized below.A triplicate experiment was conducted to determine a proper level of wheat bran-vectoring maggot inoculum (～2000neonate maggots per gram) for the composting of fresh pig manure (with72.3%moisture) at Deqing Pig Farm (Hangzhou, Zhejiang, China). Batches of200kg manure were flatly piled to～7cm thickness in cement trays (2.4x2.3x0.2m) under greenhouse conditions and inoculated with maggot inoculum at the weight ratios of0.25%,0.5%,0.75%,1.0%and1.5%respectively, forming five treatments plus control (not inoculated). After7-day composting under ambient conditions, the yields of aging maggots (near pupation) harvested by means of their photophobotaxis differed significantly among the treatments. A maximal yield of23±1.7kg aging maggots per tray (Fig. la) resulted from the inoculum treatment of0.5%(w/w) fresh manure weight, accompanied by moisture reduction to56.2%(±1.2%), which is well in agreement with the optima of50-60%for manure composting to maturity. The body weights of harvested maggots were averagely9-19.3mg per capita, decreasing with the inoculum level. Dried maggots contained54.62%proteins,1.23%methionine,4.16%lysine, and the trace contents of0.38,1.93,0.16,0.67and1.73mg/kg for the heavy metals of As, Pb, Hg, Cd and Cr, respectively. All these indices indicate that the maggot product meets commercial fishmeal requirements (GB13078-2001and GB/T19164-2003) in China. The maggot treated manure became granular in texture.In an enlarged two-stage composting experiment, the first7-day composting of1.8ton fresh pig manure in three large cement trays (7.3x2.3x0.2m) inoculated at the optimized level of0.5%maggot inoculum resulted in a harvest of193kg aging maggots. This maggot yield was equivalent to10.7%of the fresh manure weight and close to the percent yield of11.5%at the same inoculum level in the previous experiment. After maggot harvest on day7, all the manure was piled up into a peak-shaped compost (4.5m in length,2.2m in width, and0.8m in height), namely maggot-treated compost (MC), on the ground in a rainproof workshop and a natural compost (NC) was constructed as a control in the same way using1.8ton manure composted for7days in other three trays without maggot inoculum. Both MC and NC were covered with plastic film for24h to stifle possible residue maggots and then entered the second-stage composting to maturity for12weeks, during which both composts were turned upside down every3days. As a result, reaching the thermophilic phase and final maturity faster was characteristic of MC versus NC in the two-stage composting. Upon MC transit to the second stage, the composting temperature maintained around55℃for9days and the moisture decreased to-40%. Moreover, higher pH, faster detoxification and different activity patterns for some microbial enzymes were observed from the MC samples taken daily (first stage) or every3-6days (second stage). There was a strong material loss (35%water-soluble carbon and16%total nitrogen) caused by the maggot culture in the first stage.Moreover, a headspace solid-phase microextraction method (HS-SPME) was modified to assess the contents of low-molecular organic components in the samples from MC and NC by gas chromatography with mass spectrometric detection (GC/MS). Technical parameters were optimized as the extraction head of CAR/PDMS, the extraction temperature of60℃and the extraction time of30min. With the modified method,87low-molecule organic compounds were identified from the samples taken during the two-stage composting, including some substances that may resist plant diseases or promot plant growth. Based on the temperal changes of such substances, detected phytotoxicity and other physiochemical and biological parameters, the composting of fresh pig manure to maturity needed no more than25days (～22days) for MC but45days for NC.Overall, the results highlight that a higher economic value of pig manure can be achieved by rapid production of maggots as feed supplement and qualified organic fertilizer through the two-stage composting without bulking agents.更多还原