摘要：
As one of the harmless treatment methods for animal carcasses, the composting has attracted more and more attention. There will be odor and volatile organic compounds (VOCs) emission during the composting of pig manure and the carcass composting. In order to study the feasibility of odor and VOCs removal by biofiltration, the pilot mixed composting experiment of dead pig and pig manure was carried out. The fermentation materials were pig manure and corn stalks, pig manure was taken from one pig farm in Anding Town, Daxing District, Beijing City, and the corn stalks were taken from local farms, which were cut to 5 cm by the crusher. Corn straw and pig manure were mixed at a volume ratio of 2:1; the water content of mixture was 69.4%, and the total carbon and total nitrogen contents of the mixture (dry-basis) were 34.4% and 3.0%, respectively. Blower used for composting ventilation ran intermittently at 10-minute/20-minute (on/off) cycles, and air was supplied to the composting piles at air flow rate of 60 L/(m3·min). The fermentation period was 42 d. The fermented mature compost was used as the biofilter medium and activated sludge as added material. The odor concentrations and VOCs components during dead pig composting were analyzed. The key parameter i.e. the residence time of the filter material in biofiltration was studied. The results showed that, during the 7-week composting period, the daily average temperature was maintained above 55 °C for more than 12 days, so all the composting trials could meet the requirement of China national standard, in which more than 50 °C temperature lasting 10 days is required for sterilizations. The odor concentration from pig manure and carcass composting was influenced mainly by composting temperature. The odor concentration was the highest in first 7 days of composting, and relatively weak in the second and third week, but the odor concentration reached another peak value after pile-turning. Thirty-seven kinds of VOCs were discharged during the composting, including 12 kinds of aromatic hydrocarbons, 21 kinds of halogenated hydrocarbons, one kind of ketones and 3 kinds of mercaptans thioethers. Among the VOCs, the smelly and odor-causing matters were trimethylamine, dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide. The biofiltration system presented good performance for odor and VOCs removal. With the retention time of 30-100 s between odor and biofilter medium, the removal efficiency of odor concentration could reach more than 90%, and there was no significant difference between different treatments. And with the retention time of 30-100 s between odor and biofilter medium, the removal efficiencies of the main odorant of VOCs, trimethylamine, dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide, were 82.2%-100%. With the retention time of 60-100 s between odor and biofiltration medium, the removal efficiencies of the main odorant had no significant difference, but was significantly higher than that with the retention time of 30 s. The optimum empty bed retention time (EBRT) of biofiltration for the removal of odor and VOCs was 60 s, and the removal efficiencies of the main odorant of VOCs could reach 82.2%. The study provides data support for mitigating odor and VOCs gas emissions during the composting of pig manure and dead pigs.%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.
