沼渣与畜禽粪便混合堆肥发酵效果的综合评价

摘要

In general biogas residue, along with livestock and poultry manure and straw as raw material, is not suitable for composting alone. Because it is mainly composed of cellulose and contains less readily biodegradable organic matter. The biogas residue mixed with livestock and poultry manure co-composting has two advantages. Firstly, the biogas residue fermentation is driven by easily degradable organic matter in manure. Secondly, the biogas residue is used as a conditioning agent during the composting, which is conducive to ventilation. A variety of comprehensive evaluation methods have been used for evaluating the compost maturity, but lack of study on the biogas residue mixed with livestock and poultry manure co-composting. In this study, four biogas residues mixed with pig manure and chicken manure co-composting experiments, with different material ratios (dry weight), were tested for amount of biogas residue, pig manure, and chicken manure using orthogonal experiment design. Physical (e.g. time required to reach 50℃, heating rate, duration time above 50℃, maximum temperature), chemical (e.g. pH value, organic matter, C/N, NH4+-N, NH4+-N/NO3--N, total nutrient) and biological (e.g. faecal coliform value and GI) indicators were characterized during composting. Correlation analysis among all above-mentioned indicators was conducted in order to determining the fermentation effect of biogas residue mixed with livestock and poultry manure co-composting more accurately,. A compost maturity evaluation index systemincluded pH value, duration time above 50℃, T value, NH4+-N, NH4+-N/NO3--N and GI after eliminating parameter overlap influnce. The fermentation effect of co-composting was evaluated using fuzzy comprehensive evaluation method, gray correlation analysis method and attribute recognition methodin order to provide a theoretical basis for biogas residue mixed with livestock and poultry manure compost utilized as fertilizer. The results showed that T3 (w (biogas residue amount): w (pig manure amount): w (chicken manure amount)=5.85:8.49:8.19), reaching the highest heating rate, the longest high temperature phase and the highest temperature in high temperature phase. T2 (5.85:7.425:6.825), was the second, T1 (7.02:7.425:8.19) and T4 (7.02:8.49:6.825) were the worst. The fermentation effect of T2 and T3 is better T1 and T4 based on the results of chemical indexes, such as pH, organic matter, C/N, NH4+-N, NH4+-N/NO3--N and total nutrient content. End facal coliform value of T1, T2, T3 and T4 was 1, 10-1, 10-2 and 1, respectively. GI of the four composting was 96.72%, 103.35%, 98.42% and 85.13%, respectively. Fermentation effects of T1, T2 and T3 were the same by fuzzy comprehensive evaluation method, gray correlation analysis method and attribute recognition method except T4. Better mature, better maturity reached for primary maturity and badly immature. In summary, the evaluation of compost fermentation effect should synthetically consider physical, chemical and biological indicators instead of a single index. Compared to other two methods, gray correlation analysis method is better suited for evaluating compost fermentation effect.%采用正交试验设计方法实施了4组不同物料配比（以干质量计）沼渣与畜禽粪便混合物料堆肥试验，并采用模糊综合评价、灰色关联分析和属性识别法对其发酵效果进行了评价，为沼渣的肥料化利用提供参考。结果表明：T3（沼渣∶猪粪∶鸡粪=5.85∶8.49∶8.19）升温速率最快、高温维持时间最长，所达温度最高，T2（5.85∶7.425∶6.825）次之，T1（7.02∶7.425∶8.19）、T4（7.02∶8.49∶6.825）最差；从pH值、有机质、C/N、NH4＋-N、NH4＋-N/NO3--N和总养分等化学指标看，T2、T3发酵效果优于T1、T4；堆肥结束后，T1、T2、T3、T4粪大肠菌值分别为1、10-1、10-2、1，发芽指数GI分别为96.72%、103.35%、98.42%、85.13%。上述3种评价方法对T1、T2、T3发酵效果评价一致：较好腐熟，但对T4评价结果分别为较好、基本和极未腐熟。综上所述，由单一指标或单一评价方法评判堆肥腐熟度有局限性。对堆肥发酵效果的评价应综合考虑物理、化学和生物学指标，对比3种评价方法原理，灰色关联分析法是评价堆肥发酵效果的较优方法。