添加生物炭对猪粪好氧堆肥的影响

Influence of biochar on the aerobic compost of pig manure

在猪粪好氧堆肥过程中添加污泥生物炭或猪粪生物炭,研究生物炭对堆肥温度、pH、电导率(EC)、营养成分和重金属的影响。结果表明,添加污泥生物炭组的堆体温度在第10d达到50℃,快于对照组的12d,但由于高温期停留时间较短,未达到粪便无害化卫生要求(GB 7959-2012);添加猪粪生物炭组的堆体温度在第4d达到50℃,最高温度达到66.2℃,高于对照组的63.4℃,且能够满足GB 7959-2012。污泥生物炭和猪粪生物炭的加入可以降低堆体可溶性盐的浓度;添加猪粪生物炭可以降低堆体铵态氮的损失,促进速效钾的增加,而污泥生物炭则呈现相反的作用。堆肥后与对照组相比,添加污泥生物炭组Cr和Cu的残渣态比例分别从93.82%和36.78%增至94.44%和41.94%,添加猪粪生物炭组Cr和Cu的残渣态比例分别增至94.27%和60.26%,这说明添加污泥生物炭和猪粪生物炭有利于堆肥产物Cr和Cu的固化。此外,猪粪生物炭的加入还可以降低产物的潜在风险指数。综合分析,与添加污泥生物炭相比,添加猪粪生物炭的堆肥效果更好,可以作为一种良好的堆肥添加剂。

In this work, we used sludge and pig manure biochars as additives for the aerobic compost of pig manure to study their effects on temperature, pH, electrical conductivity(EC), nutrient content, and heavy metals during composting. Our results showed that the temperature of the compost pile added with sludge biochar reached 50 ℃ on Day 10, faster than the control, which reached that same temperature on Day 12. However, the compost with sludge biochar addition did not meet the hygienic requirements for the harmless disposal of night soil(GB 7959-2012), due to its short residence time in the thermophilic phase. On the other hand, the temperature of the pile added with pig manure biochar reached 50 ℃ on Day 4, reaching its maximum at 66.2 ℃(a higher temperature than the 63.4 ℃ of the control)and satisfying the GB 7959-2012. The concentration of soluble salts in the two piles was reduced by adding sludge biochar and pig manure biochar,respectively. The addition of pig manure biochar reduced the loss of ammonium nitrogen and promoted an increase in available potassium in the compost pile, while the addition of sludge biochar had the opposite effect. Furthermore, the addition of sludge and pig manure biochars in the compost increased the residual fractions of Cr and Cu:from 93.82% and 36.78% in the control, they reached 94.44% and 41.94% with the addition of sludge biochar, and 94.27% and 60.26% with the addition of pig manure biochar, respectively. These results indicated that the addition of sludge and pig manure biochars improved the immobilization of Cr and Cu in the compost products. Moreover,the addition of pig manure biochar could reduce the potential ecological risk of compost products. Overall, pig manure biochar is more effective when it is added to the compost, compared with sludge biochar, and it can be used as a suitable compost additive.