化学法浸提污泥土地利用的适用性

Feasibility of Chemical Extraction Sewage Sludge in Land Utilization

以L一天冬氨酸、氨三乙酸、DL一苹果酸和丙二酸为浸提剂，研究了化学法浸提污泥对重金属（Cu、Zn、Pb、cr）形态、营养元素流失、污泥农用后作物生长状况及重金属累积的影响，分析了化学法浸提污泥土地利用的适用性．结果表明：浸提剂对cu、zn、Ph、cr最高去除率分别为89．1％、32．4％、52．7％、39．2％，化学浸提后，残留于污泥中的重金属不稳定态含量显著减少，提高了污泥土地利用的安全性；污泥经化学法浸提后总氮和总磷的流失率分别为9．0％～92．0％和56．4％～77．3％，但仍能保持较好的肥效，满足土地利用的需要．将污泥适量施于农田，小麦植株干重明显增加，但随着污泥施用量的增加，小麦根系和茎叶中重金属的累积量随之增加．从小麦生长状况与重金属残留综合考虑，污泥与土壤的配比为50％较为合适．

A batch of experiments of the heavy metals contaminated sewage sludge with L-aspartic acid, nitrilotriacetic acid, DL-malic acid and malonic acid were conducted to investigate the effects of chemical extraction sludge to heavy metals＇ form （Cu, Zn, Pb, Cr） , the loss of nutrient elements and the crop growth status and heavy metal accumulation after sludge applied, and also to analyze the feasibility of chemical extraction sludge in land application. Results show that, the highest removal rate of Cu, Zn, Pb, Cr is up to 89.1% , 32.4% , 52.7% , 39.2% respectively,and the content of the unstable state of heavy metal in sludge was reduced significantly after chemical extraction. As a result, the security of chemical extraction sludge in land application was also significantly improved. After chemical extraction, although the variable range of the total nitrogen and total phosphorus in sludge loss rate are 9.0% 92.0% and 56.4% -77.3% respectively, it can still maintain the good fertilizer efficiency and satisfy the need of land use. When the right amount of sludge is applied to farmland, the dry weights of wheat are increased sharply. However, the accumulations of heavy metals in wheat root and shoot are also increased with the increase of sludge. So the appropriate ratio of sludge and soil is 50% when taking wheat growth status and heavy metal residues into consideration.