污水污泥堆肥重金属总量及形态变化

采用高温好氧静态强制通风堆肥工艺，研究了污水污泥与锯末、粉煤灰或磷矿粉按不同比例混合堆肥前后重金属(Cu，Pb，Zn，Cd和As)总量的变化，以及重金属在交换态、碳酸盐结合态、铁锰氧化物结合态3种不稳定态和包括有机结合态、残渣态的稳定态含量的变化，同时探讨了粉煤灰和磷矿粉在堆肥过程中所起的钝化效果. 结果表明:该试验可以显著降低污泥中交换态Cu，Pb，Zn，Cd和As的含量，提高其他形态的含量，但不能降低重金属总量；对重金属的作物可利用态含量的降低以及其他形态含量升高的效果来看，试验A最好，试验B和D次之，试验C最差. 粉煤灰和磷矿粉都是良好的钝化剂，在起钝化效果时，其用量并不是越多越好；在与污泥、锯末混合堆肥中，应控制粉煤灰和磷矿粉用量在15%左右，但是粉煤灰的钝化效果优于磷矿粉. 

Study on the Changes of Total Contents and the Status of Heavy Metals for SewageSludge Composting

The high temperature, aerobic and forced aeration static-composting system wereadopted to study the changes in total contents of heavy metals, including Cu, Pb, Zn, Cd and As, as well as their status contents of unstable states (includingexchangeable state, carbonate combination state and Fe-Mn oxide combination state) and stable states (including organic combination state and residuum state) during different proportion mixed of sewage sludge and sawdust, fly ash or phosphate rocks composting process. Then the passivation effect of fly ash and phosphate rocks in the compost process was discussed. The results show that this process may remarkably reduce the content of sludge exchangeable Cu, Pb, Zn, Cd, As and increase the content of others, but cannot reduce the heavy metals over all contents. To reduce crops available state and increase the content of other states of heavy metals, it is discovered that test A is best, B and D are secondary, and test C is final. Meanwhile, fly ash and phosphate rocks are found to be goodpassivators; their usages are necessarily as many as possible for the passivation effect. In these tests, the usages of them were about 15%, and the passivation effect of fly ash was superior to that of phosphate rocks.