The sewage sludges can be used as amendments on crop land.

但是，如果污水淤渣中含有超标准的重金属元素，它将污染土壤。

Sludges forming in the acid interfere with storage and handling.

在酸中形成淤渣，妨碍贮存和运输。

Typically these sludges settle rapidly but do not compact very well.

这些污泥一般沉降迅速，但并不很紧密。

Better methods of dewatering and disposing of these sludges are needed.

需要研究更好的污泥脱水和处置方法。

The granular sludges had high methanogenic activity and good settleability.

颗粒污泥活性高、沉降性能好。