The potential use of waterworks sludge in greening: A bioassay with bermudagrass [Cynodon dactylon (L.) Pers.

Abstract

Owing to the escalating production of waterworks sludge from growing population and water consumption, conventional options for the management of waterworks sludge may no longer be economically and environmentally viable. It is imperative to develop alternative measures for the sustainable management of waterworks sludge. This study explored the potential use of waterworks sludge as a soil substrate for greening through a bioassay with bermudagrass [Cynodon dactylon (L.) Pers.]. Treatments of the experiment varied with loading rates of waterworks sludge, soil types, and combined uses of fertilizers and peat moss. Several key findings were identified. First, the optimal rate of sludge application was approximately 25 % wt/wt, which was at least 1.5 times higher than the existing literature suggested. Second, it is necessary to add fertilizers and peat moss to make the sludge-loaded soil a suitable growing substrate for plants. The combined use of fertilizers and peat moss were more effective than fertilizers or peat moss used alone. Third, no significant environmental risk was ascertained, in terms of heavy metal pollution, when the loading rate of waterworks sludge was 25 % wt/wt. The results indicated waterworks sludge has a higher potential to be a soil substrate in greening, therefore, it could be a cost-efficient and safe surrogate to traditional measures.