Planting grass on stabilized chemically assisted precipitated sewage sludge

The feasibility of growing plants on pulverized fuel ash (PFA) plus lime and PFA stabilized chemically assisted precipitated sewage sludge was investigated. Apropyron elongatum (tall wheat grass) was used in the plant growth experiment. The experiment was conducted by using four application rates of the stabilized sludge mixtures to soil (2.5%, 5%, 10% and 20%). The results showed that an application dosage up to 20% exerted no inhibitory effect on plant growth. Besides, the germination rate and yield of the grass increased when the application dosage was increased. Applying the stabilized sludge to the soil generally decreased Zn and Ni while increased Cu and Pb availability to the plant. There was a good correlation (r > 0.9) between Zn uptake by the plants and the application dosage of stabilized sludge to the soil. There was no observed difference in the effects of sludge-ash and sludge-ash-lime amendment. It was demonstrated that alkaline stabilized Chemically Assisted Primary Sedimentation sludge had positive fertilizing effects for plant growth, provided that the application dosage was carefully controlled.