Soil-like material prodn. from sewage sludge - by adding acidic ferrous salt soln., alkaline earth base, silicic cpd., dry alkaline earth base, removing water and ageing

摘要

Sewage sludge is treated to produce a soil-like material. An acidic ferrous salt solution is first added to the sludge to reduce its pH to below 4. An alkaline earth base is then added to raise its pH to at least 10. A silicic compound is added in an amount by volume up to twice the volume of the sludge, and a dry alkaline earth base is added in a volume of 0.05 to 0.2 of the added silicic compound. The resulting product is processed to remove excess water, if necessary. The product is finally allowed to age in contact with a natural environment to produce the soil-like material.