Powdered lime is utilised extensively in the treatment of wastewater; for example, to reduce odour in raw, primary sludge, as a cost-effective alternative to using digesters. It is also used in other water treatment processes to help balance pH levels and as part of composting methods for sludge removed from the bottom of primary tanks after it has been de-watered and compressed. The lime and remaining water in the sludge together creates a heated chemical reaction, accelerating the process.