Sewage sludge treatment is expensive and a big environmental issue. Researchers used lime to stabilize sludge at a wastewater treatment plant. By raising the pH level, they found that microorganisms in the sludge were either killed or made inactive. They tested different amounts of lime and found that 120 grams of quicklime per 3 kilograms of sludge met one set of guidelines, while 450 grams per 3 kilograms met stricter guidelines. This method could be a good way to handle sludge as long as it doesn't harm the soil.