Investigating the sludge conditioning behavior and improving sludge conditionability were the primary objectives of this study. The effects of calcium ion with and without polyelectrolyte conditioning behavior on two industrially activated sludge systems were studied via Capillary Suction Time (CST) tests.

Experimental results indicated that the calcium ion can strongly enhance the conditionability of the industrial biological sludge system. The good conditionability of calcium ion added system could have possibly resulted from the interaction of polysaccaride from activated sludge with calcium ion. Additionally, adding polyelectrolyte solution first would produce more suitable conditioning in a situation in which calcium ion is involved with polyelectrolyte system.