Waste water treatment generates a large quantity of sludge, which can be treated by (a) anaerobic digesters (b) floc (c) chemicals (d) oxidation pond
Option A. Sewage treatment involves primary and secondary treatment: Primary treatment: Physical removal of debris and solid particles. Secondary treatment: The primary effluent is aerated allowing the growth of flocs. In the settling tank, the flocs settle down. This sediment is called activated sludge. Some of this sludge is fed back as inoculum into the aeration tank. The rest is pumped into anaerobic digesters
