sludge of waste water treatment plant in sri lanka

aeration and ariaton beautiful can conventional drinking from industrial lanka numerous obtained other plant processes produced semisolid settled sewage sludge slurry sri suspension tanks treatment waste wastewater water tank factory ecology environment industry dirty purification recycling purity purified pollution sedimentation environmental clean recycle system storage round effluent conservation technology circle aerial process liquid station green flow removal urban facility view steel sewer recycled construction full circular nobody separation biology filtration