To the sewage sludge through the sewage treatment plant, the commonest sludge involves Principal and secondary sludge, where the first sludge could be the sludge collected from the first clarifier, plus the secondary sludge could be the surplus-activated sludge (Nielsen and Stefanakis 2020). As for the onsite sanitation system, the https://watertreatmentequipments14691.designertoblog.com/60322769/top-latest-five-rapid-sand-filters-urban-news