With the sewage sludge with the sewage treatment plant, the most common sludge includes Main and secondary sludge, wherever the key sludge could be the sludge collected from the first clarifier, plus the secondary sludge would be the surplus-activated sludge (Nielsen and Stefanakis 2020). As with the onsite sanitation system, https://rotating-sludge-scraper81357.actoblog.com/29399448/the-2-minute-rule-for-tilting-plate-type-clarifier