disinfection released good bacteria pipes put isinfection disinfection biotic disinfection released back drinking water drinkable water recycled water high flows union times ultraviolet light solid matter high impure turbidity ph significantly reduce progressively effective uv light tiny holes isolated types helpful elements crawfish waters protected waterways higher standard people animals utilized processes flowing wastewater drain network waste water tertiary refiners primary function tertiary treatment sewage treatment primary secondary treated sewage focus environment tertiary treatment turn waste water humans waste water biological treatment stage water exits homes tertiary treatment suppose tertiary treatment restores sewage treatment facilities sewage treatment plants sewage treatment plant sludge mud wastewater large coarse materials primary setup receives secondary treatment assuming secondary treatment breaks screening secondary treatment collected raw sewage foregoing treatment succession sodium hypochlorite monochloramine target living things disinfectant measure industry