Abstract: A tertiary treatment unit is provided that has a first filtration unit operatively connected to an influent for filtering solids therefrom to form an effluent, a second filtration unit operatively connected to the first filtration unit to receive the effluent and to filter finer solids and bacteria and viruses from the effluent, a supply tank operatively connected to the effluent to provide chemicals that are mixed into the effluent, and a reactor that receives the effluent and removes nitrogen and some phosphorous therefrom to form a treated effluent. The treatment unit further has a first adsorption unit that receives the treated effluent and adsorbs additional nitrogen, BOD, TSS and certain chemicals from the treated effluent, and a second adsorption unit that receives the partially adsorbed treated effluent from the first adsorption unit and adsorbs additional phosphorous from the treated effluent to form the final effluent.