abstract |
Disclosed are apparatus and methods for treating wastewater. In one example a system for treating wastewater treatment is provided. The system comprises a biological reactor having an inlet in fluid communication with a source of wastewater and an outlet, the biological reactor configured to treat wastewater from the source of wastewater and output a biologically treated wastewater from the outlet, a solids-liquid separation system having an inlet in fluid communication with the outlet of the biological reactor and configured to separate the biologically treated wastewater into a solids-lean effluent and a solids-rich waste activated sludge (WAS), a treatment subsystem comprising a digester, an inlet in fluid communication with a WAS outlet of the solids-liquid separation system, and an outlet for providing ballasted and digested WAS, and a ballast feed system configured to deliver ballast to one of the biological reactor and the treatment subsystem. |