Abstract: Systems and method for treating wastewater including a vessel having an inlet and an outlet, a pump in fluid communication with the outlet of the vessel, the pump configured to pump wastewater out of the vessel, a separator in fluid communication with the pump, the separator configured to separate grit from the wastewater, the separator having a first outlet for discharging a grit stream and a second outlet for discharging a wastewater stream, a grit washing system in fluid communication with a source of washing fluid and the first outlet of the separator, the grit washing system configured to wash and dewater grit from the grit stream, the grit washing system having an outlet for discharging a wash wastewater stream, and a return conduit configured to recycle the wastewater stream discharged from the separator to one of the inlet of the vessel and an inlet to the pump.

Abstract: Systems and method for treating wastewater including a vessel having an inlet and an outlet, a pump in fluid communication with the outlet of the vessel, the pump configured to pump wastewater out of the vessel, a separator in fluid communication with the pump, the separator configured to separate grit from the wastewater, the separator having a first outlet for discharging a grit stream and a second outlet for discharging a wastewater stream, a grit washing system in fluid communication with a source of washing fluid and the first outlet of the separator, the grit washing system configured to wash and dewater grit from the grit stream, the grit washing system having an outlet for discharging a wash wastewater stream, and a return conduit configured to recycle the wastewater stream discharged from the separator to one of the inlet of the vessel and an inlet to the pump.

Abstract: A sludge digester including a vessel and floating cover. The vessel includes a sidewall and an interior volume configured to receive and contain sludge. According to one embodiment, the cover comprises a frame structure that is constructed and arranged to form a skirt member formed at a periphery of the cover and extending downwardly into the vessel, and a continuous ballast ring attached to a lower portion of the skirt member and configured to form a trough member with an interior surface of the skirt member. The sludge digester may also include a guide system coupled to the sidewall and the skirt member and configured to allow vertical displacement of the cover with change in volume of at least one of a gas and a sludge contained in the vessel beneath the cover.