Patent ID: 9181120
Filing Date: 2015-11-10
Classification: C02F,Y02E,Y02W

Abstract:
1. A process for treating low strength wastewater comprising two or more of the steps of, a) treating the wastewater with a primary treatment to produce a primary effluent and a primary sludge, the primary treatment comprising i) contact aeration of the wastewater or the addition of a flocculant and/or a polymer to the wastewater prior to ii) passing the wastewater through a clarifier or micro-screen such that the primary sludge contains at least 50% of the BOD in the wastewater; b) treating primary sludge by anaerobic digestion wherein the anaerobic digestion is performed at a solids content of 4% dry solids or more produced or maintained by way of influent thickening or recuperative thickening; and, c) treating primary effluent by a secondary treatment, wherein the secondary treatment comprises i) nitritation and denitritation, ii) digestion by anammox bacteria, or iii) passing through a moving bed bioreactor at a hydraulic retention time of 90 minutes or less or at a loading rate of at least 6 kg BOD per cubic meter of tank per day.