Process for treating wastewater with high COD loads by circulating oxygen / oxygen-rich gas, removing part of the CO¶2¶ and returning oxygen to the circuit

摘要

Liq. sewage flowing through an enclosed container is treated by O2 or air injected from the container floor area to dissolve in the liq. and react with entrained material. Gas collected from the space above the liq. surface, together with CO2 formed by reaction and not dissolved in the liq. The collected gas is extd., compressed and returned for recycling, with O2 losses made good. For sewage whose chemical O2 demand is from 2500-15000 mg CSB per litre, part of the gas extd. from upper accumulation and pref, amounting to 5-15% of the total gas circulation, is branched off to a CO2 adsorber, e.g. of the pressure-cycling active carbon type, and after CO2 removal is returned to the general gas circulation. ADVANTAGE - Removal of excess CO2, which untreated, could reduce efficiency of biological sewage treatment, to max. 20% enables purificn. to proceed normally.