UASB+A/O+Breakpoint Chlorination Process The High Organic Wastewater With High Ammonia Nitrogen

The paper aimed at the wastewater containing high concentration of organic pollutant and ammonia nitrogen discharged in the productive process of a biopharming factory, located at a city of Jiangxi Province. According to the features of wastewater, choosing the combination of UASB and A/O was practicable to dispose the pollutant. Controlled the technological conditions of UASB to remove large of organic pollutant effectively,ensuring the outlet water is suitable for the follow-up treating; Denitrification of ammonia nitrogen is proceeding in oxygen-deficient tank through using the surplus organic matter as carbon source and nitrate nitrogen from the reflux miscible liquids as electron acceptor, and nitrification of ammonia nitrogen proceeds in aerobic tank with removel of most of ammonia nitrogen; using break point chlorination to remove more surplus ammonia nitrogen in outlet water. After almost four months about starting、debugging and normal working these reactors, the condition of outlet water was stable and suitable,up to the national discharge standard.(1) The high concentration of organic pollutant in wastewater, between4600mg/L and5200mg/L,can be disposed in UASB reactor. Put almost150m3seed sludge from digestion pool. The preliminary concentration of sludge was about1.325kgVSS/m3.The way of previous low load operation and gradually increased load was adopted when UASB started. previous load was about0.96～1.15kg/(m3·d) by the means of controlling the rate of flow and concentration of pollutant. Gradually improved the load later, strictly managed the operation conditions including pH、 basicity、sludge loading、temperature、hydraulic load、etc. After40d,the anaerobic granule sludge in tank was successfully cultured and The granulated degree of the formed sludge bed was high. When the unit operated smoothly and reliably, the volume loading was up to3.3kg/(m3·d) and the removel rate of COD was about75%.(2) The wastewater contained a high concentration of ammonia nitrogen, between200-250mg/L.Adopting technology of A/O was suitable and efficient to dispose the ammonia nitrogen and surplus organic matter.The way of previous low load and intermittent water importing and later increased load and continuous water importing. As the rise of temperature, The sludges had high activity and good settleability. Managing the reflux ratio of nitrification mixed liquid、reaction temperature、DO、pH、reflux ratio of sludge from secondary sedimentation tank,the concentration of organic pollutants and ammonia nitrogen has dropped gradually. A/O start successfully after five months. When the reactor worked stably,DO was0.5mg/L in A pool,3～3.5mg/L in the front of O pool and3～5mg/L in the back of O pool; The pH was7.5～8.0in A pool,7～7.5in O pool; The reflux ratio of nitrification mixed liquid was2.75～3; Reflux ratio of sludge was1.0.The removel rate was above85%and COD was under200mg/L.(3) The outlet water from A/O pool still contained a certain amount of ammonia nitrogen need to be disposed. Adopting break point chlorination and managing related factors conditions made the concentration of ammonia nitrogen in outlet water significantly less than the national standard. In order to discharge to nature safely, dispose residual chlorine of water by passing the coke columns.(4) After starting> debugging and normal working these reactors, concluded that the combination of UASB+A/O was extremely stably effective about wastewater disposing. The removel rate of organic pollutant was about97%and the removel rate of ammonia nitrogen was above85%.The final outlet water achieved the goal of Discharge standards of water pollutants for pharmaceutical industry existing enterprise emission limits, being friendly to natural environment.