Research On Municipal Sewage Treatment With The Process Of High-effective Contact Oxidation And Enhanced Coagulation

With the application of integrated process of contact oxidation and enhancedcoagulation, low concentrated municipal sewage can be treated with high efficiency.Under the optimal condition, the total removal of pollutants can reach COD 84%,NH_3-N 85%, TN 38%, TP >90% and turbidity 95%, respectively. Correspondinglythe effluent with the characteristics of COD<50mg/L, NH_3-N<5mg/L, TN<20mg/Land TP<0.5mg/L can meet the first standard of GB 18918-2002.Biological contact oxidation is efficient for the removal of dissolved organicmatters. The result shows that the optimal condition for the process can concludeHRT = 2.5h and A value standing for cross influence of temperature and DO ranges 2to 3. The efficiency can reach 65%⁷0% for COD, 30%-40% for NH3-N (lowtemperature) and 80% (normal temperature). Sewages with the characteristics ofCOD from 100 to 320mg/L, Nt-I3-N from 18 to 35mg/L and TP from 3 to 8mg/Laverage the effluents of COD 74mg/L, NH3-N 20mg/L (low temperature) and 8mg/L(normal temperature) and TP 4.5mg/L.Enhanced coagulation is available for suspended pollutants and colloids. Theresearch utilizes the self-made new coupling oxidation flocculant for the advancedtreatment of effluents from previous process. The condition including the amount ofchemicals, precipitation time, flocculation reaction time and mix strength best follows180mg/L, 25min, 15min and 100r/min correspondingly. The removal rate reachesCOD56.5%, NH₃-N51%, TP91.3% and turbidity 97.3%, respectively. Flocculantamount for the treatment to meet the discharge standard is accord to the equation:y = 1.2194x - 25.805.The mechanism of pollutants removal depends on kinds of analytical ways.From the results of GC-MS, the biological technology can well treat the alkane, areneand heterocyclic compounds; the simultaneous nitrification and denitrification can beindicated by the accumulation of nitrite; the removal of phosphorus depends on theremoval mechanisms, such as dissolved orthophosphate can be treated by chemical precipitation while non-orthophosphate by adsorption.