Full Scale Experiment of Applying CEPT to Treat Municipal Wastewater with Lower Concentration of Contaminants

摘要

The concentration of contaminants in municipal wastewater is lower in Wuhan. BOD_5 is normally less than 100 mg/L. If Chemically Enhanced Primary Treatment, CEPT, is applied to treat the wastewater, more contaminants will be removed with less operation expenses. Full scale experiment was conducted in Wuhan Wastewater Treatment Plant. The quantity of wastewater was 35000 m~3/d. The HRT in flocculating zone was 10 min and the HRT in settling zone was 50 min. The dose of M1011 was 0.15 mg/L and the doses of PAC were 50, 40 and 25 mg/L during the periods of high, medium and low concentration of contaminants. The results of the experiment are as follows: (1) The SS in the effluent is less than 30 mg/L, and the average SS removal is 79.2%. (2) The COD in the effluent is less than 85 mg/L, and the average COD removal is 62.0%. (3) If the BOD_5 in the influent is no more than 75 mg/l, the BOD_5 in the effluent is normally less than 30 mg/L. If the BOD_5 in the influent is no less than 75 mg/l, the average BOD_5 removal is 62.0%. (4) The average removal of total phosphorous is 67.3%. The removal of contaminants is too low to treat the municipal wastewater with lower concentration of contaminants applying primary treatment. And the energy consumption is too great to treat the wastewater applying secondary treatment. If CEPT is applied to treat the wastewater, both the construction cost and operation expenses will be low while the removal of contaminants will be comparatively high.