Performance And Key Affecting Factors Of A Simultaneous Desulfization And Denitrificaion Process

An innovative integrated technology for simultaneous desulfurizatin and denitrification (SDD) was developed based on high bio-technology contraposing to the complicated, high-cost, and low efficiency current high strength sulfate-and ammonia- laden organic wastewater treatment. Sulfate reduction & carbon removal (SR-CR) unit and denitrifying sulfide removal (DSR) unit are the two key units of the SDD process system. By cooperated the two units can not realize the simultaneous removal of carbon, nitrogen and sulfur, but eliminate the second environmental pollution, which a high effective, low cost, low pollution, high stable technology.This study mainly focuses on performance and key parameters of the combinated process for simultaneous nitrogen and sulfur removal. Firstly the simultaneous sulfate reduction and carbon removal performance of SR-CR unit was investigated.Then the key parameters and kenetic model of DSR unit was discussed. Based on this, the performance of combinated process system was explored. The results provide further theoretic and technical support for the high strength sulfate-and ammonia laden wastewater treatment.SR-CR unit could be successfully set-up adoped EGSB reactor by inoculated with methanogenic granule sludge and no sulfate addition initially. At the organic loading rate of 5.0kgCOD/(m3·d), C/S ratio of 3.3, the removal efficiencies of COD, TOC and sulfate could reach as high as 80%,91.6%,96%, respectively.The effect of C/S ratios, sulfide concentrations and nitrion on DSR unit was discussed. The results indicated nitrite had little restrain on DSR operation even at 190mgN/L. All sulfides removed were convert to elemental sulfur. The results proved the feasibility of short-cut denitrifying sulfide removal (short-cut DSR).Based on ASM1, DSR kinetic model was established adopting Aquasim2.0 by introduced competing parameters and restricting parameters. The effects of sulfide and C/S ratio were predicted based on the kinetic model. The prediction results showed thatS2-<11000mg/L and C/S of 0.5~3.0 were benefit for DSR operation.The performance of combinated process system was investigated by associated SR-CRunit with DSR unit. The result indicated the removal rates of COD, sulfate and nitrate were as high as 91%,98%,99%, and the S0 production rates could reach 0.30 kgS/(m3·d) at organic loading rate of 5.0kgCOD/(m3·d), sulfur loading rate of 0.33 kgS/(m3·d) and nitrogen loading rate of 0.033 kgN/(m3·d). Similarly, the removal rates of COD, sulfate and nitrate were as high as 93%,92%,99%, and the S0 production rates could reach 0.39 kgS/(m3·d) at organic loading rate of 5.0kgCOD/(m3·d), sulfur loading rate of 0.5 kgS/(m3·d) and nitrogen loading rate of 0.14 kgN/(m3·d).