进水COD浓度对厌氧同步脱氮除硫特性的影响

Effect of Influent COD Concentration on Characteristics of Simultaneous Desulfurization and Denitrification

研究了不同进水有机物浓度条件下,接种物不同的厌氧体系的同步脱硫反硝化特性。结果表明:当进水COD浓度从零增加到250mg/L时,两个接种物不同的反应器对硫化物、硝态氮和COD的去除率变化不同。接种厌氧污泥的1#反应器对硫化物的去除率从85%逐渐增加到99%,80%～90%的进水COD被去除,但产气量逐渐降低,出现了亚硝态氮的积累,反硝化脱氮困难;接种脱氮硫杆菌到厌氧污泥中的2#反应器对硫化物的去除率一直稳定在99%,相应的产气量也逐渐增大,脱氮效率高,55%～73%的进水COD被去除。此外,在这个浓度范围内,还观察到两个反应器出水硫酸盐的浓度由不加乙酸钠的23mg/L分别降到18mg/L和19mg/L,理论上硫转化率提高了4%～19%。当进水COD>400mg/L时,仅60%～76%的硫化物被去除,相应的产气量也迅速降低,硫化物的氧化和反硝化过程均明显受到抑制。总而言之,在进水COD为250mg/L时,2#反应器对硫化物和硝态氮的去除率均达到了100%左右,对硫化物的比降解速率和产气量也提高了1.1～1.2倍,相应的出水硫酸盐浓度最低,80%左右的硫化物转化为单质硫,73%的COD被去除,可以实现同时脱氮、除硫和除碳,为同步脱氮除硫工艺的实际应用提供了新的思路。

The characteristics of simultaneous desulfurization and denitrification in anaerobic systems with different inoculums were investigated at different influent organic concentrations. The results show that the removal efficiencies of sulfide, nitrate nitrogen and COD are different in both reactors with different inoculums when the influent COD concentration is increased from 0 to 250 mg/L. In 1^# reactor inoculated with anaerobic sludge, the removal rate of sulfide is gradually increased from 85% to 99%, and 80% to 90% of the influent COD is removed. However, the gas production is decreased, the nitrite nitrogen is accumulated in the effluent, and the denitrification is difficult. In 2^# reactor inoculated with pure Thiobacillus and anaerobic sludge, the removal rate of sulfide is stable at 99%, the corresponding gas production is gradually increased, the denitrification efficiency is high, and 55% to 73% of the influent COD is removed. In addition, it is observed at this concentration that sulfate concentrations in the effluent from both reactors are decreased from 23 mg/L without sodium acetate to 18 mg/L and 19 mg/L respectively. The theoretical sulfur conversion rate is increased by 4% to 19%. When the influent COD concentrations exceed 400 rag/L, only 60% to 70% of the influent sulfide is removed, the corresponding gas production is rapidly decreased, and the oxidation and denitrification processes of sulfide are inhibited obviously. It is concluded that when the influent COD is 250 mg/L, the removal rates of sulfide and nitrate nitrogen in 2^# reactor are all 100%, the specific degradation rate and gas production are increased by 1.1 to 1.2 times, the corresponding effluent sulphate concentration is lowest, 80% of the sulfide is transferred into elemental sulfur, and 73% of the COD is removed. The simultaneous desulfurization, denitrification and decarbonization are achieved, which provides a new idea for actual application of simultaneous desulfurization and denitrification process.