Study On Treatment Of Sulfide Wastewater Using Adsorption-Biological Contact Oxidation Process

Sulfur water, which has complex composition, substances difficult to be biodegradable, is more difficult to treat. After doing study on water quality characteristics and such wastewater treatment situation and existing problems, the method called Adsorption-Biological Contact Oxidation was used to deal with the sulfide wastewater.In the experiment, Adsorption-biological contact oxidation process starts by the method of feeding and culture. After about 50 days, the biofilm grows well and the removal rate of COD is above 90%.The results show that:when Q=1 mg/L, DO=2～5 mg/L, temperature= 18～30℃, pH=7.5～8.5, the optimal hydraulic retention time is 12h. At this point, the adsorption tank has a strong ability to adapt for water changes in water quality and quantity, and the COD removal rate is up to 40%, sulfur removal rate is 40%～60%. When the influent COD, NH3-N and S2- average concentrations is respective 1071.53mg/L,26.3 mg/L and 177.06 mg/L, the effluent COD average concentration is 64.8 mg/L, the removal rate up to 94%; the effluent NH3-N average concentration is about 13.12 mg/L, the removal rate up to 50%; and the sulfide average concentration is 4.72 mg/L, the removal rate about 97%.In the experimental, DO concentration in the first biological contact oxidation tank was changed, so that study the removal of sulfide and production sulfate. The results showed that: different DO concentration in the first biological contact oxidation tank has little effect on the removal of sulfide, to the contrary, it has more effect on the production of sulfate.The removal rate of sulfide is about 90%, and the effluent sulfide concentration is less than 2 mg/L. When the DO decreased from the 5 mg/L to 2 mg/L, the sulfate production rate also fell, most of the sulfide is oxidized to elemental sulfur, not sulfate.