IASBR Treatment Of Landfill Leachate Denitrification Effect And Carbon Source Optimization Study

The characteristics of high ammonia nitrogen and low carbon to nitrogen ratio of the landfill leachate,making biological nitrogen removal is more difficult.In 2008,National Environmental Protection Agency promulgated the "landfill pollution control standards(GB 16889-2008)",the TN emission requirements to further improve.The low nitrogen-nitrogen ratio limits the nitrification and denitrification of nitrification,and therefore requires an additional carbon source to achieve higher denitrification efficiency.Intermittently aerated sequencing batch reactor(IASBR)has obvious advantages in the treatment of high ammonia nitrogen,low carbon and nitrogen ratio(COD/TN)compared with conventional nitrification and denitrification technology.Therefore,this paper uses the two-stage series IASBR process to investigate the denitrification efficiency of landfill leachate under different carbon sources.The removal efficiency of the pollutants in the reactor with different carbon and nitrogen ratios was studied.Under the condition of optimized carbon source,the experimental study was carried out to obtain the best available carbon Nitrogen ratio.Achieve the following research results:(1)Two-stage IASBR for denitrification of landfill leachate,the first grade HRT is 4 d,the secondary HRT is 3 d,the pH is 6.5-8.5,the temperature is 25 ± 2 ?,the first aerobic DO When the concentration is 0.5-2 mg·L-1,the ammonia nitrogen volume load is about 0.2 kg·(m3·d)-1,and the stability of ammonia nitrogen removal in landfill leachate can be ensured by using sodium acetate or glucose as carbon source,the ammonia nitrogen concentration below 25 mg·L-1,ammonia nitrogen can meet the "landfill pollution control standards(GB16889-2008)" water quality requirements;(2)The addition of COD/TN was 2.3±0.3,and the secondary COD/TN was 2.8±0.4 when the volume of TN was 0.2 kg·(m3·d)-1,the secondary effluent was(40 ±10)mg·L-1,the removal rate of TN was over 80%,and the effluent could be discharged at the same time;(3)When the carbon source is added to the water source,the carbon source utilization rate is higher.In the case of glucose supplementation,the COD/TN was 2.2 at the primary TN volume load of 0.2 kg·(m3·d)-1,and the secondary COD/TN was 2 ~ 3,nitrogen effect is better,the second TN concentration below 40 mg·L-1,the removal rate can reach 90%,to discharge standards;(4)Dosing too much sodium acetate(more than 4.2 g·L-1)will cause the reactor pH to be too high,affecting the growth of aerobic and nitrifying bacteria,resulting in high nitrogen concentration of the effluent;glucose as a carbon source,the reactor pH decreased faster,and because of its high-carbon compounds,microbial growth is large,easily lead to sludge expansion;(5)A mixture of glucose and sodium acetate(sodium acetate 25%,glucose 75%,COD)as an additional carbon source,single-stage IASBR system treatment of landfill leachate pilot study,HRT 6.5d,ammonia nitrogen volume load of 0.11 kg·(m3·d)-1,TN volume load of 0.12kg·(m3·d)-1 under the conditions,plus COD/TN=3,the effluent ammonia nitrogen concentration ? 10 mg·L-1,effluent TN concentration ? 40 mg·L-1,with a certain economic rationality.