Study On Dairy Wastewater Treatment By Biological Aerated Filter With New-style Ceramsite As Filter

Single-BAF was chosen to deal with wastewater of high concentration from middle-small scale dairy factory. And the BAF reactor could greatly decrease occupancy area of wastewater treatment structure, thus to reduce expenses. Moreover, BAF was a close pillar, which could alleviate stench during the bio-treatment process of dairy wastewater, thus to reduce environmental pollution. At the same time, the late-model ceramsite filter made-by-self was porous and light, which just need ecumenic supporting layer, thus to save filter and construct investment. Meanwhile, bioaugmentation was adopted into the BAF system, in order to improve the performance for wastewater treatment of self-made ceramsite filter and its competitiveness furthermore. At last, it could provide reference and basis for popularity in the practice of the self-made ceramsite throughout the study, which could also increase the possibility for the resourses of the solid wastes. It contained some innovation of technics on dairy wastewater treatment.The operational parameters of self-made ceramsite BAF on dairy wastewater treatment were optimized in the study by sigle-factor and orthogonal test. After that, the self-made ceramsite and traditional ceramsite BAF were operated synchronously under the optimal conditions and comparative analysis was made for the wastewater treatment performance of the two. High-efficiency degradation bacterium of COD and NH₄⁺-N were chosen, and a cross test was made among the COD and NH₄⁺-N high-efficiency degradation bacterium, to investigate the degrade capacity among the mixed bacterium and the simplex bacteria. At the same time, preliminary identification was in progress for the chosen COD and NH₄⁺-N high-efficiency degradation bacterium. In the end, the wastewater treatment effect of self-made ceramsite BAF was enhanced by the method of bioaugmentation with the chosen bacterium.The results showed that: The optimal operational parameters of the self-made ceramsite BAF on dairy wastewater treatment were ascertained through the orthogonal test. And it was that the influent COD concentration of 1500²000 mg/L, HRT of 8 h, pH of 8, influent NH₄⁺-N concentration of 40⁵0 mg/L. Then the two BAF of self-made and traditional ceramsite were operated under the above conditions. The COD average removal rate of self-made ceramsite BAF was 97.19%, while the average NH₄⁺-N, TN and TP were separately 97.2%, 65.02% and 66.65%. And the average COD, NH₄⁺-N, TN and TP removal rates of traditional ceramsite BAF were 96.12%, 94.05%, 49.44% and 66.68%, respectively. It was obvious that the self-made ceramsite BAF made a better performance on cabon and nitrogen removals in contrast of traditional ceramsite BAF, and made a well-match performance of the two BAF on TP removal effect. So, it was self-made ceramsite BAF that made preferable performance on general for dairy wastewater treatment.There were two COD high-efficiency degradation bacterium, C6# and C10#. And C13# and S15# were another two chosen NH₄⁺-N high-efficiency degradation bacterium. All the four were chosen from the production department of Zhengzhou huahuaniu dairy plant including the active sludge from its processing system and biofilm in self-made ceramsite BAF reactor. It was revealed by the preliminary identification that C6# was pseudomonas, C10# and C13# were terrabacter and S15# was bacillus. Meanwhile, it was ascertained from cross test that the degradation rates of all combinations among the four high-efficiency degradation bacterium were inferior to the degradation rate of single bacteria, which exhibited that the four high-efficiency degradation bacterium had no cooperative effect.NH₄⁺-N high-efficiency degradation bacterium and COD high-efficiency degradation bacterium were added into the self-made ceramsite BAF by two steps for bioaugmentation. Throughout operating for 70 days, finally the effluent COD average removal rate was 98.43%, while NH₄⁺-N, TN and TP removal rates were separately 97.84%, 78.89% and 70.55%, which were better than non-bioaugmentation. It was revealed that the high efficiency degradation bacterium added into the ractor made certain function. The first step increased the number of NH₄⁺-N degradation bacterium, which enhanced nitrification and promoted nitrogen removal in the system. The second step increased the number and activity of bacterium for organism degradation, which raised the COD degradation and restrained NH₄⁺-N nitrification and promoted the dephosphorization of dephosphorization microorganism. After bioaugmentation of the two steps into the BAF system, the effluent average COD, NH₄⁺-N, TN and TP were 32.38 mg/L, 1.04 mg/L, 24.79 mg/L and 2.79 mg/L, respectively. And the effluent COD and NH₄⁺-N both achieved the first degree of discharge standard based on integrated wastewater discharge standard and contamination emission standard for urban waster water treatment plant, respectivally. While the effulent TN and TP achieved the second degree of discharge standard based on contamination emission standard for urban waster water treatment plant.