【作者】 王力；

【导师】 曾明；

【作者基本信息】 天津科技大学 ， 环境科学与工程， 2023， 硕士

【摘要】 针对干湿分离集约化养猪废水因浓度高,生化处理难以达标排放的现状。首先使用无生物毒性的蛭石絮凝剂和阳离子聚丙烯酰胺（C-PAM）,进行一级强化絮凝预处理,再使用序批式活性污泥法（SBR反应器）处理絮凝后的上清液,使其达标排放。最后总结归纳蛭石絮凝剂在养猪废水中的絮凝机理。分析了SBR出处理性能和一级强化絮凝预处理后,对浊度、化学需氧量（COD）、悬浮物（SS）、总磷（TP）、氨氮（NH₃-N）和重金属的去效果以及絮体的沉降速度和体积大小的影响。蛭石絮凝剂对养猪废水具有很好的絮凝效果,在蛭石絮凝剂的投加量为8 g/L情况下,废水中的浊度、COD、SS、TP和NH₃-N的浓度分别减少到73.4 NTU、611.7mg/L、60 mg/L、2.5 mg/L和284.4 mg/L。4 g/L蛭石絮凝剂和24 mg/L C-PAM组合下,浊度、COD、SS、TP和NH₃-N的浓度分别减少到19.2 NTU、454.5 mg/L、34 mg/L、5.5 mg/L和267.1 mg/L,优于蛭石絮凝剂单独使用的效果。说明阳离子助凝剂C-PAM的投加有助于污染物的去除,具有很好的协同效应,不仅降低蛭石絮凝剂用量,而且还可以有效地降低后续生化处理的负荷。由上清液与絮凝沉积物的重金属分析结果表示,符合排放标准和农业用肥标准,沉积物可以作为堆肥的原料,实现资源化。与传统无机絮凝剂PAC絮凝效果相比,蛭石絮凝剂以及与C-PAM协同处理后的絮体的沉降速度更快,体积更小。蛭石絮凝剂依赖自身溶解态物质和颗粒态物质发挥絮凝作用,溶解态物质以电中和为主导,迫使胶体脱稳,脱稳的粒子在相互之间的范德华力和颗粒态物质与脱稳粒子之间的质量力的双重作用下相互吸附,形成不同大小的絮体,在密度大的颗粒态物质作用下快速沉降。C-PAM与蛭石絮凝剂的协同效应依赖于C-PAM中的阳离子基团和长链高分子聚合物亲油基团,对仍然带有负电荷的胶粒进一步产生压缩脱稳,同时聚合物亲油基团对絮体和有机污染物进行卷扫、吸附,形成更大的二次聚团,在颗粒物重力的作用下更容易沉降分离。SBR反应器处理上清液期间,SBR出水COD和NH₃-N浓度分别为190 mg/L和20 mg/L,整个工艺出水的浊度、COD、SS、TP和NH₃-N的浓度分别减少到38.1 NTU、190 mg/L、60 mg/L、4.2 mg/L和20 mg/L,出水水质均能达到相关排放标准《畜禽养殖污染物排放标准》。通过对SBR反应器中微生物进行测序,发现其中变形菌门,髌骨细菌门,绿弯菌门和拟杆菌门为主要的优势菌门。这些优势菌种在降解有机物和去除NH₃-N方面发挥重要作用。更多还原

【Abstract】 Owing to the high concentration of swine wastewater produced via dry-wet separation,the current volume of discharge is difficult to process with biochemical treatments.Firstly,primary enhanced flocculation pretreatments were conducted using both vermiculite as an ecological,non-toxic inorganic mineral flocculant and the conventional cationic coagulant C-PAM,and then a sequencing batch activated sludge reactor（SBR reactor）was used to treat the flocculated supernatant to meet the discharge standards.Finally,the flocculation mechanism of vermiculite flocculant in swine wastewater is summarized and summarized.The effects of SBR effluent performance and primary enhanced flocculation pretreatment on turbidity,chemical oxygen demand（COD）,suspended solids（SS）,total phosphorus（TP）,ammonia nitrogen（NH3-N）and heavy metal removal,as well as the sedimentation rate and volume size of flocs were analyzed.Results show that vermiculite has a good flocculation effect on swine wastewater.When the dosage of vermiculite flocculant alone was 8 g/L,the turbidity,COD,SS,total phosphorus and ammonia nitrogen of the swine wastewater were reduced to 73.4 NTU,611.7 mg/L,60mg/L,2.5 mg/L and 284.4 mg/L,respectively.t.After primary pretreatment with 4 g/L of a vermiculite flocculant and 24 mg/L of C-PAM.Then the synergistic effect was studied,and turbidity,COD,SS,total phosphorus and ammonia nitrogen in the swine wastewater were19.2 NTU,454.5 mg/L,34 mg/L,5.5 mg/L and 267.1 mg/L respectively.These values were better than those of the vermiculite flocculant alone.This indicated that the addition of C-PAM could help to remove pollutants and result in a good synergistic effect as it not only reduced the amount of vermiculite flocculant needed but could also be used as a raw material for composting with pig manure.Compared with the flocculation effect of traditional inorganic compounds,the load of the subsequent biochemical treatment was reduced effectively.The heavy metal concentration of the supernatant and flocculated sediment meet emissions and agricultural fertilizer standards.Additionally,the synergistic effect of vermiculite flocculant and C-PAM meant that the floc settling speed in the sediment flocculant PAC was faster and the volume was smaller.The flocculation mechanism of vermiculite flocculant depended on the flocculation effect of dissolved and granular substances.The dissolved state material was dominated by electric neutralization,forcing the colloid to destabilize,and under the dual action of van der Waals force between the destabilized particles and the mass force between the granular state material and the destabilized particles,the destabilized colloids adsorbed each other and formed flocs of different sizes,and then settled rapidly under the action of the granular state material with high density,so the dissolved state material and the granular state material were indispensable.The synergistic effect of C-PAM and vermiculite flocculant depended on the cationic groups of C-PAM and the lipophilic groups of long-chain polymers.These groups promoted the flocculation effect of vermiculite flocculant and further compressed and destabilized the still negatively charged colloidal particles,while the polymeric lipophilic groups swept and adsorbed the flocs and organic pollutants,forming larger secondary clusters,and the formed flocs settled and separated easily under the action of gravity of the particulate matter.During the treatment of supernatant by the SBR reactor,the concentrations of COD and NH3-N in the SBR effluent were 190 mg/L and 20 mg/L,respectively.The turbidity,COD,SS,TP,and NH₃-N concentrations in the entire process effluent were reduced to 38.1 NTU,190 mg/L,60 mg/L,4.2 mg/L,and 20 mg/L,respectively.The effluent quality could meet the relevant emission standards,"Emission Standards for Pollutants from Livestock and Poultry Breeding.".By sequencing microorganisms in the SBR reactor,it was found that Proteobacteria,Patescibacteria,Chloroflexi,and Bacteroidota were the main dominant bacteria.These dominant strains play an important role in degrading organic matter and removing ammonia nitrogen.更多还原