腌制废水处理单元工艺与耐盐菌试验研究

发布时间：2018-09-03 16:41

【摘要】：腌制废水是以食盐为主要腌渍成分制作产品过程中产生的废水。腌制废水具有高有机物、磷、氮的特点,尤其它具有的高盐特性会明显抑制常规生物处理工艺,使得处理腌制废水过程难度增加。本课题进行腌制废水预处理(气浮、混凝沉淀)、生化处理(MBR)和深度处理(活性炭吸附、紫外线杀菌)及影响因素研究,并从生化工艺驯化成熟的耐盐活性污泥中分离纯化出具有高效去除污染物的耐盐菌,开展菌株特性研究,以实现高盐、高浓度有机废水的高效处理,同时为工艺的工程实际应用提供技术支持,对水处理技术产业化应用与推广具有重要意义。采用气浮方法对腌制废水预处理,通过试验确定当曝气量为4L/h时,出水COD、SS值分别降到14680mg/L和35mg/L,对COD、SS去除率分别为26.6%和65%。采用混凝沉淀方法对腌制废水预处理,经过试验确定最佳混凝剂为聚合氯化铝、最适投药量为100mg/L、最佳废水pH值为8.5,对废水的处理效果最好,此时废水的COD、SS值为12780mg/L、69.1mg/L,去除率分别是36.1%和30.9%。采用膜生物反应器(MBR)工艺对腌制废水进行处理,经过试验确定MBR法最佳溶解氧(DO)、最佳水力停留时间(HRT),当DO为1～1.5mg/L、HRT为12h时,对废水的处理效果最好,此时对COD的去除率为92%左右。采用活性炭吸附对经生化处理后腌制废水进行处理,经过试验确定活性炭吸附最佳滤速,当滤速为4.2m/h时,出水COD值为43mg/L,此时COD的去除率为34%。采用紫外线杀菌对经生化处理后腌制废水进行处理,经过试验确定紫外线照射最佳时长、废水极限浊度,当照射时间为2min、废水浊度为8NTU时,对废水的处理效果可达最佳,此时出水的细菌总数和大肠菌群数均不足100个/L。以生化工艺驯化成熟的耐盐活性污泥为菌种来源,通过筛选分离出12株高效耐盐菌,经过形态观察、生理生化试验、PCR扩增、16SrRNA序列测序,鉴定12株耐盐菌均为盐单胞菌属Halomonas sp.)。考察盐度为9%、15%、18%、21%时菌株的生长特性,发现12株菌在盐度5%-15%时生长情况良好,接种后能迅速进入对数生长期,当盐度超过15%时,12株菌均未呈现良好的生长态势,得出菌株生长的耐盐性可达15%。在不同盐度(6%、9%、15%)下,所分三组菌株对COD去除率达到75%以上,对于氨氮去除率达到62%以上。对三组菌株影响因素进行考察,发现培养条件一定下,在pH值为中性7-8,温度为30～35℃时,三组菌株对污染物的去除效果最好,此时三组菌株对COD的去除率均在80%-90%之间。
[Abstract]:Pickling wastewater is produced in the process of making products with salt as the main pickling component. Pickled wastewater has the characteristics of high organic matter, phosphorus and nitrogen, especially its high salt property will obviously inhibit the conventional biological treatment process, which makes it more difficult to treat pickled wastewater. In this paper, pretreatment of pickled wastewater (air floatation, coagulation and sedimentation), biochemical treatment (MBR) and advanced treatment (activated carbon adsorption, ultraviolet sterilization) and its influencing factors were studied. The salt-tolerant bacteria with high removal efficiency were isolated and purified from the salt tolerant activated sludge domesticated by biochemical process, and the characteristics of the bacteria were studied in order to achieve the efficient treatment of high salt and high concentration organic wastewater. At the same time, it provides technical support for the practical application of technology, which is of great significance to the industrialization and popularization of water treatment technology. The air flotation method was used to pretreat the pickled wastewater. When the aeration rate was 4L/h, the COD,SS value of the effluent was reduced to 14680mg/L and 35 mg / L, respectively, and the removal rate of COD,SS was 26.6% and 65% respectively. The method of coagulation and precipitation was used to pretreat pickled wastewater. The optimum coagulant was polyaluminium chloride, the optimum dosage was 100mg / L, the optimal pH value of wastewater was 8.5, and the treatment effect of the wastewater was the best. The COD,SS of wastewater is 12780 mg / L ~ (-1) mg / L, and the removal rate is 36.1% and 30.9% respectively. The (MBR) process of membrane bioreactor was used to treat the pickled wastewater. The best MBR method was determined to be the best for the treatment of the wastewater when the best HRT of (DO), was 12 h when the DO was 1 ~ 1. 5 mg 路L ~ (-1) 路L ~ (-1) h. The removal rate of COD is about 92%. Activated carbon adsorption was used to treat pickled wastewater after biochemical treatment. The optimum filtration rate of activated carbon adsorption was determined by experiments. When the filtration rate was 4.2m/h, the COD value of effluent was 43 mg / L, and the removal rate of COD was 34%. UV sterilization was used to treat pickled wastewater after biochemical treatment. The optimum time of ultraviolet irradiation and the limit turbidity of wastewater were determined by experiments. When the irradiation time was 2 min and the turbidity of wastewater was 8NTU, the treatment effect of wastewater was the best. The total number of bacteria and coliforms in the effluent was less than 100 / L. Twelve strains of high-efficiency salt-tolerant bacteria were isolated by screening 12 strains of salt-tolerant bacteria from activated sludge domesticated by biochemical process. After morphological observation, the sequence of 16s rRNA was amplified by physiological and biochemical experiments, and all 12 strains of salt-tolerant bacteria were identified as Halomonas sp.). Of halomonas. By investigating the growth characteristics of the strain at salinity of 9 and 21, we found that the 12 strains grew well at the salinity of 5- 15%, and could enter the logarithmic growth period quickly after inoculation, and when the salinity exceeded 15, none of the 12 strains showed a good growth trend. The results showed that the salt tolerance of the strain could reach 15%. Under different salinity (15%), the COD removal rate and ammonia nitrogen removal rate of the three groups of strains were more than 75% and 62%, respectively. The influence factors of three groups of strains were investigated. It was found that when the pH value was neutral 7-8 and the temperature was 30 ~ 35 鈩，

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