【作者】 刘莉莉；

【导师】 高大文；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2018， 硕士

【摘要】 近几十年来,厌氧膜生物反应器得到了很大的发展,其不仅具有厌氧处理的优势,还能够通过膜组件的截留作用保证系统的污泥浓度,实现SRT和HRT的分离,提高出水质量,但是膜污染导致的膜清洗和更换费用是限制该技术推广应用的主要因素。因此有必要从膜材料本身及操作运行方式方面改进厌氧膜生物反应器,减缓其膜污染速率。相比在废水处理领域应用最多的有机膜材料,陶瓷膜本身具有耐酸碱腐蚀、耐高温和耐污染等优点,因而将其用于处理生活污水或能在一定程度上减缓膜污染。基于此,本论文将陶瓷膜与厌氧反应器耦合,构建分置式的厌氧陶瓷膜生物反应器(Anaerobic Ceramic Membrane Bioreactor,An CMBR),并将其应用于处理实际生活污水,探究其在不同HRT下的运行效能和膜污染特性,并进一步研究了不同反冲洗频率及时间对膜污染的影响。研究结果表明,在进水为模拟生活污水的条件下,首先厌氧反应器UASB在30℃经60天的运行启动成功,在第109 d将陶瓷膜组件与UASB耦合进行An CMBR系统的启动,仅运行3天,COD去除率就超过95%,启动成功。An CMBR稳定运行期间,膜出水COD平均为28.83 mg/L,总COD去除率达到93.38%。系统运行过程中膜出水VFAs含量始终小于20 mg/L,反应器未出现酸化现象,甲烷日均产率为0.054 m3/kg COD去除。HRT为12 h时,An CMBR膜污染周期为14 d,而且膜污染物主要为EPS。另外,EPS和SMP中的蛋白含量均高于多糖,因此,蛋白对An CMBR膜污染的贡献最大。进水为实际生活污水阶段,随着HRT由18 h缩短至12 h,最后变为8 h,系统有机物去除效果也由84.76%减小为82.21%和73.27%。由于HRT为8 h时膜出水COD仍能维持在50 mg/L左右,因此,综合考虑选择8 h为An CMBR处理实际生活污水的HRT。在三个HRT条件下,系统均未出现挥发酸大量累积的现象,且UASB出水及膜出水p H均在7.0~8.0之间,系统运行稳定。An CMBR反应器的膜污染周期受HRT影响显著。随着HRT减小,膜污染周期也逐渐缩短,HRT为8 h时膜污染周期最短,仅为6 d。混合液EPS的含量远远高于SMP,且多糖略高于蛋白。滤饼层的SMP含量明显高于EPS,特别是SMPc,且滤饼层SMP中多糖含量明显高于蛋白含量。随着HRT的减小,混合液中SMP和EPS含量均有所增加,多糖和蛋白含量也随之增加。反冲洗频率为每天1次和每天2次时,TMP达到25 k Pa的时间都为7 d左右,而当反洗频率为每天3次时,经过11 d左右TMP才达到25 k Pa;反冲洗频率为每天3次,反冲洗时间分别为1 min、2 min和3 min条件下TMP的增长速率分别为0.14 k Pa/h、0.13 k Pa/h、0.11 k Pa/h,反洗时间为3 min的增长速率相对较慢,但反洗时间为3 min时每天反洗所用水量占比相对较大。综合TMP的变化情况及膜组件的处理效率,认为反洗频率为每天3次、每次反洗2 min为较合适的减缓膜污染的方式。更多还原

【Abstract】 In recent decades,the anaerobic membrane bioreactor has been greatly developed.It not only has the advantages of anaerobic treatment,but also can ensure the sludge concentration of the system through the prevention of the membrane module,achieve the separation of SRT and HRT,and improve the quality of effluent.But the membrane cleaning and replacement costs caused by membrane fouling are the main factors limiting the application of this technology.Therefore,it is necessary to improve the anaerobic membrane bioreactor in terms of the membrane material and operation mode to slow down the membrane fouling rate.Compared to organic membrane materials used most in wastewater treatment,ceramic membranes have the advantages of acid and alkali corrosion resistance,high temperature resistance,and pollution resistance.Therefore,its use in the treatment of domestic sewage may reduce the membrane fouling to a certain extent.Based on this,the paper coupled a ceramic membrane with an anaerobic reactor to establish an external Anaerobic Ceramic Membrane Bioreactor(An CMBR),which was applied to the treatment of actual domestic wastewater,explored operating efficiency and membrane fouling characteristics under different HRT,and the effects of different backwash frequency and time on membrane fouling were further studied.The results showed that the anaerobic reactor UASB was successfully started after60’days operation at a temperature of 30 ℃ and the influent was synthetic domestic sewage.On the 109 th day,the ceramic membrane module was coupled with the UASB to start the An CMBR system.After only 3 days,the COD removal rate exceeded 95%and the startup was successful.During stable period,the average effluent COD of the membrane was 28.83mg/L,the total COD removal rate of the system was 93.38%.The concentration of VFAs in membrane effluent was always less than 20mg/L,no acidification occurred in the reactor.The daily average yield of methane was 0.054m3/kg CODremoved.When the HRT was 12 h,the cycle of ceramic membrane fouling was14 d,and EPS was the main substance that causing membrane fouling.In addition,the protein concentrations in both EPS and SMP were higher than those of polysaccharides,therefore,the protein contributed the most to An CMBR membrane fouling.When the influent water was the actual domestic sewage,as HRT was shortenedfrom 18 h to 12 h and finally to 8h,the organic removal rate of the system was reduced from 84.76% to 82.21% and 73.27%.It was considered that the 8h was the best HRT for the treatment of actual domestic wastewater because the COD of the membrane effluent can still be maintained at about 50mg/L.Under this three HRT conditions,no significant accumulation of volatile acids occurred in the system.The p H of the UASB effluent and membrane effluent were all between 7.0 and 8.0,system was stable.The membrane fouling cycle of the An CMBR reactor was significantly affected by HRT.With the decrease of HRT,the cycle of membrane fouling was also shortened.The membrane fouling cycle was the shortest at HRT of 8h,only 6d.The concentration of EPS in mixed liquor was much higher than that of SMP,and the concentration of polysaccharide was slightly higher than protein.The SMP concentration of the cake layer was significantly higher than EPS,especially SMPc,and the polysaccharide concentration of SMP in cake layer was significantly higher than the protein.The concentration of SMP and EPS,polysaccharide and protein in mixed liquor increased with the decrease of HRT.When the frequency of backwash was 1 time per day and 2 times per day,the time for TMP reaching 25 k Pa was about 7 days,and when the frequency of backwash was 3times per day,TMP reached about 25 k Pa after about 11 days.When the backwash frequency was 3 times per day,the growth rates of TMP at the backwash time of 1min,2min,and 3min were 0.14 k Pa/h,0.13 k Pa/h,and 0.11 k Pa/h,respectively.TMP with a3 min backwash time had a relatively slow growth rate,however,the proportion of water used for daily backwash was relatively larger.Based on the changes in TMP and the processing efficiency of the membrane module,it was considered that the backwash frequency of 3 times per day and the backwash time of 2min were suitable ways to slow the membrane fouling rate.更多还原