| The increasing demand for clean water in the world impels the development of theseawater utilization. So a large amount of saline wastewater was emerged. Faced withincreasing amount of saline wastewater, the interest in saline effluent treatment processes,both for salt and organic matter removal, has been increasing rapidly. The saline wastewaterwas always treated by biological treatment, especially the Membrane Bio-Reactor. As a newwastewater treatment technology, Membrane Bio-Reactor is very suitable for biologicaltreatment of saline wastewater. But the disadvantages of treating salt wastewater by utilizingtraditional Membrane Bio-Reactor (MBR) were still existed, which were including twoaspects. Firstly, the salt-resistant activated-sludge was difficult to be domesticated. Secondly,the permeation flux of membrane became lower owing to its pollution. In light of the previousstudies, this study was designed to enhance bio-treatment of saline wastewater by proposingan innovative process halophilic bacterium-modified UHMWPE sintered tubular filtercoupling technique. The improved membrane bioreactor (IMBR) was applied to treat thesaline wastewaters by adding halophilic bacterium in activated sludge and using modifiedUHMWPE sintered tubular filter to replace traditional membrane module.First, We isolated the7domesticated strains named NY1, NY2,…, NY7from thebiological system, and the strain with the better quality for organic matter degradation wasfurther studied. The NY6showed the best adaptability to survive in different salinity and havehighest degradation efficiency to COD. So the strain NY6was chosen as an alternative forfurther study. The NY6was classified as Bacillus sp. based on16S rRNA sequence and themorphological and physiological properties. Its optimal growth conditions were as followings:salinity was2%; temperature was37℃; pH was in6.5-7.0; the ratio of C: N: P was100:5:1.According to salt-tolerant mechanism research, when the salinity was below2%, the stainNY6absorbed K+and Na+to maintain osmotic equilibrium, and when the salinity was above2%, the NY6kept its life by producing a large amount of spores.Second, Three different Particle diameters were used to make three kinds of UHMWPEsintered tubular filter, which were60,120and200mash number. With the scanning electronmicroscope(SEM)， we could check the membranes micro-structure characterization，it wasfound that the UHMWPE sintered tubular filter, which was made by200mash number, has the smallest pore size(1～50μm). So the UHMWPE sintered tubular filter, which was madeby200mash number, was chosen to modify with nano silicon dioxide and activated carbon.According to the scanning electron microscope, addition of nano silicon can reducemembrane pore. But the UHMWPE sintered tubular filter, which was modified with activatedcarbon, whose membrane pore was almost invariable. In order to determine filtration effect ofUHMWPE sintered tubular filters, we did the Further Research on the filtering precision. Theresult showed that the UHMWPE sintered tubular filter, which was modified with nanosilicon, had the best effect of filtering and could reach2μm.This study also researched the compressive strength of different kinds of UHMWPEsintered tubular filter. The result shows that addition of nano silicon, whose inner diameterwas10mm, has highest compressive strength. So we choose it as membrane module.The NY6was amplified and add it to the Activated Sludge of MBR. The traditionalmembrane module was replaced by modified UHMWPE sintered tubular filter, and thehalophilic bacterium-modified UHMWPE sintered tubular filter coupling technique wasproposed. After continuously operating for6months to treat synthetic saline wastewater with2%NaCl, the system reached the steady-state conditions. The COD, NH3-N and BOD5wereinvestigated, and the results showed that they were92.8％、74%and96%respectively. Wecan concluded that the new MBR showed better effect of treating wastewater than traditionalone. |
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