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柑橘罐头生产工艺排放水资源化利用研究

Study on Resource Utilization of the Discharged Water in Mandarin Canning Production

【作者】 吴丹

【导师】 叶兴乾; 陈健初;

【作者基本信息】 浙江大学 , 食品科学, 2014, 博士

【摘要】 我国人均水资源仅为世界平均水平的1/4。2012年3月,水利部公布了《节水型社会建设“十二五”规划》,要求万元工业增加值用水量降低到63立方米,比2010年降低30%以上,全面部署“十二五”时期节水型社会建设工作。目前柑橘罐头工业用水量约为30-50吨/吨产品,水耗量巨大,排放水含有大量的有机物,处理难度较大,成本高,对企业和政府来说是双重挑战。本论文以柑橘罐头生产工艺排放水为研究对象,着重进行了水耗量较大的轻度污染水(中水)回用技术研究和重度污染水中的可利用资源研究,以期减少废水排放,实现清洁生产。主要的研究结果如下:(1)柑橘罐头生产中各工序排放水水质研究:首次将柑橘罐头生产排放水分段收集和分析,按其综合水质分为轻度,中度和重度污染水。第三次漂洗水、分级机水、挑选输送水和杀菌冷却水为轻度污染水,COD在32.00-110.35mg/之间;碱处理后的第一次和第二次漂洗水为中度污染水,COD最低值在500mg/L左右。酸处理水和碱处理水为重度污染水,COD则在6827.80mg/L以上。(2)柑橘罐头生产中水回用处理系统工程设计研究:利用布袋过滤,活性炭过滤,精密过滤不同组合方式处理轻度污染水(分级机水和挑选输送水),结果表明,经过布袋过滤+活性炭过滤+精密过滤的处理效果最好,色度、浊度、总糖、果胶、COD去除率分别为27.64%,55.56%,22.55%,21.35%和42.22%,处理后水质无臭和味,无肉眼可见物,pH值适宜。水中余氯浓度达到0.5-1.0mg/L时,菌落总数小于lOCFU/ml,无大肠菌群检出。在此研究基础上,建立了处理量为50t/h的中水回用中试系统,本系统将挑选输送水和分级机水收集到集水池后,经过加氯处理、布袋过滤,活性炭过滤,二次加氯和紫外杀菌一系列组合工序处理后,出水水质指标除COD在23.30mg/L左右外,相关检测指标均达到国家饮用水标准GB5749。(3)柑橘罐头生产酸碱流槽排放水糖类物质研究:柑橘罐头工厂酸碱排放水水分含量可达98.60%左右,干物质含量1.40%左右,其中醇沉多糖占干物质含量的7%-10%。利用PMP柱前衍生HPLC法测得酸水,碱水以及酸碱水多糖均由8种单糖组成,包括甘露糖(Man)、鼠李糖(Rha)、半乳糖醛酸(GalUA)、葡萄糖(Glc)、半乳糖(Gal)、木糖(Xyl)、阿拉伯糖(Ara)和岩藻糖(Fuc),组成比例不同。酸碱水多糖均含半乳糖醛酸,为低酯化度酸性杂多糖。利用Cellulose DE-52离子交换柱和超滤膜对酸碱水多糖进行进一步分级纯化,SGJ得到2个酸性多糖级分,M,为3417kDa(SGJ-S1)和70kDa(SGJ-S2);JGJ得到1个中性多糖级分(JGJ-Z)和2个酸性多糖级分(JGJ-S1和JGJ-S2),M,为3928kDa(JGJ-Z)、3760kDa(JGJ-S1)和29kDa(JGJ-S2)。SGJ-S1、JGJ-S1、JGJ-S2含有上述8种单糖,SGJ-S2含除Fuc外上述7种单糖,JGJ-Z含除GalUA外上述7种单糖。SGJ-S1、SGJ-S2、JGJ-S1和JGJ-S2的半乳糖醛酸含量分别为50.67%、20.03%、35.46%和19.07%;FTIR分析和NMR分析均表明,酸性多糖级分具有果胶类多糖的特征谱,SGJ-S1、SGJ-S2的甲酯化程度高于JGJ-S1、JGJ-S2,存在α-GalpA(1→4)糖苷键连接。(4)酸碱水多糖的流变学特性研究:SGJ的线性粘弹区应力范围为0-10%,JGJ的线性粘弹区应力范围为0-2%。扫描应力为1%,频率扫描范围0.1-10Hz内,弹性模量G’>粘性模量G”。流变曲线表明,2种多糖溶液是假塑性流体,Ostwald’s模型能很好地关联其流变方程;多糖浓度对SGJ溶液流体性能的影响大于对于JGJ溶液。2种多糖溶液粘度-温度关系满足Arrhenius定律。SGJ具有更加复杂的聚合体结构。(5)碱水多糖的抗氧化和体外抗肿瘤活性研究:JGJ的抗氧化能力指数ORAC值为1514.0±214.2μmol Trolox/g,该多糖对人乳腺癌细胞株MDA-MB-231的抗细胞增殖的作用与剂量成一定的正相关性,浓度达到10mg/mL时,抑制率为24.53±5.34%:对人乳腺癌细胞株MCF-7的抗增殖效果不明显:对人肝癌细胞株HepG2几乎无效。

【Abstract】 China consumes less than one-quarter of the world average per capita water usage. Ministry of Water Resources released "The12th five-year plan water-saving society construction" in march2012. The plan claimed that the water consumption for every10thousand yuan worth of industrial value added in2015was must reduced to63.3cubic meters, down by30percent compared with2010. A basic plan for building a water-saving society was drafted. Using current processing technologies, the water requirement was quite high, as up to30-50kL of water was required to produce a single metric ton of canned mandarin oranges. The environment could be seriously impacted if the discharged water is not properly treated. To make matters even worse, The discharged water from canning mandarin contains large amounts of organic components. Treatment of this type of discharged water is both complex and difficult, and the cost is expected to be very high. It is the challenge before mandarin canning factory and government. The paper studied the discharged water from different processing steps of mandarin canning factory. The research focused on discharged water polluted in a less degree reusing treatment technologies, and available resources in discharged water polluted in seriously polluted. It has important practical and social significance.(1) Research on the quality of the discharged water from different processing steps of mandarin canning factory:the discharged water was collected and detected separately in according to the different processing step. It was divided in three parts compared with pollution degree. The discharged water from the processing of the third bleaching, sorting/grading and cooling was low-polluted water, the COD value was between32.00mg/L and110.35mg/L. The discharged water from the processing of the first and second blenching was moderate-pollution water, the COD value was above500mg/L. The discharged water from the processing of acid treating and alkali treating was serious-polluted water. the COD value was were above6827.80mg/L.(2) Research on the water reclamation system in a mandarin canning factory:The low-polluted water (the discharged water of the processing of sorting/grading) was investigated to improve quality for the purpose of reclamation through four different filtration treatments. The results showed the joint treatment of cloth bag filter, activated carbon filter and precision filter improved the quality of the discharged water best. The ratio of elimination for chroma, turbidity, total sugars, pectin, COD were individually27.64%,55.56%,22.55%,21.35%and42.22%. The water was clear and no abnormal smell was detected. The pH values of the water were suitable. When adding concentration of residual chlorine was above0.5mg/L, the total bacterial count in discharged water was below10CFU/ml, the coliform group was not detected. According to the research above, the pilot scale water reclamation system was established with a production scale of50,000L of water per hour. The low-polluted discharged water was collected in a pool. After chlorination, cloth bag filtering, active carbon filtering, chlorination again, and ultraviolet (UV) sterilization, water improved by the system and the main physicochemical properties and sensory index were conformed to the requirements of Chinese National Standard GB5749except the index of chemical oxygen demand (23.30mg/L).(3) Research on the carbohydrates in the discharged water from the processing of acid treating and alkali treating in a mandarin canning factory:the moisture content of the discharged water from the processing of acid treating and alkali treating was98.60%, the dry matter content was1.40%, The ethanol soluble extract of the discharged water was7%-10%of the dry matter. The monosaccharide composition by PMP-HPLC showed that discharged water and its ethanol soluble extract (SGJ and JGJ) were composed of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose, arabinose, fucose. Their component ratios were different. The two kinds of polysaccharide extracted with alcohol was low-esterified and contained galacturonic acid, they could to be use in further separation and purification. By Cellulose DE-52ion exchange column and ultrafiltration, the polysaccharides extracted from the discharged water of acid process (SGJ) was separated into two major acidic polysaccharide (SGJ-Sl:Mw=3417kDa and SGJ-S2:Mw=70kDa), the polysaccharides extracted from the discharged water of alkali process (JGJ) was separated into two major acidic polysaccharide (JGJ-S1:Mw=3760kDa and JGJ-S2:Mw=29kDa) and one neutral polysaccharide (JGJ-Z:Mw=3928kDa). SGJ-S1、JGJ-S1and JGJ-S2contained8kinds of monosaccharide above,SGJ-S2contained7kinds of monosaccharide above except fucose, JGJ-Z contained7kinds of monosaccharide above except galacturonic acid. The contents of galacturonic acid for SGJ-S1、SGJ-S2、JGJ-S1、JGJ-S2were50.67%,20.03%.35.46%and19.07%. By the means of NMR and FTIR, The acidic polysaccharide fractions has characteristic absorption of pectin polysaccharide.SGJ-S1and SGJ-S2had higher degree of esterification than JGJ-S1and JGJ-S2.there were the linkage type of a-GalpA(1→4) glycosidic bond for SGJ-S1,SGJ-S2,JGJ-S1and JGJ-S2.(4) Research on rheological properties of SGJ and JGJ:The deformation value ranges of0-10%for SGJ,0-2%for JGJ, were in the linear viscoelastic region. To determine the dependence of G’and G" on the frequency, frequency sweeps were performed over a range of0.1to10Hz at strain of1%. The modulus G’was higher than the modulus G". The flow behavior of polysaccharides showed that SGJ and JGJ solution were pseudoplastic fluid, they could be fitted by Ostwald’s model. The concentration of SGJ solution had greater influence on JGJ solution. Two of polysaccharides solution met the Arrhenius equation. SGJ had more complex structure than JGJ.(5) Research on antioxidant and anti-tumor activity of JGJ:The oxygen radical absorbance capacity value for JGJ was1514.0±214.2μmol Trolox/g. The polysaccharides inhibited the human MDA-MB-231breast cancer cells; the effect level was in a dose-dependent manner. When the concentration was10mg/mL, the antiproliferative ratio was reached to24.53±5.34%. The Inhibition effect of JGJ on human MCF-7breast cancer cells was not obvious; it had little effect on human HepG2liver cancer cells.

【关键词】 柑橘排放水多糖回用减排
【Key words】 orangedischarged waterpolysaccharidereuseemission reduction
  • 【网络出版投稿人】 浙江大学
  • 【网络出版年期】2014年 07期
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