Study On Resource Utilization Of The Discharged Water In Mandarin Canning Production

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.