物化法去除糖蜜酒精废水硫酸盐效果及其产气性能的比较

糖蜜酒精废水中高浓度的硫酸盐会抑制生化处理产甲烷性能。该文采用活性炭、Ba Cl2·2H2O、Ca(OH)2及铁碳微电池法对糖蜜酒精废水中的硫酸盐进行预处理,并分析了预处理前后硫酸根及化学需氧量COD的变化,同时,也分析评价了几种方法对产气性能的影响。结果表明:在500.0 g糖蜜酒精废水中加入8.0 g活性炭,硫酸根去除率达80.0%以上,且产气性能相对最好,累计产气率可达437.3 m L/g。在500.0 g糖蜜酒精废水中,根据S元素含量和Ba SO4的分子组成比例,添加70%的化学试剂Ba Cl2·2H2O,能全部去除硫酸根,累计产气率可达483.2 m L/g,产气效果相对最好,同等条件下,添加70%的Ca(OH)2,硫酸根也能全部去除,累计产气率可达436.6 m L/g。铁碳微电池处理的糖蜜酒精废水,能有效抑制硫酸根的影响,并且可以提高废水的可生化性,累计产气率为451.0 m L/g,是对照处理293.1 m L/g的1.5倍。各处理效果的产气性能排序为70%Ba Cl2·2H2O铁碳微电池8.0 g活性炭吸附70%Ca(OH)2对照组。

Sulfate removal effect of molasses alcohol wastewater pretreated by physical and chemical methods and its biogas production performance

Molasses alcohol wastewater normarlly contains high quantity of SO42-which can restrain the production of the biogas. In this paper, we used the activated carbon, BaCl2·2H2O, Ca(OH)2 and iron carbon micro cell to pretreat the molasses alcohol wastewater. Results showed that addition of 8.0 g activated carbon in 500.0 g molasses alcohol wastewater, the sulfate removal rate reached 80% and the gas production was the best which reached 437.3 mL/g. Activated carbon adsorption of sulfate can reach more than 80%, with a small amount of adsorption COD (<12%). Based on the content of S element and BaSO4 molecules, in the 500 g molasses alcohol wastewater, addition of 70% of BaCl2·2H2O removed all sulfuric acid. The cumulative gas production rate reached 483.2 mL/g. In the same way, addition of 70% of Ca(OH)2removed all the sulfuric acid, the cumulative gas production rate reached 436.6 mL/g, which is the relatively best. The removal rate of chemical reagents sulfate can reach 100%, and there was no effect on the COD. But the introduction of new ion could have a potential impact on the anaerobic fermentation. Calcium sulfate is slightly soluble in water, so the removal effects of sulfate is not better than that with BaCl2·2H2O pretreatment, though low Ca2+ concentrations can accelerate the formation of biofilm. Using the Iron carbon micro cell method to handle the molasses alcohol wastewater can effectively suppress the influence of sulfate and improve the wastewater treatment. For daily gas production rate, gas production cycle was shorter in the experimental group than the control group for 2 to 3 d. The first small peak gas production of molasses alcohol wastewater treated with iron-carbon micro-battery appeared in the first 12 d. The cumulative gas production rate with iron carbon micro cell addition can reach 451.0 mL/g which was 1.5 times of the control group. Iron-carbon micro-cell affected sulfate removal by producing iron sulfide and sulfate-reducing product FeS which precipitated in the wastewater. As such, the addition can improve the wastewater treatment. Although BaCl2·2H2O could improve sulfur removal and increase gas production in treating molasses alcohol wastewater, its high cost limited its application. The iron-carbon micro battery in the gas production, although slightly lower than BaCl2·2H2O had a low cost. The treatment effect of gas production performance was: 70% BaCl2·2H2O> iron carbon micro cell > 8.0 g activated carbon adsorption > 70% Ca (OH)2 > the control group.