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长链二元酸是碳数≥10的直链二羧酸,是一类广泛应用于化工、医药、农药等领域的重要精细化工中间体。生物发酵制备长链二元酸由于其生产工艺简单、成本低且收率高,是目前二元酸生产的最主要工艺。伴随着生物发酵过程,每生产1 t长链二元酸会排放约50~60 t废水,这些废水具有有机物浓度高、盐度大、高SO42−等特点[1-2]。二元酸废水多采用“混凝沉淀(除盐和硫酸根)+好氧曝气(除有机物)”预处理后排入化工园区综合污水厂的方式与其他废水进行混合处理。由于废水的有机物浓度高,而好氧生物处理的有机负荷率低,使好氧曝气预处理单元的占地面积大、处理能耗高,而且产生大量剩余活性污泥。相比好氧处理,以上流式厌氧污泥床(up-flow anaerobic sludge bed,UASB)反应器为代表的厌氧生物处理具有能耗低、污泥产量少、可产生二次能源、耐冲击负荷等优势[3],常用于高浓度有机废水如石油化工[4]、生物制药[5]、食品发酵[6]等工业废水的处理。但在厌氧条件下,硫酸盐还原菌(sulfate reducing bacteria,SRB)会将SO42−还原为硫化物并生成有毒气体H2S,抑制微生物活性,降低有机物去除效率,威胁现场工作人员的健康。因此,厌氧处理二元酸废水过程必须控制体系中的硫化物浓度,降低沼气中H2S的含量。
有研究表明,添加金属或金属盐可与S2−形成硫化物沉淀,可减轻其对产甲烷菌的抑制作用[7-8];利用微曝气将S2−氧化为单质硫,也可以有效减少沼气中H2S的含量,同时抑制SRB的活性和避免硫酸盐厌氧还原产生S2-[9-11]。然而,2种方法应用于二元酸废水的厌氧生物处理过程并未见相关报道。本研究通过分析上述2种不同控制策略对废水中有机物的去除、硫化物的控制效果和微生物群落结构的影响,探究了零价铁和微曝气在二元酸废水厌氧生物处理过程中的作用机制,以期为厌氧生物处理二元酸废水的高效稳定运行提供参考。
UASB处理高硫酸盐二元酸废水的效果及硫化物控制技术
Treating effect of dicarboxylic acids wastewater with high sulfate content by UASB and the sulfite control technology
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摘要: 长链二元酸生产废水具有高有机物和硫酸盐含量的特点。本研究探索了在控制出水硫化物的条件下厌氧生物处理工艺对二元酸废水的处理效能。实验在空白对照(R0)、添加Fe0抑制剂(R1)和微曝气(R2)3组UASB反应器中进行。经过93 d的连续运行后发现:添加Fe0和微曝气均可提高UASB的运行性能;在稳定期,R1和R2的COD去除率相比R0分别提升了104%和77%,并减少了48%和78%的出水硫化物含量。添加Fe0有助于产生甲烷,但微曝气降低了沼气产率和甲烷含量。微生物群落分析表明,AUTHM297、Desulfovibrio、Macellibacteroides、Longilinea是厌氧生物处理二元酸废水中的优势菌属。硫酸盐还原和产甲烷过程可共同作用于二元酸废水中有机物的去除。
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关键词:
- 二元酸废水 /
- 硫酸盐 /
- 上流式厌氧污泥床(UASB) /
- 微曝气 /
- 零价铁
Abstract: Long chain dicarboxylic acid wastewater has the characteristics of high organic matter and sulfate content. In this study, the anaerobic treatment performance of long chain dicarboxylic acid wastewater under the condition of controlling effluent sulfite concentration was investigated. Three reactors were set up which were R1 added with Fe0 and R2 with micro-aeration, R0 as control. After 93 days of continuous operation, Fe0 addition and micro-aeration improved the operational performance of UASB. In the stable period, the COD removal efficiencies of R1 and R2 increased by 104% and 77%, respectively, compared with R0, and effluent sulfide content was reduced by 48% and 78%. Fe0 improved the methanogenesis, but micro-aeration reduced biogas yield and methane content. The dominant genus in the anaerobic treatment systems were AUTHM297, Desulfovibrio, Macellibacteroides and Longilinea. Both of sulfate reduction and methanogenic processes contributed to organic compounds removal from long chain dicarboxylic acid wastewater. -
表 1 各反应器进出水有机物组成
Table 1. Organic composition of influent and effluent in each reactor %
取样单元 有机酸类 醇酯醛酮类 芳香类 杂原子类 烷烃类 其他 进水 51.3 18.4 7.6 21.9 0 0.7 R0出水 20 6.2 13.2 59.2 0 1.4 R1出水 14.7 13.8 11.5 59.7 0 0.3 R2出水 16 11 15.5 55.6 0 1.9 表 2 Alpha多样性指标计算结果
Table 2. Alpha diversity index results
样品来源 Ace Chao Shannon 覆盖率/% 种泥 998.03 986.13 5.04 99.88 R0 956.94 923.31 4.31 99.74 R1 939.49 920.79 4.65 99.74 R2 1 074.58 1 064.39 4.60 99.70 -
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