摘要
为了研究电解锰渣场污染地下水中复杂废水的修复问题,以农业废弃物柚子皮为原材料制成生物炭作为菌株Acinetobacter baumannii AL-6固定化载体(MBC),得到菌株生物炭耦合体系(MBC)。探究了该耦合体系对含锰、氨氮以及高钙镁离子复合废水的综合处理能力,同时构建序批式间歇反应器(SBR)以探究其在废水处理中的应用潜力。实验结果表明,MBC在48 h内去除了98.46%的锰。与2个独立的实验组(生物炭组,菌株AL-6组)相比,MBC对锰的去除具有良好的协同作用。MBC对锰的平均去除率为15.87 mg/(L∙h),是菌株AL-6组的1.09倍,生物炭组的14.33倍。此外,MBC对氨氮的最大去除率为71.92%,对钙镁离子也有一定的去除效果,分别为41.46%和26.95%。在SBR中,MBC能去除90.1%的锰和85.44%的氨氮。结果表明,微生物固定化具有巨大的应用潜力,可用于处理电解锰渣复合污染废水。
金属锰是工业发展的关键原材料和重要的战略资源。在过去的几十年中,中国的金属锰产量位居第一,占世界总产能的97.0%以
微生物固定化法因其在不利环境下能有效维持微生物的生物量而受到广泛关
此前,已经分离出一株异养硝化好氧反硝化菌株Acinetobacter baumannii AL-6。本研究使用柚子皮生物炭作为菌株AL-6的固定化载体,构建菌株和生物炭的耦合体系。探究了炭菌耦合体系对含锰、氨氮以及钙镁离子的复合废水的处理能力。同时,讨论了耦合体系在处理复杂废水时可能的机理。此外,还建立了一个序批式生物反应器(SBR),以评估该耦合体系在含锰复合废水处理中的应用潜力。本研究为微生物和生物炭在含锰复合废水处理中的应用提供了新的探索。
柚子皮:购自中国江西,在自然条件下风干,放于恒温烘箱中(60℃)烘干至恒重,剪碎成1~2 cm小块备用。菌株:从鸡冠石污水处理厂(中国重庆)的活性污泥中分离出的具有异养硝化–好氧反硝化功能的鲍曼不动杆菌Acinetobacter baumannii AL-6。
主要化学试剂:氯化锰(MnCl2·4H2O),用于配制含锰废水;氯化铵(NH4Cl),用于配置氨氮废水;氯化钙(CaCl2)、氯化镁(MgCl2),用于配置含钙镁离子废水;硝酸(HNO3)、盐酸(HCl)、氨基磺酸(NH2SO3H)、酒石酸钾钠(KNaC4H4O6·4H2O)、过硫酸钾(K2S2O8)等用于检测各类指标含量。所有试剂均为分析纯。
仪器:恒温培养振荡器(SHZ-82)、电子分析天平(AL104)、电热鼓风干燥箱(DHG-9070A)、台式高速离心机(TG16-WS)、紫外分光光度计(UV-1200)、无菌操作台(SW-CJ-IFD)、真空氮气箱式炉(GB11Q-B)、灭菌锅(LHS-24C)等。
将准备好的柚子皮盛于坩埚中并放置到真空氮气箱式炉中,通过高温热解的方式制备柚子皮生物炭。首先将热解炉中空气排出,之后充入氮气,用五步升温法将温度升高至500 ℃热解2 h,待温度降至室温后取出柚子皮生物炭。用研钵将热解后的柚子皮进行研磨并过40目筛,控制粒径在0.25~0.38 mm之间。将研磨后的生物炭使用前用去离子水进行清洗,当洗涤滤液pH为中性后,将得到的生物炭放于恒温烘箱中保存,以备实验之用。
电解锰渣废弃物浸出的渗滤液成分十分复杂,其中锰、氨氮、钙和镁的浸出含量占比很
为了探究菌株AL-6、柚子皮生物炭以及炭菌耦合体系(MBC)对复合废水的去除特性,设置了3组实验,分别为菌株AL-6组(纯菌)、BC组(纯生物炭)和MBC组(炭菌耦合体系)。将菌株AL-6活化后按照1%(v/v)的接种量接种至含250 mL硝化培养基的锥形瓶中,其中菌株AL-6组含有1%(v/v)的活化菌株,BC组含有1 g生物炭,MBC组则含有1%(v/v)的菌株AL-6和1 g生物炭。随后在转速为120 r/min,温度30 °C的恒温摇床中连续培养144 h。每24 h取样,离心(7 000 r/min,10 min)并过滤(0.22 μm滤膜)测定各项水质指标。通过紫外分光光度法测定锰、总氮、硝态氮、亚硝态氮的含量,使用钠氏试剂法快速测定氨氮含量,以及使用火焰原子吸收法测定钙镁离子含量。实验一式三份。
为探究MBC在未来水处理中的应用潜力,设计了一个SBR反应器,反应装置图见

图1 SBR反应器装置图
Fig.1 The SBR reactor installation diagram
在前期的研究中探究了柚子皮生物炭的特、—CH/—CH3的弯曲震
、—CH/—CH3、C—O—C、C—O、C—H。在之前的研究中发现生物炭表面官能团对锰和氨氮的去除起着重要的作用。An
)之间具有显著相关性;而稻壳生物炭对氨氮的吸附能力相关性最显著的则为生物炭的比表面积,其次是表面官能团(—OH、C—H、
),最后是灰分含量。

图2 柚子皮炭红外光
Fig. 2 The FTIR of pomelo pee
前期的研究中发现菌株AL-6有着良好的锰处理效果,当锰质量浓度为300 mg/L时,菌株对锰的最大去除率可达到98.69%(144 h

图3 菌株AL-6的X射线衍射图、红外光谱图以及扫描电
Fig. 3 The XRD, FTIR and SEM of strain AL-
为了探究MBC中菌株AL-6的固定情况,在前期的研究中通过磷脂法、好氧速率法(OUR)分析了菌株的生物量和生物活性,并使用扫描电镜观察菌株在生物炭上的分布状

图4 炭菌耦合体系扫描电镜
Fig.4 The SEM of co-syste
菌株AL-6对含锰复合废水的去除情况由

图5 菌株AL-6 MBC对复合污染物去除特性
Fig. 5 Removal characteristics of strain AL-6 for complex pollutants
与菌株AL-6相比,柚子皮生物炭对各污染物的吸附作用要小的多。由

图6 BC对复合污染物去除特性
Fig. 6 Removal characteristics of BC for complex pollutants

图7 MBC对复合污染物去除特性
Fig. 7 Removal characteristics of the coupling system for complex pollutants
t

图8 炭菌耦合体系在SBR实验中的复合废水处理性能
Fig. 8 Composite wastewater treatment performance in SBR experiment by the coupling system
考察了菌株AL-6、柚子皮生物炭以及炭菌耦合体系对锰、氨氮、钙镁离子复合污染水体的修复能力,并设计了SBR反应器来探究炭菌耦合体系的潜在应用价值,得到以下结论:
1)柚子皮生物炭有着良好的孔隙结构和丰富的含氧官能团,是微生物固定化的良好载体。
2)MBC对锰、氨氮的去除主要机理是由于微生物的作用,通过生物氧化的方式将M
3)在SBR反应器中的应用,炭菌耦合体系表现出了良好的锰和氨氮的去除能力,48 h内M
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