化学预氧化耦合生物锰氧化对水中有机物的去除

在饮用水处理过程中,高锰酸钾与铁锰氧化物预氧化作为化学预氧化的典型工艺,能有效去除饮用水中有机物的污染,并控制消毒副产物(DBPs)的产生.但研究发现,这两种预氧化都会生成具有遗传毒性效应的Mn2+.为解决该问题,研究构想在化学预氧化后耦合生物锰氧化技术,通过生物作用将Mn2+转化为具有较强氧化吸附能力的生物锰氧化物,从而对水质进一步净化.在以天然有机物酪氨酸(Tyr)和人工合成有机物2-羟基-4-甲氧基二苯甲酮-5-磺酸(BP-4)为基质的模拟污染源水中,试验结果验证了上述构想.高锰酸钾或铁锰氧化物预氧化能够去除Tyr,但无法去除BP-4,并会产生Mn2+;在以锰氧化细菌Pseudomonas sp.QJX-1构建的生物体系中,Pseudomonas sp.QJX-1能利用Tyr进行生长并产生锰氧化,生成的生物锰氧化物能有效去除BP-4;在最优试验条件下,特定强度的高锰酸钾预氧化耦合生物锰氧化试验中Tyr、BP-4及Mn2+去除率分别为100%、50%和98.9%.

Removal of Organic Matter from Water by Chemical Preoxidation Coupled with Biogenic Manganese Oxidation

In the process of drinking water treatment, potassium permanganate and iron-manganese oxides are typical pre-oxidation methods that can not only effectively remove organic matters in drinking water, but also reduce the production of disinfection by-products (DBPs). However these two pre-oxidation methods will produce Mn²⁺ that is genotoxic. In order to solve this problem, a concept was proposed to connect biogenic-manganese oxidation technology after chemical oxidation. The manganese-oxidizing microbe may convert Mn²⁺ into the bio-manganese oxide, which can further remove the pollutants by its strong oxidative and adsorption capacity to improve water purification. In the simulated contaminated water composed of natural organic tyrosine (Tyr) and synthetic organic 2-Hydroxy-4-Methoxybenzophenone-5-Sulfonic Acid (BP-4), we verified the proposed the concept. Pre-oxidation by potassium permanganate or iron-manganese oxides efficiently removed Tyr, but had negligible effect on BP-4. During this, Mn²⁺ was generated. In the subsequent biological system, the manganese-oxidizing bacteria Pseudomonas sp. QJX-1 could utilize the Tyr for growth and oxidize Mn²⁺ to Mn⁴⁺ oxide. The generated manganese oxides could then effectively remove BP-4. In comparison, the moderate potassium permanganate preoxidation coupled with bio-manganese oxidation had a desirable treatment effect, with 100%, 50%, and 98.9% removals for Tyr, BP-4, and Mn²⁺, respectively. Importantly, the study provides a new method for drinking water treatment.