School of Civil, Environmental and Chemical Engineering, RMIT University, Australia.
School of Civil, Environmental and Chemical Engineering, RMIT University, Australia.
Water Res. 2016 May 1;94:103-110. doi: 10.1016/j.watres.2016.02.046. Epub 2016 Feb 22.
The concentrate streams generated from reverse osmosis (RO)-based municipal wastewater reclamation processes contain organic substances and nutrients at elevated concentrations, posing environmental and health risks on their disposal to confined receiving environments such as bays. The impact of salinity (TDS at 7, 10 and 16 g/L) of a RO concentrate (ROC) on the treatment efficiency of a biological activated carbon (BAC) system after pre-oxidation with UV/H2O2 was characterised in terms of removal of organic matter and nitrogen species, and the bacterial communities. Organic matter removal was comparable for the ROC over the tested salinity range, with 45-49% of DOC and 70-74% of UVA254 removed by the combined treatment. However, removal in total nitrogen (TN) was considerably higher for the ROC at the high salinity (TDS ∼ 16 mg/L) compared with the low (∼7 g/L) and medium salinity (∼10 g/L). Effective nitrification with high ammonium removal (>90%) was achieved at all salinity levels, whereas greater denitrification (39%) was obtained at high salinity than low (23%) and medium salinity (27%) which might suggest that the bacterial communities contributing to the greater denitrification were more halotolerant. Microbiological characterisation using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and culture based techniques showed that diversified bacterial communities were present in the BAC system as evident from different 16S rDNA. The major bacterial groups residing on the BAC media belonged to Bacillus (Firmicutes), Pseudomonas (γ-Proteobacteria), and Rhodococcus (Actinobacteria) for all salinity levels, confirming that these microbial communities could be responsible for carbon and nitrogen removal at the different salinity levels. This has implications in understanding the effectiveness and robustness of the BAC system over the salinity range of the ROC and so would be useful for optimising the treatment efficiency of the BAC system.
反渗透（RO）市政污水再生工艺产生的浓缩液中含有高浓度的有机物质和营养物质，如果将其排放到封闭的受纳环境（如海湾）中，会对环境和健康造成风险。本研究采用 UV/H2O2 预氧化技术，考察了反渗透浓缩液（ROC）盐度（7、10 和 16 g/L）对生物活性炭（BAC）系统处理效能的影响，重点分析了有机物和氮形态去除效果以及细菌群落结构的变化。研究结果表明，在所考察的盐度范围内，ROC 对有机物的去除效果相似，DOC 和 UVA254 的去除率分别为 45-49%和 70-74%；但高盐度（TDS 约 16 mg/L）条件下，TN 的去除率明显高于低盐度（约 7 g/L）和中盐度（约 10 g/L）条件。所有盐度条件下均实现了高效的硝化作用，铵去除率>90%；高盐度条件下的反硝化作用更强（39%），高于低盐度（23%）和中盐度（27%），这可能表明参与反硝化作用的细菌群落具有更强的耐盐性。聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）和基于培养的微生物学分析结果表明，BAC 系统中存在多样化的细菌群落，不同盐度条件下 16S rDNA 序列存在差异。BAC 介质上主要的细菌类群为芽孢杆菌（Firmicutes）、假单胞菌（γ-变形菌纲）和红球菌（Actinobacteria），这表明在不同盐度条件下，这些微生物群落可能是实现碳氮去除的主要功能菌群。该研究结果有助于深入理解 BAC 系统在反渗透浓缩液盐度范围内的处理效能和稳定性，为优化 BAC 系统的处理效率提供了理论依据。
