Qiu Shuang, Yu Ziwei, Hu Yanbing, Chen Zhipeng, Guo Jianhua, Xia Wenhao, Ge Shijian
Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China; Department of Biology, Queen's University, Kingston, ON, Canada K7L 3N6.
Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiao Ling Wei 200, Nanjing 210094, Jiangsu, China.
Water Res. 2021 May 15;196:117038. doi: 10.1016/j.watres.2021.117038. Epub 2021 Mar 10.
It is necessary to develop sustainable technologies for centrate wastewater (CW) and biogas treatment from sludge anaerobic digestion (AD) systems in an environmentally friendly and economical manner. The microalgae-based bioremediation approach presents a competitive alternative due to its capacity for nutrient recovery and carbon sequestration. However, process instabilities and operating challenges limit its development and implementation largely due to the complexities in the CW and biogas. In this study, the evolved native microalgal consortium (ENMC) was firstly developed using the gradual stress increase method to enhance their adaptation in high ammonium condition. The supplementation of local snow (with Ca and Mg) and biogas into CW significantly enhanced ENMC growth through batch tests. Subsequently, an integrated ENMC-snow (ENMCS) system was proposed consisting of a hydrolysis-acidification reactor (HAR), biogas upgrade reactor, and photobioreactor (PBR). The ENMCS system was systematically investigated under both batch and semi-continuous operations, by adjusting primary process parameters including the fill ratio, feeding time, hydraulic retention time (HRT), wastewater pretreatment, and PBR type. It was eventually optimized as a 24 h, 70% fermented CW diluted with 30% snow water, semi-continuous feeding system with a fill ratio of 50% and HRT of 6 d in an open-PBR. Long-term operation (310 days) showed superior biomass yield (0.3059 ± 0.0039 g/(L•d)) and nutrient removal efficiencies (95.6 ± 0.13% and 90.8 ± 0.44% for NH-N and PO-P removal). Meanwhile, biogas was upgraded with an 82.2% CO reduction. The economic and environmental analysis further demonstrated the ENMCS system as an effective alternative for the bioremediation of AD effluents while simultaneously producing value-added biomass, especially applicable to snowy regions.
有必要以环境友好且经济的方式开发用于处理污泥厌氧消化（AD）系统产生的浓缩废水（CW）和沼气的可持续技术。基于微藻的生物修复方法因其具备养分回收和碳固存能力而成为一种具有竞争力的替代方案。然而，由于CW和沼气的复杂性，工艺不稳定性和操作挑战在很大程度上限制了其发展和应用。在本研究中，首先采用逐步增加胁迫的方法开发了进化后的本地微藻群落（ENMC），以增强它们在高铵条件下的适应性。通过批次试验，向CW中添加当地雪水（含钙和镁）和沼气显著促进了ENMC的生长。随后，提出了一种集成的ENMC-雪水（ENMCS）系统，该系统由水解酸化反应器（HAR）、沼气升级反应器和光生物反应器（PBR）组成。通过调整包括填充率、进料时间、水力停留时间（HRT）、废水预处理和PBR类型等主要工艺参数，在批次和半连续操作条件下对ENMCS系统进行了系统研究。最终将其优化为一个在开放式PBR中运行的系统，该系统采用24小时、70%发酵CW与30%雪水稀释的半连续进料系统，填充率为50%，HRT为6天。长期运行（310天）显示出优异的生物质产量（0.3059±0.0039克/（升•天））和养分去除效率（NH-N和PO-P去除率分别为95.6±0.13%和90.8±0.44%）。同时，沼气中的CO减少了82.2%。经济和环境分析进一步证明，ENMCS系统是一种有效的AD废水生物修复替代方案，同时能生产增值生物质，尤其适用于降雪地区。
