College of Environment, Hohai University, Nanjing 210098, China; Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing 210029, China.
Center for Eco-Environmental Research, Nanjing Hydraulic Research Institute, Nanjing 210029, China.
J Environ Sci (China). 2016 Sep;47:174-182. doi: 10.1016/j.jes.2016.02.004. Epub 2016 Mar 7.
Carbon source is a critical constraint on nutrient removal in domestic wastewater treatment. However, the functions of particulate organic matter (POM) and some organics with high molecular weight (HMW) are overlooked in the conventional process, as they cannot be directly assimilated into cells during microbial metabolism. This further aggravates the problem of carbon source shortage and thus affects the effluent quality. Therefore, to better characterize organic matter (OM) based MW distribution, microfiltration/ultrafiltration/nanofiltration (MF/UF/NF) membranes were used in parallel to fractionate OM, which obtained seven fractions. Hydrolysis acidification (HA) was adopted to manipulate the MW distribution of dissolved organic matter (DOM) and further explore the correlation between molecular size and biodegradability. Results showed that HA pretreatment of wastewater not only promoted transformation from POM to DOM, but also boosted biodegradability. After 8hr of HA, the concentration of dissolved organic carbon (DOC) increased by 65%, from the initial value of 20.25 to 33.48mg/L, and the biodegradability index (BOD5 (biochemical oxygen demand)/SCOD (soluble chemical oxygen demand)) increased from 0.52 to 0.74. Using MW distribution analysis and composition optimization, a new understanding on the characteristics of organics in wastewater was obtained, which is of importance to solving low C/N wastewater treatment in engineering practice.
碳源是制约生活污水处理中营养物质去除的关键因素。然而，在传统工艺中，颗粒态有机物（POM）和一些高分子有机物（HMW）的作用被忽视了，因为它们在微生物代谢过程中不能被直接同化到细胞中。这进一步加剧了碳源短缺的问题，从而影响了出水水质。因此，为了更好地描述有机物（OM）基于 MW 分布的特征，采用微滤/超滤/纳滤（MF/UF/NF）膜对 OM 进行了平行分级，得到了 7 个级分。采用水解酸化（HA）来操纵溶解有机物（DOM）的 MW 分布，并进一步探讨分子大小与可生物降解性之间的相关性。结果表明，废水的 HA 预处理不仅促进了 POM 向 DOM 的转化，而且提高了可生物降解性。经过 8 小时的 HA 处理，溶解有机碳（DOC）的浓度从 20.25mg/L 增加到 33.48mg/L，增加了 65%，BOD5（生化需氧量）/SCOD（可生化需氧量）的可生物降解性指数从 0.52 增加到 0.74。通过 MW 分布分析和组成优化，对废水中有机物的特性有了新的认识，这对于解决工程实践中低 C/N 废水处理具有重要意义。
