《Water Research》杂志刊登“废水中的化石有机碳及其在污水处理厂中的归宿”

作  者：Yingyu Law, Geraldine E. Jacobsen, Andrew M. Smith, Zhiguo Yuan, Paul Lant

刊  物：《Water Research》，2013年，47卷第14期，5270-5281页

关键词：生物二氧化碳；温室气体核算；化石二氧化碳；易变排放；废水处理厂；碳足迹

摘  要：本研究描述了废水中存在的化石有机碳及其在废水处理工程中的归宿。调查结果表明，按目前温室气体的统计方法，把污水中所有的有机碳都定义为生物源是不精确的。在配备有二次活性污泥处理设备的4个城市污水处理厂中，稳定放射性同位素（¹³C和¹⁴C）测量贯穿整个过程。同位素质量平衡分析表明：进水中4-14%的总有机碳（TOC）起源于化石，其浓度在6-35mg/L之间，该部分的88-98%在废水中去除。TOC质量平衡分析表明：进水中39-65%的化石有机碳通过吸附或者细胞同化被并入活性污泥，然而29-50%在二次处理中转化为二氧化碳（CO₂）。污泥中化石有机碳在厌氧消化过程经过进一步生物降解，质量减少12%。推测1.4-6.3%的进水TOC同时包括生物和化石有机碳，其仅在活性污泥处理中以CO₂形式排出。研究结果表明：目前假设所有排出CO₂均来自废水中生物有机碳的温室气体计算准则可能会低估CO₂排放值。

Fossil organic carbon in wastewater and its fate in treatment plants

Authors: Yingyu Law, Geraldine E. Jacobsen, Andrew M. Smith, Zhiguo Yuan, Paul Lant

Journal: Water Research, Volume 47, Number 14 (2013), 5270-5281

Key words: Biogenic carbon dioxide; Greenhouse gas accounting; Fossil carbon dioxide; Fugitive emissions; Wastewater treatment plant; Carbon footprint

Abstract: This study reports the presence of fossil organic carbon in wastewater and its fate in wastewater treatment plants. The findings pinpoint the inaccuracy of current greenhouse gas accounting guidelines which defines all organic carbon in wastewater to be of biogenic origin. Stable and radiocarbon isotopes (¹³C and ¹⁴C) were measured throughout the process train in four municipal wastewater treatment plants equipped with secondary activated sludge treatment. Isotopic mass balance analyses indicate that 4-14% of influent total organic carbon (TOC) is of fossil origin with concentrations between 6 and 35 mg/L; 88-98% of this is removed from the wastewater. The TOC mass balance analysis suggests that 39-65% of the fossil organic carbon from the influent is incorporated into the activated sludge through adsorption or from cell assimilation while 29-50% is likely transformed to carbon dioxide (CO₂) during secondary treatment. The fossil organic carbon fraction in the sludge undergoes further biodegradation during anaerobic digestion with a 12% decrease in mass. 1.4-6.3% of the influent TOC consists of both biogenic and fossil carbon is estimated to be emitted as fossil CO₂ from activated sludge treatment alone. The results suggest that current greenhouse gas accounting guidelines, which assume that all CO₂ emission from wastewater is biogenic may lead to underestimation of emissions.

原文链接：http://www.sciencedirect.com/science/article/pii/S0043135413004934