A novel online analyzer for accurate and rapid measurement of volatile fatty acids in anaerobic wastewater treatment  

作　　者：Qingshan Lin Yanchao Yuan Feixiang Zan Hui Lu Zongping Wang Gang Guo 

机构地区：[1]School of Environmental Science and Engineering,Huazhong University of Science and Technology(HUST),Key Laboratory of Water and Wastewater Treatment,MOHURD,Wuhan 430074,China [2]Department of Environmental Science and Engineering,Beijing University of Chemical Technology,Beijing 100029,China [3]School of Environmental Science and Engineering,Sun Yat-sen University,Guangzhou 510275,China

出　　处：《Journal of Environmental Sciences》2022年第12期72-82,共11页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 52100040);the National Key Research & Development Program of China (No. 2019YFC1904005);the Natural Science Foundation of Hubei Province (No. 2020CFB403)。

摘　　要：Volatile fatty acids(VFAs), which are largely generated during the anaerobic acidification process, are considered to be reliable indicators of the stable process operation. However,the common methods for monitoring VFAs are offline, and they are typically manual requiring time-consuming, costly and complex instruments. This study aims to develop a novel online analyzer for automatic measuring VFAs, which was based on the 5-p H point titration, embedded with a proportional-integral-derivative(PID) feedback control system. The results show that it can achieve accurate and rapid monitoring of VFAs ranging between 0-400 mg/L(<9 min/sample) but simultaneously faces the problems of overtitration and interference of complex characteristics of wastewater. In order to improve its accuracy and stability, the effects of three general coefficients(K_(I),K_(P), and K_(D)) of PID on the titration were investigated, and the optimal values of K_(I), K_(P), and K_(D)were found to be 1.5, 1.0, and-1.0~0.5,respectively. Besides, the initial titration speed was set at 0.06 m L/min, equal to the minimum speed of the peristaltic pump, and the dichotomy approach was integrated into the PID feedback controller. Owing to the above improvements, the relative mean deviation and standard deviation of measuring VFAs in both synthetic and real wastewaters were mostly lower than 5.0% and 5.0 mg/L, proving the online analyzer is rapid, accurate and reliable.

关 键 词：Volatile fatty acids Online analyzer 5-pH point titration PID feedback control Anaerobic process 

分 类 号：X703[环境科学与工程—环境工程] X853