Effect of short-term exposure to thallium on SBR activated sludge performance
ZHAO Xiao-jing1, LUO Yuan-ling2, WU Hong-hui3, DING Yu-ting1, XIANG Ke-yi1, HUANG Jun-guo1, GAO Jia-ni1, JIA Mei-ying1, HU Xin-jiang1, ZHU Jian1, WANG Ping1, XU Hai-yin1
1. Central South University of Forestry and Technology, Changsha 410004, China; 2. Changsha Vocational and Technical College, Changsha 410018, China; 3. Hunan University, Changsha 410082, China
Abstract：In this study, using the Sequencing Batch Reactor (SBR) process as an example, the short-term disturbances and recovery behavior of activated sludge performance with respect to Tl exposure concentration were investigated, focusing on nitrogen and phosphorus removal, microbiological and enzyme activity. The results indicated that both nitrogen and phosphorus removal efficiency and COD removal rate of activated sludge were susceptible to the influence of Tl. When Tl was at a concentration of 500μg/L, nitrogen and phosphorus removal processes were inhibited, but upon the elimination of Tl exposure, the performance could recover. However, at a Tl concentration of 1000μg/L, although the phosphorus removal efficiency could be restored to 65%, the nitrogen removal process was completely inhibited and the inhibition of the nitrogen removal process was irreversible. Low concentrations of Tl increased the COD removal rate, and the effect of high concentrations of Tl on the COD removal rate was reversible. Furthermore, a Tl concentration of 200μg/L was found to increase microbial activity, but at 1000μg/L, Tl led to a significant reduction in the relative production of catalase and superoxide dismutase by 71.9% and 30.8%, which greatly inhibited microbial activity. The specific oxygen uptake rate was highly sensitive to the presence and elimination of Tl, making it an indicator for Tl exposure in wastewater treatment plants. Characterization through Fourier-Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy revealed that Tl bound to hydroxyl groups in extracellular polymeric substances or oxidized from Tl+ to Tl3+, which might have been the mechanism by which activated sludge mitigated Tl cytotoxicity. Therefore, when exposed to short-term Tl, it was necessary to enhance the nitrogen and phosphorus removal performance of activated sludge and strengthened its ability to remove Tl to ensure the stable operation of wastewater treatment plants. This study revealed the potential impacts of short-term Tl exposure on activated sludge systems and proposed mitigation strategies.
[1] Xu H Y, Luo Y L, Wang P, et al. Removal of thallium in water/ wastewater: A review [J]. Water Research, 2019,165:114981. [2] 张睿琦,吴红辉,徐海音,等.基于RuO2-IrO2/Ti和Fe0电极的电氧化-电絮凝处理含Tl废水[J]. 中国环境科学, 2022,42(6):2656-2661. Zhang R Q, Wu H H, Xu H Y, et al. Electrooxidation-electrocoagulation treatment of thallium containing wastewater based on RuO2-IrO2 /Ti and Fe0 electrodes [J]. China Environmental Science, 2022,42(6): 2656-2661. [3] 李炳堂,胡智泉,刘冬啟,等.活性污泥中菌群多样性及其功能调控研究进展[J]. 微生物学通报, 2019,46(8):2009-2019. Li B T, Hu Q Z, Liu D Q, et al. Research progress of bacterial diversity and functional regulation in activated sludge [J]. Microbiology China, 2019,46(8):2009-2019. [4] Sun F L, Fan L L, Xie G J. Effect of copper on the performance and bacterial communities of activated sludge using Illumina MiSeq platforms [J]. Chemosphere, 2016,156:212-219. [5] Bhat S A, Cui G, Li W, et al. Effect of heavy metals on the performance and bacterial profiles of activated sludge in a semi- continuous reactor [J]. Chemosphere, 2020,241:125035. [6] 孙嘉龙,肖唐付,宁增平,等.几株真菌对铊吸附作用的初步研究[J]. 矿物岩石地球化学通报, 2011,30(3):341-344,349. Sun J L, Xiao T F, Ning Z P, et al. Adsorption of thallium by microbes:A case study of fungus [J]. Bulletin of Mineralogy, Petrology and Geochemistry, 2011,30(3):341-344,349. [7] Ralph L, Twiss M R. Comparative toxicity of thallium (I), thallium (III), and cadmium (II) to the unicellular alga Chlorella isolated from Lake Erie [J]. Bulletin of Environmental Contamination and Toxicology, 2002,68:261-268. [8] Lan C H, Lin T S. Acute toxicity of trivalent thallium compounds to Daphnia magna [J]. Ecotoxicology and Environmental Safety, 2005, 61(3):432-435. [9] Wei X, Li X, Liu P, et al. Integrated physiological, biochemical, and transcriptomic analysis of thallium toxicity in zebrafish (Danio rerio) larvae [J]. Science of the Total Environment, 2023,859:160265. [10] Vakondios N, Koukouraki E E, Diamadopoulos E. Effluent organic matter (EfOM) characterization by simultaneous measurement of proteins and humic matter [J]. Water Research, 2014,63:62-70. [11] 杨张洁.重金属对SBR反应器性能及微生物菌群的影响研究[D]. 西安:西安理工大学, 2018. Zhang Y J. Effect of heavy metals on the performance of SBR reactor and microbial flora [D]. Xi'an University of Technology, 2018. [12] Aftab B, Khan S J, Maqbool T, et al. Heavy metals removal by osmotic membrane bioreactor (OMBR) and their effect on sludge properties [J]. Desalination, 2017,403:117-127. [13] Third K A, Sepramaniam S, Tonkovic Z, et al. Optimisation of storage driven denitrification by using on-line specific oxygen uptake rate monitoring during SND in a SBR [J]. Water Science and Technology, 2004,50(10):171-180. [14] D'Abzac P, Bordas F, Van Hullebusch E, et al. Extraction of extracellular polymeric substances (EPS) from anaerobic granular sludges: comparison of chemical and physical extraction protocols [J]. Applied Microbiology and Biotechnology, 2010,85:1589-1599. [15] Ma C, Huangfu X, Zou Y, et al. Kinetics and mechanism of thallium (I) oxidation by permanganate: Role of bromide [J]. Chemosphere, 2022,293:133652. [16] 李静,严红,肖本益.活性污泥活性的表征及其检测方法研究[J]. 工业水处理, 2016,36(8):5-10. Li J, Yan H, Xiao B Y. Research on the characterization and detection methods for the activity of activated sludge [J]. Industrial water treatment, 2016,36(8):5-10. [17] 王云燕,许欢,傅杰,等.铅锌冶炼含铊废水铊形态分析及深度处理技术研究[J]. 中南大学学报(自然科学版), 2023,54(2):485-494. Wang Y Y, Xu H, Bo J, et al. Thallium morphology analysis and advanced treatment process of thallium wastewater from lead-zinc smelter [J]. Joumal of Central South University (Science and Technology), 2023,54(2):485-494. [18] Sheng G P, Xu J, Luo H W, et al. Thermodynamic analysis on the binding of heavy metals onto extracellular polymeric substances (EPS) of activated sludge [J]. Water Research, 2013,47(2):607-614. [19] Julienne F, Delorme N, Lagarde F. From macroplastics to microplastics: Role of water in the fragmentation of polyethylene [J]. Chemosphere, 2019,236:124409. [20] 王春燕,曾薇,许欢欢等.混合外源菌强化剩余污泥微氧水解产酸[J]. 中国环境科学, 2020,40(1):252-260. Wang C Y, Zeng W, Xu H H, et al. Effect of mixed yeast of acetic bacteria on acid production from micro-aerobic hydrolysis of excess sludge [J]. China Environmental Science, 2020,40(1):252-260. [21] Wan S, Ma M, Lv L, et al. Selective capture of thallium (I) ion from aqueous solutions by amorphous hydrous manganese dioxide [J]. Chemical Engineering Journal, 2014,239:200-206. [22] Liu J, Yin M, Zhang W, et al. Response of microbial communities and interactions to thallium in contaminated sediments near a pyrite mining area [J]. Environmental Pollution, 2019,248:916-928.
