The effects of varying Zn2+ on the activated sludge properties and its distribution patterns. (February 2022)

• Record Type: Journal Article
• Authors: Zhang, Lanhe; Liu, Yaling; Wang, Changyao; Guo, Jingbo; Ma, Dongmei; Liu, Shili; Liu, Qiang
• Is Part Of: Bioresource technology reports. Volume 17(2022)
• Publication Date: 2022-02
• Subjects: Zn2+ -- Distribution patterns -- Chemical forms -- Flocculation -- EPS; Biomass energy -- Periodicals; Biotransformation (Metabolism) -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Waste products as fuel -- Periodicals; Waste products as fuel; Organic wastes; Factory and trade waste; Biotransformation (Metabolism); Biomass energy; Agricultural wastes; Periodicals; Electronic journals; 662.88
• DOI: 10.1016/j.biteb.2022.100990
• Languages: English
• ISSNs: 2589-014X

Abstract

Abstract: Metallurgy, electroplating and pharmaceutical industries generate a large amount of wastewater containing Zn 2+, which influences the activated sludge properties. The present work investigated the effects of Zn 2+ on sludge properties and its distribution patterns and chemical forms under a Zn 2+ concentration range of 0–20 mg/L. When the influent Zn 2+ concentration was 1 mg/L, parameters indicating sludge properties such as Zeta potential (−14.80 mV), contact angle (78.93°), particle size (54.43 μm) and re-flocculation (FA, 30%) reached the optimal states. Zn 2+ was adsorbed by the functional groups of extracellular polymeric substances (EPS) and low EPS promoted the sludge flocculation. The lower pH affected the EPS functional groups, which in turn affected the adsorption of Zn 2+ . The FeMn oxidation state Zn (2.66–6.86 mg/gVSS) predominated in the sludge and decreased as sludge flocculation increased. The results provided evidence to make full use of low concentration of Zn 2+ to ensure wastewater treatment performance. Graphical abstract: Unlabelled Image Highlights: Low concentration of Zn 2+ promoted the pollutants removal and sludge activity. Concentration distribution of Zn 2+ : RS > TB-EPS > supernatant >LB-EPS > SMP. High concentration of FeMn oxidation state Zn decreased sludge flocculation. Sludge flocculation rose first and then worsened as Zn 2+ concentration increased. Lower pH decreased the EPS functional groups and the adsorption of Zn 2+ .