Coagulation efficiency of polyaluminum chloride for natural organic matter removal from low specific UV absorbance surface water and the subsequent effects on chlorine decay

Natural organic matter (NOM) is easily soluble in surface water and difficult to be removed thoroughly. In this paper, polyaluminum chloride-polyacrylamide (PAC-PAM), as a new water treatment material, was proposed to solve this problem by coagulation treatment. The performance, mechanism and kinetic process of NOM removal were investigated systematically. Results showed that the optimum dosage of PAC and PAM was 10 mg/L and 0.5 mg/L for NOM removal of Yellow River water. In this condition, NOM could be removed effectively due to positively charged PAM addition. The size, growth rate and recovery factor of flocs generated by PAC-PAM reached 419 μm, 34.9 μm/min and 0.48, respectively, while only 355 μm, 27.9 μm/min and 0.31 were obtained by PAC. Moreover, the adsorption and bridging effect of PAM assisted the formation of multi-branched flocs, which brought fast settle velocity and low turbidity of supernatant after coagulation.

Download Full-text

Mechanism of natural organic matter removal by polyaluminum chloride: Effect of coagulant particle size and hydrolysis kinetics

Water Research ◽

10.1016/j.watres.2008.04.017 ◽

2008 ◽

Vol 42 (13) ◽

pp. 3361-3370 ◽

Cited By ~ 142

Author(s):

Mingquan Yan ◽

Dongsheng Wang ◽

Jinren Ni ◽

Jiuhui Qu ◽

Christopher W.K. Chow ◽

...

Keyword(s):

Particle Size ◽

Organic Matter ◽

Natural Organic Matter ◽

Hydrolysis Kinetics ◽

Polyaluminum Chloride ◽

Organic Matter Removal ◽

Chloride Effect

Download Full-text

Natural Organic Matter Removal from Raw Surface Water: Benchmarking Performance of Chemical Coagulants through Excitation-Emission Fluorescence Matrix Spectroscopy Analysis

Water ◽

10.3390/w13020146 ◽

2021 ◽

Vol 13 (2) ◽

pp. 146

Author(s):

Raymond John C. Go ◽

Hui-Ling Yang ◽

Chi-Chuan Kan ◽

Dennis C. Ong ◽

Sergi Garcia-Segura ◽

...

Keyword(s):

Organic Matter ◽

Surface Water ◽

Natural Organic Matter ◽

Surface Waters ◽

Polyaluminum Chloride ◽

Coagulant Dosage ◽

Initial Ph ◽

Pre Treatment ◽

By Products ◽

Chemical Disinfection

Chemical disinfection of surface waters has been proven effective in minimizing the risk of contamination by water-borne pathogens. However, surface waters contain natural organic matter (NOM) which, upon chemical disinfection, is readily converted into hazardous disinfection-by-products. Hence, NOM removal from these waters is critical. Chemical coagulation is a readily implementable technology to minimize these undesired side-effects by NOM removal. Herein, capabilities of ferric chloride (FeCl3) and polyaluminum chloride (PACl) as pre-treatment for NOM abatement from natural raw surface water have been benchmarked. Excitation-emission fluorescence matrix (EEM) spectroscopy characterization of NOM fractions demonstrated high removal efficiency. A two-level full factorial design was employed to analyze the effects of coagulant dosage and initial pH on the removal of turbidity, humic acid-like substances and fulvic acid-like substances from the raw water. Higher removal of ~77% NOM was attained with PACl than with FeCl3 (~72%). Optimization through response surface methodology showed that the initial pH—coagulant dosage interaction was significant in removing NOM and turbidity for both PACl and FeCl3. These results identify the opportunity for coagulation technologies to prevent and minimize disinfection-by-products formation through NOM removal.

Download Full-text