Advanced Treatment of Coking Wastewater by Polyaluminum Silicate Sulfate for Organic Compounds Removal

Abstract

Coking wastewater is a typical high-strength organic wastewater, for which it is difficult to meet discharging standards with a single biological treatment. In this study, effective advanced treatment of coking wastewater was achieved by coagulation with freshly prepared polyaluminum silicate sulfate (PASS). The performance advantage was determined through comparison with commercial coagulants including ferric chloride, polyferric sulfate, aluminum sulfate and polyaluminum chloride. Both single-factor and Taguchi experiments were conducted to determine the optimal conditions for coagulation with CODCr and UV254 as indicators. A dosage of 7 mmol/L PASS, flocculation velocity of 75 r/min, flocculation time of 30 min, pH of 7, and temperature of 20 °C could decrease the CODCr concentration from 196.67 mg/L to 59.94 mg/L. Enhanced coagulation could further help to remove the organic compounds, including pre-oxidation with ozonation, adsorption with activated carbon, assistant coagulation with polyacrylamide and secondary coagulation. UV spectrum scanning and gas chromatography-mass spectrometry revealed that the coagulation process effectively removed the majority of organic compounds, especially the high molecular weight alkanes and heterocyclic compounds. Coagulation with PASS provides an effective alternative for the advanced treatment of coking wastewater.

Study on Preparation of Poly Aluminum Ferric Sulfate Flocculant from Municipal Solid Waste Incineration Fly Ash

“…(10) As the solution's alkalinity rises, the [Al(H2O)6] 3+ and [Fe(H2O)6] 3+ obtained through acid leaching will further hydrolyze and polymerize, forming [Al(OH)aSO4]b and [Fe(OH)aSO4]b macromolecular polymers that will also cross-polymerize with one another. All of the resulting polymers will then be linked together to form stable macro-molecular long chains in any order and any quantity, in which the hydroxyl groups will bridge, and the resulting floc is PAFS (Pan et al 2012;Gao et al 2023;Wang et al 2023) 3.2. Single-factor experiment 3.2.1.…”