Elucidating co-conditioning strategies of aluminium-based sludge using natural biopolymeric magnetite composite for leveraging dewaterability

Abstract

Abstract Significant co-conditioning of aluminum-based sludge using alternative conditioner (natural biopolymer-magnetite/H2O2) as a Fenton conditioner for improving the sludge dewaterability is investigated in the current study. Firstly, natural biopolymer/magnetite (NBP-M) were prepared in various ratios and the samples labeled as (NBP-M-(1:1); NBP-M-(1:3) and NBP-M-(2:1). Focuses were placed on factors influencing such novel Fenton conditioner. Capillary suction time (CST) was utilized to assess sludge dewaterability. Experiments have exhibited that significant development of alum sludge dewaterability could be attained at minimum reaction time and using low concentrations of the applied catalyst, i.e. natural biopolymer/magnetite and H2O2. It was found that sludge conditioning and dewaterability became better with increasing both reagents concentrations. A Box–Behnken experimental design based on the response surface methodology was investigated to explore the optimum of the influencing variables, i.e. catalyst (NBP-M) concentration, H2O2 loading and pH. The optimized values for NBP-M, H2O2, and pH are 46 and 380 mg/L, respectively at pH 3.0, at which the CST reduction efficiency of 58 ± 3% can be attained, this approved with that predicted by an established polynomial model in the current investigation.

Keywords

• Alum sludge
• Conditioning
• Dewatering
• Fenton’s reaction
• Chitosan-magnetite composite