Application of waste materials as 'low cost' sorbents for industrial effluent treatment: a comparative overview

In all management practices two important elements are considered: 1) wastewater management; 2) integrated waste management, among others. These elements can be simultaneously linked treating wastewater by sorption onto 'low cost' waste materials. Thus, sorption becomes an attractive alternative as single–stage treatment of industrial effluents (usually as pre–treatment or final treatment stage). The main objective of this paper is to describe the 'low cost' sorbents (natural and industrial ones) and also sorption characteristics used for industrial–scale applications, especially of three categories of waste materials: peat, sawdust, and coal ash/coal ash modified with lime, for colour and organics removal from industrial effluents produced in manufacturing of textile fabrics. Special attention is focused on influencing factors of sorption process (operating regime, pH, sorbent dose, temperature, and sorption time) for high removal with low cost and no supplementary environmental protection needs. The aforementioned aspects are presented for treated effluent discharged in natural receptor and/or sewerage system.