Treatment of confectionery and gum factory wastewater effluent

Abstract

A pilot plant for the treatment of wastewater was designed, constructed and installed for the continuous treatment of 250 l/d wastewater originating from a gum and confectionery factory. The pilot plant consisted of an equalizer, chemical mixing tank, aerator, clarifier, disinfectant tank and sand filter as the main components. In addition, a set of centrifugal and dosing pumps, an air blower and a pH controller were added. The industrial-scale treatment unit could handle a 50 m3/d effluent flow rate composed of combined industrial and municipal wastewater effluents heavily loaded with organic and biologically resistant pollutants (sugars, gums, pesticides and detergents) with a chemical oxygen demand (COD) value extending to 25 000 ppm. House-keeping arrangements and the isolation of some streams were necessary in order to attain an end-pipe effluent capable of treatment by conventional procedures at reasonable cost values. Different operating conditions were tested in order to treat effluent loaded with a COD value reaching 5000 ppm to obtain acceptable limits capable of containment in underground wells or re-use in irrigation.