Chronic Toxicity of Detoxified Kraft Pulp and Paper Mill Wastewater using Photocatalytic with Cu-TiO2 Foils/Sunlight on Xenopus levies (daudin) Tadpoles

Abstract

Wastewater from pulp and paper mills contain refractory toxic substances with deleterious effects to aquatic organisms when discharged before proper treatment. Most of the effluent treatment technologies used by the industry are predominantly inefficient, resulting in inadequate detoxification. The use of photocatalytic techniques has shown higher effluent treatment potential. However, there is need to evaluate their chronic toxicity reduction. The current study evaluated the chronic effects of detoxified Kraft pulp and paper effluent using photocatalytic on African clawed frogs (Xenopus levies) tadpoles. Chorionic toxicity was carried out according to the standard Amphibian Metamorphosis Assay (AMA) test for 21 days. Chronic toxicity of photocatalytic combined with photovoltaic (PHCPVC); photocatalytic combined with wood ash leachate as an electrolyte (PHCASH); photocatalytic alone (PHCALON); and photo-treatment without Cu-TiO2 foils (PHOALON) were studied. No Effect Concentration from the Control (NOEC) and Lowest Concentration with an Effect from the Control (LOEC), obtained in the FETAX study were used to evaluate chronic toxicity of the various photocatalytic treatment methods. The study revealed that the most effective photocatalytic treatment was PHCPVC followed by PHCALON, then PHCASH and lastly PHOALON treatment for both Kraft pulp mill effluent (PME) and biologically treated pulp and paper mill effluent (BPPME). PHCPVC reduced average mortality and malformation of tadpoles by 26% and 22% respectively. PHCPVC treatment reduced growth retardation of tadpoles by an average of 18%. Therefore, the study recommends the treatment of Kraft pulp mill effluent by PHCPVC.