Primary treatment and ozonation of model wastewater from the production of soft capsules

Abstract

The lipid extract of fruits of the royal palm Cubana (Roystonea regia), developed at the National Center for Scientific Research (CNIC), will be used in the treatment of benign prostatic hyperplasia (BPH). The product is a liquid oil to be encapsulated in soft gelatin capsules. In Cuba, there was no industrial plant for soft capsule production; a plant was built for this purpose, which was necessary for the previous study of the wastewater model. A treatment scheme to laboratory scale of three stages: Trap of fat, primary sedimentation, and ozonation was evaluated. In the first two stages, hydraulic retention times of 15, 30, and 45 minutes were studied, obtaining the best condition for 30 minutes. The ozonation process was carried out with an experimental design 2³, with two ozone concentrations in the gas (40 and 60 mg O₃/l), two gas flows (10 and 20 l/h), and two pH values (3 and 7); the ozonation time was 30 min. Ozone doses of 330, 500, and 660 mg O₃/l were applied. Statistical analysis showed that the best results were obtained with ozone concentration: 60 mg O₃/l; gas flow: 10 l/h, and pH: 3. The combination of the treatment stages allowed achieve a total efficiency of reduction of COD (51.6 %), BOD₅ (64.7 %), ST (21 %), SSed (100 %), fats and oils (79.3 %), detergents (91.6 %), nitrogen (30.1 %), phosphorus (93.1 %), turbidity (85.8 %) and color (90.1 %), guaranteeing compliance with the Cuban NC standard 27: 2012.