Waste - Water of Sugar Industries - A Serious Threat to the Natural Environment

Abstract

Over recent years, great concern has been given throughout the globe regarding the environmental pollution in many ways due to the rapid industrialization and subsequent urbanization. Industrialization is a critical means for the improvement of any country. With the fast development of business market (sugar, tannery material, sago, color, commercial enterprises) in the nation and worldwide, contamination in fresh water and soil by mechanical waste water has expanded vastly. The developed countries worldwide have always been exploiting each bit of natural resources or raw material to convert them into goods for their own comforts and the exportation of them to the down and out developing countries. In executing this, industrialized countries dump lot of waste materials in their environment which becomes polluted. Even though rapid urbanization and industrialization in the developing countries like India are facing acute problems in collection, treatment and disposal of industrial effluents. Unmanaged organic waste fractions from industries, municipalities and agricultural sector decompose in environment resulting in large scale contamination to the land, water and air.

Several chemical elements are used in sugar industries mainly for coagulation of impurities/contamination and refining of end products. Ca(OH)2 is usually used to clarify and to increase pH of juice. A small quantity of H₃PO₄ is added prior to liming to improve clarification. CO₂ gas is bubbled through the defecated juice to lower pH, which results in improvement of precipitation of impurities. Polyelectrolyte, which are polymer based chemical are also used for the coagulation of impurities during defecation and carbonation process. SO₂ is bubbled through the defecated raw sugar to remove color. Dilute solutions of NaOH or Na₂CO₃ are used for the periodic descaling of heaters followed by neutralizing it with dilute HCl. Lead acetate is used for the analysis of sugar content. All the chemicals, one way or another, are contributing towards increasing the organic strength, dissolved solids and suspended matter.

The sugar mill’s waste-water is characterized by its brown color, low pH, high temperature, turbidity, electrical conductivity, chloride, total alkalinity, high BOD, high COD, odour problem, total hardness, sulphate, phosphate, total acidity, calcium, magnesium, total solids and high percentage of dissolved organic and inorganic matter. So, this untreated water creates the problem to the environment up to a large extent.