Textile, dying & printing
industry waste water is a colored effluent with high COD & BOD. In
many countries it is prohibited to dispose colored & high COD water
into environment or even in common effluent treatment plants. Many
times due composition of colored effluent it is difficult to bring
down color & COD in textile effluent.
Ozone is applied in textile effluent for colour removal or odor reduction. Either ozone is applied in primary stage or tertiary stage of effluent treatment plant.
First let us understand role of ozone in tertiary treatment.
Ozone has unique property of treating multiple pollutants in the
waste water. Ozone is effective on reducing colour, odor, organic
impurities, micro organisms, COD, BOD, heavy metals, colloidal etc.
Depending upon the strength of the pollutant & efficiency of
biological treatment, ozone works on pollutant & in the process gets
consumed. Generally ozone rising is done on the basis of colour
present in the treated effluent.
Ozone is very effectively applied in primary stage where it works two ways, one ozone breaks the chemical bonds of disparents making color pigment to settle very efficient in primary treatment. Key to success depends greatly on ozone dose, integration stage, and technique of implementation. Over the period of time scientist & environmental engineers has mastered these techniques of use of ozone in textile industry.
Well designed ozone integration can significantly reduce the capacity of secondary stage. This is return reduce capital cost, operational cost, plant foot print, colour from waste water & time. When textile waste water is required to be recycled and to be reclaimed, ozone is very effective. Recycling of textile waste water generally uses stages like coagulation, flocculation, biological, micron filtration, ultra filtration & reverse osmosis. Using ozone in this loop increases the performance & life of other components in recycling scheme.
Textile industry effluent generates very high quantity of
primary stage due to extensive use of flocculants & lime. As ozone
works over wide range of plt, requirement of lime as a ph correction
is reduced & eventually primary sludge. This significantly reduces
operational cost with high performance.