Sustainable design of textile industry effluent treatment plant with constructed wetland

Abstract

Textile has become a major source of income for India’s economy. Steps involved in textile manufacturing are fabrication of yarn, fabric production, dying, printing and finishing. Dying, printing and finishing are mainly water intensive processes which results in the generation of liquid waste. This effluent contains essential compounds such as salts, acids, alkalis and anthropogenic dyes in good concentration Many times dyes acts as sources of heavy metals also. Effluent from this type of industries not only makes the water body unfit for downstream use but also disturbs the natural aquatic ecosystems. Coloured textile effluent after joining any water body make the water unfit for downstream usage as well as interfere with natural activities of aquatic life. Developing countries thus require effective, economic and environment friendly sustainable treatment option.Constructed Wetlands (CW) provide an economic, easy as well as environment friendly treatment option having the ability to treat even different industrial effluents. CW has been found to be 42 %more economical than activated sludge process where as 80% more economical based on operation and maintenance expenses. In the current study, effort has been given to design a sustainable textile industry effluent treatment plant with Constructed Wetland. CW has been designed by various methods, under different flow conditions and indifferent weather conditions. The site under study had a green belt of 1500 sq. meter. According to k-C* model while considering the chemical oxygen demand (COD) load both horizontal as well as vertical subsurface flow, CW can be constructed in these green belt. As a result of current study, it was concluded that CWs are capable enough to replace the conventional activated sludge process (ASP). CW design has been done on the basis of both biological oxygen demand (BOD) as well as COD load for summer and winter conditions. K-C* model gave reliable result. The organization under study is having a green belt of 1500 sq. mts. According to k-C* model the horizontal CW can be designed after giving pre-treatment by ASP where for vertical subsurface flow CW the treatment can be more sustainable and the effluent can be wholely treated by CW.