Phytoremediation of dairy effluent by constructed wetland technology

Abstract

Constructed wetlands are artificial wastewater treatment systems consisting of shallow ponds or channels which have been planted with aquatic plants and which rely upon natural microbial, biological, physical and chemical process to treat wastewater and are gaining acceptance in the recent years as a viable option for the treatment of industrial effluents and removal of toxic components. In this study, an attempt was made to compare the efficiency of aquatic macrophytes like Typha sp., Eichhornia sp., Salvinia sp., Pistia sp., Azolla sp. and Lemna sp. to treat the effluents from dairy factory, under laboratory conditions in constructed wetlands. The biological oxygen demand and chemical oxygen demand of dairy effluent were reduced up to 65.4-83.07% and 70.4-85.3%, respectively, after treatment with constructed wetland technology.

Waste Water Purification Potential of Eichhornia crassipes (Water Hyacinth)

“…Similar findings had also been reported by Dipu et al, (2010), Yadav et al, (2011), Dhote (2007), Shah (2010), Mahmood et al, (2005).…”

“…This reduction in turbidity is due to the root hairs as they have electrical charges of colloidal particles such as suspended solids and cause them to adhere on the roots where they are slowly digested and assimilated by the plant and microorganism. Similar findings had also been reported by (Johnston, 1993;Gudekar and Trivedi, 1989;Dipu et al, 2010;Neralla et al, 2007).…”

“…Nitrogen is also taken up by plants and incorporated into the biomass. Similar findings had also been reported by Al-Omari (2003), Sommer (2000), Dipu et al, (2010), Baskar (2001 and Shah (2010).…”

“…The reduction in pH favoured microbial action to degrade BOD and COD in the waste water. Similar finding had also been reported by Zimmels et al, (2006), Zhang et al, (2007), Haris (2007), Tegegne et al, (2008), Dipu et al, (2010), Shah (2010) and Dhote (2007).…”

“…The total dissolved solid reduction by test plant (Eichhornia crassipes) is almost similar in all three treatments for both the years. Similar findings had also been reported by (Dipu et al, 2010;Shah 2010;Groudev et al, 2001 andWirojanagud et al, 2002.) The turbidity reduction by test plant (Eichhornia crassipes) was maximum in T 2 treatment and minimum in T 1 treatment where it decreases from 2.61 NTU to 1.52 NTU in year 2010-11 and from 2.80NTU to 1.49 NTU in 2011-12.…”