Indian Journal of Science and Technology

Abstract

Objectives: Investigation for low cost, small scale, decentralized waste water treatment system for small communities and suburbs was done in this study. Total passive system, artificially engineered to treat domestic wastewater by mimicking the natural water purifying processes of river, swamp and wetlands, gives us what is known as constructed wetland. Methods: In this paper, we carried out the design and installation of two laboratory scale vertical flow constructed wetland within the premises of Lovely Professional University sewage treatment Plant. Two separate systems of height 45 cm and average diameter 15 cm was created, one with gravel and sand as a media and other with gravel, sand and soil as a media. Both the wetland was planted with Canna sp as an excellent phytoremediating plant and was available easily in locality. This plant shows very high growth rate and has a large rhizome. The waste water was fed through the 1.5cm diameter pipe. Eight liter of pretreated wastewater from the university Sewage treatment plant was fed with a retention period of 2 days, feeding was done in such a way that the gravitation does all the work, as the feeding tank was placed higher above both the wetland. Feeding was control by the valve. Findings: Initial analysis of wastewater subjected to wetland shows dramatic reduction in the visible suspended solids and color. Dissolve oxygen was improved from 3.6±0.4mg/L to 5±.2mg/L in both the wetland system. pH in effluent from both the CW was in between 6.5-8.5, pH of influent was in between 9±0.4. BOD5 at 20o C of both the effluent form vertical flow CW was found to be below 30mg/L as against the 180-190mg/L of influent given to wetland, which was well within the range as per as Environment (protection) rules, 1986 of GOI for inland surface water discharge. Application/Improvement: Potable water is already a scare resource; even the water for irrigation is becoming scarce and not to forget the depleting ground water table. The findings of this study shows us a potential cheap method to treat wastewater generated, which can be used to met our agricultural water demand and can even be used to recharge ground water.

Keywords: Canna, Constructed Wetland, Phytoremediation, Vertical Flow, Wastewater Treatment