Treatment performance of artificial floating reed beds in an experimental mesocosm to improve the water quality of river Kshipra

Abstract

The discharge of untreated wastewater in River Kshipra had brought annual average of BOD, TKN and TS levels up to 39 mg/l, 38 mg/l and 781 mg/l respectively in the study area. Treatment performance by Artificial Floating Reed Beds (AFRB) was evaluated for removal efficiency of TS, NH4-N, NO3-N, TKN and BOD from river water, initially, under a pilot scale by an AFRB of size 200 m2 planted with local reed grass, Phragmites karka, in the part of River Kshipra at the confluence with meeting point of a wastewater stream. The system performance was recorded as 43% reduction in TS, 38% reduction in TKN and 39% BOD reduction. The experimental AFRBs were buoyant structure planted with reed grass, each unit had a rectangular size and covered an effective surface area of 2 m2. The experiment with the mesocosms with treatment of River water resulted that AFRB was reducing pollution load by 55-60% of TS, 45-55% of NH4-N, 33-45% of NO3-N, 45-50% of TKN and 40-50% of BOD. AFRB may be recommended as an in-situ, eco-friendly river water treatment structures for small shallow, slow flowing (or slightly stagnant) water bodies.

Floating Wetlands: A Sustainable Tool for Wastewater Treatment

“…The biological processes are more effective in FTWs as compared to the constructed wetlands due to the free suspension of roots in the water column; this establishes direct contact between contaminants and the root‐associated microbial community . Microorganisms decompose organic matter into simple nutrients which are removed by plants through direct uptake . Moreover, plant roots grew horizontally and vertically developing a large surface area for the nutrients uptake …”

“…Furthermore, plants take up nutrients for their growth and development and hence lower the eutrophication level. It has been reported that emergent plant species in floating wetlands are able to take up nitrogen from 200 to 2500 kg ha −1 per year . Accordingly, plants boost the removal of fine suspended particles by adhering them to the root system and lead to a prominent reduction in turbidity of water.…”

“…The hanging roots of plants below mat provide a large area for biofilms development and wastewater treatment . This is the reason that FTWs even have been proved effective for treatment of polluted surface water, sewage, industrial, and agricultural wastewater . Retention ponds are efficient to remove coarse and particulate forms of contaminants but not capable of removing dissolved contaminants effectively .…”

Effect of Stubble Heights and Treatment Duration Time on the Performance of Water Dropwort Floating Treatment Wetlands (FTWS)

“…In the past 30 years, the FTWs have been tested and applied in laboratories and at pilot scales [3][4][5][6][7][8][9]. Characterized by no extra land demand and adaption to a wide range of water depth, FTWs have been widely used in the treatment of domestic wastewater [10], river water [7,11,12], lake water [5,13,14], agricultural runoff [4,15], swine sewage [16], rainfall [17], storm water [18] and urban runoff [19].…”

Possibilities of Small Water Reservoir Impact Improvement on Surface Water Quality in Agricultural Landscape

“…The volume of experimental tanks was chosen according to the experience of authors who dealt with the research of CFW efficiency, e.g. Wang and Sample (2014) or Billore and Prashant Sharma (2009). Purposefully we fulfilled almost whole the tank with the root system because we focused at "living filter".…”