Natural Wastewater Treatment
Vegetation Filters/Constructed Wetlands
Vegetation filter is a soil based natural treatment system which promotes treatment of wastewater through nature’s own treatment process, recycling and reuse of wastewater through plant irrigation, conversion of nutrient energy into biomass and provide exploitation of food, fuel and fodder production besides eco-restoration. The basic principle of the system is phytoremediation strategies, which employ trees, shrubs, and grasses for treating wastewater. The natural process of wastewater purification by soil and trees is exploited in this practice which is commonly known as “Vegetation Filters”. They are also better known as “Biofilters” and “Living filters”. It is an approach for wastewater treatment and management that utilizes the high water and nutrient uptake capacity through fast-growing, intensively planted trees and increases the microbial activity of the soil, it also remove pollutants from wastewater by soil absorption.
Together with water purification they provide soil conditioning, ground water recharge, soil carbon accumulation, and high biomass which increase their economic incentives.
Constructed or artificial wetland systems mimic the treatment that occurs in natural wetlands by relying on plants and a combination of naturally occurring biological, chemical, and physical processes to remove pollutants from water.
Natural wetlands occur naturally throughout the landscape as transitional areas between aquatic ecosystems and uplands.Most of the constructed wetlands employ herbaceous plant species rather than tree or shrubs.
They are generally divided into two main categories: Free Water System (FWS)/ Surface flow wetlands: the water level is above the ground surface; vegetation is rooted and emergent above the water surface; water flow is primarily above ground; vegetation may be planted or allowed to colonize voluntarily.
Vegetated Submerged Bed (VSB)/ Sub-Surface flow wetlands: the water level is below ground; water flow is through soil or gravel bed; root penetration is to the bottom of bed; wetland plants are generally common reed, bulrush, or cattail.