Petrochemical wastewater treatment using constructed wetland technique

Abstract

Constructed Wetlands are artificially developed ecosystem created to treat the wastewater it was normally like wetlands that occur where water conditions are intermediate between uplands and deep-water aquatic systems. Natural wetlands are capable of improving; the water quality. The ability of natural wetland systems has been recognized for more than 25 years and during this period, the use of engineered wetlands has evolved from a research concept to an accepted pollution control technology. The engineered wetland systems or Constructed Wetland Technology are treatment technologies that mimic natural wetland systems and these treatment techniques were incorporated as components of waste water treatment systems. Two general types of shallow vegetated ecosystems are being used for water quality treatment: (1) free water surface (surface flow) and (2) subsurface flow (vegetated submerged bed) systems. This paper reviews treatment of petrochemical wastewater using constructed wetland. The analysis was done on a lab scale model developed using a PVC tub with a size of 70X40X30 cm and a slight slope of (<1%) between inlet and outlet zones. This technology acts as a natural and low cost treatment facility for wastewater. In this study the plants used were Typha latifolia and Pragmites Australis. The parameters like Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS), Nitrogen, Phosphorus, Phenolic Compounds were studied based on APHA guidelines. The pollutant removal mechanism was also reviewed. It was found that the reduction efficiency of BOD, COD, TSS was found to be 90 to 95 % and the Phenolic compound removal efficiency was found to be 65 to 90%. Pollutant removal was highly dependent on retention time and influent concentration and by the action of internal plant communities and microorganisms, water depth. Copyright EM International.