IJEP 41(9): 1041-1045 : Vol. 41 Issue. 9 (September 2021)
Sreedevi Sarsan*, G.R. Ksheeraja, Manne Supriya, S. Dedeepya Maha Lakshmi and D. Anusha
St. Pious X Degree and P.G. College, Department of Microbiology, Hyderabad, Telangana, India
Water pollution has become a perennial concern all over the world especially in developing countries due to rapid urbanization and increased industrialization. This polluted water is of great concern which impacts our social life, health and environment. There are various conventional wastewater treatment methods available, like activated sludge, trickling filters, slow sand filtration, UV radiation, etc., but they have certain limitations, like expensive equipment requirement, skilful manpower requirement and formation of carcinogenic bypro-ducts. Constructed wetlands are effective and environmental friendly ecosystems that are applicable for the reduction of pathogens from wastewater apart from the removal of chemical pollutants. There are many types of pathogens found in wastewaters that originate from human and animal activities. It is practically impossible to identify all the microbial species present in a wastewater sample due to technical difficulties, complexity and expense. Also, due to the complexity of pathogen removal mechanisms and various influencing factors, the knowledge on the fate and removal of bacteria in constructed wetlands (CWs) is still not sufficient. The main objective of our study was to test the efficiency of constructed wetlands in the reduction of pathogens from wastewater. The inlet and outlet water samples were collected from the constructed wetlands, serially diluted and spread plated on specific media plates. The colonies obtained were identified as well as enumerated using viable count technique and percentage reduction in pathogens was determined. The results showed that there is a 60-80% reduction in the number of different bacterial pathogens in the wastewater samples treated by Cw systems.
Wastewater treatment, Constructed wetlands, Pathogenic microorganisms, Bacteria isolation
- Okoh, A.I., et al. 2007. Wastewater treatment plants as a source of microbial pathogens in receiving watersheds. African J. Biotech., 6(25): 2932–2944.
- Zhang, K. and K. Farahbakhsh. 2007. Removal of native coliphages and coliform bacteria from municipal wastewater by various wastewater treatment processes: implications to water reuse. Water Res., 41: 2816–2824.
- Alexandros, S.I. and C.S. Akratos. 2016. Removal of pathogenic bacteria in constructed wetlands: Mechanisms and efficiency. Springer International Publishing. pp 327-346.
- Koukouraki, E. and E. Diamadopoulos. 2002. THM formation during chlorination of treated municipal wastewater. Water Sci. Tech. Water Supply. 2(3): 235–242.
- Blatchley, E.R., et al. 1997. Effects of disinfectants on wastewater effluent toxicity. Water Res., 31(7):1581–1588.
- Wu, S., et al. 2016. Sanitation in constructed wetlands: A review on the removal of human pathogens and fecal indicators. Sci. Total Env., 541: 8–22.
- Shingare, R. P., et al. 2019. Constructed wetland for wastewater reuse: Role and efficiency in removing enteric pathogens. J. Env. Manage., 246: 444–461.
- Vymazal, J. 2010. Constructed wetlands for wastewater treatment. Water. 2: 530–549.
- Hans, Brix., 1987. Treatment of wastewater in the rhizosphere of wetland plants- The root-zone method. Water Sci. Tech., 19:107-118.
- Wang, J., et al. 2018. Capacity of various single-stage constructed wetlands to treat domestic sewage under optimal temperature in Guangzhou city, South China. Ecol. Eng., 115:35–44.
- Yang, C.H. and D.E. Crowley. 2000. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status. Appl. Env. Microbiol., 1:345–351.
- Wu, S., et al. 2015. Treatment of industrial effluents in constructed wetlands: Challenges, operational strategies and overall performance. Env. Poll., 201: 107–120.
- Gottschall, N., et al. 2007. The role of plants in the removal of nutrients at a constructed wetland treating agricultural (dairy) wastewater. Ecol. Eng., 29:154–163.
- Valentina, R., et al. 2019. Root bacteria recruited by phragmites australis in constructed wetlands have the potential to enhance azo-dye phytod-epuration. Microorganisms. 7:384-405.
- Desena, M. 1999. Constructed wetlands provide cost-effective treatment for Florida town. Water Env. Tech., 11:38-39.
- Gerba, C.P., et.al. 1999. Optimization of artificial wetland design for removal of indicator microorganisms and pathogenic protozoa. Water Sci. Tech., 40(4-5):363-368.
- Neralla, S., et al. 2000. Improvement of domestic wastewater quality by subsurface flow constructed wetlands. Bioresour. Tech., 75:19-25.
- Stott, R., et al. 1999. Capacity of constructed wetlands to remove parasite eggs from wastewaters in Egypt. Water Sci. Tech., 40(3):117-123.
- Kela, P. W. and L.L. Raymond. 2008. Pathogen removal in constructed wetlands. In Wetlands: Ecology, conservation and restoration. Ed Raymundo E. Russo. Nova Science Publishers. pp 1-36.
- Kadlec, R.H. and R.L. Knight. 1996. Treatment wetlands. Lewis Publishers Inc., Florida, USA.
- Vymazal, J. 2005. Removal of enteric bacteria in constructed treatment wetlands with emergent macrophytes: A review. J. Env. Sci. H. – Part A : Toxic/Hazardous Substances Env. Eng., 40(6-7): 1355-1367.
- Cronk, J.K. 1996. Constructed wetlands to treat wastewater from dairy and swine operations: A review. Agric. Ecosyst. Env., 58(2-3): 97-114.
- Nokes, R.L. 2000. Reduction of enteric microorganisms in small scale, subsurface flow constructed wetlands. M.S. Thesis. University of Arizona, USA.
- Eiler, A. and S. Bertilsson. 2004. Composition of freshwater bacterial communities associated with cyanobacterial blooms in four Swedish lakes. Env. Microbiol., 6:1228–1243.