Constructed Wetlands–Australian Environmentally Friendly Natural Wastewater Treatment System - An Ideal Low-Cost Solution for Bangladesh
[1]
Sheikh Mahabub Alam, Director of Technical Operations, The Australasian Water and Environmental Services (AWES) Pty. Ltd., Sydney, Australia..
A properly designed, constructed, operated and maintained wetland is a very reliable and effective natural wastewater cleansing system where aquatic plants, floating plants and submergent aquatic plants are encouraged to grow. These plants in conjunction with soil substrata /gravel beds and microorganism aided by the flow regime and hydrologic condition creates an environment that facilitates a wide range of physical, chemical and microbial process. These processes separately or in combination performs the cleaning of wastewater and converting chemicals to a useable form, by removing BOD, TSS, transforming nitrogen (TN), recycling phosphorous (TP), providing storage for metals and attenuated organisms/pathogens reducing human health risks. The biogeochemical cycling of macro and micronutrients within the wetlands constitute the framework of wastewater treatment capability. There is no anthropogenic energy source or chemical requirements, naturally driven, environmentally friendly process, performs the cleansing acts. Two basic types of wetlands are used extensively around the world the world and they are known as: (1). Free Water Surface (FWS) Wetlands and Vegetated Subsurface Beds (VSB) Wetlands. Selective popular methods have been used for current research for calculating wetland sizing, Detention Time, Rate of Hydraulic Loading as well as the temperature, depth and porosity which are very conformable with international standard. Current Australian project parameters reveals that: (a) Largest (VSB, 144.5m2) and Smallest (VSB, 2.8m2) Wetland Size; (b) Longest (VSB, 22.5 days) and Shortest (VSB, 0.6 day) Detention Times; and (c) Largest (VSB, 38.46cm/day) and Smallest (VSB, 0.69cm/day) Hydraulic Loading Rate respectively. Temperature, Depth and Porosity has been identified as the most sensitive parameters for wetland sizing. A Wetland Size of 50m2 with a suggested detention time of 5 days is recommended for Utopia College and further research is desirable. Wetlands works very effectively in warm, humid and temperate climatic conditions from that point of view it would be an ideal technology to treat wastewater and reclamation of treated water.
Wetlands, Aquatic Plants, Greywater, Microorganisms, Biochemical, Hydrology
[1]
Craft and Richardson (1993). Progress Toward Restoring Everglades. Board on Environmental Studies and Toxicology. https://www.google.com.au/search?q=Craft+and+Richardson+1993&oq=Craft+and+Richardson+1993.
[2]
Economopoulou, MA and Tsihrintzis, VA (2004). Design Methodology of free water Surface Constructed Wetland. https://scholar.google.com.au/scholar?hl=en&as_sdt=0%2C5&as_vis=1&q=Economopoulou+and+tsihrintzis+2004&btnG=.
[3]
Kadlec, Robert, and Knight, (1996). Treatment Wetlands. Lewis Publishers. Boca Raton, Florida, USA.
[4]
Kadlec et al (1998). EconPaper: An empirical examination of the amortized spread. Journal of Financial Economics, vol. 48, issue. 2, 159 – 188. https://econpapers.repec.org/article/eeejfinec/v_3a48_3ay_3a1998_3ai_3a2_3ap_3a159-188.htm.
[5]
Kadlec (2005). Issuer surplus and the partial adjustment of IPO prices of public information. https://econpapers.repec.org/article/eeejfinec/v_3a77_3ay_3a2005_3ai_3a2_3ap_3a347-373.htm.
[6]
Kadlec, R. and Wallace, Scott, D., (2009). Treatment Wetlands (eBook). Second Edition. Boca Raton: Taylor and Francis Group, LLC, Florida, USA.
[7]
Reed, S. C., et al (1995). Natural Systems for Water Management and Treatment. 2nd Edition, McGraw - Hill, New York, USA.
[8]
The NSW Wetlands Policy, 2000. http://www.water.nsw.gov.au/__data/assets/pdf_file/0009/549171/nsw_wetland_management_policy.pdf.
[9]
USEPA (2000). The role of constructed wetlands in secondary effluent treatment and water reuse in subtropical and aid Australia. https://scholar.google.com.au/scholar?q=usepa+2000+Wetland+design&hl=en&as_sdt=0&as_vis=1&oi=scholart
[10]
Wallace & Knight (2006). Small Scale Constructed Wetland Treatment System. https://www.researchgate.net/publication/230887801_Small_Scale_Constructed_Wetland_Treatment_Systems_Feasibility_Design_Criteria_and_OM_Requirements
[11]
WERF. (2001). Natural Systems for Wastewater Treatment, Manual of Practice FD-16, 2nd Edition, Water Environment Federation, ISBN 1-57278-165-3.
