To Treat Wastewater, Case Study Example

Secondary Water Treatment :  is a biological treatment process of human waste.  It works on the basis of using micro organisms to convert non settleable solids.  This process of sedimentation allows the settleable solids to settle out.  This second treatment is in fact, the minimum  level of treatment required and defined by the clean air act.  The concept of activated sludge is the most common approach in secondary treatment.. ” it starts with a aeration  that encourages the growth of microbes in the waste, these in turn feed off the organic material which allows the solids to settle out.  The bacterial  activated sludge is then  recirculated back into the aeration base  increasing the rate of organic decomposition”.  (California State University, 2010)  Figure 1 refers.

Figure 1 Activation Sludge Process

Tertiary Water Treatment : ” sometimes called “advanced treatment” ) includes any level of treatment beyond secondary treatment. These processes can be physical, biological, or chemical. Processes for treating drinking water can be adapted to tertiary treatment. They can include: filtration, activated carbon adsorption, and coagulation.”  (California State University, 2010)

Fig 2 illustrates how all of these come together in one integrated process flow chart and integrates both secondary and tertiary treatment processes.

Figure 2: Integrated treatment process flow

Within the process we have reclaimed water .  This has been  used for recycling purposes and in particular at the cooling towers for electric power plants. An example is that of the program in New Jersey where ”  Reclaimed water from LRSA wastewater treatment plant is piped to an auxiliary treatment facility where the water is chlorinated and filtered. After filtration, the reclaimed water is pumped approximately one mile to the Linden power station and further treated.  It is then pumped at 8,100gpm via a 24in pipe to the plant’s cooling tower basins. The water is conventionally treated in the cooling basins”.  (NRI, 2010).

In North America there has become an increased need to inject waste water back into the ground because of decreasing ground water tables, land subsidence and saltwater intrusion. The reuse of waste water has now become recognised as an economic and ecologic necessity. ” Since 1987, ultraviolet radiation has been successfully used to disinfect reuse effluents. UV is a non-chemical disinfection technology for wastewater that can protect the public against pathogenic microorganisms including protozoa, bacteria and viruses. As an alternative to chemical disinfection, UV does not produce harmful by-products and is non-toxic to the environment.”  (SAKAMOTO, 2000).

Works Cited

California State University. (2010). Waste Water. Retrieved 5 10, 2010, from California State University: http://www.csun.edu/~vchsc006/356b/b08.html

NRI. (2010). Water Technology Net. Retrieved 5 11, 2010, from Linden Combined Cycle Plant Reclaimed Water Reuse System, NJ, USA: http://www.water-technology.net/projects/reclaimed_water/

Sakamoto, G. (2000, 10). UV disinfection of reclaimed wastewater:. Retrieved 5 11, 2010, from Environmental Protection: http://www.mindfully.org/Water/UV-Disinfection-Wastewater.htm