Porposal-4.docx

Desalination of Water Abstract The utilization of sand filters as the secondary stage in water treatment process and various design schemes of sand and gravel filtration beds were studied in this paper. The design schemes include gravel filter (Up flow and Down flow), sand filter (Down flow and Horizontal flow), sand and gravel filter. The primary stage was always considered as the gravity sedimentation in the storage tank. The final results were in acceptable range of the standards of National Regulatory water used for irrigation. Introduction Chronic reduction of underground water compels the researcher to focus on the treatment of greywater which is not as much polluted as the blackwater. The conservation of water becomes the key necessity due to the depleted natural water resources. Water resource management working on recycling and re-utilization of greywater by separating it from the blackwater which ultimately considered as wastewater. It saves the natural sources on one hand and reduce the risk of environment toxicity on the other hand. The need is to separate the greywater from toilet water which will ultimately reduce the contents of contaminants from it as well. Some Middle East countries are working on Ablution greywater treatment from last few years. Aden, a city of Yamen, worked with the UN (United Nations) on a project of recycling the Abluted greywater of six mosques. The selection of suitable technology is the key factor in this regard. A very good quality water is produced using the appropriate design of conventional sand filtration. Sand filters are constructed bed of sand and gravels of varying particulate size in an arranged pattern. The preliminary treatment is a necessary step in sand filtration technique to get quality effluent in less time. The wastewater is collected in a storage tank where sedimentation occurs and then the water is allowed to move towards sand filters. The sand filtration process itself contribute in three modes as shown in Figure 1.

Filtration

Particles are physically strained

Chemical sorption

Assimilation Contaminants stick to the surface of sand

Figure 1: Modes od Sand Filtration Treatment

Microbes consumes the nutrients of wastewater

Sand filter is considered as the most effective, cost-efficient and easy technique which require less maintenance as compared to other techniques utilized in water treatment. An attempt has been done in this paper in order to get the most suitable and effective design of sand filter to utilize in small communities for water treatment economically. Materials and Methodology This attempt completed in a time of approximately three months in the National Research Centre in 2012. All the designs of sand filters incorporate the gravel particulates of size of 2-4 mm and the sand particulates of size 1-2 mm, same dimension and the only difference is of flow direction. Analytical Analysis All the experimental characterization was done using standard methods and the parameters are listed in the Table 1. Table 1: Characterization Parameters of Greywater

Characteristic Parameters pH COD BOD TKN Ammonia Nitrate Nitrite Phosphorous Oil Grease Anionic Surfactants TSS

Statistical Analysis MS Excel was used to get the statistical analysis, average evaluations, Mean and trend results of the sample results. Figures were also drawn on it.

Results & Discussion The contaminants of household greywater highly depend on the number and health of the individuals living in the house. Generally, some common contaminants include oil, shampoos, soaps, surfactants, tooth paste, dyes, body wash etc. The results of all the designs and the pre-liminary stage are shown below in the Figure 2.

Comparative Characteristic Parameters 600 500 400 300 200 100 0 Raw water

Sedimentation

GFD

GFU COD

BOD

SFD

G&SF

HSF

TSS

Figure 2: Comparative results of All the designs of Sand and Gravel Filtration

Conclusion This attempt gives us a vision of comparing all the designs and the results depict that the use of combined gravel and sand filter and the sand filter in horizontal flow shows the best results in removal of contaminants with low cost effectively. In general, sand filters have a wide range of applications comprises from small to large scale for the treatment of wastewater and sewage. Notation GFD = Gravel Filter (Downflow), GFU = Gravel Filter (Upflow), SFD = Sand Filter (Downflow), G & SF = Gravel and Sand Filter and HSF = Sand Filter (Horizontal Flow).