Project 4: Evaluating filtration capacity of soil

Project 4: Evaluating filtration capacity of soil

Introduction:

Soil acts as a physical (sieving action), chemical (adsorption and precipitation) and biological filter (decomposition of organic waste materials). It has an important role in people’s efforts to maintain a suitable environment, as a waste disposal site and to minimize pollution. In majority of area around cities and towns, municipal sewage water (which usually contains inorganic and organic pollutants) is used for irrigation to crops. In some situations, urban runoff and storm water carrying various chemical and pathogenic contaminants also finds its way into the land area. Unless filtered, these have the potential to contaminate water bodies.

Objective:
To estimate filtration capacity of soil
Materials required:
1. Industrial effluent and/or municipal sewage water
2. Copper sulphate
3. Nickel chloride
4. Empty mineral water bottle of one litre capacity
5. Note book
6. Soil from river bank, soil from dried pond bed, soil from cultivated land, and soil from forest area

Methodology:

1. Collect industrial effluent, domestic sewage from few sites of the city.
2. Prepare 16 soil columns: For this, cut one-third of the top portion of the bottle; make 3-4 fine holes with needle at the bottom of the bottle; put a thin cotton layer at the bottom. .
3. Pack the bottle with 500 g of soil and place it over a funnel.
4. Prepare solution of nickel chloride or copper sulphate (like: 10g salt/ 100 ml)
5. Add 200 ml of the salt solution, Industrial effluent and/or municipal sewage water in separate soil columns.
6. Collect the water leached through the soil column at the bottom of the funnel.
7. Note down the color of leached water


Observations:
Note :Table is not included.

Interpretation: If there is a colored leachate, the soil has poor filtration capacity. On the other hand, colorless leachate indicate high filtration capacity. In case, if a colored leachate is obtained for salt solution and colorless leachate is observed for industrial effluent or municipal sewage water, soil has good filtration capacity for particulate solids but poor filtration capacity for metals.

Relevance:
This experiment will help the student to understand which type of soil has good filtration capacity. By having information about the types of soil and industries in their area, they can predict the susceptibility of water bodies of their area from getting contaminated.