Sewage Disposal Cities Science Project Idea

Sewage Disposal in Cities Science Project Idea

The too common method has been the easiest ; that of discharging sewage into streams, lakes, or oceans. In the cases of cities like New York, located on the ocean, this method has not been so serious as in that of cities on lakes and rivers. Previous to 1900 the sewage of Chicago was emptied into Lake Michigan, from which body of water the city also obtained its drinking water. The average annual death rate from typhoid fever for the ten years preceding 1900 was 66.8 per 100,000. In that year the drainage canal was completed by which the Chicago River, which emptied into Lake Michigan, was connected with the Illinois River, which empties into the Mississippi River. So the lake water which now flows toward the Gulf of Mexico carries away with it the sewage of Chicago, leaving the lake uncontaminated.

In the ten years following the opening of the canal, the annual death rate from typhoid fever fell to 22.3 per 100,000. It was found that pathogenic bacteria in the Chicago sewage had disappeared long before the water had reached the Mississippi River. The chief influences that bring about such a condition are sedimentation, activity of other microorganisms, light, temperature, and lack of food supply.

Many cities use a method somewhat similar to the septic tank system on a large scale. The ideal plan would be such treatment of sewage that the products could be safely used as a fertilizer to enable the land to produce better crops. A moment's thought will cause you to realize what an enormous amount of material, which should be returned to the soil, passes to the ocean every day in the sewage from New York City alone.

Each pupil should find out the method of sewage disposal practiced by his community and determine the points in which the system is a good one and points in which it is deficient.