Clean, pure water is essential to our daily lives, and to the health of the natural environment. The water cycle show below includes the natural cycle of water flow from the oceans, to the atmosphere, to the land, and back to the oceans.
There are many parts of the above process where humans play a role in using and treating water. We use water for drinking, cooking, cleaning, and for scientific and technological research and commercial applications. In the process, we add all sorts of bacteria, nutrients, and potentially harmful chemicals to the water. As the water continues to follow the water cycle, those added chemicals and nutrients affect the natural environment, through both ground-water and fresh-water storage basins. The full affect of these chemicals and nutrients on both humans and the natural environment is still unknown to scientists, and is an area of currently active research and investigation on many fronts.
AP Investigation on PharmaceuticalsOne affect which has been well-documented is the impact of nutrient-rich water in fresh-water storage basins. Once the chemical and nutrient-rich water reaches fresh-water storage, it affects the native algae, fish and aquatic wildlife, the base of the food chain. The excess nutrients in the wastewater contribute to an excess growth of algae. When the algae reach the end of their life cycle, they die and fall to the bottom of the basin. The process of fermentation of the algae may consume so much oxygen that the de-oxygenation of the water kills fish and marine life.
return to topThe proper treatment and purification of wastewater is often essential to the preservation of the natural environment. There are two major methods to purify water: by physical and chemical filtration processes, and by biological processing of harmful substances. Physical and chemical filtration methods, while more costly to implement, provide much purer water than biological processes. Biological methods emply bacteria, and can be further categorized into aerobic and anaerobic digestion methods.
The most common method of treatment for wastewater is biological in nature, including both aerobic and anaerobic digestion by bacteria, with aerobic digestion being more widely-used. Biological treatment cleans wastewater of excees nutrients, thereby protecting the ecological environment and the health of the aquatic surroundings. However, biological treatment does not clean wastewater of all bacteria, nor does it eliminate all chemicals such as pharmaceuticals. The resultant cleaned water is often sent back out to rivers and streams, entering the water cycle once more. There are various technologies available for the biological treatment of wastewater, and the actual implementation most often depends on the size and scale of the desired wastewater treatment. Depending on the actual implementation, the cost of entry can be very low.
Physical and chemical filtration methods are generally much more technologically advanced, and at the same time prevent a much higher barrier to entry in terms of both costs and infrastructure. Physical filtration cleans out everything: bacteria, pharmaceuticals, excess nutrients, and other additives. The resulting cleaned water is of deionized quality, and is often used in labs and technological applications.
return to topIn some parts of the world there are water shortages, requiring those nations and communities to reuse the results of filtered wastewater. For instance, the country of Singapore in Southeast Asia imports clean, filtered water from Malaysia. In Singapore the clean resultant water is used mostly for scientific laboratories and technological use. The resultant filtered water is of "deionized" quality after going through the filtration process.
Singapore's NEWaterOrange County, CA, also experiences water shortages, and brings water in through pipelines from Northern California and the Colorado River to the east. In addition, Orange County treats their wastewater through physical filtration processes, and then sends the cleaned water back to the groundwater basin. There, the filtered water joins the natural groundwater and is treated again before being sent to the municipal drinking water supplies.
New York Times ArticleAnother example of the use of wastewater is in Namibia. There is such a critical shortage of water that the cleaned filtered wasterwater is combined directly with the drinking water supply.
Namibia Water Supply return to top
