Water Supplies and Wastewater Treatment

Uses of water, diseases transmitted by water, the hydrological cycle, water supply, and wastewater treatment practices.

ENVT 2560: Module 7

INSTRUCTIONS: As you scroll through the content, be sure to read the information and explore the resources presented. Information from additional resources (usually links) may be included in the Small Parties.

Introduction

Water is one of the most important and valuable natural resources on the planet. Life cannot exist without water. It makes up roughly two thirds of the human body. Although it covers approximately 71% of the Earth’s surface, less than 1% of water is available for human use.

Because it is a part of an ecosystem, water contains living organisms such as animals, bacteria, and viruses (regardless of the source) which increase morbidity and mortality in a population. Before it can be consumed by humans, water must be treated. Once used, whether by humans, farmers, industrial processes, or recreational purposes, water becomes contaminated to the point that it cannot be used without causing serious illnesses.

Observations from nature and advances in science and technology help communities reclaim contaminated water for use again. The management of water and its treatment is the first line of defense against disease, as discussed in module 5. Therefore, it is an important part of the planning process and of sustainable development. We will discuss the uses of water, diseases that can be transmitted via water, the hydrological cycle, the water supply, and wastewater treatment management practices cities use to prevent and control the spread of diseases.

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3D illustration showing release of parasite sporozoites from oocyst inside small intestine.

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Water moving to the atmosphere in arrow-shaped clouds.

Dark clouds and thunderstorm with rainy, dramatic black clouds in summer.

Photo of a spring with clear and cold mountain water.

Photo of worker performing maintenance on equipment, including replacement of water filters that will be used.

3D illustration of giardia lamblia protozoan, the causative agent of giardiasis.

Photo of a glass of contaminated water on grey background.

Summary

Water and wastewater treatment technologies are important environmental health practices that help prevent and control the spread of disease. Water has many important uses in society. Natural bodies of water contain pathogenic organisms. WHO has identified five classes of water-associated diseases. While there is an abundant supply of water, less than 1% is fresh. The rest covers the planet's surface as ocean water, which is inaccessible as a drinking water supply source.

Water is distributed throughout the Earth via the water cycle. There are two major sources of water supply: surface water and groundwater. Once used, water may be chemically, biologically, and physically altered. Used water is collectively called wastewater. Before it can be reintroduced to the environment it must be treated to avoid damage to the ecosystem.

Wastewater treatment is the main mechanism used to protect the environment and the public. However, today’s sewage treatment plant does more than treat sewage—they reclaim important resources as well. These management practices are beneficial not only to the plant but to the environment.