Over 70% of the Earth’s surface is covered in water. This water is essential to our survival as a species. With the Earth’s population increasing yearly, will we have enough quality water to carry us into the decades to come? What types of treatment are being used to ensure that we have clean water to drink? This case assignment will compare and contrast secondary water treatment method to the tertiary water treatment, which is also known as advanced/final water treatment, method in the context of the wastewater treatment process.
It will discuss the appropriate uses of reclaimed water and explain whether to recommend secondary treatment or tertiary treatment for the groundwater recharge in regards to drinking purposes. Water Quality Earth, air, fire and water are all essential in daily survival. Quantity of water alone will not sustain life; quality of water will. It is essential to life to have clean, safe, drinking water. Water covers 71% of the Earth’s surface. Ninety-seven percent of this water contains salt in oceans and seas. The remaining three percent is contained in icebergs or deep underground, unavailable to humans or animals for consumption.
Less than one percent of the Earth’s water is accessible and available for human use, in the form of rivers, streams, lakes and accessible underground sources. These sources of water need to be purified and disinfected prior to distribution to the public. Therefore, protecting these resources from contamination -such as contamination by wastewater- is imperative for the health and development of humans (Natural Resources Defense Council, 2008). This means there must be some method of treating our water so that the quality is beneficial for all who consume it.
According to Bartram, et al (2005) although access to safe drinking water and basic sanitation can have a strong positive effect on human health, the development and management of water resources as a whole also has significant health implications, usually a combination of negative and positive. The balance between these effects and protection of the health of vulnerable groups is in the hands of those who plan and implement interventions, which can be strongly influenced by the health sector and health arguments.
A comprehensive health impact assessment (linked to a health management plan) is crucial for development of water resources. According to the Natural Resources Defense Council (2008), one billion people around the world do not have access to clean, safe water. Wastewater Management Without proper sanitation, human waste pollutes waterways and wildlife habitat (NRDC, 2008) Wastewater is water that has been used, as for washing, flushing or in a manufacturing process and so contains waste products. Proper wastewater treatment and disposal is one of the most important functions for healthy communities.
Failure to treat wastewater may render a community completely unsafe to live in and result in a significant public health problem for residents. The American cities that experienced the highest death rates were those that lacked an adequate domestic water supply system and wastewater disposal (NRDC, 2008). Simple sanitation improvements, like digging pit latrines and treating drinking water with chlorine, filters and other simple, existing technologies can save millions of lives. This can be done by treating the water.
According to the City of San Jose’s Environmental Services (n. d. ), there are three types of treatment for recycling water: primary, secondary and tertiary. Primary treatment is a process designed to remove organic and inorganic solids by the physical processes of sedimentation and flotation. Raw sewage flows into primary treatment devices referred to as sedimentation tanks or primary clarifiers, where the material that is denser than water will settle out and the material that is less dense than water will float to the surface.
Approximately 40-60% of the suspended solids and 25-35% of the biochemical oxygen demand (BOD) are removed from the waste stream. The solids that remain in suspension, as well as dissolved solids will usually be biochemically treated are subsequent processes for physical separation and removal. Secondary treatment consists of unique biological systems designed to remove BOD, suspended solids and some dissolved solids through a biological conversion of these materials to a settleable form. The biomass is then separated from the product water in a final clarifier.
This treatment removes about 80-95% of suspended solids and BOD. Tertiary treatment is the polishing process that filters the treated water through fine sand or granular material to remove fine suspended solids. The water is then chlorinated for disinfection. Tertiary treatment provides the needed process to make water cleaner and safer to use. Clean water is vital to safeguarding public health and the environment, yet our nation’s waters are at risk; more than 300,000 miles of rivers and shorelines — and some 5 million acres of lakes — are considered polluted by the Environmental Protection Agency.
In the United States, there are an estimated eight million cases of infectious waterborne illnesses every year from drinking contaminated water, eating tainted shellfish and swimming in polluted waters. The most appropriate use for this reclaimed water is to distribute it to areas that do not access to clean water or who use a lower treatment level. Since it is obvious that the tertiary treatment is better than the secondary, areas that have secondary treatment, facilities should have access to the reclaimed water.