Human beings, like any other animal, produce wastes. In urban areas in older times, these wastes were emptied into the gutter where there were washed away by rainwater. These were the first sewers and although they did get waste out of homes, it tended to lie in the gutter until it rained. Not the healthiest of situations. Eventually, modern plumbing and sewers evolved to carry waste away from the population. The sewer treatment plant took things a step further.
The Purpose of Sewage Treatment
Modern sewers carry wastewater efficiently and can be kept in good shape with sewer repair products. In many communities, the destination of the wastewater is a sewage treatment plant. It is here that waste products and harmful chemicals are removed from the water. The treatment also includes killing harmless microbes that live in the wastewater. The aim is to produce an effluent that can be released into the environment without causing any harm. There are several processes that can be used to treat wastewater.
Low-tech treatment processes utilize nature to remove wastes. They are generally less expensive than their high-tech counterparts and use very little or even no energy. A septic tank is an example of low-tech treatment, although it is actually a pre-treatment and the resulting waste requires further processing. The effectiveness of low-tech processes varies with some only providing partial treatment, while others do a more thorough job.
High-tech processes provide a higher level of treatment and some of them produce a very high-quality effluent that is completely safe for the environment. High-tech treatment is more expensive and some processes are energy-intensive.
Choosing Which Process
When a community chooses which sewage treatment process to use, several factors are taken into account. One is the population equivalent which is generally one person per 200 liters of sewage per day. A larger population will naturally produce more sewage.
Other factors are economic and environmental. Different communities have different budgets and the needs of the local lands and waterways must be carefully considered. Feasiblity studies are conducted to determine what the best option is for a local sewage treatment plant.
Society has come a long way from throwing waste into the gutter. Modern sewers and septic tanks safely carry waste away from inhabited areas. Sewage treatment plants then clean it, removing all harmful matter and release clean effluent back into the environment, keeping it healthy for all.