What is a Municipal Sewage Treatment Plant?

Sewage treatment plants are essential parts of our surroundings. They are established to evade garbage and contaminants from sewage and ensure an effluent treatment system so that water pollution doesn’t occur.

These treatment plants can be funded by the local government which is referred to as a “municipal sewage treatment plant”. Sewage treatment plants are one of the most important inventions of modern science and have the human life cleaner and healthier.

Defining a Municipal Sewage Treatment Plant

Sewage (also known as domestic sewage, domestic wastewater, or municipal wastewater) is a type of wastewater generated by a segment of the population. Sewage is a combination of macro-and micro-pollutants, as well as some municipal solid waste and pollutants from industrial wastes. It is made up of wastewater from households and workplaces, as well as perhaps pre-treated industrial products.

A frequently asked question is “what is a municipal sewage treatment plant?” Sewage treatment (also known as domestic wastewater treatment or municipal wastewater treatment) is a type of wastewater treatment that eliminates pollutants from the sewage to produce an effluent that is ideal for disposal of wastewater or recycling it, restricting water pollution from raw sewage releases.

Types of Municipal Sewage Treatments

There are numerous sewage treatment processes from which to choose. Decentralized systems (including on-site treatment systems) to huge centralized systems incorporating a network of pipelines and pump stations (referred to as sewerage) that transport sewage to a treatment plant are examples.

The sewers will also convey urban runoff (stormwater) to the sewage treatment facility in communities that have a combined sewer.

The sewage treatment process is divided into three stages: primary, secondary, and tertiary water treatment. Using aerobic or anaerobic biological processes, secondary treatment can reduce organic matter (measured as biological oxygen demand) in sewage.

More advanced treatment, known as quaternary water treatment, is necessary for some applications. This stage deals with contamination levels of a few parts per million to billions of parts per billion, and it frequently involves oxidation or fine filtration. Each of these stages targets a different pollutant, and as the water progresses through the stages, it becomes cleaner.

Primary Sewage Treatment

Water is briefly stored in a settling tank during the primary treatment when heavier solids sink to the bottom and lighter solids float to the surface. These components

are held back until they have settled, while the remaining liquid is discharged or moved to the more stringent secondary phase of wastewater treatment. Mechanical scrapers in the tank's base continuously drive collected sludge to a hopper, where it is pumped to sludge treatment facilities.

Secondary Sewage Treatment

Secondary sewage treatment is designed to significantly degrade the biological content of the waste through aerobic biological processes, and it acts at a deeper level than primary treatment. Secondary sewage treatment reduces common biodegradable contaminants to tolerable levels, allowing for safer release into the surrounding ecosystem.

It can be accomplished in one of three ways

Biofiltration

Sand filters, contact filters, and trickling filters are used in biofiltration to guarantee that any further sediment is removed from the effluent.

Aeration

Aeration is a lengthy process that introduces air to wastewater to improve oxygen saturation. The aeration process can take up to 30 hours to complete, but it is quite effective.

Oxidation Ponds

This approach, which is most commonly employed in warmer areas, uses natural bodies of water such as lagoons to enable wastewater to run through for a specific length of time before being held for two to three weeks.

Tertiary Sewage Treatment

The goal of tertiary sewage treatment is to improve the water's quality to meet domestic and industrial standards, as well as to meet specific requirements for water discharge safety. In the case of municipally treated water, the tertiary treatment also includes the elimination of pathogens, ensuring that the water is safe to consume.

Read More: Types of Sewage Treatment Plants

Different Kinds of Municipal Sewage Treatment Plants

There are several types of sewage treatment plants available at present. These include:

Activated Sludge Plant (ASP)

The activated sludge process is one of the most widely utilized waste treatment technologies in the UK, as it is used not just as home systems but also in big sewage treatment plants. A biozone chamber and a settlement chamber are the two basic components of these systems.

These systems are a low-cost solution because they contain no mechanical or electrical parts, making them simple to maintain and with low maintenance costs. However, these systems' power consumption may be higher than that of other systems on the market.

Non-electric Filter

Non-electric treatment plants, as the name implies, do not require any electricity to operate because everything is done by gravity. Again, with this method, there are two chambers: a basic settlement chamber and a treatment chamber.

Rotating Disc System

Most households that require an off-mains system will have one of these installed. Rotating discs systems are the most recognized treatment plant in the UK. Similar to a non-electric system, these systems have a 'bio disc' inside the tank, which is essentially one large media disc on which the bacteria live.

Submerged Aerated Filter (SAF)

A submerged aerated filter system is similar to a fixed bed reactor in that it treats wastewater with both media and aeration and has three chambers. A primary settlement chamber, a secondary treatment chamber, and a third settlement chamber are included in these systems.

These systems offer similar advantages and disadvantages to fixed bed     reactors in that, even though they have no mechanical or electrical parts inside the tank, they still require a continual source of electricity to the compressor, which is always running.

There are many other sewage treatment plants such as Suspended Media Filter (SMF), Sequencing batch reactor (SBR), Trickling Filter, etc.

Importance of Municipal Sewage Treatment Plants

Municipal and industrial wastewater, when properly handled, can be a useful source of energy and nutrients. Sludge from municipal wastewater, for example, can be utilized to extract energy and bio-solids for agricultural purposes, while phosphorus from eutrophication can be used to make fertilizers. So, it is essential to ensure the proper utilization of municipal treatment plants.