Types of Sewage Treatment Plants

Sewage treatment plants are an important element of our environment. They were built to keep garbage and toxins out of sewage and to assure an effluent treatment system to prevent water pollution.

The local government can support these treatment plants, which are referred to as "municipal sewage treatment plants." Sewage treatment plants are one of modern science's most important inventions, making human existence cleaner and healthier.

What is a Municipal Sewage Treatment Plant?

Sewage is a sort of wastewater produced by a portion of the population (also known as domestic sewage, domestic wastewater, or municipal wastewater). Sewage is a mix of macro-and micropollutants, as well as municipal solid waste and pollutants from industrial waste. It's made up of wastewater from homes and businesses, as well as perhaps pre-treated industrial waste.

Sewage treatment (also known as residential wastewater treatment or municipal wastewater treatment) is a type of wastewater treatment that removes contaminants from sewage to generate an effluent that is suitable for wastewater disposal or recycling, reducing water pollution caused by raw sewage releases.

Learn More: What is a Municipal Sewage Treatment Plant?

Various Sewage Treatment Processes

There are a variety of sewage treatment methods to choose from. Primary, secondary, and tertiary water treatment are the three steps of the sewage treatment process. Secondary treatment can reduce organic matter (measured as biological oxygen demand) in sewage by using aerobic or anaerobic biological processes. For some applications, more extensive treatment, known as quaternary water treatment, is required.

This stage involves oxidation or fine filtering and deals with contamination levels ranging from a few parts per million to billions of parts per billion. Each of these steps tackles a different pollutant, and the water becomes cleaner as it passes through the stages.

Primary Sewage Treatment

During the main treatment, water is temporarily kept in a settling tank, where heavier solids sink to the bottom and lighter solids float to the surface. While the remaining liquid is discharged or transported to the more stringent secondary phase of wastewater treatment, these components are held back until they have settled. Mechanical scrapers in the tank's base continually transport collected sludge to a hopper, from whence it is transferred to sludge treatment plants.

Secondary Sewage Treatment

Secondary sewage treatment is intended to destroy the biological content of waste by aerobic biological processes at a deeper depth than the initial treatment. Secondary sewage treatment lowers the quantities of common biodegradable contaminants to acceptable levels, allowing for a safer discharge into the environment.

It's possible to do it in one of three ways:

Biofiltration

In biofiltration, sand filters, contact filters, and trickling filters are utilized to ensure that any remaining sediment is removed from the effluent.

Aeration

Aeration is a time-consuming technique that introduces air to wastewater to increase oxygen saturation. It can take up to 30 hours to finish the aeration process, but it is very effective.

Oxidation Ponds

This method, which is most typically used in warmer climates, involves allowing wastewater to flow through natural bodies of water such as lagoons for a set amount of time before being stored for two to three weeks.

Tertiary Sewage Treatment

The purpose of tertiary sewage treatment is to improve the water's quality to meet home and industrial standards, as well as specific water discharge safety criteria. The tertiary treatment of municipally treated water also includes the removal of pathogens, guaranteeing that the water is safe to drink.

Types of Sewage Treatment Plants

Alike sewage treatment processes, there are also several types of sewage treatment plants available around the world. Some of the mentionable ones are:

Activated Sludge Process (ASP)

The activated sludge process is one of the most extensively used waste treatment processes in the United Kingdom, with applications ranging from home systems to large sewage treatment plants. The two main components of these systems are a biozone chamber and a settlement chamber.

Because these systems have no mechanical or electrical parts, they are easy to maintain and have low maintenance expenses. However, because the air diffuser is on most of the time, these systems' power consumption may be higher than other systems on the market, and the system's installation costs may be higher than other systems because it is larger, requiring more excavation.

Non-electric Filter

Non-electric treatment plants, as the name suggests, work without the use of electricity because everything is done by gravity. There are two chambers in this method: a basic settlement chamber and a treatment chamber.

Submerged Aerated Filter (SAF)

In that, it processes wastewater with both media and aeration and has three chambers, a submerged aerated filter system is comparable to a fixed bed reactor. These systems feature a primary settlement chamber, a secondary treatment chamber, and a third settlement chamber.

Rotating Disc System

One of these will be put in most residences that require an off-the-grid solution. The most well-known treatment facility in the UK is the rotating disc system. These systems have a 'bio disc' inside the tank, which is simply one giant media disc on which the bacteria dwell, similar to a non-electric system.

Sequence Batch Reactor (SBR)

SBR sewage treatment plants are known for producing high-quality effluent after treatment by using air diffusers to provide oxygen to the indigenous microorganisms in the tank. These systems are similar to ASP systems in that they contain a primary settlement chamber and a secondary treatment chamber.

Fixed Bed Reactor

A fixed bed reactor system treats waste from a property by combining media and aeration. These systems have three chambers, unlike other plants: the main settlement chamber, a secondary treatment chamber, and a final settlement chamber.

Other sewage treatment plants include Suspended Media Filter (SMF) and trickling filter. All of these are quite efficient and worth considering.

Significance of Sewage Treatment Plants

When managed appropriately, municipal and industrial sewage can be a valuable source of energy and minerals. For example, sludge from municipal wastewater can be used to extract energy and bio-solids for agricultural use, while phosphorus from eutrophication can be used to manufacture fertilizers. As a result, proper utilization of municipal treatment plants is critical.