Types of Sewage Treatment Plant
Waste and sewage management are essential aspects of our domestic and business lives. You may have to deal with your home and business waste, and you must handle the waste correctly. Sewage treatment plays an essential role in maintaining the hygiene and quality of water used in our homes.
Sewage treatment is the process of treating sewage using different methods. It ensures that the water is clean enough for discharge into the environment. Sewage treatment involves many processes, and the most important of which involves biological and chemical treatment. The various types of sewage treatment plants are:
1. Activated Sludge Process/Plant
2. Moving Bio Bed Reactor(MBBR)
3. Membrane Bio-Reactor(MBBR)
4. Electro Coagulation System
5. Sequential Bio-Reactor(SBR)
6. Rotating Bio-Reactor (RBC)
7. Submerged aerated Filter (SAF)
8. Suspensed Media Filters (SMF)
9. Trickling filter
10. Non-electric filter
11. Fixed bed reactor
This blog will give you an insight into different methods of sewage treatment and how it is done. As we will see in this blog, a sewage treatment plant can help with this.
What Is A Sewage Treatment Plant?
Sewage treatment is all about polluted water. These are created in different types of industries, and this water contains harmful chemicals that are harmful to living beings. Sewage treatment plants are used to treat the sewage into a usable form.
A sewage treatment plant is defined as a facility that converts all kinds of waste liquid, solid, and gas into final harmless substances. There are different ways to refine the water from sewage; the most popular methods are chemical and biological processes.
What Are The Different Types Of Sewage Treatment Plants?
Sewage treatment for residential or commercial buildings requires different processes depending on the size and type of building. One way to make this determination is by the amount of water that flows through each day (gallons per day), determining what kind of equipment is needed.
1. Activated Sludge Process/Plant
The activated sludge process is often the most common and widely used in wastewater treatment. It is designed to sustain the growth of microorganisms or activated sludge that removes dissolved and suspended material in the wastewater.
The activated sludge process often refers to a system in which the activated sludge is treated aerobically by adding air to ease the removal of nitrogen compounds. It is also accompanied by excess sludge returning from a clarifier as a bulking agent. It is essential to maintain the required concentration of microorganisms.
2. Moving Bio Bed Reactor(MBBR)
MBBR is the most used system for treating wastewater by municipal and industrial plants. The MBBR plant requires a lot of space and a complex control system. So, moving an MBBR plant and setting it up to a new location is not a small job.
A bioreactor or biological reactor is a device that uses living material to convert toxic or polluting compounds into less harmful or less polluting compounds. In wastewater treatment, bioreactors do a similar thing, and they contain growing biological material that converts the pollutants into less harmful pollutants.
Bioreactors can be made from materials like concrete or fiberglass, and MBBR is a relatively new technology. Here the biomass is treated in a rotating drum or disk reactor before being transferred to the aerated vessel for further processing. The process is carried out under strict conditions of oxygen and wastewater concentration.
3. Membrane Bio-Reactor(MBBR)
Membrane bioreactors (MBR) combine membrane-based technologies with biological wastewater treatment. These technologies have become widespread for municipal and industrial wastewater treatment applications.
The MBR process has been around for years. But there are concerns about its high cost and the loss of high-quality products due to membrane fouling. Recent technological advances have made MBRs more feasible and cheap. As a result, the MBR process has gained more attention and has many potential applications.
4. Electro Coagulation System
Electrocoagulation is a process that uses an electric field to help remove particles from water. Electrocoagulation can be used for the pretreatment of wastewater to enhance the performance of tertiary sand filtration, and it can be used as a method of wastewater treatment.
Water passing through an electrocoagulation cell is exposed to alternating electrical potential, and it can cause dissolved and suspended solids in water, including colloidal material, to flocculate.
Flocculation refers to the clumping together of tiny particles into larger aggregates. After flocculation, You can more easily be separated from the liquid.
Coagulation involves charges. Thus, separating the solids from the water is needed after coagulation occurs. It is usually accomplished by passing the processed wastewater through a rapid gravity sand filter. Here excess solids drop out as waste sludge, and clean water exits as filtered water.
5. Sequential Bio-Reactor(SBR)
A Sequential Bio Reactor is a wastewater treatment system involving biological processes. Specifically, aerobic microorganism-driven conversion of soluble chemical compounds into biomass and residues.
The process has long been used in sewage treatment plants for disposal of organic carbon content to meet the EPA’s standards on biochemical oxygen demand (BOD), ammonia nitrogen, phosphorus, and nitrate.
A Sequential Bio-Reactor may be used to treat wastewater or stormwater runoff. This system is an alternative to the Conventional Treatment Process, and that is a traditional activated sludge system that uses a high energy level.
6. Rotating Bio-Reactor (RBC)
Rotating Bio-Reactor (RBC) is a biological process of the sewage treatment plant. It does not require primary settling, and therefore it can be placed downstream of the primary sedimentation processes if sewage contains a high percentage of solids.
It is an aerobic biological process with no methane generation and very little objectionable odor. The process consists of a single shaft rotating slowly inside a tank partially filled with sewage mixed by one or more paddle arms attached to the post.
Aerobic bacteria growing on the arms and shaft develop a slime layer, which helps to enhance the settling of solids. The treatment process is efficient and can handle large volumes of sewage.
7. Submerged Aerated Filter (SAF)
Submerged aerated filter (SAF) is a developed form of Strainer type. It can meet the challenge of many pollutants in sewage with high efficiency and little secondary pollution.
The utilization of interior air introduction and submerged aeration purifies water under bubble-stirred conditions.
The polluted water is discharged from the upper part of the submerged aerated filter. After that filtration cake formed in it is taken away by a scraper to the stage. In this process, solid matter in sewage purifies all.
Right under the submerged condition with aerobic microorganisms being developed on its surface. It can be used alone or combined with another treatment process.
Submerged aerated filters are more suitable for purifying raw sewage than aerobic surface filters. They can complete all types of treatments without being exposed to air, thus avoiding secondary pollution. A submerged aerated filter needs only about 10 percent of land area as a sedimentation tank of equal capacity.
8. Suspensed Media Filters (SMF)
Suspense media filters are a filtration process that, compared to other methods such as sand or diatomaceous filter presses, have been found to have many advantages.
Backwashing SMFs with little or no draining of sludge is a prominent example. It is an excellent advantage over other filters that require the sludge on the surface to be drained entirely before being cleaned.
In most cases, the settling basin is left dry in this process. It allows easier raking and cleaning of solids on top of the bed without worrying about pulling all the sludge out from underneath it first. It makes backwashing more efficient as there is less time wasted trying to drain it first.
9. Trickling filter
A trickling filter is a biological sewage treatment that uses a bed of granular media to provide both aeration and an environment where bacteria can form biofilms.
The function of this type of wastewater treatment plant is essentially odor control, and it is done by transforming retained sludge into inert, dewatered pellets or cakes.
The trickling filter is generally preceded by primary treatment. Processes like screening and sedimentation remove coarse material like sticks and other debris.
Primary effluent receives continuous trickling filter treatment, which the plant operator manages the process by adjusting pH levels; along with that, nutrients are added to promote bacterial growth. The blower house then pulls air into the system.
The air bubbles created by the blower house mix oxygen (approx. ten parts per million) with the wastewater in the trickling filter. This process is known as aeration, and it is an essential aspect of biological treatment.
The release of methane gas in this type of system is minimal due to the low temperatures in this stage of the treatment, unlike other locations. Solids trapped in primary sedimentation tanks are sludge, and these solids are separated from the wastewater upon entering the trickling filter.
10. Non-electric filter
This filtration process requires physical contact between the solid particles of the sewage sludge and air bubbles. The force generated by this action is called ‘filtration pressure’ or ‘backwash pressure.’
The filtration pressure is applied to the sewage sludge by rotary valves, which are turned on and off. This type of filtration system requires an external power supply for its operation.
In a traditional rotating disk or moving chain filter, most of the energy required is consumed in rotating the disks or chains at high speed. It necessitates the use of an electric motor which reduces filter efficiency further.
11. Fixed bed reactor
A fixed bed reactor is a cylindrical pressure vessel containing various blades or corrugated sheets. These are made to rotate to reduce solid clumps. Several different types of blade material are used, e.g., carbon steel, stainless steel, nickel-titanium alloy (e.g., nitinol), and rubber. The rubber is used to make a flexible impeller.
The blades are fitted on the inside of the reactor with baffles, sometimes referred to as diffusers or spacers. These allow wastewater to enter at one end and flow over the surfaces of the different blades as it moves down through the reactor using gravity.
The blades are designed to push the solids toward the impeller’s shaft, which causes it to spin. Solids that entered wastewater flow get trapped by features on the lower end of baffles and carried through with the wastewater exiting through outlet pipe at the opposite end of the reactor.
The solids collected in a fixed bed reactor tend to be denser than the wastewater, which provides a means of eliminating them from the system. The solids may exit with water flow through an impeller at the bottom end of the shaft, or they may be ejected into an external chamber for later removal.
Fixed bed reactors are used in wastewater treatment applications ranging from small residential systems to large municipal plants. One reason is that you can use it in combination with other types of equipment. For example, at the end of a septic tank or cesspool before the flow enters a soil absorption system.
Conclusion
Sewage Treatment Plants have become a vital sector in the waste management industry. This is the primary reason for new environmental threats from pollutants and hazardous wastes.
It has led to the development of new technologies. Those can effectively reduce or prevent these pollutants from entering our communities’ groundwater and surface water resources.
Various methods are used to treat the sewage. These different approaches have pros and cons, but one thing remains constant. They all need regular maintenance, and otherwise, the performance will degrade over time due to wear-and-tear or other factors.
For example, corrosion can cause significant problems down the road if left unchecked. Sewage treatment plants can be vast and complicated. Even if the plant is designed to handle a particular flow, many things can go wrong. That’s why it is essential to appoint only professionals for this job.
