Waste water management is an exercise that affects both residential and commercial buildings. The main reason for a sewage water treatment system is to produce an effluent that is safe to be discharged into the environment or reused for other purposes. The stages and the process that are involved vary slightly from place to place. In general, however, there are four main successive stages that are involved. These include pre-treatment, primary, secondary and tertiary treatment.
During pre-treatment (screening), meshes are used to remove extraneous elements carried in the sewage. There are three sizes of meshes arranged in series. The largest grate is about 5 centimeters and helps to get rid of wood, rocks, pieces of cloth and other objects. In larger plants, this may be achieved by use of large mechanical bar rakes that apply a continuous motion. The medium size is between 0.5 and 0.3 cm while the smallest is 1.5 to 3.0 millimeters.
Grit removal is another important process that takes place during the pre-treatment stage. Most of the grit found in sewage comes from street runoff when it rains. The process that is used here is gravity dependent. By allowing the effluent to flow through a V-shaped shaped channel on a gentle slope allows grit to settle at the bottom making easier to remove. As a result of all these process, damage to hardware found downstream is markedly reduced.
Several large tanks are used to hold the effluent that is undergoing primary treatment. In this stage, the effluent is allowed to sediment so that solids settle at the bottom. This solid waste (also known as sludge) can be digested anaerobically to produce methane gas. The residual waste is usually disposed of in landfills. There is a continuous flow of sewage into and out of the tanks. The time for which water is held is enough for most of the suspended solids to be removed.
In the secondary stage, the main activity that is carried out is biological digestion. This is facilitated by anaerobic bacteria, aerobic bacteria and protozoa in some cases. These organisms break down the biologic substrate and reduce the survival of harmful bacteria. There are two main types of systems that are used. The first is the fixed film system that uses rotating biological contactors and trickling filters. The second is known as suspended growth technique in which sewage is mixed with biomass.
A different approach that may be adopted at this stage is the use of enzymes rather than organisms. This option is, however, less popular due to a number of the downsides that are associated with it. One of the major disadvantages is that it is not possible to have all the enzymes that are needed which makes it inefficient. The other disadvantage is that it is more expensive.
The final stage, the tertiary stage, is used to optimize on the process that have taken place in the other stages. The effluent is taken through sand filtration, phosphorous removal, odor reduction and disinfection among others. The methods that are used for disinfection include UV radiation, chlorination and use of ozone gas. Most plants skip this stage especially if there is no intended direct human contact.
It is possible to carry out the treatment using your own septic tank. All you need to do is to ensure that you are conversant with the public health guidelines that govern the installment and the operation of the tank. Most onsite plants comprise a two stage system rather than the standard four stages.
During pre-treatment (screening), meshes are used to remove extraneous elements carried in the sewage. There are three sizes of meshes arranged in series. The largest grate is about 5 centimeters and helps to get rid of wood, rocks, pieces of cloth and other objects. In larger plants, this may be achieved by use of large mechanical bar rakes that apply a continuous motion. The medium size is between 0.5 and 0.3 cm while the smallest is 1.5 to 3.0 millimeters.
Grit removal is another important process that takes place during the pre-treatment stage. Most of the grit found in sewage comes from street runoff when it rains. The process that is used here is gravity dependent. By allowing the effluent to flow through a V-shaped shaped channel on a gentle slope allows grit to settle at the bottom making easier to remove. As a result of all these process, damage to hardware found downstream is markedly reduced.
Several large tanks are used to hold the effluent that is undergoing primary treatment. In this stage, the effluent is allowed to sediment so that solids settle at the bottom. This solid waste (also known as sludge) can be digested anaerobically to produce methane gas. The residual waste is usually disposed of in landfills. There is a continuous flow of sewage into and out of the tanks. The time for which water is held is enough for most of the suspended solids to be removed.
In the secondary stage, the main activity that is carried out is biological digestion. This is facilitated by anaerobic bacteria, aerobic bacteria and protozoa in some cases. These organisms break down the biologic substrate and reduce the survival of harmful bacteria. There are two main types of systems that are used. The first is the fixed film system that uses rotating biological contactors and trickling filters. The second is known as suspended growth technique in which sewage is mixed with biomass.
A different approach that may be adopted at this stage is the use of enzymes rather than organisms. This option is, however, less popular due to a number of the downsides that are associated with it. One of the major disadvantages is that it is not possible to have all the enzymes that are needed which makes it inefficient. The other disadvantage is that it is more expensive.
The final stage, the tertiary stage, is used to optimize on the process that have taken place in the other stages. The effluent is taken through sand filtration, phosphorous removal, odor reduction and disinfection among others. The methods that are used for disinfection include UV radiation, chlorination and use of ozone gas. Most plants skip this stage especially if there is no intended direct human contact.
It is possible to carry out the treatment using your own septic tank. All you need to do is to ensure that you are conversant with the public health guidelines that govern the installment and the operation of the tank. Most onsite plants comprise a two stage system rather than the standard four stages.
About the Author:
You can get a detailed overview of the benefits of installing a sewage water treatment system and more info about an experienced installer at http://proteinmatrixllc.com right now.
0 التعليقات:
Post a Comment