Studying and designing the automation system of water and sewage treatment plants
Water treatment plants:
Automation of water treatment plants is an undeniable necessity due to the increase in the number of precision instruments and control loops and the sensitivity of water purification processes and water production with the quality of drinking water standards. Studying and implementing the automation of the Mahabad water treatment plant with a capacity of 750 liters per second and 8 filtration sets and sub-systems such as DAF, chlorine generator, chemical unit, filter press, automatic operation and savings in the operation costs of the treatment plant. .
Sewage treatment plants:
The automation of sewage treatment plants is of particular importance considering that their input cannot be bypassed, and various methods for sewage treatment have been implemented since 1357, using traditional methods to advanced automation methods. The automation of cash and cash transactions has been studied and implemented during the years 2016 to 2017.
The different methods of designing wastewater treatment plants are as follows:
Primary treatment:
Primary wastewater treatment includes removing suspended solids from the wastewater or preparing the wastewater to enter the secondary treatment section. The different parts of primary treatment are:
1- Garbage collection
2- Sedimentation
3- Floating
4- neutralization and balancing
Secondary treatment:
The term secondary treatment refers to all biological treatment processes carried out in the treatment plant, both aerobic and anaerobic. The common methods of secondary wastewater treatment are:
1- activated sludge method
2- Continuous aeration
3- Aeration lagoons
4- Balancing pools
5- Anaerobic treatment
Final treatment:
Final treatment includes the processes that are applied in order to obtain treated wastewater with a higher quality than what is done in the secondary treatment part. In this section, some common methods of final purification are mentioned.
Chlorination is a method that is widely used in urban and industrial wastewater treatment. Some industries that must treat their wastewater before discharging into the environment are: canning, dairy, paper, textile, petrochemical, and metal industries. The main reasons for chlorination of wastewater are:
1- Disinfection, due to the high oxidizing capacity of chlorine, stops and destroys the growth of bacteria and algae.
2- BOD reduction
3- Removing or reducing the color and odor of the effluent
4- Oxidation of metal ions
5- Oxidation of cyanides into harmless substances
New methods in wastewater treatment (SBR, UASB,….):
SBR unit
The SBR unit consists of a filling and emptying reactor where complete mixing takes place, and in addition, aeration and sedimentation, which is after the reaction stage, is done in a tank. In all SBR systems, the purification process is carried out sequentially in the following 5-step format.
1- Filling
2- Reaction (aeration)
3- Settling
4- Evacuation
5- Free
UASB unit
One of the significant advances in technology related to anaerobic purification systems is the UASB reactor, which was formed in the Netherlands in the late 70s. In this process, the wastewater enters from the end of the UASB reactor and flows upwards through the sludge coating unit. The main components of the UASB reactor are the inlet wastewater distribution system, the gas phase separator from the solid, and the treated wastewater exit plan.
The main feature of UASB systems, which allows it to use wastewater with a much higher COD load compared to other anaerobic processes, is the production of sludge in the form of granules. Production of sludge in granular form in UASB systems requires several months, which can be reduced with some additives.
