Sewage Treatment Control Solution
Sewage Treatment Technique
Sewage Treatment
Municipal sewage and industrial sewage can be safely disposed by multiple separation and transformation methods, and basic methods include physical method, chemical method, physical-chemical method and biochemistry method.
Basic Methods
Physical method
Chemical Method
Physical-chemical method
Biochemical method
Basic Principle
Physical or mechanical separation process
Adding chemicals in the sewage water to casue chemical reactions process
Physical chemical separation process
Microbiology and organic matter cause oxidation and decomposition reaction in sludge
Technology
Filtration, sedimention, centrifugal separation, flotation
Neutralization, oxidization, restoration, decop -osition, coagulation, chemical precipitation
Gas stripping, air stripping, adsorption, extraction, IEX,electrolysis, electrodalysis, reverse osmosis
Activated sludge,catalytic oxidaton, BAF, rotating biological contactor, lagoon, anaerobic nitrification
Sewage treatment is the process of removing contaminants from wastewater, primarily from municipal sewage. It includes physical, chemical, and biological processes to remove these contaminants or transform to innocuous substance, so it can meet the national discharged standard of sewage.
Sewage treatment generally involves three stages, called primary, secondary (biochemical) and sludge treatment, tertiary and reuse of regenerated water treatment.
Typical Process of Municipal Sewage Treatment
Sewage Treatment Technique
Mechanical Treatment (Primary Class) mainly includes coarse screen, lifting pumping house, fine screen, sedimentation tank, Pre-sedimentation tank and other equipments, the purpose of this process is to remove heavy solids and floating materials. The principle is using physical method to separate the solid from liquid, and remove the contaminant from sewage.
Coarse Screen
Key equipment: Screen cleaner, screw conveyer, ultrasonic level meter.
Control points: utlize the difference of liquid level or according to technology requirements to set a time to control the screen cleaner and screw conveyer automaticlly startup and shutdown.
Sequence: conveyer and bar screen start simultaneously, and bar screen will be prior to be shut down.
Inlet Pumping House
Key equipment: Submersible pump, electric gate valve, ultrasonic level meter.
Control points: depending on the depth of the incoming, the stations make use of variable-speed drives to automatic control the quantity of operated pumps and pump frequency, and it can control the pumps operate in turns which will ensure all the pumps have same operation time.
Principle: the pump make use of constant water level to control the on-off time, when the water level is below the minimal water level then the pump will automatically stop running, while when it reaches to the constant water level the pump will automatically start.
Fine Screens/ Aerated Grit Chamber
Key equipment: Screen cleaner, screw conveyer, rotational flow grit device, grit-water separator, ultrasonic level meter
Control points: utlize the difference of liquid level or according to technology requirements to set a time to control the fine screen bar and screw conveyer automaticlly startup and shutdown, and fine screen bar and screw conveyer are linked.
Sequence: conveyer and fine screen bar start at the same time, while bar screen will be prior to be shut down.
Rotational flow grit system operation cycle: Operation cycle of rotational grift system: Start mixer 3 hours (adjustable) or operate continuously, then turn on blower, open gas valve for 1-3 mins (adjustable) and then close it, open gas lift valve for 15-30 mins (adjustable), operate blower for 10-30 mins (adjustable), and then close them. It is one cycle. Run blower and grit-water separator simultaneously, firstly turn off the blower, then stop grit-water separator after 5-10 mins. When one device defaults, the following devices will turn off subsequently.
Flush valve is auxiliary, it can be washed by hand or center control once in a while. Grit chamber devices run in turns automatically in a set time.