DAF unit is also called dissolved air flotation system. As its name implies, DAF unit is the waste water treatment equipment that uses tiny air bubbles to clear float impurities in the liquid medium out of the water surface. DAF unit can realize solid-liquid separation or liquid-liquid separation which is widely used in sewage treatment. The air float of the DAF system can handle liquid media containing particle suspensions. Since the density of these kinds of liquid is close to the density of water, the impurities cannot sink or float by depending on their weight. For example, liquid media have low turbidity, high chroma, high organic content and low oil content. Low surface active ingredients are rich in algae and other characteristics. Dissolved Air Flotation Unit (DAF unit) is widely used in the treatment of industrial waste-water and municipal waste-water such as refining, chemical, brewing, paint, food, vegetable oil production and refining, slaughtering, electroplating, printing and dyeing.
DAF Unit Working Principle
The DAF unit is mainly composed of a flocculation reaction tank (with a mixer), an air floating tank (mainly referred to as a gas floating tank), a dissolved gas system (a dissolved gas tank, an air compressor, a reflux pump, a release device), a scraper system and the medicine device and the electronic control system. The working principle of the DAF unit is as followed.
The clean water is pumped through the air floatation circulating pump, then pressurized into the dissolved gas tank and mixed with the air, and the air is dissolved into the water. The air in the dissolved gas tank is controlled by the liquid level by automatic controller and automatically replenished into the dissolved gas tank. The dissolved gas from the dissolved gas tank passes through the releaser, and the pressure is reduced to zero or released after the negative pressure. The air dissolved in the water is released from the water to form a large amount of micro-bubbles.By adding coagulant, the suspended particles in the liquid medium are attached to these large and small air bubbles to form impurities having a relative density smaller than water. Under the action of buoyancy, the suspended solids attached to the bubbles float up to the surface to form scum, thereby achieving solid-liquid separation or liquid-liquid separation of the liquid medium. The scraper on the air flotation machine then collects the dross floating on the upper layer of the waste water.
Slaughterhouse wastewater treatment process
Heze Dingtao food processing plant is mainly engaged in the processing of meat food. The composition of meat processing waste-water, which contains a lot of blood, oil, minced meat, animal hair, undigested food and feces, urine, nitrifying liquid pollutants, is very complex. After the actual and detailed site investigation, our technical team has come up with the following technical solutions.
1.Pre-treating the waste-water before entering the biological treatment to ensure the normal operation of the biological treatment.
2.After analysis, the comprehensive waste-water contains a large amount of suspended matter and floating matter which can be effectively removed by Materialized treatment. Among the practical techniques of materialized treatment, the coagulation air flotation method is superior to the coagulation sedimentation method. RUNNENG Environmental Protection adopts air floatation method for materialized treatment to remove suspended matter and colloidal substances effectively in wastewater through high-efficiency DAF unit.
3.RUNNENG Environmental Protection Co., Ltd. combines the actual daily production volume and sewage discharge of Heze Food Company with a fully automatic DAF unit with a treatment capacity of 75m3/h.
Specifications of RUNENG brand DAF unit for this Slaughterhouses:
- Model – DAF75
- Treatment capacity is 75m3/h
- Container water volume is 35-40 m3/h
- Main motor power is 15KW
- Scraper power is 0.55 KW
- Air compressor power is 3 KW
- Gas tank size is φ800×1980mm
- Machine size is 11000×2500×2000mm
In December 2016, the fully automatic DAF unit was delivered to the factory. After installation and operation, the COD of wastewater discharged by Heze Food Company was reduced from 1800mg/L before treatment to less than 50mg/L. Wastewater BOD decreased from 600mg/L to less than 10mg/L.SS, NH3-N, animal and vegetable oils and other indicators meet the water quality standards of the key watersheds of “Comprehensive Discharge Standard for Water Pollutants along the South-to-North Water Diversion Project of Shandong Province” (DB37/599-2006), and meet the relevant requirements of the company for effluent quality.
RUNNENG brand fully automatic DAF unit has the advantages of low investment, small ground occupation, high degree of automation, convenient operation and management, etc. The DAF unit has been running efficiently and smoothly since its installation. DAF unit effectively reduces the wastewater treatment load and fully meets customer requirements. DAF unit is widely used in the treatment of industrial wastewater, municipal wastewater and slaughter wastewater.
Shandong RUNNENG Environmental Technology Co., Ltd (RUNNENG) had been dedicated to supplying one stop wastewater equipment and Water Resource Recovery Facility (WRRF) solutions to worldwide customers for over 20 years. RUNNENG has over 30 professional experts and more than 150 staffs. Our high quality innovative wastewater equipment includes dissolved air flotation equipment, bar screen waste remover, sludge scraper and integrated sewage treatment equipment, etc. All our wastewater equipment has been passed the certificates of ISO9001, ISO14001 and OHSAS18001, we also have the Grade B engineering design certificate issued by the Ministry of Environmental Protection. Hope to be your partner.
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