MIXING SYSTEMS, INC.
7058 Corporate Way, Dayton, Ohio 45459, USA
APPLICATIONS FOR JET AERATORS AND JET MIXERS
Mixing Systems' custom designed jet aeration and jet mixing systems are extremely versatile and are suitable for a variety of applications. A few case histories have been included under their corresponding application.
Activated sludge treatment
Activated Sludge Treatment
Jet aeration systems are used for oxygen transfer and mixing in activated sludge treatment plants. Typical F/M ratios are 0.05 to 1.0 lb BOD5 (0.02 to 0.45 kg) per day-MLSS. Typical HP for mixing activated sludge tanks is 50 BHP per million gallons. This BHP represents the total pump and blower BHP.
Oxidation ditches are used in situations where high treatment efficiency and plug flow conditions are required. In the oxidation ditch the flow goes around the channel several hundred times before treatment is complete. Oxidation ditches achieve 99% BOD5 removal.
This concept has also been used where denitrification is required. A portion of the channel is used for creating a mixed anoxic zone for denitrification purposes. Typical velocities achieved in the oxidation ditch are 0.6 to 1.0 feet (0.18 to 0.3 M) per second. Minimum HP intensity for mixing oxidation ditches is 40 BHP per million gallons.
Aerobic Sludge Digesters
Jet mixers have been used for mixing aerobic digesters. Typical solids handling capacity of the nozzles used for aerobic digesters is 2-inch (5 cm) solids. Typical HP intensity for mixing aerobic sludge digesters is 100 BHP per million gallons.
Anaerobic Sludge Digesters
Jet mixers are used for mixing deep anaerobic sludge digesters. Anaerobic sludge digesters are typically designed on blending.
Aerobic and Anaerobic Selector Tanks
Jet mixers are used for mixing aerobic and anaerobic selector tanks. Selector tanks are designed to control filamentous bacteria in the aerobic reactors. Typical detention time in the aerobic or anaerobic selector tanks is 30 minutes to one hour. These selector tanks can also be used for creating anoxic conditions for denitrification and anaerobic conditions for phosphorous removal.
Sludge Holding Tanks
Jet mixers are used for mixing sludge holding tanks where the concentration of sludge can be as high as five percent. Special pumps are required when the sludge concentration exceeds three percent solids. Most sludge holding tanks are designed to be aerobic such that further volatile solids can be reduced. Typical HP intensity for mixing sludge holding tanks is 100 to 200 BHP per million gallons.
Jet mixers have been used for mixing large equalization basins where the liquid level can vary from 3 to 30 ft (1 to 9 M). The jet mixers are installed near the bottom of the tank such that the tanks can be mixed at low and high liquid level conditions. Typical HP intensity for mixing equalization basins is 40 to 80 BHP per million gallons.
Stripping (VOC Removal)
Jet aerators are used for stripping BTX (benzene toluene xylene) and VOC (volatile organic compounds) from wastewater. This is normally accomplished in closed tanks where the air can be collected and thermally oxidized or sent through a carbon adsorber.
Jet mixers are used for pH control in neutralization tanks. Typical holding times in neutralization tanks is 30 minutes to one hour. Typical mixing intensity for pH neutralization tanks is 100 BHP per million gallons.
Stormwater run off is collected in large holding tanks. These tanks are mixed using jet mixers to prevent stratification and to minimize odor. These tanks can be mixed without air or can have the option to add air in the future.
Blending tanks are normally used in process industries for mixing two or more liquids. Jet mixers are cost effective for mixing tanks greater than 10 ft (3 M) diameter or depths greater than 15 ft (4.6 M).
Jet mixers are used for suspending solids in process tanks. Typical applications include mixing sludge tanks, phosphoric acid storage tanks, and corn steep tanks.
Chlorination and Disinfection
Jet disinfection nozzles are used for creating complete contact between the disinfectant with wastewater. Typical disinfectants used are bromine chlorine dioxide and chlorine. Plug flow conditions are maintained in the contact chamber.
Sulfur dioxide is used for dechlorination. Sulfur dioxide is contacted through the jet nozzles with the wastewater that needs to be dechlorinated. The dechlorination system is designed such that no short circuiting will occur.
Pure Oxygen Systems
Pure oxygen is used for biological treatment in open or closed tanks. Jet oxygen contactors are ideal for replacing surface aerators that are used in Unox (R); and other pure oxygen processes. The jet oxygen contactors are powered using recirculation pumps which can be controlled using variable frequency drives. Typical HP intensity for pure oxygen activated sludge tanks is 100 to 200 BHP per million gallons. This power is required to effectively contact oxygen with microorganisms and to keep the tank completely mixed.
Jet mixers are used for flocculation tanks in water and wastewater treatment plants. Variable frequency drives are used on the recirculation pumps to control the mixing action in the flocculation tanks.
Jet aerators are used for oxidizing chemicals such as iron, sulfide, and sulfite in wastewater treatment plants.
Jet mixers are used for high intensity flash mixing tanks. These mixers are used to contact the chemical directly through the mixing nozzles. Typical holding time in flash mixing tanks is 30 seconds to 2 minutes.
Pure oxygen is used to enhance the level of dissolved oxygen in rivers and streams. During the summer months when the temperature of the water in the river is high or when hot wastewater is discharged into the river, the dissolved oxygen level of the river falls. Pure oxygen jet contactors are used for increasing the oxygen concentration of these rivers.
Copyright © 2000 -
Mixing Systems, Inc.
7058 Corporate Way, Dayton, Ohio 45459, USA
Phone: 937-435-7227, Fax: 937-435-9200