Model:W11
Use:The Armfield Aerobic Digester is a benchtop unit designed as a comprehensive study facility of this process.
Waste water is drawn from a floor-standing feed tank (not supplied) by a DC motor-driven peristaltic pump. Rotational speed – and thus flow rate – is accurately set by a ten-turn potentiometer.
The pump delivers the feed to the reactor vessel through a transparent lid. Air is supplied at a measured rate by a small compressor, and discharges into the base of the reactor via a spider-arm dispenser. This design prevents blockages and produces sufficient bubbling for stirring and reaction. The liquid level in the reactor is maintained at a constant value of five to ten litres, by an adjustable overflow device connected to the outer annular chamber of the vessel. Discharge is by gravity to a floor-standing product tank (not supplied).
The reactor temperature is maintained by a three-term controller, which varies power to an immersion heater within the vessel. Any temperature between ambient and +35°C may be selected, the best conditions being a few degrees above the diurnal maximum in the user’s laboratory.
Dissolved oxygen and pH probes and meters are included.
The reactor lid contains a gas exit port, suitable for sampling the gases for subsequent analysis.
Small Scales bench mounted design
Provides demonstration of continuous activated sludge process
Acclimation of a completely mixed biological reactor
Measurement of COD and MLSS changes as criteria of performance
Establishing the stoichiometry and kinetics of aerobic processes
Gas/liquid mass transfer
Residence time distributions
100% scale-up to industrial requirements
Studying the effect on effluent quality of:
Inflow substrate concentration (‘loading rate’)
Liquid flow rate and reactor volume (‘detention time’)
Air flow rate
Temperature
pH stability
Nutrient deficiency