W8 Anaerobic Digester Didactic Equipment Vocational Training Equipment Water Treatment Trainer
DESCRIPTION The anaerobic digester comprises two five-litre upward-flow packed bed reactors with feed rate and temperature control facilities. This allows steady, continuous operation at up to seven litres per day over periods of several days. The reactors may be operated in series or parallel. A buffer vessel between the reactors permits discharge of excess flow from the first reactor when the second reactor is operated in series but at a lower flow rate. The flow rates to the vessels are set and controlled by calibrated peristaltic pumps. The temperature of each reactor is controlled by an electric heating mat wrapped around the external wall. The temperature distribution within each reactor is maintained to ±0.5°C. Reactor temperatures may be separately set at any desired value in the range ambient to 55°C. The gas off-take from each reactor is taken to a volumetrically calibrated collector vessel operating by water displacement. A constant head, liquid seal device ensures the gas pressure in the reactor is maintained at a constant value throughout the test run. The collected gas can be exhausted from the vessel and the volume refilled with water during a run without breaking the liquid seal. Liquid and gas sampling points are located at all strategic points around the reactors. Non-return valves and liquid seal syphon breaks are included in the process pipework to ensure each reactor operates at a constant volume without the ingress of air or the danger of accidental syphonic action. The equipment is mounted on a vacuum-formed plastic base with an integral drain channel to cope with spillages and wash down.
TECHNICAL SPECIFICATIONS Reactors: Two identical reactors Nominal capacity: 5L Packed volume: 4L 150mm dia x 250mm high Reactor packing: 25mm diameter Bio-balls Temperature control: For each reactor 200W heating jacket with PID control from a temperature sensor positioned inside the reactor, set point within range ambient to 55°C, the jacket is thermostatically protected by a cut-out set at 85°C Feed pumps: Two identical peristaltic pumps variable speed using 10 turn potentiometer to 4rpm supplied with three tube diameters, 1.6, 3.2 and 4.0mm, flow rates from 0.2 to 5.8 l/day Reactor vessel: 2 x 5L (4.3L packed sestion) Gas collecting vessel: 2 x 5L Heat jacket: 2 Temperature sensor: 2 Pump: 2 x 0-40mL, supplied with 4.0, 3.2 and 1.6mm tubes