The Klargester BioDisc is a self-contained, single-piece wastewater treatment system designed to process crude domestic sewage and produce an effluent suitable for discharge into a watercourse or soakaway system, subject to regulatory approval. This system is engineered for efficiency and a long service life, with minimal maintenance requirements.
Function Description
The BioDisc system operates on a biological treatment process, utilizing colonies of live natural micro-organisms, known as biomass, to break down pollutants in sewage. The system is self-regulating and does not require specialized operational knowledge.
The treatment process begins in the Primary Settlement Tank (PST), where crude sewage enters through an inlet pipe. Solids are settled out and retained in this tank for periodic desludging. The PST is designed to handle high flows over short periods, and a patented Managed Flow System allows the liquid level to fluctuate, accommodating such surges.
Following the PST, the sewage moves into the Biozone, which houses the Rotor. The Rotor consists of corrugated polyethylene discs mounted on a horizontal shaft, supported by bearings at each end. These bearings can be either plastic, requiring no lubrication, or roller bearings continuously lubricated by pressurized grease cartridges. The Rotor is slowly rotated by an electric motor and reduction gearbox, typically via a chain or belt drive. Chain drives are continuously lubricated by a pressurized grease cartridge and brush assembly.
As the discs rotate, their surface becomes colonized by micro-organisms, forming a visible coating called biomass. The rotation alternately submerges the biomass in the settled sewage and exposes it to the atmosphere, allowing for efficient breakdown of pollutants. The Biozone is divided into two stages by a fixed baffle. Settled sewage enters the first stage through a submerged transfer slot, where the liquid level fluctuates, exposing bacteria to varying sewage strengths and concentrations of domestic chemicals. This stage minimizes the impact of shock loads that could otherwise inhibit the treatment process. The second stage of the Biozone is hydraulically sealed from the first, maintaining a constant liquid level. Liquid is transferred from the first to the second stage at a steady rate by a series of buckets attached to the rotor. This controlled flow is central to the patented Managed Flow System, which promotes healthy and balanced growth of the micro-organisms essential for efficient treatment. Excess biomass, also referred to as humus, sloughs off the disc surfaces and flows into the Final Settlement Tank.
The Final Settlement Tank (FST) is located beneath the drive motor and receives the treated effluent from the Biozone. Here, the humus settles out and is retained for periodic desludging. N-range units incorporate a timer-controlled pump return sludge system to periodically return settled humus to the PST for co-settlement. The final treated effluent is discharged from the FST through a dip pipe. The FST is covered by a pedestrian-duty walkway, providing service access and preventing personnel from falling into the tank.
A GRP cover protects the BioDisc from weather and prevents injury. The cover sections are secured by latches, operated with keys provided with the unit.
The Control Panel, a weatherproof unit, should be mounted adjacent to the BioDisc. Three types of panels are available, all featuring current overload protection, power isolation, and automatic re-start after power failure. N-range control panels also include a timer and relay to manage the sludge return pump and its motor's current overload protection.
- Standard Control Panel: Provides basic control functions.
- Alarm Control Panel: Replaces the Standard Control Panel and includes a Loss of Rotation (LOR) Alarm. This alarm activates after a 2-3 minute delay if the rotor stops turning for any reason other than a power supply failure. It features stop and run lights on the door and an optional alarm beacon. A remote slave beacon can also be fitted. The LOR is sensed by a reed switch near the BioDisc motor, interacting with a magnet on the rotor.
- Independent Remote Alarm Panel: This panel is an addition to the Standard Control Panel, suitable for indoor locations up to 100 meters from the BioDisc. It typically connects to an independent power supply and functions similarly to the Alarm Control Panel, with an audible alarm, mute button, and warning light.
Usage Features
The BioDisc is designed for ease of use, with its biological treatment process being largely automatic. However, users should be aware of certain operational guidelines to ensure optimal performance and longevity.
Process Initiation: During installation, the unit is filled with water to prevent flotation. Sewage is then introduced, gradually displacing the clean water. Biomass colonization typically begins naturally within 3-6 weeks, depending on site conditions, and continues to develop, influenced by chemical and temperature factors.
Chemical Usage: The system relies on live micro-organisms, which can be inhibited or killed by excessive amounts of certain chemicals. While common household cleaning fluids are generally acceptable when used according to manufacturer instructions and stipulated concentrations, it is crucial to avoid pouring neat disinfectants or bleach down sinks or outside gullies. Nappy disinfectants and bottle sterilizing fluids should be well diluted before disposal, preferably by flushing down the toilet.
Waste Disposal: Waste disposal units are not recommended as they can increase the treatment load, potentially unbalancing the process. Composting vegetable peelings is a more environmentally friendly and cost-effective alternative. Home beer and wine making waste also significantly increases the treatment load.
Prohibited Discharges: To protect the biomass and prevent system malfunction, the following must NOT be discharged into the drains:
- Motor oil, grease, anti-freeze, brake fluid, etc.
- Cooking oil and fat.
- Weed-killers, insecticides, fungicides, and other gardening chemicals.
- Paint, thinners, white spirit, turpentine, creosote, etc.
- Unused medicines (dispose of safely via a pharmacist).
- Chemical toilet waste.
- Photographic developing fluids.
- Nappies, sanitary towels, rags, soft toys, tennis balls, etc. Even "disposable" items may not fully degrade and can cause blockages.
Maintenance Features
Routine preventive electro/mechanical maintenance and desludging are crucial for the BioDisc's proper functioning and should be performed by suitably qualified personnel at appropriate intervals. Klargester offers planned contract maintenance and commissioning services.
Initial Start-Up Procedure:
- Pre-Operation Check: All mechanical components are factory-fitted, adjusted, and lubricated. However, transportation and installation may necessitate re-adjustment. If adjustments are needed, contact Klargester for commissioning.
- Water Level: Ensure the BioDisc is full of water to the outlet level.
- Electrical Connection: Verify the power supply is connected to the control panel and all electrical components are earthed.
- BioDisc Inspection: Check for any obvious damage or misalignment.
- Electrical Component Connection: Confirm all electrical components (Drive Motor, Sludge Return Pump, LOR Alarm sensor) are connected to the Control Panel.
- Sludge Return Timer (N-range units): Ensure the timer is set correctly as per the wiring diagram.
- Automatic Grease Cartridges: If fitted, these must be activated before starting the unit. Turn the control knob until figure 6 aligns with the arrow (for 12 months lubrication), depress the red button to secure the setting, and then rotate the knob clockwise to activate.
- Switch On: Open the control panel, set the isolating switch/circuit breaker(s) to "on," then close and lock the panel. If a sludge return pump is fitted, it should start and run for its set time.
- Running Checks: Verify the rotor runs smoothly in the correct direction without contacting fixed structures. Check that forward feed buckets discharge correctly from the first to the second stage Biozone.
- Loss of Rotation Alarm Check (if fitted): Isolate the drive motor at the control panel while maintaining power to the alarm circuit. After 2-3 minutes, the alarm should activate. Push the reset button; the alarm beacon/sounder should cease, and the red indicator light should remain illuminated. Re-connect power to the drive motor; the alarm should cease after about one minute. Depress and release the "Beacon Off" button to reset. Malfunctioning of the LOR Alarm should be reported to a maintenance engineer.
Customer Maintenance Checks (Approximately Monthly):
- General Condition: Visually inspect the plant and listen for unusual noises. Report any concerns to your maintenance engineer.
- Biomass Appearance: The biomass should be light grey to brown at the first bank, gradually darkening towards the drive end of the rotor. Excessively thick or predominantly grey growth indicates an overload.
- Fixings: Visually check that all fixings are secure.
- Debris Removal: Clear any debris from inlet and outlet pipes.
- Dosing Buckets and Transfer Baffle: Check for debris buildup and clean with a stiff bristled brush if necessary.
- Loss of Rotation Warning Device: Check for correct operation as per the initial start-up procedure.
Automatic Re-Start After Power Failure: BioDiscs are designed to re-start automatically after power is restored, though this may not always succeed, especially after extended power cuts. After power is re-established, verify the rotor is turning correctly. Contact Klargester if difficulties arise.
Sludge Removal (Desludging): This is a critical maintenance task.
- Frequency and Volume: Desludging periods and volumes can be adjusted if the system is not fully loaded, but it is essential to prevent sludge accumulation that could harm the process. All settled sludge and floating matter must be removed during each desludge visit.
- Procedure:
- Isolate power to the BioDisc at the Control Panel.
- Undo cover latches and fold back hinged cover sections or remove covers entirely to gain access.
- Remove surface scum from the Primary Settlement Tank through the desludge ports on either side of the rotor.
- Lower the sewage level by approximately 500mm, using the ports alternately.
- Lift off the walkway covering the Final Settlement Tank and remove settled sludge and floating matter. Replace the walkway. If a sludge return pump is exposed, refill the chamber with water to cover the pump before switching on.
- Lower the hose into the bottom of the Primary Settlement Tank and remove settled sludge. Use each port sequentially and cover unused ports. The tank may need to be emptied completely for full sludge removal. Replace all port covers.
- DO NOT attempt to remove liquid from the Rotor Section or clean the gelatinous growth on the rotor.
- Ensure the BioDisc inlet and outlet pipes and Forward Feed Buckets are free of debris.
- Replace the walkway and all desludge port covers, then close and lock the BioDisc covers.
- Re-connect the power supply and ensure the Control Panel door is locked.
- For units with Loss of Rotation Alarms: Wait two minutes. If the alarm does not activate, the rotor has successfully re-started. If it activates, switch off power at the Control Panel, then immediately switch on again. If the alarm persists, isolate power and notify the plant owner for investigation.
- Units should be refilled with water.
Mechanical and electrical maintenance must be performed by properly trained engineers, adhering to appropriate guidelines. Klargester offers various maintenance packages.
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