Graf one2clean+ - Page 24

7. Operation and maintenance
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Maintenance by a maintenance specialist 7.2
The maintenance should be undertaken by a specialist company (experts)
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at regular intervals (every 6
months). The intervals and work defined by the local water authority in the licence issued under water law
also apply. The system owner should take out a maintenance contract with a qualified specialist for this
work.
Note During retrofitting or any work related to maintenance on the electrical parts of the system, the
control cabinet must be de-energised.
Maintenance should include the following:
- Inspection of the operating log to check for correct operation (nominal/actual comparison)
- Check the air filter of the air compressor and the supply/exhaust air openings on the con-
trol cabinet
- Air compressor maintenance according to details provided by manufacturer.
- Function check on mechanical, electro-technical and other system parts key to operation, such
as aerator, lifter, control unit, valves
- Calibration of the level measurement
- Inspection of sludge height If necessary, the operator must arrange for the sludge to be removed
- Carry out general cleaning work, e.g. remove deposits
- Check the structural condition of the system
- Check sufficient aeration and ventilation
- Analysis of the aeration basin:
 Even aeration pattern (bubbles)
 Oxygen concentration (O
2
/l > 2 mg), if necessary adapt the compressor operating times
 Sludge as proportion of volume SV30 (if the sludge makes up more than 900 ml/l, sludge
removal is required)
The maintenance work undertaken, any damage found, repairs undertaken and other information should
be summarised in a maintenance report by the maintenance company. A suitable template is provided in
the Annex. Anything established during the analyses should also be documented in this report. The sys-
tem operator should be given the maintenance report so that it can be passed to the responsible authori-
ties if demanded. The maintenance report should be attached to the operating manual. Please keep the
operating log in a place where it can be easily accessed.
Note: System failures resulting from insufficient maintenance (e.g. of the compressor) will not be
covered by free replacement under warranty.
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Specialist companies are those not affiliated to an operator, whose staff (specialists) are suitably
qualified to operate and maintain small wastewater treatment systems through their professional train-
ing and from having received relevant qualification measures.