Specifications
7 Operating Instructions
7.1 Start-Up Instructions
Prior to start-up operation cleaning of the basin regarding contamination like stones, wood pieces
etc. is mandatory. Time between assembly and filling of the basin should be as short as possible.
If this is not possible, the following must be taken into account:
• It is not permitted to carry out other jobs in the area of the aerators, which could damage
to the diffuser system, like painting, welding, concrete sealing etc.
• The aerators must be protected against dropped parts.
• To check the air tightness, fill the basin with clean water. Potable water is not necessary,
but the water must be free of silt or debris. Water level should be at least 20 cm / 8” above
diffuser. Start short time aerating. Immediately after turning or shutting off the air supply,
inspect visually on excessive airflow. A large air volume in localized area points could be a
possible air leak of the piping or damaged diffuser sleeves.
• If normal operation does not start directly after leakage inspection raise water level to at
least 1 m / 40“ above diffuser (protection against UV-radiation and severe cold or hot
weather conditions). For longer dwell times compensate evaporation losses.
• Diffusers must operate at least 10 minutes daily at medium air flow rate.
• At temperatures below freezing, the water level must be chosen in such a manner, that a
through freezing can be avoided safely (approx. 1,5 - 2 m / 60” - 80”).
• All diffusers must operate at least 3 days up to 1 week at maximum air flow rate prior to
oxygen transfer measurements because of increasing SOTE.
7.2 Standard Operation
At standard operation, the air flow rate must be adjusted to maintain desired dissolved oxygen
levels in the basin. When adjusting the air flow rate, the diffusers should be operated within the
permitted operational range of the diffuser. An excessive air flow rate leads to high pressure drops
and reduced oxygen transfer performance. Low air flow rates may result in uneven utilization of
the diffuser (membrane) and reduced air distribution.
Furthermore, at low air flow rates and an increased growth of biological materials on the mem-
brane occur, which leads to agglutination of the perforation and therefore to increasing pressure
drop.
Keep the air flow rate not higher than maximum diffuser air flow rate. This is depending on diffuser
design, material, slit pattern, etc.
Keep the water temperature within 5°C / 41°F and 35°C / 95°F (ATV A-115).
The air temperature at diffuser entrance may not exceed 60 °C / 140 °F. Higher temperatures are
possible, please consult Gummi-Jaeger GmbH Aeration Components.
Good air filtration is required for operating fine bubble aeration systems. The air blown into the sys-
tem must be free of oil, dust and solvents. The compressed air must correspond to the guidelines
the German TA-Luft or corresponding regional regulations.
Dust filters for environmental dust have to be designed in accordance with DIN EN 779 for a
removal by at least 80% (filter class G3), better 90% (filter class G4) to prevent clogging of the
diffuser media.
Diffuser head loss should be constantly monitored. An increase of more than 20 hPa / 8” WC
reflects a possible clogging problem. Clogging may be caused by deposit of carbonates, biological
film etc., which can usually be removed by high pressure water hosing.
Inspection of diffusers should be made on a regular basis, at least once a year.
