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| |  Posted 7/5/2007 1:56:51 PM | |
| Supreme Being
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| | We are planning to install air lifts in 2 secondary settling tanks that presently have air diaphragm pumps that return the biomass. We are replacing them because of years of maintenance and operational problems. My question is?............how close to the bottom do you install the return line, at what height do you connect the air supply and is there any reason why we cant use a heavy wall plastic pipe instead of steel? |
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| | | Posted 7/5/2007 3:34:48 PM | |
| Junior Member
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| Place a tee on the bottom of the pipe and rest it on the bottom of the tank. The air line should be about 60% to 75% from the top. Add a valve on the discharge of the airlift in the event of plugging. This will allow you to blow back down the pipe.
Hal Davis
Marketing Analyst
Siemens Water Technologies Corp. |
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| | | Posted 7/6/2007 8:13:39 AM | |
| Supreme Being
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| | Is that 65 to 75% from top water level or top of the tank walls? The tee sounds like a great idea but should there be any concern about blockages at the bottom of the tank? Also what size return line..........3 inch? |
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| | | Posted 7/8/2007 9:01:14 AM | |
| Junior Member
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| From water level. We used 3" on all airlifts.
Hal Davis
Marketing Analyst
Siemens Water Technologies Corp. |
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| | | Posted 8/4/2007 5:52:53 AM | |
| Junior Member
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Last Login: 2/1/2008 6:26:27 AM
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| | A few issues: Run you air supply from above the tank downwards. When the blowers go off you get backflow of sludge up the supply. Keep you design simple at the air injection point because of this backflow of sludge into hot pipework, which can cause blockages. I think our airlifts are all 4 inch. 3 inch can block with rags. Pipeworck can be UPVC, but say mild steel at the injection point, due to heat. At the discharge point, use a tee to discharge the fluid at right angles. If you mount your airlift outside the tank then you need to run a vertical at least one metre above the discharge for the air to escape. Regards Grant H |
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