Small (22-foot Diameter) WWTP Clarifier Mech. Replacement 1

[WLAfts]

I am in the process of preparing Contract Docs. for the replacement of two small WWTP clarifier mechanisms. I would like to solicit input from any who have recently gone through this. As retrofitting can reveal unpleasant surprizes.

Thanks

 

[LHA]

Are you talking about the skimmer arms? And/or their drive motors? Please define exactly what is being replaced.

Generally, though, this will be a rare moment of draw down, so make sure nothing else below the normal water surface needs replaced, or include it now. In particular will be the weirs and troughs which carry the clarified water away. I'd bet that, since the skimmers have reached end-of-life, the weirs and troughs have sever corrosion.

Even if they are still sound, point out that maybe the client might wish to have them replaced during this time, to avoid another shutdown later.

At least put in the specs to check the anchor bolts - which you normally can't see - and replace any substandard ones. Make sure to define what is substandard.

Remember, amateurs built the ark...professionals built the Titanic. -Steve

 

[WLAfts]

All mechanical and metal fabrications assoc. with the original equipment are to be replaced. I hope to possibly salvage the bridges, and use them to support the new mechanisms. But the spec witll provide for new bridges with a deduct for utilizing the existing bridges. The weirs, scum baffel, et. al. are to be new. I anticipate screeding in new grout on the tank bottoms, in the same manner as is typically effected with new installations.

Thanks, Fred