'mix valve' design for lift station 1

[chileheadcraig]

I am doing a upgrade for an exisiting lift station with a siltation problem. It has been suggested to use a 'mix valve' design that will re-suspend the sediment when pumping begins.

Anyone have experience with this design? I've never heard of it.

 

[KRSServices]

To begin, firstly check within the municipality as to records when the station was put into service. If siltation is due to gradual infiltration the records should show a proportional increase, as well as comments from staff. For me, the staff discussions were the most fruitful because they can get very specific (fouling of gauges, clogging of pitots and checkvalves, etc.). If the sewer is a combined system, then the operations staff will be crucial because they will pinpoint the areas of high maintenance for you and this will aid in your report preparation. I used the 20 year life cycle because that would be a reasonable cycle for the sump system. I would use records from municipalities with non-silt/grit problems in lift stations and extrapolate to your situation (flow, residentail vs industrial vs commercial) or perhaps there are examples in the community itself. Many pump manufacturers have "typical" wear data for impellers and are keen to recommend different material types...that could be a possible reference too. In my system, the wear due to grit on the impellers and appurtenances was about 50% to 75% higher (depending on the time of year) than without the trap. Mind you, the pumps were also high duty pumps too, and extremely expensive to service for shutdown due to configuration. In the end, it will come down to one set of costs versus another, but I'm confident that an analysis will demonstrate not only a reasonable payback period, but a lengthening of the duty life of the station, hence a "cheap" longterm savings for the municipality (capital replacement cost). KRS Services

http://www.krs-services.com