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Recent content by semo

  1. semo

    Fine Air Bubble Diffuser

    I agree with bimr on his statements and if your DO levels are up, the diffusers are doing their job. During transition from surface aeration to diffused, I would expect to see what you are describing. Most likely your surface aerators were not reaching the bottom of the lagoon and only...
  2. semo

    How would you estimate peak water demand?

    Pedarrin2, While I agree with your scenario, we are talking apples to oranges. In a stadium like you are discussing, the users are there for a few hours, there is a higher popluation per fixture, and during breaks, there will be times that almost all of the fixture units are flowing. In a...
  3. semo

    How would you estimate peak water demand?

    USDA (as well as Missouri) has an equation that is commonly used for sizing a distribution line. It is 9 * x^0.515 = Q. Based on an x (connections) of 50 you get a peak flow of 68 gpm. This equation takes into account that low numbers of connections use a higher flow per connection; but, also...
  4. semo

    Temporary Bypass Water

    On a lot of past projects where we've replaced mains no temporary was installed. Instead the new mains were installed for the area (sometimes a complete community) connected to the distribution system, and tested. This meant that at some point there were two live distribution systems. The...
  5. semo

    problems in WWTP

    What kind of blowers do you have? Are your air filters clean? Centrifugals can see a large decrease in SCFM with a dirty filter. And washing them or blowing them out with compressed air may not clean them enough to get your rated capacity. Has your waste stream changed? Is someone dumping...
  6. semo

    Gas Chlorination Booster Pump Selection

    Your pump doesn't have to match the 5 gpm at 109 ft specifically. If your flow rate is higher, it will create a larger vacuum through the venturi which will be better for the pull of chlorine gas. They should also have various sized ejectors (venturis) for various flows and pressures. The...
  7. semo

    Check Valve Causing Water Hammer

    Been down this road before when pumping into a sedimentation tank from a well. Some of the problem may come from the air release valve. Is there a possibility that it is actually and air/vacuum valve? That would allow air to reenter the line upon shutdown allowing the check valve to hammer as...
  8. semo

    Sodium Hypochlorite Dosing & Calcium Deposits

    The injection point of the sodium hypochlorite will scale and plug. Just a matter of how soon/often. Doesn't matter what material it is. We always call out for a retractable injection quill to be installed. It too will scale; but, a spare quill can be purchased and every so often swapped...
  9. semo

    Electrocoagulation

    Does anyone have any experience with electrocoagulation for wastewater treatment? Primarily in a municipal setting; but, general experience is helpful too? I know it is used primarily in industrial wastewater for metals removal; but, my concern is its effectiveness at removing nutrients (N &...
  10. semo

    Standpipe level indicators not reading accurate causing overflows

    I'm assuming that the transmitter is a transducer and not a switch. Either way, you need to make sure that if the transducer is on the top of the pipe, there is a side blowoff to flush the line to the transducer. Probably need to with a switch also; but, I haven't seen problems with them. A...
  11. semo

    Vertical Bends in Sewer Force Main

    Another question would be what kind of pipe are you using. You might consider directional boring HDPE or yellowmine pipe for your gradual grade you discussed. If PVC and you do use fitings; restraints are important. Not only on the fittings; but, also on the carrier pipe within your casing...
  12. semo

    Filter backwash from elevated tank

    As BIMR mentioned, this is starting to go way overboard. KISS method. First, I wouldn't really be concerned with pressure. The concern is flow. You don't want the backwash rate higher than recommended for the type of underdrain and media installed. The pressure will reduce accordingly. On...
  13. semo

    Pressure Sand Filter Media Options

    The filter will not remove soluble iron from the water. You will have to get it out of solution so that the filter can remove those particles. Oxidation is typically performed with aeration, chlorination, permanganate, or a combination. You really need your water analysis before you can do...
  14. semo

    UV on Lagoon WWTP Discharge

    There are several lagoons utilizing UV for disinfection. The main concern is the TSS levels (clarity) in the water. The higher the level, the more bulbs needed. This must be an aerated lagoon to keep the TSS below 45 or you have some sort of filter before discharge. Because of the higher...
  15. semo

    Chemical Injection Quills

    Saf-T-Flo manufactures quill assemblies of various sizes and materials. I've had good luck with their product and mainly used a pvc or cpvc tube (depending on the chemical). Always double check the chemical compatibility. Most of what I have used has been a saddle type installation with the...
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