Wastewater treatment lagoon effluent 2

[wespark]

I have 2 questions. My company has purchased an environmental nightmare. It's a wastewater treatment lagoon with no process control other than chlorinating and de-chlorinating. We are meeting our permit requirements- "barely". Our problem is ammonia and phosphorous removal. The plant has no aeration or pH control. The pH stays between 7.0-7.8ppm. What could I do to decrease the ammonia - nitrogen & phosphorous levels. We usually stay around 1.8 ppm and sometimes as high as 3.0ppm. Breakdown chlorination isn't a good idea.
The chlorination contact chamber lies in a flood plane. If we get 2-3" of rain, the nearby creek actually submerges the chamber. I have since had a concrete block wall built around the chamber approx. 32" high. Well, with hindsight being 20/20, when the creek rises it may not submerge the chamber but the final effluent pipe that discharges into the creek will be submerged. I'm now thinking that the effluent flow will not overcome the creek and the creek will backup into the wall. At 32" the head pressure would be approx. 6psi. The effluent has to flow approx. 300' to the final discharge point at the creek. Would 6 psi be enough to prevent a backup and allow the effluent to flow ? Any suggestions ? I have thought that by adding vertical piping at the final discharge approx. 26-28" high may help but chances are this would likely become submerged,or if not, decrease the likely hood of the effluent flowing at all due to friction loss. Sorry so lenghty, but if anyone can help I would definitely appreciate it. Thanks.

 

[LHA]

Try posting to the "Waste disposal & treatment Forum", that's where most WWTP issues are.

You need an aerator. That will decrease pH as it also decreases F:M and gives the plant more young, hungry microbes. I don't know how much control you have over detention time, but increasing DO and detention often yields ammonia removal in extended aeration plants. Don't know if it will in a lagoon or not, I have never operated one.

You are simply not going to get P removal in a lagoon, in my opinion.

But your real problem is the hydraulic grade line...it sounds like you might have to build a discharge chamber with several feet of elevation, and pump up to it for gravity flow out and isolation of cl2 tank.

 

[semo]

There is no easy solution for your problem. P removal in a lagoon is only shown to be about 50%. I don't think the lagoon system will take care of the P.

The NH3 removal can run 80% or better; but, in cold weather the nitrifying bacteria cannot survive and your NH3 level increase. The aerated lagoons look to do a better job at this too. Insulated covered aerated lagoons can help maintain higher temperatures and thus the bacteria; but, the covers are not cheap.

There are studies being done on fixed media to help nitrify; but, as far as I can see, the court is out on this subject so far. There are also some aerated lagoon systems utilizing a complete mix zone at the beginning, with a floating clarifier to return waste sludge.

Your discharge problem is a basic hydraulic question. If you know what the discharge water elevation from the lagoon is, the discharge rate, and the size, type, etc. of pipe, you can calculate your head losses to see if the discharge will overcome the stream level.

I would retain the services of a local firm that has knowledge in these types of systems.

 

[Muggle]

P can be precipitated out using lanthanum chloride - regardless of pH (2-11 is the working range) - this is done in SBR's as well as manure lagoons and freshwater fish displays. It has a much greater pH working range them alum, and has no ecological impacts on the microinvertebrates. Additionally, temperature is not issue.

ECP International provides such to Kelloggs, DisneyWorld, etc. - suggest you contact them at water@infoecp.com. They specialize in wastewater lagoon treating.