Cod Bod Ratio

Water and Wastewater.com Help Forums - COD?BOD N/P Ratios

I have been operating a .500mgd, six basin SBR.  The plant does not have a mix cycle, But alternates aerobic, anoxic cycles.  Over the past several months, I have been experiencing periods of time when my effluent has a very high ammonia level (50 or greater) but nitrate (10 mg/L) and nitrite (1.0mg/L) seem reasonable.  Also at this time, my effluent will have a dark tint (looks like black tea) but will have very little visible solids.  It is also worth noting that it has been very cold and my treatment basin temperatures are down to 11 degrees C.  My plant accepts pre-treated landfill leachate at a average flow of .065mgd.  The leachate seems to be the problem and we will be meeting with the landfill soon.  However, I have a number of questions before I sit down with them.  First, I was wondering where I could find toxicity levels for things like metals, organics, inorganics, etc?  Second, it seems my influent numbers are way out of wack, especialy when I am having the problems described above.  See below: A big part of toxicity is it's concentration-proportion to your flow. You should try some respiratory tests (OUR or the less sophisticated mix in a bucket and monitor the DO)- try the test with your normal wastestream in proportion to your MLSS and then try adding different % of the leachate and plot how long it takes for the DO to be used up. Once you see the curve change and the DO depletion inhibited you know that concentration of leachate is too high for you to handle. The ratio of COD to BOD also seems high, which suggests lower biodegradability. How are the 6 SBRs reacting (do they all react in the same way)? SJ Hennessy is right about how to check for toxicity and you should be concerned about whether the leachate is toxic to your activated sludge. You may also try to acclimate your sludge to the change in the wastewater. Try running BOD Treating the landfill leachate is profitable.  They paid for our plant upgrade ten years ago and would contribute towards a future upgrade.  We need to meet a Total P and Total N limit by 2012.  It looks like the landfill is going to add a RO filter to their process.  I'm guessing that will be enough for us to meet our limit.   My F/M is .062 at a MLSS of 4600 and.  I would actually like to try to get a little heavier but my settling has been around 700.

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