A full scale MBR facility treating domestic WW has an effluent with a total N of 20 mg/L? However, [s] of NH4-N and NO3-N is 2 mg/L? NO2-N is not detectable. Hence, TKN analysis gave 1 mg N as NH4, the rest should be an organic content 17 mg/L? Amazingly TSS content is 2 mg/L, an indirect measure for biomass [VSS], don`t support loss of organic N assimilated into biomass? NO2-N is not detectable. Now, any similar experience with MBR effluent rich in organic N? What is the origin of that? EPS is responsible for that organic N? How measure EPS? Appreciate any feedback or citation of specific articles.
I agree with the the first step being to make a complete Nitrogen balance in the reactor. But I don't understand how you can measure a TKN as 1 mg/l and a total N of 20? Normally, all organic N forms including bacterial by-products as EPS are taken in account by the TKN (Total Kjeldahl N method = strong boiling acid digestion with selenium as catalyser). So if you get such a high total N in the effluent of a MBR, this N must be a soluble form resilient to digestion - and such forms are very unlikely in an urban sewages... What are the methods you use for TKN and Total N?
"how you can measure a TKN as 1 mg/l" I meant TKN as NH4-N [as part of TKN], the rest we assume to be organic N [second part of TKN=org N + NH4-N]. The Methods of TKN analysis is according to APHA standards. For control, I sent the same sample to another Lab to check the accuracy of the first lab result. I will report on this soon.
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