ANAMMOX is an anaerobic process (anaerobic ammonium oxidation) , and the bacteria that performs this process, Planctomycetes, naturally undergoes its anaerobic phase in the absence of light.  So this requirement is to make sure that the process is anaerobic.   HTH.

Hi Damian,

for the classical nitrifiers it is described that they are photoinhibited.

The the paper below. May be you find some further information.

DOI: 10.1111/j.1574-6968.2011.02457.x

Hi Damian, 

I think you can find the right answer and reference in this article:

Van de Graaf A.A., de Bruijn P., Robertson L.A., Jetten M.S.M., Kuenen J.G..

„Autotrophic growth of anaerobic ammonium-oxidizing micro-organisms in

a fluidized bed reactor.” 142. Microbiology, 1996. 2187-2196.

Moreover I think the sunlight influence can be more direct to partial nitrification process rather than Anammox exactly. What do you think so?

Thanks a lot for your help, suggestions and adivce. Since I will couple my anammox to partial nitritation it will have to be in the dark due to the photoinhibtion of AOA/AOB

Hi Damian

When working with pure anammox biomass the worried about light can be also caused by the algae growth in the walls of the reactor. These algae can produce oxygen and inhibite the anammox bacteria. 

I have worked with PN/anammox biomass and we used uncovered glass reactors, and we think there were no inhibitions caused by light.

 Oh.. yes. Nicolas is absolutely right. I completely forgotten about that, however the algae could be a problem in fact, especially if you are working on synthetic medium ex. proposed by Trigo et al. in 2006. In my research I found that this medium is well suitable for algae, mainly Chlorella sp. I found both common species Ch. Elipsoidea and Ch. Vulgaris. The problem of algae on the walls of the bioreactor is depended of mixing. In my reactors there was no algae on walls, but the tubes for influent and effluent were almost always covered with it. Additionally, stepping by the oxygen generation, the algae growth changes the environmental conditions in your reactor, because they use nitrogen for their living mechanisms.

Yes, the tubes for influente are also important. In our research about the use of anammox for the treatment of wastewater in the main line (low temperature, low N concentration), in our laboratory reactor, we found that part of the N oxidation or transformation happened in the tubes, and not in the reactor. It was important to use non oxygen permeable tubes, minimize the lenght of the tubes, avoid the growth of biofilms in the tubes and so on... For the algae issue, black, opaque tubes were the most suitable.

When you implement these processes to full scale, the wall effect, or the light effect are negligible. In addition, I think nobody have a glass full scale anammox reactor!