The limited research on biological degradation formalin/formaldehyde/formic acid suggests a handful of Psuedomonads (up to 400 ppm). Phenol is considerably more well-known and range of cultures can break it down under the right conditions - most academia for aerobic cultures suggests very similar strains (at least to the species level) as mentioned for formalin. So a good mixed culture of Gram negatives should be sufficient.

I would suggest performing on-site flask studies with pure and mixed Pseudomonas spp. bacteria culture samples. PM for more info.