So yesterday morning, Jonathan Eisen and myself headed down to Antioch, CA to sample a pilot wastewater treatment facility. In a couple of hours I went from knowing literally nothing about the process to having some handle on at least the latter stages. Pretty cool microbiology.
As I understand the problem at hand, conventional wastewater treatment leaves a lot of ammonia in the effluent… which usually gets dumped into nearby bodies of water (ocean, lake, river, etc.). In addition to the ecological concerns (and impending restrictive legislation), there is an increasing drive to re-use wastewater for industrial purposes and ammonia isn’t great for brass fittings/valves either. Microbial degradation of ammonia is relatively well-understood but requires two separate processes, a aerobic nitrification step followed by an anaerobic denitrification step (Anammox). There are various chemical and/or biological solutions that are used in different facilities, but all are relatively expensive.
The folks that we were working with (Rob Collison from Collison Engineering, and Mark Grismer from UCD) are experimenting with a process to bring these two stages together into a single bioreactor using Zeolite to concentrate the ammonia where the bugs can eat it. The process appears to be working but the exact microbiology is still relatively unknown. The goal today was to sample the shallow (aerobic) and deep (anaerobic) parts of of the pilot bioreacter. Not easy since it’s basically a giant tub of rocks. The solution, using a big coring column and then a ShopVac to suck up the rocks/liquid seemed to work fairly well. Nothing like sterile technique though!
Next steps; DNA extraction and metagenomics to see who is living on these rocks!
(edit on 5/23/18. Dr. Grismer suggested anyone wanting to understand the problem in more detail check out the introduction from this paper)