Attachment 3B - Process Design Strategy - OREZ · 132005.638.06

PR25001 Noosa Composting Facility
Process Design Strategy




   5. The partially composted material is fed into a stationary drum screen where it is
      separated into two fractions, fines and oversize.
   6. The fines fraction is then stored in the maturation building prior to becoming a
      saleable and useable product.

Aeration and Process Control

Forced aeration is what allows a tunnel to reliably reach and hold the temperatures required
for pathogen destruction and weed seed kill, even with the dense, low free-air-space
feedstock mixes typical of green waste and food organics blends. This is a meaningful
advantage over open windrow methods, where uneven pile density and limited turning
frequency can leave cool zones without adequate temperature exposure. The trade-off is
that IVC systems provide limited or no in-vessel agitation. Without periodic turning,
decomposition proceeds somewhat unevenly through the pile, which is why tunnels are
treated as the first stage of a two-stage process rather than a complete solution on their
own, with the partially composted material requiring a further maturation period outside the
tunnel to complete decomposition evenly throughout the batch.

Exhaust air drawn from the tunnel headspace is directed to a biofilter or equivalent air
treatment system before release, rather than vented directly. Typically, a portion of this
exhaust air is recirculated back into the incoming aeration supply, which both returns heat
and moisture to the process and reduces the volume of air the biofilter must treat. This
recirculation capability is a key reason enclosed tunnel systems achieve better odour and
emissions control than open composting methods, and is central to why IVC was the
technology nominated for this project given the airshed sensitivity around the NRRF site.




          Figure 2: Example IVC and air management system render from Noosa CF tender
                                 submission (Drawing No. P0052_1).

Leachate Management

Composting feedstock releases moisture as it decomposes, and forced aeration draws
additional moisture out of the pile as vapour in the exhaust air stream. Any moisture that
condenses or drains rather than leaving as vapour is collected as leachate at the tunnel



                                                                                              7