I am interested in the possibility of recycling the water used to keep logs damp while they await processing into veneer. At what point will contaminants make the water unsuitable for further recycling because of possible damage to the logs?
The best way to keep out the majority of the solids is to let the runoff accumulate in one basin (a settling pond) and then let it cross over into the holding basin via a spillway. The settling pond will essentially always be full of water and the trick is to keep the spill to the holding pond moving at a very low velocity, so as to leave most of the solids in the settling side. This gets down to the size of your log storage area vs. the size of your settling pond. It needs to be big enough not to fill too quickly, or your spill will be at high speed.
Once into the holding pond, a healthy volume of vigorous aeration should be able to knock out the contaminants. I would go with at least 20 percent aeration-flow to sprinkler-flow ratio, i.e., 50 gallons per minute sprinkler to 10 GPM aeration. You need to check with a water analyst or chemist, because you might have a more rapid buildup of comtaminants over time, and in that case you would need more aeration.