PET-o-RAMA, page-104

Geoffo the discussion by BobF on the video thread made me think about the timing flagged for Lake Dianchi when it was announced. Why do the small reservoir, followed by the catchment and only THEN the much larger Lake Dianchi?

The answer I suspect is that phoslock works best on canals and small waterways (eg Serpentine in London) without much new inflow. It captures most of the phosphate when first applied and locks it at bottom starving the algae of food. The challenge is now much larger lakes with a lot of new phosphate flowing in.

To do repeat full treatments of large lakes would be very expensive. So before any treatment of any large lake they would try to limit new inflows of phosphate to the lake, presumably by creating ponds or other means to treat catchment area inflows before they get to the lake. Only when that has been done would they treat the lake for the first time.

So at Dianchi they first treat the reservoir, which looks like it has controlled access, to show the locals that Phoslock works. You are right it may be done. It is low hanging fruit.The next step will be engineering works on the catchment area for the much larger Lake Dianchi to reduce inflows of new phosphate. It is Chinese New Year and this will only start afterwards and take much longer. Only when that work is done will they actually start applying phoslock to Lake Dianchi. That would suggest work on the main lake will be much later in 2020.

This should be clarified by asking the company, but I doubt if I will get a response, so I leave that to others.