04Limits
What this record does not establish.
The chemical oxygen demand figure is the one to sit with: it went up while suspended solids came down by eighty-three per cent, over the same four months in the same lagoon. A rising COD alongside falling suspended solids is what you would see if solids were being broken into dissolved organic material faster than that material was being oxidised — treatment part-finished rather than treatment failing — but that is a reading, and the record establishes none of it. The window ran October to January, which south of the equator is the warm half of the year, and warmth alone moves a lagoon. No volatile fraction at the start, no dosing detail, and nothing left untreated.
Only the volatile organic fraction of a sludge responds to any of this. Grit, sand, silt, mineral precipitates and plastics remain at any dose, here and everywhere else.