Note on back of photograph: "Dandina Nagarajo Rao (left) assembled the pilot plant in a chemical engineering laboratory at the U of S before taking it by truck to Prince Albert. Here, he discusses the plant's operation with Profs. N.N. Bakhshi (centre) and Doug Macdonald. The two containers at the top receive effluent from the pulp mill's bleach plant, the one on the left highly colored caustic effluent and the one on the right acid-containing effluent goes into the bottom right container where the fly ash is introduced. The acidified fly ash is then piped across to the bottom left container to treat the caustic effluent, which flows in from the top left container".