_GENERAL DOCUMENTS - C1981017 (205)

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*Five minutes of clarification were required to lower TSS from >600 ppm to <15 ppm at a dosage of 1 ppm flocculant. •Flocs, about 1/8", are formed immediately upon addition. *Stirring(not shaking)appears to assist in scavenging small suspended"pin flocs"into the larger flocs. The flocs are firm and do not break up upon stirring for 5-10 minutes. *Clarification is "non-Kynch" in that there is no zone demarking settled solids and decantate. •A small amount of unwetted solids float on the surface, some are attached to small air bubbles. *Method of flocculent addition is critical in minimizing formation of "pin-flocs" especially for short duration (5 minutes) evaluation. •Nalco 8170, a cationic acrylamide polymer, ranked second in effectiveness at a dosage of 1 ppm. (See Fig. 1) *The guar gum flocculant (MRL 100)presently used in the 016 pond system required a dosage of 4-8 ppm for an equivalent clarification effectiveness. From a cost standpoint, it is probably comparable to Nalco 8170. MRL 100 generates a finer. floc, about 1/16 inch in diameter. •Percol 351, a nonionic acrylamide product, was relatively ineffective at a dosage of 4 ppm. *Anionic polymeric flocculants such as Nalco 9708 and 9709 show no flocculation at all. *Addition of coagulant such as Ca+2, added as the chloride salt,was not significantly beneficial when added in conjunction with MRL 100. *Samples collected on May 29 and June 12 exhibited sparkling clear decantates. A sample taken May 31, two days following the May 29, sample produced a noticeable white haze decantate. Not enough of this material could be collected for analysis to see if it was an inorganic precipitate, eg; silica, or perhaps an organic emulsion. •Solids settled to a terminal pulp density (-200 mesh) of about 12-15% in one-half hour. A raked or compacted solids density in a pond would probably average about 20%.