Factors Influencing Small-Scale Testing

The process variables known to influence arsenic capacity and column performance of alumina, GFH, and other adsorbents are as follows adsorbent, adsorbent particle size, flow rate, EBCT, and water quality parameters including arsenic concentration, As(III)/(V) speciation, pH, silica, phosphate, fluoride, hardness, and sulfate concentrations. Even with a complete water analysis, it is prudent to perform pilot studies with competitive adsorbents on the water to be treated because of the numerous factors that influence arsenic adsorption. Equilibrium isotherms and rapid small-scale column tests (RSSCTs) are typically run prior to the pilot study (7). 

The turbidimetric determinaticm of hyaluronidase activity of Kass and Seastone (91) is a modification of the M. C. P. test in which the unreacted substrate is determined by the development of turbidity Avith acidified protein. The method requires only small amounts of purified substrate and is suitable for assa3 on a large scale. Compared with the viscometric method, it is less sensitive to variations in substrate properties. The method has been criticized, however, because of ttie indirect determination of the unreacted substrate. The factors which influence the formation of a stable suspension of the substrate-protein complex are poorly understood and difficult to control. The development of turbidity has been eliminated in a recent colorimetric modification by Greif (52). 

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