Recovery and identification of Klebsiella from chlorinated water supplies substantiate the need for improved laboratory procedures in water‐treatment plants.

This study investigated the reactions that occur when hydrogen sulfide‐bearing waters are treated with potassium permanganate, with or without the additional presence of iron manganese.

This article discusses a method for iron and manganese removal from the water supply by continuously feeding potassium permanganate to the water before it passes through a manganese greensand filter. This method has been found effective on iron‐ and manganese‐bearing waters, some of which had been unsuccessfully treated by other conventional iron removal systems.

Figure 7. Influence of particle size upon effectiveness of Prototype Dichotomous samplerRotating Cowl and Impactor. This system, developed by G. A. Sehmel, was the most effective sampler tested. For a velocity of 5 ft/s and 8% approach flow turbulence, the sampler inlet was 82% effective up to a 15-jum particle size. Without the turbulence generating grid, the inlet system was essentially 100% effective and the overall capability limited only by the inherent losses in the 20 CFM Andersen head. Conclusions

Personnel of the Water Purification Lab. of Chicago conclude that the use of atomic absorption is superior to that of wet chemistry for the analysis of heavy metals. The authors present the basic operating principles, procedures for adjusting the instrument settings, and precautions concerning operation—if problems are to be avoided.