Algae Control in Small Water Plants

Abstract

difficulties attributable to algal growths constitute a perennial problem to the operators of treatment plants using surface waters as a source of supply. Each year these troubles must be overcome or endured. It is well to take stock, from time to time, of the preventive or ameliorative techniques that are available to minimize the plant difficulties and the public complaints arising from this recurrent phenomenon. In this paper, the subject will be considered particularly from the point of view of the smallplant operator who does not have expert technical advice at his immediate disposal, but who is expected, nevertheless, to know at least the possible courses of treatment that may be applicable to his situation. The operator of a plant subject to algae troubles should make an effort to acquire some knowledge of these organisms. Of the many hundreds of algae species that occur in appreciable numbers in natural waters, comparatively few perhaps a dozen or a score, at most are regular causes of treatment plant difficulties. It is possible to learn to identify these with only a little training, as one learns to recognize the common wild plants and animals of the macroscopic world. Simple counting methods can be used to indicate roughly whether the population density of an algal species is great enough to account for the operational difficulties that may be experienced. Training of this nature is one of the most obvious advantages accruing from attendance at short schools for water works operators. It is highly desirable to know and recognize the causitive organisms rather than to treat blindly the symptoms observed in the plant. Some of the objectionable symptoms that are usually the effect of algae may occur in the complete absence of the organisms. It is evidently futile to take measures directed against algae it they are not the source of the difficulty. The two most serious effects of algae in water treatment are interference with nitration and production of objectionable tastes and odors. The filter difficulties are generally due to a rather limited group of filter-blocking diatoms, although a few other organisms are occasionally present in sufficiently large numbers to be troublesome. The tastes and odors are