iency there was 62%,
and some qualified observers expressed a conviction that Blue Plains had
never consistently functioned at much over 50%--in other words, it had
been returning to the estuary unassimilated organic materials equivalent
to the raw discharges of a population of roughly 500,000 to 700,000
people each day. Nor do these figures include a great deal of sludge
that has been flushed on into the river when digesters have failed to
function properly, or the plant's frequently inadequate use of
chlorination against bacterial pollution and odors. Since the same 1957
conference required of the other metropolitan jurisdictions only that
they do equally as well as the main plant in quality of treatment, they
have clearly not been obligated to superhuman effort.

[Illustration]

Criticism of Blue Plains is in part criticism of ourselves. Because of
the distinctive relationship between the District and the Federal
Government, the District's treatment plant is in a sense a Federal
installation, funded through Congress and with more direct links to
Federal water quality agencies than any other big municipal plant in the
country. The number of people the plant serves has, of course, increased
greatly in the past ten years. It may have been, as has been claimed,
somewhat underdesigned to begin with, and it undoubtedly needs expansion
now. Yet a rather substantial improvement in the quality of treatment
there in quite recent months, mainly under the stimulus of this planning
effort and the present surge of interest in the Potomac, indicates that
had emphasis on low operating costs been subjugated to pride in
results, the present plant could long ago have been made to function
reasonably well and the estuary would have had to cope with a much
lighter load of wastes.

The truly spectacular manifestation of pollution in the metropolitan
Potomac is the periodic growth of algae there in summertime. When
conditions are right--when sun, summer temperatures, low inflows from
the river above, and a heavy concentration of nitrate and phosphate
nutrients all combine to make of the upper estuary one vast inspired
pool of fertility--the whole surface of the river may be covered with a
thick bright emerald mat, and boats that pass at speed leave wakes of
green instead of white. The infestation may extend downstream for thirty
or forty miles, in various degrees of concentration, and even if the
water were bacterially safe this "bloom,