Growth of Selenastrum capricornutum in natural waters augmented with detergent products in wastewaters

A determination of whether the removal of phosphate builders from detergents would modify the ability of domestic secondary treated sewage effluent to stimulate the growth of a test alga (Selenastrum capricornutum-Printz) in receiving waters alone and augmented with detergent products was made. The lakes used as sources of test waters were located in northeastern New York State and possessed total phosphorus concentrations ranging from ca. 0.01 to 0.04 mg P1^?1.

The alga experienced stimulation in all three test lake waters from secondary sewage containing detergent with phosphate or detergent without phosphate. A concentration of 60 μg P 1^?1 was sufficient to effect significant algal growth in two of the test waters; however, concentrations ranging up to 110 μg P 1^?1 did not generate such a response in the third test water. This latter result and others suggested that neither phosphorus nor other nutrients from these wastewater additions were the factors fully accountable for the observed response(s).