The initial goal of this project was to study the types of organic compounds which affected the growth of unicellular green algae such as are found in stabilization ponds, to investigate the occurance of these compounds in domestic sewage, and to determine the importance of direct algal assimilation of organic compounds in the process of biochemical oxygen demand reduction in stabilization ponds. Investigations of some ecological factors were undertaken in order to evaluate the importance of light intensity, carbon dioxide concentration, pH, and algal concentration upon algal growth and BOD removal in stabilization ponds. Thus this report includes the results of four separate investigations concerning the ecology of stabilization ponds.