A study of the feasibility of lagoon-intermittent sand filter treatment of dairy wastewaters from the Utah State University dairy was performed from 1978 through 1980. The report also includes an analysis of alternative dairy wastewater treatment systems utilizing a computer model. A simple and inexpensive method of dairy wastewater treatment is needed so that the small (50- 300 cows) dairy farmer can meet the 30 mg/ ~ of BODs federal effluent standard and still earn a profit. The influent to the USU dairy treatment system, the lagoon effluent and the filter effluent were sampled during the summers of 1978 and 1979 for BOD s , suspended solids and volatile suspended solids . The data show t hat removal efficiencies over 90 percent were achieved by the lagoon-intermittent sand filter system, but the effluent BODs and suspended solids concentrations did not meet the federal standards. The high effluent concentrations were a. result of the lagoon being overloaded. The treatment system's construction allowed runoff, groundwater and milking center washwater to enter the lagoon causing greater than expected hydraulic and organic mass loading rates. Despite high influent concentrations the intermittent sand filters consistently removed 80 percent of the suspended solids from the lagoon effluent. If the quality of the lagoon effluent were improved by reducing the organic mass loading rate, the effluent from lagoon intermittent sand filter treatment of dairy wastewaters would meet the federal standards.