The aim of the study was to compare the composition of wastewater from the facility producing fruit and vegetable juices and dairy processing plant in Podlasie province. Their composition is also influenced by processes of washing and disinfecting of production lines. The washing process moves solid, colloidal, and dissolved impurities to the wastewater, depending on the type of raw material processed and the technological process used. At the same time, cleaning and disinfecting components at the amounts difficult to determine, penetrate the wastewater. The seasonal oscillations in the quantity and quality of sewage composition originating from fruit-vegetable and dairy processing became a problem for many conventional wastewater treatment plants, to where they are discharged. Based on the survey, it was found that wastewater from the fruit and vegetable industry as well as dairy industry contained large amounts of organic matter expressed in BOD₅ (fruits and vegetables processing from 860 to 3 200mg O₂/dm³, dairy from 1 410 to 3 850 mgO₂/dm³) and COD (fruits and vegetables processing from 919 to 3 700 mgO₂/dm³, dairy from 1 680 to 5 420 mgO₂/dm³). Significant differences were found in concentrations of nitrogen and phosphorus in compared raw wastewater.