Biodegradation has been proven as the most efficient, eco-friendly and cost-effective technique for the treatment of wastewater. The present investigation was planned to identify the bacterial strains which are effective for the biological degradation of dairy wastewater. Samples were collected from Arab dairy factory located at Sendbes Al-Qanater El-Khayria City, Qalubia, Egypt. Seven bacterial isolate were isolated and screening of protease producing bacteria on skim milk agar. Using 16S rDNA sequence analysis to identify the best metabolizing bacterium for different carbon and nitrogen compounds similar to those from the dairy effluent, the bacterium was identified as Bacillus subtilis. The biodegradation ability of the Bacillus subtilis was assessed, Inoculated with 107 cell concentration and with volume 10 % (v/v) showed a maximum chemical oxygen demand removal of 79 % in 15 days and significant decrease in biological oxygen demand (BOD).Two-stages low coast laboratory model was designed. The first coloum contain untreated dairy effluent and inoculated by 10 mL of identified bacterial culture. Activated carbon, small stones and sand layers were used as filtration media in the second coloum. Results represent the high ability of Bacillus subtilis in removal of BOD and COD demand in the dairy effluent with removal percent 82% and 85% respectively. Activated carbon, small stones and sand bed were added causing enhancement the quality of physicochemical parameters as total dissolved solids removal percent were 92 % and increased the removal efficiencies.
