Bioaugmentative Approaches for Dairy Wastewater Treatment

Problem statement: The achievement of a good ecological status of water receivers after discharge of waste or partially treated water from dairy industry requires harmonic interaction between water treatment technology and self-purification processes. Approach: The present research included two modules. First: an anaerobic treatment process for dairy wastewater in broadly spread sequencing batch bioreactor with fixed biomass was studied. As a source of active biological system specially treated and acclimated activated sludge from Sofia Wastewater Treatment Plant was used. The acclimation and immobilization of initially inoculated biomass, the addition of microbiological preparations and its modification for increase of the biodegradation activity to target pollutants were studied as opportunities for the stimulation of water treatment process in bioreactors and water receiver. Second: self-purification processes in a water receiver for partially treated dairy wastewater were investigated. The functional role and restructuring of the microbial communities in the water, sediment water and sediments were studied. Results: The results showed that the most important approaches for achieving high effectiveness of wastewater treatment process were both the acclimation and immobilization of biomass. In that aspect the data for the water receiver confirmed this conclusion. These two processes increased biodegradation effectiveness of the target pollutant (protein) with 67%. Conclusion: The effect of the added preparations was smaller (protein biodegradation was increased to 9% for the different biological systems). It was thoroughly related to low improvement of the rate of metabolism and functioning of the biological system mainly on an enzyme level.