Diploma work is based on technological, economic and legislative assesment of the problem of using bekary returns to propose alternative solution in relation to the processing technology of anaerobic fermentation. The participation of bakery returnts were laboratory simulated in automatic anaerobic fermenters called Stix. Teoretical part is focused on valid legislation. The economical assessment was evaluated by the index of the net present value. The highest production of methan was evaluated in propotion 100:0 of bakey returns and dung. Although the ideal proportion is 50:50 from economic assessment.