Today, Moroccan WWTPs must comply with the IPPC Directive (2008/1 / EC) (Integrated Pollution Prevention and Control) through their international regulations, justifying the use of the best available techniques. The "Bacterial Bed" process set up for wastewater treatment in the city of Khenifra, showed a strong robustness of the purification system, which can ensure a significant elimination of the organic load and wait for very encouraging purification yields. These results have led us to ask the following question: can our process be considered as the best available technique? The comparison of the bacterial bed process has therefore been performed with other methods available in Morocco. To do this and given the lack of evaluation methods, we propose the "Focus L-BAT" method based on a thorough analysis of the 12 IPPC Directive considerations. The method is structured according to a tree structure with 3 levels (BAT performance evaluation objectives, criteria and indicators). The evaluation mode is qualitative and based on a five-level scoring system. Although weaker on criteria such as energy consumption, maintenance, maintenance or ease of implementation, the bacterial bed process has its strong points on criteria such as - control of consumption and recycling, regulatory compliance, prevention of risks related to chemicals. The results show that, for the bacterial bed process, 42% of the criteria are rated as having good or very good performance compared to activated sludge and aerated lagoon processes. The bacterial bed process is therefore more efficient than the activated sludge and aerated lagoon processes in terms of BAT criteria. It can therefore be candidate for BAT of BREF urban wastewater treatment as a performance technique.