**9. Conclusion**

From the above analysis, it is evident that BES excels at removing certain types of refractory xenobiotic compounds more efficiently than other conventional treatment technologies. Certain types of xenobiotic pollutants such as azo dyes that resist biotransformation and subsequent degradation in conventional treatment systems can be dealt with relatively easily using BES systems such as MFCs and MEC systems or with hybrid systems combining BES with conventional treatment systems such as activated sludge systems and UASB reactors. The current level of scientific knowledge on the utility of this technology in biodegradation processes is insufficient but it is currently evolving into a better level of understanding where it could potentially be applied in pilot or industrial scales in order to deal with these refractory organic waste types in a more meaningful manner.
