In one embodiment, a method includes receiving wastewater having a first total organic carbon (TOC) at a wastewater treatment system comprising a reactor system, wherein the reactor system comprises an anaerobic moving bed biofilm reactor (MBBR) and an aerobic MBBR. The method further includes treating the wastewater in the anaerobic MBBR, wherein the anaerobic MBBR comprises first bio-carriers configured to degrade at least a portion of the first TOC in the wastewater to generate a first treated wastewater and biogas, wherein the first treated wastewater has a second TOC that is less than the first TOC. The method also includes providing the biogas to an external system.