Advanced treatment of landfill leachate using anaerobic-aerobic process: organic removal by simultaneous denitritation and methanogenesis and nitrogen removal via nitrite.

A novel biological system coupling an UASB and a SBR was established to treat landfill leachate. In order to enhance organics and nitrogen removal, simultaneous denitritation and methanogenesis (SDM) was performed in the UASB. Free ammonia (FA) inhibition on nitrite-oxidizing bacteria (NOB) and process control was used to achieve nitrite pathway in the SBR.