摘要 |
A system comprising a first anaerobic digester (12), an ammonia recovery vessel (16) and a second anaerobic digester (14). Microorganisms in the first digester are primarily hydrolyzers and acetogens, while those in the second digester are primarily methanogens. A nitrogen containing feed stock undegoes hydrolysis ans acetogenesis in the first digester. The effluent is passed to the ammonia recovery vessel in which ammonia is removed. The low ammonia effluent stream is passed to the second digester to undergo methanogenesis, generating a biogas. In an alternate embodiment, a single anaerobic digester is used. The effluent is treated for ammonia removal and recycled to the digester to keep the ammonia levels sufficiently low to avoid ammonia inhibition.
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