The invention describes a new method for treating
sludge, which can result in the production of
high nitrogen organically-augmented
inorganic fertilizer that incorporates municipal sludges or
biosolids or organic sludges that can compete with traditional fertilizers such as
ammonium phosphate,
ammonium sulfate and
urea on the commodity
fertilizer marketplace. The method takes
advantage of the thixotropic property of dewatered
biosolids or organic
sludge to create a pumpable paste-like material from the
biosolids or organic
sludge that is then treated with an oxidizer to reduce odorant effects and an acid. This mix is then interacted with concentrated sulfuric and or phosphoric acids and an
ammonia source or alternatively a hot or molten melt or salt of
ammonium sulfate /
phosphate to form a
fertilizer mix. The present invention controls the heat,
atmospheric pressure and
retention time of the
fertilizer mix in the reaction vessel. When a fertilizer melt is formed ammoniation is subsequently completed by the specific use of vaporized
ammonia. The invention can also be an add-on to commercial production of ammonium salts. The fertilizer produced by the present invention contains more than 8 wt. %
nitrogen and preferably 15 wt. %
nitrogen. The invention is oriented to be tailored to the biosolids production for individual municipal
waste treatment plants in order to keep the fertilizer manufacturing plants of the present invention small with a minimization of logistics and liability.