Method of making an acid-absorbing biosolid composition

Abstract

The method of making an acid-absorbing biosolid composition provides a method for the use of recycled materials to produce an acid-absorbing composition that may then be recycled as a fertilizer after absorbing the acid. The method includes the steps of: collecting sewage sludge; drying the sewage sludge to remove water therefrom to form dried sludge; adding hydrochloric acid to the dried sludge to form a liquid intermediary product; heating the liquid intermediary product to produce a dried porous biomass; and mixing inorganic waste material with the dried porous biomass to produce the acid-absorbing biosolid composition. Thereafter, the acid-absorbing biosolid composition may be placed in a gas flow to absorb an acidic component therefrom; and then recycled for use as fertilizer following absorption of the acidic component from the gas flow.

I claim: 
     
         1 . A method of making an acid-absorbing biosolid composition, comprising the steps of:
 collecting sewage sludge;   drying the sewage sludge to remove water therefrom to form dried sludge;   adding an acid to the dried sludge to form a liquid intermediary product;   heating the liquid intermediary product to produce a dried, porous biomass; and   mixing inorganic waste material with the dried porous biomass to produce an acid-absorbing biosolid composition.   
     
     
         2 . The method of making an acid-absorbing biosolid composition as recited in  claim 1 , further comprising the step of adjusting the sewage sludge to a pH of about 4.0 prior to said drying step. 
     
     
         3 . The method of making an acid-absorbing biosolid composition as recited in  claim 2 , wherein said step of adding the acid to the dried sludge comprises adding hydrochloric acid to the dried sludge to form the liquid intermediary product. 
     
     
         4 . The method of making an acid-absorbing biosolid composition as recited in  claim 3 , wherein the hydrochloric acid is dilute hydrochloric acid. 
     
     
         5 . The method of making an acid-absorbing biosolid composition as recited in  claim 1 , wherein said step of drying the sewage sludge comprises heating the sewage sludge to a temperature between about 600° C. and about 1,000° C. 
     
     
         6 . The method of making an acid-absorbing biosolid composition as recited in  claim 1 , wherein said step of mixing the inorganic waste material with the dried porous biomass comprises adding the inorganic waste material to the dried porous biomass so that the inorganic waste material constitutes about 45 wt % of the acid-absorbing biosolid composition. 
     
     
         7 . The method of making an acid-absorbing biosolid composition as recited in  claim 1 , wherein the inorganic waste material comprises at least one material selected from the group consisting of magnesium waste, calcium waste, iron waste, iodine waste, rocks, and sand. 
     
     
         8 . The method of making an acid-absorbing biosolid composition as recited in  claim 1 , further comprising the step of adding organic waste material to the dried porous biomass. 
     
     
         9 . The method of making an acid absorbing biosolid composition as recited in  claim 8 , wherein said step of adding the organic waste material to the dried porous biomass comprises adding wood powder to the dried porous biomass. 
     
     
         10 . A method using an acid-absorbing biosolid composition prepared according to  claim 1 , comprising the step of placing the acid-absorbing biosolid composition in a gas flow to absorb an acidic component therefrom. 
     
     
         11 . A method of recycling the used acid-absorbing biosolid composition according to  claim 10 , comprising the step of recycling the acid-absorbing biosolid composition as fertilizer following absorption of the acidic component from the gas flow.