Treatment using fixed film processes and ballasted settling

Abstract

A system and method is provided for water and wastewater treatment. The system comprises a fixed film biological process and a ballasted flocculation process.

1 . A system for treating wastewater comprising:
 a fixed film reactor fluidly connected to a source of wastewater and configured to provide a fixed film effluent;   a source of ballast fluidly connected to the fixed film effluent and configured to provide a ballasted effluent; and   a clarifier fluidly connected to the ballasted effluent, the clarifier comprising a treated effluent outlet and a ballasted solids outlet and configured to separate a treated effluent from a ballasted solids.   
     
     
         2 . The system of  claim 1 , further comprising a source of flocculant fluidly connected to the ballasted effluent. 
     
     
         3 . The system of  claim 1 , further comprising a source of coagulant fluidly connected to the fixed film effluent and configured to provide a coagulated effluent. 
     
     
         4 . The system of  claim 1 , wherein the fixed film reactor comprises at least one of a moving bed bioreactor, a trickling filter, and a rotating biological contactor. 
     
     
         5 . The system of  claim 1 , wherein the fixed film effluent comprises about 50 mg/l to about 300 mg/l of biological solids. 
     
     
         6 . The system of  claim 1 , wherein the ballast comprises magnetite. 
     
     
         7 . The system of  claim 1 , wherein the system is configured to treat between about 200 gallons per day per square foot of a surface area of the clarifier to about 6,000 gallons per day per square foot of the surface area of the clarifier. 
     
     
         8 . The system of  claim 3 , wherein the ballasted solids outlet of the clarifier is fluidly connected to at least one of the coagulated effluent and the fixed film reactor. 
     
     
         9 . The system of  claim 8 , further comprising a ballast recovery system positioned downstream of the ballasted solids outlet of the clarifier and upstream of at least one of the source of ballast and the fixed film reactor. 
     
     
         10 .- 20 . (canceled)