Side stream treatment for overflow

1. A system for treating wastewater, comprising:

a first biological reactor fluidly connected to a source of wastewater and having a treated wastewater outlet, further comprising a first clarifier fluidly connected to the treated wastewater outlet and configured to provide a first treated effluent;

a second biological reactor being a fixed film biological reactor connected to the source of wastewater and having a fixed film effluent outlet;

a ballasted system fluidly connected to the fixed film effluent outlet, the ballasted system comprising:

a ballast reactor tank configured to provide a ballasted effluent; and

a source of ballast material fluidly connected to an inlet of the ballast reactor tank; and

a bypass line having an inlet fluidly connected to the source of wastewater, a first outlet fluidly connected to the ballasted system, and a second outlet fluidly connected to the fixed film biological reactor, the bypass line configured to bypass the fixed film biological reactor.

2. The system of claim 1 , wherein the ballast material is magnetic.

3. The system of claim 2 , wherein the ballast material is magnetite.

4. The system of claim 1 , further comprising a source of flocculant fluidly connected to an inlet of the ballast reactor tank.

5. The system of claim 1 , further comprising a source of coagulant fluidly connected to an inlet of the ballast reactor tank.

6. The system of claim 1 , wherein the second treated effluent comprises about 100 mg/l to about 500 mg/l of biological solids.

7. The system of claim 1 , further comprising a second clarifier fluidly connected to an outlet of the ballast reactor tank, the second clarifier comprising a second treated effluent outlet and a ballasted solids outlet and configured to separate the ballasted effluent into a second treated effluent from a ballasted solids portion.

8. The system of claim 1 , wherein the fixed film biological reactor comprises a carrier onto which biomass is fixed.