Two-sided horizontal flow bioretention stormwater system

1. A dual-chamber wetland biofilter comprising:

a first chamber with a filtration screen system including a filter screen which receives an influent;

a second chamber with a media filtration bed, wherein the second chamber is in communication with the first chamber via two openings on each side of an end of the second chamber to receive a filtered influent from the first chamber and further filter the influent to produce an effluent, and

wherein the first chamber and second chamber are arranged laterally with respect to each other;

wherein the first chamber has top with an access hatch and the second chamber is open to the atmosphere and contains live vegetation,

wherein the water must pass through the filtration screen in the first chamber to enter second chamber, said second chamber having two void areas vertically on two side walls of the second chamber, said second chamber having a pervious wall opposite each of the side walls and spaced apart from the side walls to create the two void areas, each said pervious wall containing media on the side opposite the void area,

wherein water from the void area passes through the pervious wall into the filter media and flows horizontally to the middle of the chamber which contains a rock material and perforated underdrain on the floor to direct water to an outside of the second said underdrain containing at least one orifice to limit the flow rate out of the chamber.

2. The dual-chamber wetland biofilter of claim 1 , wherein the media filtration bed contains vegetation.

3. A method of filtering influent in a dual-chamber wetland biofilter, comprising:

providing the dual-chamber wetland biofilter of claim 1 ,

receiving an influent into the first chamber with the filtration screen system; filtering the influent through the filtration screen system;

discharging the filtered influent to the second chamber with filtration system the media filtration bed which is arranged laterally with the first chamber;

filtering the filtered influent through the media filtration bed to produce an effluent;

collecting the effluent and discharging the effluent from the dual-chambered wetland biofilter to the outside.

4. A biofilter chamber comprising:

two outer side walls defining a chamber;

a first media filtration bed disposed within the chamber wherein the media filtration bed extends from a floor of the first chamber and is enclosed by two permeable inner side walls, each of the permeable inner side walls being separated from the outer side walls by a respective void area for receiving an influent;

an outlet opening coupled to an outside of the chamber, the outlet opening connected to a perforated horizontal tube configured to receive the filtered influent from the first media filtration bed;

said horizontal tube containing an orifice plate to control the flow rate out of the chamber.

5. The biofilter chamber of claim 4 , wherein the first media filtration bed contains live plant material.

6. The biofilter chamber of claim 4 , further comprising a removable permeable cover disposed over the void area.

7. The biofilter chamber of claim 4 , further comprising a removable impermeable cover disposed over the void area.

8. The biofilter chamber of claim 4 , wherein the first media filtration bed contains one or more granular filtration media composed of organic, inert, or sorptive substances that provide physical, chemical and biological filtration of contaminated fluid.

9. The biofilter chamber of claim 4 , wherein the one or more outer side walls comprise an transfer opening into the void area.