Abstract: A wastewater treatment unit (10) includes a recirculation chamber (32), a dosing chamber (34) having no direct fluid connection to the recirculation chamber, and at least two filter layers (28,30) in a single tank (12). Each filter layer contains filter media (56) and is located atop the recirculation and dosing chambers. The wastewater treatment unit also includes an influent pipe (50) connected to the recirculation chamber, a recirculation pump (72), a recirculation valve (74), and an effluent discharge pipe (88) connected to the dosing chamber. In operation, the influent pipe directs wastewater entering the unit into the recirculation chamber. The recirculation pump feeds wastewater from the recirculation chamber onto the filter layers. The recirculation valve then directs the filtrate back to the recirculation and dosing chambers. The filtrate is then discharged from the unit via the effluent discharge pipe.