Decentralized Wastewater Treatment (DEWATS): Hydraulic Kinetics, Passive Bioreactor Mechanics, and Nature-Based Solutions
Decentralized Wastewater Treatment Systems (DEWATS) provide non-sewered, localized sanitation solutions designed to treat domestic and commercial wastewater at or near the point of generation. Operating predominantly via gravity-driven hydraulics and low-maintenance biological mechanisms, DEWATS eliminates the excessive capital expenditure and energy overhead associated with centralized sewer conveyance networks and continuous mechanical aeration. A standard DEWATS configuration integrates primary sedimentation in Biogas Settlers or Septic Tanks, secondary anaerobic treatment in Anaerobic Baffled Reactors (ABR) and Anaerobic Filters (AF) , followed by tertiary polishing in Constructed Wetlands (CW) . In an ABR, wastewater flows alternatingly under and over vertical baffle walls. The hydraulic retention time ($t_h$) required for organic degradation is evaluated as: $$t_h = \frac{V_{\text{ABR}}}{Q} = \frac{N \cdot (W \cdot L_c \cdot H)}{Q}$$ Where $V_{\text{ABR}}$ is the total ac...