Commercial high-strength sewage may have high organics and nitrogen, variable diurnal and seasonal flows, use of disinfectants and grease-strippers, and fast-food type employees. A ‘preengineered’ treatment process developed to counter these challenges results in a more consistent effluent quality. Consistency is important for nitrogen removal, for difficult disposal sites, and for irrigation or toilet re-use. The standard process includes an exterior grease trap, septic tanks with effluent filters, surge flow storage in the pump tank, timed dosing to Waterloo Biofilter trickle filters, and 50-67% recirculation to the septic tank inlet. For on-site subsurface disposal, a shallow, thin Area Bed made of medium-fine sand is preferred for optimum fecal removal. For irrigation re-use, UV disinfection is added for irrigation re-use, and multi-media filtration plus ozone + chlorine are added for toilet re-use. The additional key component is a separate, closed-loop BIOFILTER with 100% return to the surge-pump tank. This independent BIOFILTER is hydraulically loaded at very high rates to remove organics and nitrogen, and to oxygenate the pump tank. Median effluent values in the first few months at five commercial sites are <10 mg/L cBOD and TSS, even though influent sewage is variable and high-strength.