High-Rate Anaerobic Tower

An anaerobic tower is a tall, up-flow reactor (8–25 m height) that converts dissolved organics into biogas (60–70 % CH₄) while removing 70–90 % COD at 5–30 kg COD m⁻³ d⁻¹ loading. Wastewater enters the bottom cone and passes through a granular sludge bed; internal 3-phase separators retain biomass and collect gas, eliminating the need for a downstream settler. Recirculation loops dilute toxic compounds and maintain up-flow velocity 0.5–2 m h⁻¹. Tower configuration reduces footprint 50 % versus conventional lagoons and recovers 0.35 m³ CH₄ kg⁻¹ COD, generating renewable energy. Typical applications include brewery, distillery, pulp & paper, dairy and pharmaceutical effluents with COD 2 000–30 000 mg L⁻¹. Constructed from epoxy-coated steel or reinforced concrete, the tower operates 30–40 °C (mesophilic) or 50–55 °C (thermophilic) and can be paired with a heat exchanger to utilize biogas. No aeration is required, cutting power demand 80 % and sludge yield 70 % compared with aerobic systems. By combining small footprint, low energy and green energy recovery, the anaerobic tower offers industries a sustainable, cost-effective route to high-strength wastewater pretreatment.