Anaerobic treatment relies on specialized microorganisms that decompose organic matter in the absence of oxygen. While the process is more complex than aerobic treatment and requires careful monitoring, it is highly effective at removing biodegradable organics from wastewater streams with high organic loads.
By converting most of the organic material into methane and carbon dioxide, anaerobic systems produce very little excess sludge while generating valuable renewable energy in the form of biogas. This makes anaerobic treatment a preferred solution for industries such as food and beverage, biofuels, pulp and paper, and chemical production, offering an efficient and sustainable approach to treating highly-loaded wastewater.
Below you can find an overview of our different anaerobic wastewater treatment technologies.
High-rate anaerobic treatment uses reactors that retain granular sludge separately from the water, so wastewater flows through quickly while the bacteria stay inside. This allows high organic loads in a compact footprint. It is the right choice for soluble, high-strength wastewater, such as food and beverage effluent, with low suspended solids and FOG (fats, oils and grease) content.
An anaerobic MBR adds membrane separation to anaerobic treatment, retaining biomass completely and producing a particle-free effluent. It suits effluents that will not granulate (typically high-fat, high-solids or variable streams) and sites where the effluent is intended for reuse. Capex and membrane cleaning costs are higher than for a granular reactor.
Mesophilic reactors run best at 30–38°C. Below 30°C conversion rates fall sharply and reactor volume must grow, so heating with recovered biogas is usually cheaper than oversizing. Many food and beverage effluents arrive warm enough that no external heating is needed.
An EGSB (Expanded Granular Sludge Bed) is a more intensive evolution of the UASB. Its high upflow velocity expands the granular bed, improving contact between bacteria and wastewater. EGSB handles 15–30 kg COD/m³/day in a compact, tall reactor, ideal for soluble effluents such as brewery wastewater. UASB handles 5–10 kg COD/m³/day but tolerates solids and fats better.
GWE’s ANUBIX™-T EGSB reactor turns high-strength wastewater into energy rather than cost. Its granular sludge achieves low effluent COD/BOD, so only a small aerobic polishing stage is needed, and it produces far less excess sludge than aerobic treatment. With no moving parts inside, maintenance and downtime are minimal, while the biogas produced can replace natural gas.
