Anaerobic vs. Aerobic Treatment: Weighing Wastewater Treatment Options

Biological wastewater treatment uses naturally-occurring microorganisms to feed on complex organic matter, converting them into simpler substances. This type of treatment is divided into two broad categories: anaerobic and aerobic treatment.

A good starting point when selecting an on-site wastewater treatment system is to analyze organic and nutrient concentration, flow rate, and the temperature of the wastewater. Then decide how much your plant is willing to spend on operational costs such as sludge handling and power consumption.

Anaerobic Treatment

Also known as anaerobic digestion (AD), anaerobic treatment is an energy-efficient process in which microorganisms transform organic matter in the wastewater into biogas in the absence of oxygen. To achieve this oxygen-free environment, the entry of air into anaerobic tanks is prevented, typically by a gastight cover.

AD is often used to treat warm industrial wastewater, and the process offers several benefits over aerobic treatment, including lower energy requirements, less chemicals, and less sludge production. The sludge is stable and safe to use as a soil enhancer. Methane-rich biogas is also produced through the anaerobic process, which can be treated and used as a renewable energy source, helping save money and the environment.

Aerobic Treatment

With aerobic treatment, microorganisms convert organics into carbon dioxide and new biomass in the presence of oxygen. Aerobic microorganisms require oxygen so air must be continuously circulated through the tanks. Forced air from an air blower or compressor is mixed with the wastewater, where the aerobic bacteria feed on the waste in the water.

Aerobic systems can act as stand-alone systems, or polish anaerobically pretreated wastewater by further removing biochemical oxygen demand (BOD) and suspended solids (TSS). Aerobic treatment can also be used specifically to remove nitrogen and phosphorus, which is also known as a biological nutrient removal (BNR) system. Although aerobic systems require higher amounts of energy for aeration and produce more sludge than anaerobic systems, they play a necessary role in the wastewater treatment train. These systems allow industrial processors to meet even the strictest environmental requirements so that wastewater can be discharged safely.

Contact our wastewater treatment experts to determine the best option for your wastewater treatment needs.