Anaerobic Treatment
Anaerobic water treatment is a biological process that breaks down organic contaminants found in wastewater using microorganisms in the absence of oxygen.
However, these organisms use oxygen found in the oxides introduced in the system or that which is present in the organic matter found in the wastewater, slurries, and sludge. The anaerobic microorganisms, or “anaerobes,” convert the organic pollutants present in wastewater into biogas. Most of the biogas comprises methane and carbon dioxide. The biogas can be used as an alternative for fuel after it is treated to reduce or eliminate hydrogen sulfide.
Anaerobic treatment occurs in many stages and it’s popular because it stabilizes water in the first stage without too much biomass production. Anaerobic wastewater treatment is used to treat wastewater from various industries, including food production, paper and pulp, and sewage with high concentrations of organic material, often prior to aerobic treatment.
The anaerobic wastewater treatment process consists of two stages:
- Acidification stage: In this initial stage, the anaerobes break down complex organic compounds into acid or short-chain volatile acids.
- Methane production phase: This second stage consists of two steps:
- Acetogenesis: The anaerobes synthesize the acids to form acetate, carbon dioxide, and hydrogen gas.
- Methanogenesis: The anaerobes will act upon the newly created molecules to form carbon dioxide and gas. The byproducts can be used for fuel if needed, while the wastewater is routed for further treatment or discharge.
The anaerobic treatment systems can be designed and configured as single-or-multi-stage units, depending on the application and requirements of the facility. Basically, an anaerobic treatment cycle involves wastewater entering a bioreactor receptacle containing a thick semi-solid substance called sludge, full of anaerobic bacteria and other microorganisms which break down the organic contaminants present in the wastewater.