Anaerobic Treatment of Wastewater for Production of Biogas
Biological treatment is one of the prominent methods for treating wastewater. In sewage treatment plants-STP’s, biological treatment is the secondary stage of treatment along with primary and tertiary treatment. With the growing population across the world, there has been a major focus on better biological treatment of wastewater.
Anaerobic wastewater treatment is one of the popular methods used in the biological treatment of wastewater. It consists of anaerobic bacteria that are used to treat the biodegradable organic matter, break down the sludge, reduce the undesired nutrients like phosphorus and nitrogen. The other features include the removal of organic volatile compounds VOC’s and handling of high organic load.
Other than treating the wastewater efficiently, the benefits of using anaerobic bacteria and the anaerobic wastewater treatment are the production of biomass, carbon dioxide, and methane gas as the by-products. This methane gas known as biogas is one of the best alternative sources of energy. The biogas production is of immense significance as it can be used to run the anaerobic wastewater treatment process itself which consumes much energy.
For a sustainable future and to meet all the energy needs of the world it is imperative that biogas like energy can be generated from the waste treatment process. The biogas can be used for the production of heat and electricity. Let us look at the other facets of the anaerobic treatment in detail.
Principles of Anaerobic Wastewater Treatment
The anaerobic treatment of waste consists of primarily four stages where different microorganisms act in an oxygen-free environment and produce methane-CH4. A digester tank is a place where all the process takes place. The main goal is to produce biogas, clean-up water before its discharge and sometimes nutrients or organic fertilizers are also produced.
The four phases include: –
Hydrolysis – In this phase, complex organic molecules are degraded into smaller particles constituting sugars, amino acids, and fatty acids. In other words, non-soluble biopolymers get converted into soluble organic compounds.
Acidogenesis – The acidogenic bacteria release enzymes in the acidogenesis (fermentation)phase and converts soluble organic compounds into volatile fatty acids and carbon dioxide.
Acetogenesis – The acetogenic bacteria further degrade the particles into acetic acid and H2.
Methanogenesis – Methanogenic bacteria use intermediate products from previous stages and convert them into methane, carbon dioxide, and water.
There are certain environmental factors and conditions which have to be maintained for the process to be completely successful in creating methane gas. The major factors that affect the anaerobic process are temperature, alkalinity, pH, and toxicity. Depending upon the processing capacity of microbes, the loading rate of anaerobic reactors needs large bacterial mass and long retention time.
Advantages of anaerobic wastewater treatment
The advantages of anaerobic wastewater treatment are as follows: –
– The process itself consumes very little energy, because of no aeration equipment
– Sludge production on a COD basis is low when compared to an aerobic process
-It helps significantly in sludge de-watering, waste stabilization and generally provides end product without odour.
– The construction cost of an anaerobic system is low
– The space requirement is low compared to other systems
Although anaerobic treatment is a proven method to develop biogas, there are several challenges in the field. Lack of robust sewage treatment facilities and efficient microbial solutions that boost the productivity of biological treatment is the major hindrance. Organica Biotech’s Cleanmaxx ANB is one of the many products developed by the company aiming to provide a sustainable future to the upcoming generations. It consists of a diverse range of bacteria which improves the anaerobic treatment of the wastewater process and helps in the production of biogas.
Also read: Biogas – A Renewable Energy Resource