What’s BOD?

BOD, also known as Biological Oxygen Demand, refers to the amount of oxygen consumed by microorganisms in a body of water as they decompose organic matter. This organic matter may come from domestic sewage, industrial wastewater, animal and plant residues, etc. Microorganisms need to consume oxygen when decomposing these organic materials, and if there is insufficient oxygen in the water body, it will lead to deterioration of water quality, and even fish deaths and other phenomena.

BOD In Wastewater

A high BOD value in wastewater usually indicates that the water contains a large amount of organic matter that needs to be broken down by microbial metabolism.

Measuring the degree of pollution: An important indicator of the degree of organic pollutants in wastewater.The higher the BOD value, the more organic matter in the wastewater, the more serious the degree of pollution. Conversely, a low BOD value indicates that the wastewater is cleaner and contains fewer organic pollutants.
Impact on aquatic ecology: Wastewater with a high BOD value discharged into a water body will consume a large amount of dissolved oxygen, resulting in a lack of oxygen in the water body, thus jeopardizing the survival of aquatic organisms. Water bodies with high BOD are prone to “hypoxia”, which may lead to the death of aquatic animals and disrupt the ecological balance.

What Causes High BOD Values in Wastewater?

Organic wastes: Organic matter such as food scraps, oils and fats, proteins, etc. in domestic sewage, industrial and agricultural wastewater.
Agricultural runoff: fertilizers, pesticides and animal wastes enter the water body and increase the organic matter content.
Eutrophication: Excessive nitrogen and phosphorus lead to overgrowth of algae, which die and decompose consuming oxygen.
Inadequate wastewater treatment: Incomplete wastewater treatment and residual organic matter increases BOD.
Solid waste discharge: Garbage and solid waste enter the water body and increase oxygen demand as they decompose.

Factors Affecting BOD

Type and concentration of organic matter: Different organic matter is broken down by microorganisms at different rates and with different amounts of oxygen.
Temperature: As the temperature rises, microbial activity increases and the BOD value usually rises.
pH: A high or low pH will inhibit microbial activity and affect the BOD value.
Number and type of microorganisms: The number and type of microorganisms directly affects the rate of decomposition of organic matter.

Testing for BOD in wastewater

BOD in wastewater can be measured by their COD sensor and BOD sensor. Specifically, Apure multi-parameter analyzers are able to monitor BOD as a key parameter and analyze it in real time along with other important water quality parameters such as pH/ORP, electrical conductivity, dissolved oxygen, and more.

How to Reduce BOD in Wastewater?

Optimization of Wastewater Treatment Process

Aerobic treatment: Aeration of wastewater through facilities such as aeration tanks to promote oxidative degradation of organic matter. The use of appropriate amount of oxygen can help microorganisms decompose organic matter and reduce BOD.
Anaerobic treatment: Wastewater treatment through anaerobic digestion tanks can effectively reduce organic matter, and the methane produced can be recycled as energy.

Enhance Wastewater Pretreatment

Chemical precipitation method: Adding chemicals to precipitate pollutants in the water, especially organic pollutants, to reduce their contribution to BOD.

Physicochemical Treatment Method

Ozone oxidation: Ozone can decompose organic matter in water and reduce BOD.
Activated carbon adsorption: Remove degradable pollutants by adsorbing organic matter in wastewater through activated carbon, thus reducing BOD

Monitoring and Control

Real-time monitoring: Real-time monitoring of BOD value in wastewater through online monitoring equipment, timely adjustment of the treatment process to ensure that wastewater BOD is reduced to the appropriate level.
Optimization of pharmaceutical dosing: Help remove organic pollutants in wastewater by dosing reasonable flocculants or chemical oxidants, etc.

Summary

Through in-depth analysis of the causes of high BOD in wastewater, we can take a series of measures to reduce the BOD value of wastewater and improve the quality of the water environment.

APURE, as a leading company in the water quality testing industry, is known for the high accuracy and stability of its products. The company always adheres to technological innovation and provides customers with comprehensive technical support and after-sales service, welcome to contact us for customized solutions!

FAQ

BOD: Reflects the amount of biodegradable organic matter.
COD: Reflects the oxygen consumption of all reducing substances in water, including biodegradable and non-biodegradable organic matter.

Regulatory agencies set standards for the quality of treated wastewater (discharged water), and these standards usually require a certain level of treatment for organics and pollutants in the wastewater. Biomass, particularly microorganisms, play an important role in meeting these standards. For example, the U.S. Environmental Protection Agency (EPA) has the Clean Water Act (CWA), which establishes pollutant limits for wastewater discharges from wastewater treatment plants. In the European Union, the Municipal Wastewater Treatment Directive establishes minimum treatment requirements for wastewater and sets standards for treated effluent.

Protecting water sources: Reducing bacterial contamination, ensuring the safety of water sources, and preventing the deterioration of water quality.
Protect aquatic ecology: Prevent bacteria from over-consuming oxygen in the water and maintain the living environment of aquatic organisms.
Reduce disease transmission: Reduce the risk of waterborne germs and protect public health.
Improve Treatment Effectiveness: Reducing bacterial content can improve wastewater treatment effectiveness and compliance with discharge standards.
Safe reuse: Makes wastewater safer for irrigation or industrial reuse.

What Causes High Bod in Wastewater?