Is Wastewater Biodegradable?

  • By: greenorb
  • Date: April 23, 2022
  • Time to read: 4 min.

About 200 years ago, the destruction of watercourses due to organic waste pollution wasn’t a big deal. Why? People lived in small scattered communities. 

The natural self-purification abilities of water bodies also made it easier to cope with the wastes they received.

But since the start of industrialization, water pollution (wastewater) has been a severe problem. 

Over the years, industrialization stimulated urbanization, contributing further to the problem.

The quest to look for better ways of managing wastewater has left many people wondering; is wastewater biodegradable? Yes, but it depends on what components the wastewater has or where it comes from.

Here, we’ll provide everything you need to know about the biodegradability of wastewater.

What is a Wastewater?

Wastewater is a term used to describe water that humans have used. 

This includes all water that comes from homes, businesses, and industries. 

The water may contain bacteria, viruses, chemicals, or metals.

The term wastewater is often used interchangeably with the term sewage. 

However, sewage is a more specific term that refers to water contaminated by human waste.

Types of Wastewater

Wastewater can be categorized into three different types:

1. Blackwater

Blackwater is wastewater that contains human waste. This type of wastewater is often found in septic tanks and toilets. It’s what we commonly call sewage.

2. Greywater

Greywater is wastewater that contains soap, shampoo, and other cleaning products. This type of wastewater comes from bathtubs, showers, and sinks.

3. Industrial Wastewater

Industrial wastewater is the wastewater that comes from factories, plants, and other industrial sites. This type of wastewater is also known as industrial effluent.

It is typically very dirty and has a high level of contaminants. Industrial wastewater can be hazardous to the environment and human health.

4. Domestic Wastewater

Domestic wastewater is also wastewater generated by households or municipalities. 

The water comes primarily from homes, including sinks, showers, toilets, and washing machines.

Is Wastewater Biodegradable?

Biodegradable is a term used to describe a material that can get broken down by microorganisms. 

Such products will break down into smaller and smaller pieces until they become carbon dioxide, water, humus, and biomass.

Wastewater is biodegradable, but this may depend on its origin and chemical composition. 

Most household wastewaters are biodegradable as they have organic materials that microorganisms can act upon.

However, wastewater from industries and agricultural farms has high chemical quantities. 

As such, they kill microbes before they get a chance to break down the available organic matter. That makes such wastewater non-biodegradable.

Scientists have developed the enzyme phenol hydroxylase to overcome this problem of breaking down toxic chemicals in wastewater. 

The enzyme comes from genetically modified bacteria.

Enzyme phenol hydroxylase breaks down phenol, a toxic chemical in wastewater from industries and agricultural farms. 

Phenol acts as a disinfectant for the production of plastics and synthetic fibers.

For the microbes to break down the organic matter, oxygen must be present. 

Most water treatment plants use aerobic bacteria to break down the organic matter in wastewater to produce carbon dioxide, humus, water, etc.

Carbon dioxide escapes into the air, and the water returns to the environment.

Biodegradation of wastewater is a crucial treatment process that creates a safe environment for aquatic life.

What Makes Wastewater Biodegradable?

For wastewater to biodegrade, it must have the following properties:

Low concentrations of organic matter, usually less than 100 mg/L. The lower the concentration, the faster the biodegradation will be.

That’s because there is a limit to how much oxygen can dissolve in water. 

Higher amounts of organic matter reduce oxygen concentration, slowing the biodegradation rate of wastewater.

Temperatures must be warmer (at least 15°C). The biodegradation rate is slower at lower temperatures. 

That’s because, at lower temperatures, there is less microbial activity.

The wastewater must have a pH of between 6 and 9. The lower the pH, the faster the biodegradation will be. 

That’s because there is a limit to how much oxygen can dissolve in water.

Water hardness of between 1 and 5 dH. Hard water contains calcium and magnesium ions, interfering with the degradation process.

How Long Does Wastewater Take to Biodegrade?

Biodegradation is a complex process that depends on many factors, including the composition of the wastewater and the type of microorganisms present. 

In general, biodegradation rates vary from several days to months.

  • Wastewater with organic compounds may decompose in 3-6 days.
  • Wastewater with high ammonia concentrations may take 2 or more months to decompose.
  • Wastewater with high concentrations of nitrates and inorganic matter may take years to decompose.

How Do You Dispose of Wastewater?

We recommend using a professional septic tank pumping service when disposing of wastewater. 

They will pump out your septic tank and dispose of the wastewater properly.

Wastewater Treatment Processes

There are several wastewater treatment processes. They include:

Biological Treatment Processes

In nature, microorganisms such as fungi and bacteria in water digest organic matter present in the wastewater or sewage. 

By doing that, they turn it into carbon dioxide, new bacterial cells, and other waste products. This process is called biological treatment.

The same process treats sewage and industrial wastewater in a wastewater treatment plant.

These microorganisms must get enough oxygen to biodegrade the wastewater effectively.

Physical Treatment Processes

The physical treatment processes help remove solid particles from the wastewater. 

Screens, grit chambers, and sedimentation tanks help separate solid matter (sludge) from wastewater.

Chemical Processes

Chemical processes remove dissolved and suspended materials from the wastewater. The process occurs through:

  • Oxidation
  • Precipitation
  • Coagulation
  • Filtration
  • Disinfection

The process aims to reduce the pollutant concentration to a safe level for the receiving water 



So is wastewater biodegradable? Yes, but it depends on the source of the wastewater (i.e., human, animal, etc.) and the chemical composition. 

Wastewater that contains organic matter is biodegradable.

That’s because they allow for action by microorganisms present in water bodies. 

But wastewater with toxic chemicals or materials is not biodegradable as the toxic levels kill microbes that would otherwise break the organic matter in the water.