Anaerobic digestion wastewater treatment systems - BIOTIM®
Recovering biogas and digestate from every drop
What is anaerobic wastewater treatment?
Anaerobic digestion of wastewater is a biological wastewater treatment process used to treat sewage and industrial wastewater without the presence of oxygen. It's a biological treatment method where microorganisms break down organic matter in the wastewater under anaerobic (oxygen-free) conditions.
This process not only treats the wastewater but also produces biogas, a mixture of methane (CH4) and carbon dioxide (CO2), which can be used as a renewable energy source. This aspect makes anaerobic treatment an attractive option for industries looking to manage waste and generate energy simultaneously.
The process of anaerobic wastewater digestion, how does it work?
The complete anaerobic wastewater treatment process consists of 3 stages: pre-treatment, anaerobic digestion and post-treatment.
- Pre-treatment: Wastewater may undergo pre-treatment to remove inorganic solids, fats, oils, and greases that could hinder the anaerobic process.
- Anaerobic Digestion: The pre-treated wastewater is then moved to an anaerobic digester, a closed tank where the anaerobic microorganisms are housed. Here, the organic pollutants are metabolized by the microorganisms in the absence of oxygen, transforming them into biogas, water, and other byproducts.
- Post-treatment: The effluent from the anaerobic digestion process might still contain some pollutants and pathogens. Depending on the discharge standards or the intended use of the treated water, it may undergo further treatment processes such as aerobic treatment, filtration, or disinfection.
Pre-treatment
Wastewater undergoes pre-treatment to remove inorganic solids, fats, oils, and greases that could hinder the anaerobic process. This involves screening and grit removal to eliminate large debris and particles, followed by primary sedimentation to settle heavier solids. These steps ensure smoother operation and increased efficiency in the subsequent anaerobic digestion process.
Anaerobic Digestion
In the anaerobic digester, microbial processes proceed in 4 stages. The 4 stages consist of hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Initially, during hydrolysis, complex organic compounds break down into simpler forms. These compounds then undergo acidogenesis, converting into volatile fatty acids, alcohols, hydrogen, and carbon dioxide.
Acetogenesis follows, further metabolizing volatile fatty acids and alcohols into acetic acid, hydrogen, and carbon dioxide. Finally, methanogenesis occurs, where methanogenic archaea transform acetic acid, hydrogen, and carbon dioxide into methane, the primary component of biogas, with carbon dioxide as a byproduct. This series of reactions efficiently converts organic pollutants into valuable energy resources and byproducts.
Post-treatment
After the anaerobic digestion process, the effluent may still contain pollutants and pathogens. To meet discharge standards or for intended reuse, further treatment is often required, such as biogas treatment. This may include aerobic treatment, filtration, or disinfection processes. These additional steps ensure that the treated water meets environmental regulations and is safe for discharge or reuse, completing the wastewater treatment cycle.
Limiting grid dependency
We are experts in recovering energy from the organic compounds in wastewater and sludge. We help recovering biogas from municipal sludge in nearly every recently built sewage treatment infrastructure.
In the food and beverage industry, we are a privileged partner for cutting down the energy bill and carbon footprint.
In the potato processing industry for instance, up to 60% of a potato processing plant's electricity needs is recovered from anaerobic digestion of wastewater and potato waste.
Anaerobic digestion systems and reactors
There are several types of anaerobic wastewater treatment systems, each designed to suit different types of wastewater, organic load levels, and operational requirements. These systems are utilized for the treatment of industrial and municipal wastewaters, particularly where the wastewater is high in organic content.
Our BIOTIM® anaerobic reactor portfolio includes solutions for treating wastewaters with different ranges of organic load or dry matter content. Where space is scarce, our high-rate anaerobic tower combines high removal of organic load and high biogas yields with a limited infrastructure footprint.
BIOTIM reactor range and corresponding organic load
- BIOTIM® UASB 2-20 kg COD/m³
- BIOTIM® UAC 20-80 kg COD/m³
- BIOTIM® CSTR 50-70 kg COD/m³
- BIOTIM® Wet AD 100-600 kg COD/m³
- BIOTIM® Anaerobic Tower For high biogas yield in small footprint
- BIOTIM® Anaerobic MBR when high quality effluent needed
The importance of anaerobic digestion
Anaerobic digestion is vital for companies and the environment because it transforms organic waste into valuable biogas and nutrient-rich digestate. This process not only reduces waste disposal costs and greenhouse gas emissions but also generates renewable energy and promotes a circular economy. By adopting anaerobic digestion, companies can enhance their sustainability, meet regulatory requirements, and contribute to environmental protection.
In the potato processing industry, up to 60% of a potato processing plant's electricity needs is recovered from anaerobic digestion of wastewater and potato waste.
Aerobic and anaerobic treatment of wastewater
To remove the residual organic load after anaerobic treatment, a LUCAS® aerobic post-treatment is required allowing compliance with discharge regulation.
When a high-quality effluent is needed, our AQUALITY® membrane technology will enable preparing the treated wastewater for reuse, limiting tap water dependency, increasing overall water efficiency.
Biogas desulphurization
Untreated biogas contains high levels of sulfides. Biogas desulphurization increases life duration of combustion engines while reducing running costs.
Our proprietary BIOTIM® scrubber technology uses activated sludge from biological wastewater treatment as a washing medium, omitting chemicals and avoiding costs for both water and chemicals.
Do you need to cut down on energy costs?
Frequently asked questions
What types of anaerobic wastewater treatments exist?
There are several types of anaerobic wastewater treatment systems, each designed to suit different types of wastewater, organic load levels, and operational requirements. These systems are utilized for the treatment of industrial and municipal wastewaters, particularly where the wastewater is high in organic content. The most important one is the following:
1. Upflow Anaerobic Sludge Blanket (UASB)
The UASB reactor is one of the most popular anaerobic treatment systems. It allows wastewater to flow upward through a sludge blanket composed of anaerobic microorganisms. As the wastewater passes through the sludge blanket, the organic matter is degraded, and biogas is produced. UASB reactors are efficient in treating various types of industrial wastewater and are known for their simplicity and effectiveness.
What are the benefits of anaerobic wastewater treatment?
Anaerobic wastewater treatment has the following benefits:
- Process Description: Anaerobic treatment involves the breakdown of organic matter in the absence of oxygen by anaerobic bacteria. It typically takes place in a closed reactor known as an anaerobic digester.
- Biogas Production: One of the major benefits of anaerobic digestion is the production of biogas, which is a mixture of methane and carbon dioxide. This biogas can be captured and used as a fuel source, providing an energy recovery aspect to the wastewater treatment.
- High Organic Load Efficiency: Anaerobic processes are highly effective at treating wastewater with high organic loads, such as those found in dairy effluents, making them economically favourable.
- Lower Sludge Production: Compared to aerobic processes, anaerobic treatment produces less biological sludge, reducing the burden and cost associated with sludge handling and disposal.
- Operational Considerations: Requires careful control of pH, temperature, and toxicity to maintain microbial health and activity. The process is slower than aerobic treatment and may require pre-treatment to remove inhibitors.
In which fields can Anaerobic Wastewater Treatment be applied?
Anaerobic wastewater treatment can be applied across a wide range of sectors, particularly in industries that produce high-strength wastewater rich in organic materials. This treatment method is highly effective for reducing organic pollutants, minimizing sludge production, and generating biogas as a renewable energy source. Here are some key applications:
- Food and Beverage Industry: Anaerobic treatment is widely used in food processing, dairy, and beverage production, where wastewater often contains high levels of organic compounds.
- Breweries and Distilleries: These facilities produce wastewater with high concentrations of sugars and alcohol, which are well-suited for anaerobic digestion processes.
- Agriculture and Livestock: Anaerobic digesters can treat manure and other agricultural wastes, reducing odors and producing biogas.
- Pulp and Paper Industry: Wastewater from the pulp and paper manufacturing process, rich in cellulose and lignin, can be treated anaerobically to reduce its organic load.
- Textile Industry: Anaerobic treatment can handle the high-strength wastewater generated by textile manufacturing processes, including dyeing and finishing.
- Chemical and Pharmaceutical Industries: These industries produce wastewater with complex organic compounds, making anaerobic treatment a suitable option for reducing pollution loads.
- Municipal Sewage Treatment: Anaerobic digesters are used in municipal wastewater treatment plants to stabilize sewage sludge and produce biogas.
- Landfill Leachate Treatment: Anaerobic systems can treat the leachate from landfills, which is typically high in organic content.
- Petrochemical and Oil Industries: Wastewater from these industries can also be treated anaerobically, especially when it contains organic contaminants.
Can Anaerobic Wastewater Treatment Systems Generate Renewable Energy?
Anaerobic wastewater treatment systems can indeed generate renewable energy. This innovative process is at the heart of modern, sustainable wastewater management strategies, particularly appealing to industries looking to enhance their environmental credentials while optimizing operational efficiencies. Here’s how it works:
Anaerobic wastewater treatment involves the breakdown of organic matter in the absence of oxygen by anaerobic microorganisms. This process occurs in a sealed environment where these microorganisms consume organic pollutants in the wastewater, producing biogas as a byproduct. The biogas primarily consists of methane (CH4) and carbon dioxide (CO2), with methane being a valuable, renewable energy source.
How long does anaerobic digestion take?
Anaerobic digestion typically takes between 15 to 40 days, depending on factors such as temperature, feedstock composition, and system design. This duration allows for the efficient breakdown of organic material into biogas and digestate.
Is anaerobic digestion good for the environment?
Yes, anaerobic digestion is highly beneficial for the environment. It reduces greenhouse gas emissions, manages waste sustainably, produces renewable energy, and creates nutrient-rich byproducts that can be used as fertilizers, promoting a circular economy and reducing landfill use.
What is the difference between aerobic and anaerobic wastewater treatment?
The primary difference between aerobic and anaerobic wastewater treatment is the presence of oxygen. Aerobic treatment uses oxygen to break down organic matter, resulting in carbon dioxide and water. Anaerobic treatment, on the other hand, occurs without oxygen, producing biogas (mainly methane and carbon dioxide) and digestate. Anaerobic processes are energy-efficient and generate renewable energy, while aerobic processes are typically faster and simpler to manage.
Discover our BIOTIM technologies
Upflow Anaerobic Sludge Blanket - BIOTIM® UASB Reactor
Elevating Sustainability with Waterleau's BIOTIM® high rate anaerobic tower technology
BIOTIM scrubber for biogas and extraction gas pretreatment
Efficient, Flexible and Cost-effective biogas desulphurization.
Find your local contact
Our expertise is always within reach. Digital communication has cut long distances short, but we advocate the traditional way of sharing insights.
Contact us today. We are looking forward to help you reach your sustainable development goals.
