Hydrothane Anaerobic

High-Rate Anaerobic Systems: Efficient Wastewater Treatment & Biogas Recovery

Hydroflux specialises in high-rate anaerobic systems designed for the efficient treatment of high-strength industrial wastewater. These advanced systems offer exceptional organic load reduction in a compact footprint, while converting wastewater contaminants into methane-rich biogas, which can be used for energy generation.

In partnership with Hydrothane, a global leader in anaerobic wastewater treatment technology that has successfully installed over 100 anaerobic wastewater treatment plants worldwide. The most commonly deployed solution is the External Circulation Sludge Bed Reactor (ECSB), a two-stage anaerobic high-rate process renowned for its success across various industries.

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A settler being installed in a Hydrothane ECSB
A Hydrothane ECSB process showing the neutralisation tank and main reactor
A complete UASB system operating at a food processing facility

The Hydrothane ECSB is suitable or the treatment of wastewater from many industries including:

  • Meat and poultry industry
  • Dairies
  • Beverage sector
  • Fruit and vegetable processing
  • Potato and potato chips
  • Vegetable oil processing
  • General food industry
  • Manufacturing
  • Industrial laundries
  • Paper, cardboard and printing

Some of the main benefits of the ECSB high-rate anaerobic treatment system are:

  • Energy Recovery – Converts the majority of organics into methane-rich biogas, which can be used as a substitute for natural gas in boilers or for power generation, significantly reducing energy costs.
  • Compact Footprint – With typical organic loading rates of 15–35 kg COD/m³/d, the ECSB delivers the same performance as other systems but requires significantly less space.
  • High Performance – Achieves an 80% or greater reduction in organic load (COD and BOD), ensuring effective wastewater treatment.
  • Sludge Reduction – Efficient anaerobic digestion minimises sludge buildup, generating far less sludge than aerobic alternatives, reducing disposal costs.
  • Odour Control – The sealed anaerobic reactor prevents foul odours from escaping, enhancing site conditions.
  • Simple Installation & Maintenance – The reactor has no internal moving parts or rotating equipment, making it easy to install and requiring minimal maintenance.

ECSB: Efficient Wastewater Treatment with Simple Operation

The Hydrothane ECSB system consists of two primary vessels: the neutralisation tank and the main reactor.

Pre-treated and conditioned wastewater first enters the neutralisation tank, where it undergoes initial processing. A recirculation pump then transfers the wastewater into the sludge bed at the base of the ECSB reactor at a rate several times greater than the incoming feed flow.

As the wastewater moves upward through the reactor, it passes through phase separators, which efficiently retain solids (anaerobic biomass) within the system, ensuring high treatment performance. The clarified wastewater then flows over weirs near the top of the reactor before being discharged. Biogas generated during the anaerobic digestion process is collected at the top of both the neutralisation tank and the ECSB reactor, allowing for further processing and reuse as an energy source.

Pre-treatment of Wastewater Prior to Anaerobic Digestion

For optimal performance, the ECSB Reactor requires proper pre-treatment to protect the system and ensure stable operation. This pre-treatment stage may include screening for the removal of coarse solids and clarification methods, such as Dissolved Air Flotation (DAF), to eliminate excessive fats, oils, and grease (FOG) when necessary. These steps help prevent clogging, improve reactor efficiency, and enhance overall treatment effectiveness.

Beyond physical pre-treatment, flow equalisation, temperature regulation, and pH adjustment are essential for process stability. The wastewater’s pH should be maintained between 6.5 and 7.5, while temperature control measures like pre-heating or insulation may be needed to keep the reactor within the mesophilic range (30-40°C). Additionally, ensuring a balanced supply of nutrients such as nitrogen, phosphorus, and micronutrients supports anaerobic bacterial activity, maximising treatment efficiency and biogas production.


Handling of Biogas

Biogas primarily consists of 60–65% methane (CH₄) and 35–40% carbon dioxide (CO₂). Additionally, it contains trace amounts of hydrogen sulfide (H₂S), nitrogen (N₂), hydrogen (H₂), and moisture. The exact composition varies depending on the type of organic waste being digested and the efficiency of the anaerobic process

In industrial settings, biogas is most commonly used as a fuel for boilers, reducing dependence on fossil fuels. When generated in sufficient quantities, it can also be converted into electricity using gas engines or turbines, making it a viable option for energy self-sufficiency. However, before biogas can be used efficiently, it must be conditioned and treated to meet the specifications required for its intended application. This process often includes chilling to remove moisture and scrubbing to eliminate impurities like hydrogen sulfide, which is corrosive to equipment.

Regardless of whether biogas is reused or not, a gas flare system is always installed to ensure any excess gas is safely burned off, preventing the uncontrolled release of methane into the atmosphere as a greenhouse gas. Proper treatment and handling of biogas are essential for ensuring safety, maximising energy recovery, preventing corrosion and minimising the environmental impact.

A Hydroflux biogas skid comprising flare, chiller and blower
An ECSB and flare operating at a beverage facility
Cogeneration is viable for large COD loads

Hydroflux supply a range of biogas treatment systems that are engineered to maximise the recovery and utilisation including:

Biogas collection
Positive displacement blowers will often be required to transfer biogas from the reactor at a controlled rate and pressure to downstream equipment.

Biogas Chilling
Digester produced biogas is 100% water saturated as it cools in the lines to the point of reuse, large amounts of water will condense in the piping system . Hydroflux will incorporate the most suitable biogas cooling system into the treatment process.

Biogas Treatment
Removal of hydrogen sulphide from biogas is essential to avoid rapid corrosion. Hydroflux offer a range of chemical, media or biological gas scrubbers that will ensure that the biogas is suitably conditioned for reuse.

Biogas Storage
Biogas storage is typically achieved using double membrane gas holders, which provide a flexible and reliable solution for accommodating fluctuations in gas production. The outer membrane offering weather protection and an inner membrane adjusting to gas volume changes.


FAQs

Is anaerobic treatment suitable for my application?

Several critical factors must be assessed to determine whether high-rate anaerobic digestion is the right wastewater treatment solution for your facility. While anaerobic treatment effectively reduces over 80% of chemical oxygen demand (COD) and biochemical oxygen demand (BOD), it does not significantly lower nutrient concentrations. However, for high COD wastewater, integrating anaerobic digestion upstream of an aerobic process to enable environmental discharge or reuse —such as the Hydroflux SBR, MBR, or MBBR—can substantially reduce the load on the aerobic stage. This not only lowers the overall capital and operating costs but also enables the capture and reuse of biogas, contributing to sustainability and energy efficiency.

The External Circulation Sludge Bed (ECSB) reactor, despite its small footprint, requires a tank height of 14 to over 20 meters, which may necessitate regulatory approvals. Anaerobic treatment is most effective for high wastewater flow rates, and for economical biogas recovery, a minimum COD load of 3–4 tonnes per day is typically required. As a result, high-rate anaerobic systems are particularly well-suited for industries with high-strength organic wastewater, such as food processing (dairy, meat, and beverage production) and other manufacturing sectors with significant COD loads.

How much biogas will the system generate?

The amount of gas generated depends on a number of factors but of most value is the COD load. As a rule of thumb for every Kg of COD, 0.35 m3 of biogas will be generated. This biogas will need to be conditioned for reuse as it will be contaminated with carbon-dioxide (CO2) along with some trace gases such as hydrogen sulphide (H2S), nitrogen (N2), hydrogen (H2) and oxygen (O2).

Does Hydroflux conduct the complete design and construction of anaerobic systems?

Yes, Hydroflux provides complete design and construction services for anaerobic wastewater treatment systems, including process design, engineering, installation, and commissioning. Our expertise ensures a fully integrated solution that maximises efficiency, minimises costs, and optimises biogas recovery for your wastewater treatment needs.


Why Choose Hydroflux for Your Anaerobic Wastewater Treatment System?

Unmatched Quality and Innovation
At Hydroflux, we are committed to delivering high-quality anaerobic wastewater treatment systems in collaboration with our trusted partner, Hydrothane—one of the world’s leading ECSB technology providers. Our systems are designed for maximum efficiency in terms of wastewater treatment, biogas recovery, and long-term reliability. We ensure that every system we build is robust, efficient, and tailored to meet the specific needs of each facility.

Contact us for a discussion on anaerobic and other wastewater treatment options for your site.


Design and Construction Capabilities

Hydroflux has the expertise and capability to deliver design-and-construct projects that incorporate a wide range of treatment technologies for industry.

With a team of qualified civil, mechanical, chemical, and electrical engineers, as well as experienced project managers, site supervisors, commissioning engineers, and service technicians, Hydroflux ensures expert execution at every stage. Our offices across Australia provide a strong local presence, ensuring seamless project management from design through to installation. Additionally, Hydroflux offers post-installation routine service contracts to maintain system performance and longevity.


Sustainable Solutions

As Australia’s first certified carbon-neutral water and wastewater chemical supply and service business, we focus on sustainability. Developing and delivering sustainable solutions for treatment plant operation and maintenance is at the core of what we do. Our equipment is the most sustainable in the Australian and New Zealand market and is not just effective but also carbon-neutral. Click here to find out what this means for you.