Green power generation turns wastewater treatment into a ‘cash cow’ – while also preserving the environment

Amid surging energy prices and the need for measures to counter global warming, green energy generation from wastewater treatment does not always get as much attention as more traditional renewables such as solar and wind. In fact there lies a huge, often hidden, potential in using wastewater as a source of renewable energy. Global Water Engineering (GWE), represented in Australia by CST Wastewater Technologies, encourages businesses with organic content in their wastewater and waste streams to investigate the anaerobic potential for their specific case.


The concept of using wastewater to create green energy is much more widely applicable than often realized.

Any factory with a biological waste stream or wastewater with high COD (Chemical Oxygen Demand) can easily use this model to generate energy.

So far, most industries have mainly been focusing on treating their effluent to meet local discharge standards. By doing so, wastewater treatment installations have only generated additional costs and have never been seen as revenue generators.

However, applying anaerobic wastewater treatment sheds a whole different light on the cost structure of wastewater treatment infrastructure. It can now actually become a substantial additional source of income for many factories and processing plants in Australia, including vegetable and other primary product processing.


Power from Effluent

In realizing the value by anaerobically treating organic effluent and waste material, a whole series of benefits come into play.

The first benefit is of course the clean effluent, efficiently dealing with an important waste stream many companies have to contend with. On average the removal efficiency of GWE’s anaerobic wastewater treatment installations is as high as 90-95%, easily bringing the organic load down to regulatory discharge standards for most types of wastewater. For the most heavily loaded wastewaters, extra post-treatment steps can further purify the effluent, meeting even the most stringent discharge regulations for water re-use.

Besides cleaning the wastewater (which other processes can ultimately achieve) by far the greatest advantage of anaerobic wastewater treatment is the controlled, continuous production of valuable biogas that occurs during the wastewater treatment. Other types of treatment, such as aerobic, do not provide this benefit.

Closed anaerobic reactors generate large quantities of methane (CH4) from the organic materials in the wastewater that can diminish or even completely replace the use of fossil fuels in the production process. To bring some perspective to the value, one ton of COD (chemical oxygen demand) digested anaerobically can result in 350Nm3 of methane, equivalent to 0.15MW of power.

For specific industry applications with high organic loads, enough biogas can be generated to fully cover a factory’s energy needs and still have a biogas surplus to feed it into power generators and sell electricity to the national grid. A project recently completed for a 300tons/day starch factory in Thailand illustrates this.

The energy yield from the anaerobic digestion of the starch factory’s wastewater is double that which is required for the mill’s production, making the factory 100 per cent self-sufficient for its energy needs. The surplus electricity is sold back to the grid, generating additional revenues.


For a Greener Footprint

But it doesn’t end there. The GWE closed anaerobic process systems prevent large quantities of CH4 being emitted into the atmosphere. With CH4 being 21 times more harmful than CO2, GWE’s anaerobic wastewater solutions can also qualify for Emission Reduction Certificates for projects in countries listed under the United Nations Kyoto Clean Development Mechanism (CDM) and Joint Implementation (JI) programs.

Besides the economical advantage of GWE’s anaerobic wastewater treatment, there is clearly also the environmental advantage, significantly reducing factories’ carbon footprint. Not only by supplying renewable energy and thus reducing or even eliminating the use of fossil fuels, but also by replacing more traditional, CH4-polluting, open lagoons and by replacing power consuming and sludge producing traditional aerobic WWTPs.


Can I also apply it to my factory?

Anaerobic wastewater treatment with biogas recovery is possible for a very wide range of industries. The main criteria for energy-generating projects to become viable is the COD loading rate. The higher the organic load of the wastewater, the more biogas and thus renewable energy can be generated from it. Cost of fuel also plays a significant role. As the world is learning to live with higher energy prices, choosing anaerobic technology now holds the key to immediate and future safeguarding of power supply for many industries.

Typical industries amongst GWE’s proven references that are very suitable for anaerobic wastewater treatment are:

  • beer and beverages (beer, soft drinks, tea, coffee- and milk-based drinks, fruit juices)
  • food processing & canning (fruits, vegetables, meat, fish, seafood)
  • snacks, confectionary, dairy
  • fermentation industry (alcohol, yeast, monosodium glutamate etc.)
  • biofuels (ethanol, biodiesel)
  • pulp & paper
  • agro and agro-processing industries (vegetables, beet sugar, starch, palm oil)
  • petrochemical (PTA, PET, glycol and polyester factories)


Choosing the Right Technology

In selecting a suitable technology provider for wastewater treatment with biogas utilization, it is crucial to partner up with a reliable, experienced team, such as GWE/CST Wastewater Solutions, which between them provide a solid track record in this field complemented by more than 20 years of hands-on local wastewater experience.

From the design to implementation stage and beyond, into operations and maintenance of the plants, it is very important to look at the feasibility of a biogas project, both technically and economically. It is extremely important to choose the right reactor configuration. Each industry has specific wastewater characteristics, requiring thorough analysis and subsequent careful selection of the most suitable reactor design for these characteristics.

Too often we have seen companies left disillusioned after trying to implement anaerobic wastewater treatment with biogas reuse in the past. Although anaerobic technologies have improved significantly in recent years, the world is still littered with too many examples of how it is NOT supposed to be done. A significant part of GWE revenue comes from customers who had bad experiences with anaerobic treatment in the past and are often left with empty hands. Unfortunately it sheds a negative image on the technology although, in the right hands, it has so much to offer for a broad range of industries.


About Global Water Engineering (GWE) and CST Wastewater Solutions

With more than 30 years of experience, GWE has built up a unique range of seven anaerobic reactor types, each specifically designed for dedicated organic loads and specific wastewater types, which is unique in the market.

GWE is therefore very proud of its impeccable track record of meeting and regularly exceeding its performance guarantees.

It is GWE’s mission to be an ambassador for anaerobic wastewater treatment and to gain credibility for the technology by delivering quality installations that meet their performance guarantees.

CST Wastewater Solutions is one of Australasia’s leading wastewater solution groups. The company has provided a broad range of quality cost-effective solutions for 25 years, formerly as Contra-Shear Technology and now as CST Wastewater Solutions to reflect its expanded scope operating from its new combined office and warehouse in Roseville.

CST Wastewater Solutions Managing Director Michael Bambridge says the new facilities will help the company broaden its industrial and municipal services and equipment focus, while retaining the full range of mechanical and process technologies that have made it a premier provider of innovative wastewater treatment solutions throughout Australia and New Zealand, with projects also completed in Europe, Asia, Africa and America.

“Using our new facilities we will build on our reputation for customer-responsive, rapid and flexible packaged wastewater solutions for projects ranging from small individual plants to complete industrial estates and mining developments. We will also extend our anaerobic and aerobic wastewater treatment technologies focused on industries such as the food and beverage, chemical, pulp and paper and primary industries.

“Through our representation of market leading partners such as Global Water Engineering (GWE), we will further the trend toward smaller environmental footprints and conversion of industries from large energy consumers to net producers.” GWE has more than 200 plants worldwide, with clients including Coca-Cola, Pepsi, Carlsberg, Heineken, SAB Miller and Lion Nathan.

CST is a member of the Global Water and Energy Alliance, a group of select companies around the world committed to providing solutions in water and wastewater treatment for the recovery of green energy and water.



Corn Products International is one of the world’s largest corn refining and ingredient companies, with a history spanning of over 100 years. The company is a leading supplier of starches, sweeteners and other ingredients to customers in more than 60 industries, including the food, beverage, pharmaceutical, animal feed, corrugating, paper and textile sectors.

It is the world’s largest producer of dextrose and a leading regional manufacturer of starches, syrups and glucose with 27 production facilities worldwide.

In line with its policy of environmental responsibility and driven by high energy prices, in 2006, Corn Products International selected its 600 tons/day tapioca (cassava) starch factory in the North East of Thailand for a green milestone project. For the project it selected Global Water Engineering (GWE) to design and build Corn Products’ first ever anaerobic wastewater treatment plant with biogas utilization.

An audit recently performed by Corn Products International at this factory revealed several million US Dollars saving on fossil fuel from operating the GWE anaerobic wastewater treatment installation. The savings were much higher than planned and were accomplished by being able to replace costly fossil fuel with biogas, generated from the GWE ANUBIX-B™ reactors.

Where payback time of GWE installations in general lies under 2 years, in the case of Corn Products, the installation will even have a payback time of as little as 1 year.

The installation is the biggest so far in GWE’s record for native and modified starch producing factories. It was designed for a staggering organic load of 150,000kg COD/day.

The plant consists mainly of pre-treatment units, 3 high-rate ANUBIX-B™ reactors (GWE’s 6th generation design of the long standing UASB – Upflow Anaerobic Sludge Blanket) equipped with a 2-step neutralization process, and a biogas handling and reuse system.

The biogas is utilized as fuel in 4 steam boilers that can be fired in 3 modes: 100% biogas firing, dual firing i.e., biogas – fuel oil, or fuel oil only, which is another unique technical advantage of GWE’s cutting-edge technology.

Simon Denye, Managing Director of Corn Products International South East Asia said: “Although projected by GWE, and proven at many other GWE customers’ plants, we had never envisaged such astonishing cost savings for our factory. But as energy prices have gone up significantly and seeing the very high efficiency of the GWE technology, we managed these great savings”.

Jean Pierre Ombregt, CEO of Global Water Engineering added: “The savings our installation realized at Corn Products Amardass clearly prove that our technology is a serious proposition, not only for wastewater treatment, but also in the alternative energy market”.

Anaerobic wastewater treatment and organic solid waste treatment, both with biogas generation, are definitely one of the most sustainable sources of renewable energy to consider for many industries around the world. GWE installations offer a viable mixture of economical and ecological advantages, offering a greener footprint and maximized energy-efficiency for many industries’ production facilities.

Anaerobic and aerobic wastewater treatment technology was also selected for installation by one of the world’s leading vegetable processing organizations. Bonduelle awarded Global Water Engineering (GWE) a contract for a combined anaerobic and aerobic wastewater treatment plant to serve two of its production facilities in Hungary.

The plant will also include conversion of the existing boiler to dual fuel for biogas re-use. “By choosing GWE’s combined anaerobic and aerobic technologies, we will be able to deliver optimal water quality combined with generation of alternative green energy”, says Boudelle’s Director of Operations, Mr Ponthieu.

”We have chosen GWE after an extensive screening of available technologies on the market. GWE’s specialist product range and successful track record strengthens us in our belief that it is the best available technology for anaerobic wastewater treatment with biogas recovery”, Mr Ponthieu concluded.