WASTE – THE FORGOTTEN RESOURCE

As in many other industries, waste is generated at various stages during processing and manufacture in the food and beverage industry. Whilst improved efficiencies are continuously chased to reduce wastage and cost, significant opportunities are often missed along the way. An increased focus is being placed on the need to extract value from waste as legislation and increased disposal costs drives a change in behaviour, with identifying and utilising the hidden resource in waste, becoming more common place.

Wastewater is a major consideration for many industries in the food and beverage sector. Talbot & Talbot, a company that specialises in water and wastewater management, has designed and installed resource recovery plants supplying both water and energy back to the producer throughout Africa for almost three decades.  A key opportunity associated with high organic chemical oxygen demand (COD) effluents and organic waste, that is receiving more attention in recent times, is the production of biogas.

Biogas Production

Biogas is generated from the anaerobic digestion of organic matter in wastewater and wastes and comprises of primarily methane, carbon dioxide and small quantities of nitrogen and hydrogen sulphide amongst others. With processing, biogas can be cleaned up to be a substitute for natural gas.

Biogas production has a significant advantage over other biofuel production methods in that it strictly uses waste products and can cope with the fluctuating quality of the raw material. In addition, production costs are reduced by reducing the need for coal-generated power, since biogas is a free product of wastewater treatment.

Talbot & Talbot’s experience in the production of biogas

Talbot & Talbot Business Development Director, Grahame Thompson, states “our biogas projects, which are set for completion this year, entails the use of the anaerobic digestion of wastewater to produce biogas which is to be used as boiler fuel, thereby successfully utilising energy from waste back into the industry.”  He comments, however, that “although green projects such as this one have been successful with the company throughout Africa and global industries around the world, South Africa has been slow to take advantage of such opportunities.”

In South Africa, the relatively low cost of energy and water  has had a prohibitive impact on the return on investment for these types of projects. Although the technology has been around for decades, the example of providing biogas feed to boilers from an anaerobic digester is a specialised application, owing to the configurations of the technology available and experience becomes paramount in appropriately selecting the correct configuration of anaerobic digesters.

In South Africa, Talbot & Talbot has installed four anaerobic digesters in the food and beverage industry, all of which harvests the biogas generated as a fuel source for the replacement of fossil fuel. The biogas produces 10% to 11% of the production process’s total energy requirement.

Talbot & Talbot is looking at expanding its operations in Africa, and targets high organic waste and existing anaerobic digesters to harvest their biogas for green energy production. The company partners with international company Global Water Engineering, which has installed more than 400 anaerobic digesters worldwide. These digesters produce approximately 500 megawatts of power, which is about 27% of the power capacity of Koeberg, the only commercial nuclear power station in Africa.

The key to safeguarding power supplies

On-site anaerobic digestion of industrial wastewater, may hold the key to immediate safeguarding of power supply for many industries. This process has many advantages over the generation of biofuel from edible crops, and is particularly true in a world that is experiencing food shortages and soaring food prices.

Thompson encourages the food and beverage industry to focus more on waste materials, such as industrial wastewater, that can be treated anaerobically. The benefits of waste digestion are multifaceted and the process presents no side effects.
“This creation of power from rich organic effluent has become a successful reality and is being applied by an increasing number of food and beverage manufacturers worldwide.  These industries have started reaping the environmental and financial rewards,” he states.

(as featured in Food Review, July 2017)