Release
Energy – a profitable downstream product
On-site anaerobic digestion of industrial wastewater to produce methane, 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. This is particularly so in a world that suffers from food availability and soaring food prices. Our focus should be 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 organic rich effluent has become a successful reality and is being applied in an increasing number of food and beverage manufacturers worldwide.
It is a great concern to South Africans that food sources may be used to produce energy, particularly since alternative opportunities exist. Manufacturers should start producing power from their effluent to realize the associated environmental and financial benefits. Biogas production has a major advantage over other biofuel producers in that it uses strictly waste products and can cope with a fluctuating quality of raw material.
Grahame Thompson, Business Development Manager for Talbot & Talbot’s Green Energy division, encourages any manufacturer who has a by-product or produces wastewater with a high COD (Chemical Oxygen Demand), to seriously consider investing in Green Energy projects. Talbot Green Energy creates financial opportunities for industries to produce their own power from their effluent and enables them to better meet the mandated electricity quota system. Although lagging behind developed countries in implementing Green Energy projects, South Africa has many opportunities. Biogas production from South Africa’s agricultural and industrial sectors is currently largely unharnessed. Thompson says, industries often fail to realise the true value of converting organic effluent material to methane using anaerobic digestion.
The technology of anaerobic digestion has made spectacular advances over the last 5 to 10 years, particularly in the field of solid and liquid/solid mixtures. Anaerobic digestion comes into its own where the biogas recovered has a strategic value to the waste generator. By producing a substantial percentage of its own energy requirement, the industry is in a unique position of mitigating the negative effects of power outages and power capping. The fact that this is achieved through the use of renewable, green energy, and usually in a cost-positive investment environment, while cleaning up the effluent quality for discharge, makes anaerobic digestion an appealing solution.
Talbot & Talbot partners with an international company Global Water Engineering who have installed 421 Anaerobic Digesters worldwide. These digesters collectively treat 4,200,000 kg of COD per day, producing approximately 480 MW of power. This is approximately 27% the power capacity of the only commercial nuclear power station in Africa, Koeberg, north of Cape Town. If converted to coal, the equivalent would amount to 1627 tons per day and in the case of diesel, a daily production of 1.2 million litres per day.
Thompson says decision makers in industry may be hesitant because the technology is perceived as being new. However it is well established internationally and his company has extensive experience in anaerobic digestion having completed many successful projects. In South Africa alone Talbot & Talbot have installed four anaerobic digesters in the food and beverage industry, one of which harvests the biogas generated as a fuel source for replacement of fossil fuel. This creates enough methane to produce 10%-11% of the production process’ total energy requirement. A frequently overlooked benefit of biogas production from effluents is the added boost of purification, typically reducing the COD by 80% to 90%. This reduction can often lead to substantial investment payback through reduced effluent discharge tariffs.
With the growing drive towards sustainability and reducing environmental footprints, the benefits to businesses of redirecting their waste into reusable energy offers a viable value adding proposition – a winning enhancement for any corporates triple bottom line.