Local companies are currently feeling the full impact of the water shortage, but industry is fast
following on the footsteps of its European cousins.

Availability of sufficient, quality intake water is the biggest threat for the South African food and beverage industry. In terms of effluent, a large percentage of industries are not discharging at the correct discharge standards. Redox Water Technology, supplied locally through DFS Process Solutions (DFS) offers a wide range of products to assist.

Large amounts of effluent water can be reused, reducing the reliance on municipal water and utilities costs. Industry can reuse up to 40 per cent of its effluent. If legislation in the food industry allows, this could be increased to between 80 and 90 per cent. According to Walter Mengel of DFS there are a number of systems that could offer benefits to local industry. ‘The strongest and most effective piece of equipment would be the dissolved air flotation (DAF) system. This process clarifies wastewater by removing suspended matter such as oil or solids. Removal is achieved by dissolving air in water or wastewater under pressure and then releasing the air to atmospheric pressure in a flotation tank basin. Released air forms tiny bubbles which adhere to the suspended matter, causing it to float to the surface of water where it is removed.’ Additional technology is FBR biological wastewater treatment systems. ‘Wastewater after primary treatment is pumped into the aeration basin, filled with an activated sludge/water mixture. Activated sludge is flocks of bacteria, called biomass. In the presence of oxygen pollution will be decomposed by these bacteria. The oxygen supplied by the aeration system supplies optimal condition to decompose main pollutants, mainly carbon, hydrogen and nitrogen. ‘Eventually most pollutants will be converted to carbon dioxide, nitrogen gas, water and excess sludge. Water flow is continually pumped out of the aeration basin, processed by a special flotation unit which separates activated sludge from clean effluent. This flotation system is capable of handling high solids loading, and thickening activated sludge to about five per cent dry solid content. Microscopic air bubbles adhere to the sludge, reinforced by the dosing of polyelectrolyte. The sludge floats to the surface where it is then mechanically dewatered and skimmed,’ Mengel concludes.

August 2017, SA Food Review

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