The role of technology in wastewater management—Grassroots share their insights
As a global leader in the production of innovative health snacks, Grassroots is an integral part of our Group’s Food Processing segment. The company supplies health snacks under its own brand name, private label and bulk business. These products include, amongst others, the Simple Truth range and the Oh My Goodness range (from Gordon Ramsey), available at Shoprite and Checkers stores. The company uses proprietary technology to process fruit and vegetable pulp, as well as dairy products. Wastewater is a common byproduct of most agricultural processing, so wastewater management is a big part of Grassroots’ daily operations.
Johan Muller, general manager at Grassroots, provides some key insights into the role that technology plays in their wastewater management.
Johan, please tell us why wastewater management is so important.
“Wastewater treatment refers to the process of removing contaminants from wastewater or sewage, and converting it into directly reusable water (or an effluent) that can be returned to the water cycle,” says Johan.
“Wastewater can have a significant impact on the environment, so it is important to treat it effectively. As an environmentally-responsible company, we need to ensure that all waste generated on our premises is managed in a manner that complies with the National Water Act (Act 36 of 1998) and the National Environmental Management Waste Act 59 of 2008,” continues Johan.
According to Johan, some of these objectives include:
-Avoiding and minimising the generation of wastewater;
-Reducing, reusing, recycling and recovering wastewater;
-Preventing pollution and ecological degradation through wastewater; and
-Treating, storing and safely disposing of wastewater as a last resort.
Can you tell us a bit more about how Grassroots processes wastewater?
“We treat our wastewater in three stages,” says Johan. “Preliminary, which includes the screening and removal of solids. Primary, which includes settling and anaerobic digestion. Secondary, which includes biological treatment and polishing. Essentially, we first filter and screen the wastewater to physically remove any solid waste that is floating in the water, or may settle on the bottom or rise to the top. In the secondary stage, we use biological processes to treat our wastewater. This means that we use microorganisms (bacteria) to break down/ digest the unwanted waste that is still dissolved in the water. These bacteria need a steady supply of oxygen to live, so we pump air into the water to facilitate the biological digestion process,” continues Johan.
How does technology fit in to this process?
“When we aerate the wastewater (pump oxygen into it), it is vital that the maximum level of oxygen is absorbed into the water in the most efficient way,” says Johan. “We call this oxygen transfer efficiency, and it depends on the aeration system that is used to oxygenate the water. In most wastewater treatment facilities, a lot of energy is lost in the transfer of oxygen, due to inefficient aeration methods,” continues Johan.
“At Grassroots, we have designed and constructed a complete biological digestion system using fine bubble aeration tubing. Aeration tubing is cost effective, simple to use and provides numerous benefits: a major reduction in energy costs, significantly higher oxygen transfer rates and higher dissolved oxygen levels,” says Johan.
“Wastewater treatment can also be costly to install and operate. Fortunately, we have managed to reduce these costs by designing a system that uses the best technology available, is custom designed for our operational needs and is manufactured in-house,” concludes Johan.
