Frucor screens its wastewater

A compact vertical screen to remove the solid debris from the factory wastewater before its discharge into the sewer has been installed by energy drinks manufacturer Frucor.

Frucor, owned by Japanese company Suntory, is one of New Zealand’s largest drinks manufacturers and produces energy drinks, fruit juices and drinks, pure waters and sports waters, soft drinks and milk drinks. It’s the market leader in energy drinks in Australia and New Zealand and the leader in the juice category in NZ.

The vertical screen meets Frucor’s special constraints as the space was confined and there wasn’t room for bulkier equipment.

The screen uses an automated process that requires far less labour than the previous flat-screen method which necessitated regular removal of the screens by forklift, followed by hand cleaning.

Frucor’s engineering coordinator Nick Woolf said screw screens are used extensively in wastewater treatment units for augering solid material to the surface of tanks and sumps.

“Often the screens are inclined at 45°. This one is a vertical product that works very well for us,” he said.

“We initially looked at other options, but found they were quite bulky. We don’t have room to install a screen of any size. It needed to be something compact that would stand upright in the sump.”

The vertical screen at Frucor is positioned between the below-ground sedimentary sump and the main sump, which both hold wastewater from the entire manufacturing plant at the Manukau City site.

After the screen has removed solid material from the wastewater, it is pH corrected and discharged into the sewer. The solids are mainly fruit pulp, but also include extraneous debris such as plastic bottle caps and hairnets. This material is discharged into a bin for disposal.

“The flat screens we used previously had to be manually cleaned, sometimes daily. They were big and heavy, made of stainless steel and required a forklift to remove and replace them,” Woolf said.

“When the old screens got blocked, we then had a crisis to manage because we were in an overflow situation. Our vertical screen avoids us getting into that sort of crisis.

“However, the biggest benefit for us is in terms of labour saved. That makes the vertical screen very cost effective for us.

“The screen is pretty much automatic and maintenance free. Its function is controlled by the wastewater level, so that the screw switches on when the water rises. There’s not a great deal for us to do.

The compact vertical screen is easy to install and can handle up to 400 m³/h.

“The screen lifts to more than six metres for discharge and can be retrofitted into existing pump stations with depths of up to eight metres. The high-strength shaftless spiral requires no bottom bearings.”