Visy Paper Pty Ltd, Pulp and Paper, Gibson Island QLD Australia, is a large production facility producing over 1.3mln tonnes of paper, including over 750,000 tonnes of 100% recycled fibre test liner, coated liner and plasterboard liner; and over 580,000 tonnes of unbleached kraft paper. All waste waters on site are collected and sent to the industrial waste water treatment plant. The high Calcium content treatment of the collected waste water causes unwanted interruptions.
In the pulp and paper industry water re-use is best-practice. The waste water treatment facility therefore is a fundamental part of the production plant. Visy Paper suffers production interruptions because the waste water treatment plant has to be taken out of operation due to excessive Calcium settlement in the UASB reactor. In order to operate with fewer interruptions, the source of the scaling has to be taken away before the water enters the UASB reactor.
Under supervision of Royal HaskoningDHV's Technological Research Centre a pilot test has been performed on site to assess the possible options to remove the calcium. Bases on the results of these tests a system is designed wherein a mixture of water from the equalisation tank and UASB recycle water is lead through a Crystalactor reactor. Dosing of sodium hydroxide will raise the pH, which causes calcium carbonate to precipitate on the seeding material. The formed calcium pellets are re-used by Visy in another part of their production facility.
The Crystalactor unit has been produced and assembled by Aquatec Maxcon from Ipswich QLD Australia. Royal HaskoningDHV has been responsible for the total design, production and supply of the Calcium Removal System and has provided commissioning and process start-up assistance.