TasWater solves blockage and odour problem

Tasmanian water and sewage utility TasWater is responsible for providing drinking water across the state, as well as collecting and treating sewage.

The utility was experiencing issues with the magnesium hydroxide liquid (MHL) it was using at the Southern Wastewater Treatment Plant. The product was constantly blocking peristaltic pumps and dosing lines. Once blocked in the lines, the hardened, cement-like material had to be painstakingly chipped out of the pipework.

TasWater approached Netco Pumps, which ran a trial of Calix’s ACTI-Mag product at the plant. This immediately proved successful as the product had a much finer molecular structure and was more viscous than the previous MHL. Overall, it proved much easier to pump and handle, and had a good reactivity time.

Several months later, TasWater experienced odour issues in the Hobart Eastern Shore network, where stations were being injected with oxygen. Netco ran a trial using ACTI-Mag dosing at four stations over the summer months to treat the odour and measure results. Dosing packages were installed and commissioned at each site, with spectacular results — the hydrogen sulfide gas (H₂S) measurement at the receiving treatment plant was brought down to almost zero.

Netco Pumps General Manager Nathan Cruickshank said, “Calix ACTI-Mag ticked all our boxes for TasWater. While the dosing units were only supposed to be temporary, they are still in place today albeit [with] a few upgrades to make them more functional.

“The combination of an excellent product coupled with our unique delivery and maintenance service has resulted in a very painless experience for TasWater and its operators, at the same time solving odour issues and protecting their assets from the stations through to the treatment plant.”

ACTI-Mag has a higher neutralising value per kilogram compared with caustic and is reportedly safer to handle than other traditional alkalis, making it a good option for H₂S control in wastewater treatment. The product can also remove phosphorus from wastewater discharge, improving wastewater quality.

TasWater now has 14 ACTI-Mag dosing sites across its sites of various sizes.