TasWater minimises odours with Calix’s ACTI-Mag and Netco Pumps

Improving the Sustainability of Water Treatment


Formed through the merger of three Tasmanian water and sewage corporations, TasWater is Tasmania’s water and sewage utility. TasWater is responsible for providing drinking water across the state as well as collecting and treating sewage.

With a vision to be a trusted and respected provider of essential services that makes a positive difference to Tasmania, TasWater aims to efficiently provide water and sewerage services to customers in the most cost-effective manner, encourage water conservation, and deliver sustainable returns to its members.


TasWater was experiencing issues with the magnesium hydroxide liquid product it was using at a Southern Wastewater Treatment Plant. The product was constantly blocking the peristaltic pumps and dosing lines causing headaches for the operators. The product they were using was a standard type of MHL, with a low surface area and slow reactivity time.


TasWater engaged with Netco Pumps to explore different options and, after speaking with a lot of industry contacts, Netco ran a trial at the treatment plant with ACTI-Mag product from Calix. This immediately proved successful as the product had a much finer molecular structure and proved much easier to pump and handle as well as having a good reactivity time. ACTI-Mag is a concentrated stabilised suspension of magnesium hydroxide, an inorganic compound with the chemical formula Mg(OH)2. The method by which Calix produces the raw product results in a product with a much higher surface area which has multiple benefits.

A few months later TasWater were experiencing odour issues in the Hobart Eastern Shore network where stations were being injected with oxygen to try and control the odour. TasWater decided to engage Netco again to run a trial using ACTI-Mag dosing at 4 stations over the summer months to treat the odour and measure results. Netco Pumps installed and commissioned dosing packages at the sites and the result was excellent, with H2S measured at the receiving treatment plant reduced to almost zero.

Netco general manager Nathan Cruickshank commented – “Calix’s ACTI-Mag ticked all our boxes for TasWater. While the dosing units were only supposed to be temporary, they are still in place today with just 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 kilo when compared with caustic while being significantly safer to handle than other traditional alkalis, making it a very safe and cost competitive option for hydrogen sulphide gas (H2S) control in wastewater treatment.

ACTI-Mag can also safely and cost-effectively reduce phosphorus from the wastewater discharge, which improves the wastewater quality.

Netco Pumps recommends ACTI-Mag because it has a high surface area, which means it reacts quicker, and is a stable, easily flowing 60 per cent concentrated solution resulting in hassle-free dosing.


The successful relationship story between Netco, TasWater and Calix has continued, with many more ACTI-Mag dosing stations at sites across TasWater of various sizes. Netco Pumps designs and builds ACTI-Mag dosing packages and believes their attention to detail and service is what has built a successful partnership. Some of the dosing sites are situated at Wastewater Treatment Plants where the ACTI-Mag solution proves its ability to boost alkalinity in the process for nitrification and denitrification. Calix has also proved the ability of the product to tackle more than just odour.

ACTI-Mag’s unique molecular structure also helps break down fat, oil and grease (FOGs) and reduces phosphorous.


TasWater has boosted dosing at one site to help tackle the increased loading of FOGs coming into a station which has been historically problematic.

Also after five years of use, only two blockages have occurred with both being caused by foreign objects such as broken plastic.

TasWater, said, “Calix’s ACTI-Mag is a safe, environmentally-friendly solution that effectively maintains our odour and asset protection. Likewise, Necto Pumps provides us with a seamless service to deliver, run and maintain our dosing system in a problem-free way. We are thrilled with our experience using ACTI-Mag.”

ACTI-Mag for Odour Control

ACTI-Mag has a higher neutralising value per kilo when compared with caustic while being significantly safer to handle than other traditional alkalis, making it a very safe
and cost competitive option for hydrogen sulphide gas (H2S) control in sewers.

Find out more about ACTI-Mag

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