The purpose of this document is to provide information in response to commonly asked questions about the chemicals used in our process to remove water from domestic wastewater and purify it for non-drinking reuse. At the end of the purification process, our recycled water, the product name we use for the high quality recycled water we produce, is clean, crystal clear and odourless. Chemical use is part of this process. We follow the State and Federal guidelines for recycled water and meet all regulated standards. Our chemical delivery, storage and dosing is subject to independent auditing by the NSW Government.
Chemicals are needed as part of the process to remove particles and clean wastewater. Our approach is consistent with national and international practice.
We will use sodium hypochlorite, sodium hydroxide, aluminum sulphate (coagulant) and citric acid. None of these chemicals are classed as a dangerous good. We only use small quantities.
Sodium Hydroxide: This is a caustic, which is used for pH control. Neutralising the pH makes all the other processes more effective. Sodium hydroxide is one of the most used chemical substances in laboratories and industry.
Sodium Hypochlorite: This is often referred to as hypo. It is the industrial name for what is more commonly known as chlorine. We use it in liquid form for disinfection. More chlorine would be stored at your local swimming pool than we will store at our local water centre. Sodium Hypochlorite is the main ingredient in laundry bleach. We use hypo in exactly the same form as is commonly sold from petrol stations.
Aluminum Sulphate: The short name for this chemical is Alum. This is used to enhance performance and help remove phosphorus. When Alum is added to water, it causes microscopic impurities to clump together into larger and larger particles. These clumps then settle to the bottom of the container they are held in or form large enough particles to filter from water. Alum is sometimes used in swimming pools to decrease cloudiness of the water.
Citric Acid: Citric acid is used to clean the membrane filters we propose to use to separate particles from the water. Citric acid is a common cleaning agent.
The chemicals we need will be stored at the local water centre where they are used. These will be contained in closed regulation tanks, behind a bund wall, according to Australian standards. The area where the chemicals will be kept will be locked and the area monitored.
We use approved suppliers that transport all hazardous chemicals according to Australian Standards.
Every part of our process is subject to independent auditing, which is managed by the Independent Pricing and Regulatory Tribunal (IPART) and includes the NSW Environment Protection Authority and NSW Health. These routine audits include full risk assessments for chemical delivery, storage and dosing. The auditing process is extensive and includes verification of our infrastructure, risk management and protection of public health and the environment.