Recycling & Waste
The desalination process generates two main waste streams: seawater concentrate and solid waste. Seawater concentrate contains filtered seawater not used in the desalination process, salt and other elements that already occur naturally in seawater. No active chemicals are present in the seawater concentrate which is returned to the ocean.
The solid waste contains dissolved salts and organics, algae, sediment and micro-organisms, as well as ferric sulphate, a common coagulant used in many water treatment facilities worldwide, and which is used in the plant’s pre-treatment process.
The solid waste is a non-toxic substance that, if it weren’t for the salt content, could be used as an additive for soil remediation. However, because of its salt content, it currently has no use and is therefore disposed of at the Lyndhurst licensed landfill, based on its classification under EPA guidelines as non-prescribed (general) industrial waste.
The amount of waste produced by the project, if operated at full capacity, is about four to eight dry tonnes per day, which equates to around 20 to 40 wet tonnes per day or around two to three standard garbage trucks per day. This was assessed as part of the EES process, which indicated about 23 to 63 wet tonnes per day. AquaSure’s process plant design has minimised this quantity to the lower range outlined in the EES.
Rain water is collected from both the green roof and the covered treated water storage tanks and reused to water the green roof. Other stormwater runoff from the site is managed in accordance with the principles of Water Sensitive Urban Design.