Monday, September 30, 2013

Alice Springs’ new recycled water scheme ready for testing

New water recycling facilities have been commissioned in Alice Springs this week and will undergo three months of testing before the water is supplied to businesses and institutions south of Heavitree Gap.

 As part of the Alice Water Smart Reuse Project, the new treatment processes at the Alice Springs wastewater plant will improve the quality of recycled water available.

 Around ten large businesses and institutions south of The Gap will use the water for irrigation and horticultural purposes, such as watering gardens at caravan parks and the cemetery, as well as road and civil construction works.

 “It will save around 220 million litres of the drinking water that is currently used for these purposes each year. That’s equivalent to 100 Olympic sized swimming pools”, says Alice Water Smart Project Manager Les Seddon.

The new facilities include an architecturally designed building to house gravity filters and UV reactors, as well as 3.5km of new network distribution pipe and an additional 2.5 Megalitre storage tank.

 As part of the three-month testing period, Power and Water Corporation and the Department of Health will carry out a series of validation checks to ensure the system is robust.

 "Along with water quality testing, we’ll be monitoring how the system works under various operational conditions, such as when there is peak demand or low water levels in the tanks.”

 “We are currently in discussions with businesses and institutions south of the Gap about how they can access the scheme and we look forward to that first turn of the tap.”

 95 tonnes of special sand media has been brought in from NSW for use in the system’s new gravity filters; which has some irony for a place that is surrounded by sand.”

 "The certified sand has a high quartz content, so it is quite strong and won’t break down into powder form to clog the system. The sand grains are uniform in size to allow wastewater to filter through, and small enough to pick up tiny solid particles along the way.”

 After the sewerage has travelled through several wastewater ponds over a 70-day period, the recycling process takes about one hour, which includes the following five steps:

 Acid and coagulant is added to a reactor tank to modfy pH and bind fine solids together

Waste water enters a Dissolved Air Flotation (DAF) tank to inject air and allow solid particles to float to the top (which are scraped off and sent to waste)

Partially treated water enters the new gravity media (sand) filters to remove more solid particles and further improve quality

Pumps push the water through 80 high intensity UV lamps to disinfect pathogens (disease forming bacteria)

Recycled water is then injected with chlorine and stored in two 2.5 megalitre storage tanks, from where it is accessed by the end user.

 Testing is expected to be complete by mid December and will be available for customers straight away.

 Alice Water Smart is supported by the Australian Government.