Expanding from non-potable to potable reuse
Direct Potable Reuse (DPR) is an alternative, sustainable supply of water that can help Florida to meet its projected water needs.
By 2035 the sunshine state is forecast to require an additional 1.1 billion gallons of fresh water per day to help meet supply.
And with fresh groundwater supplies becoming limited, reusing water for potable uses has become a proven method across the US to augment water supplies.
Technology advancements have made the costs of treating potable reuse competitive with alternative water supply sources, such as seawater and brackish desalination.
That’s according to a new guidance document – Framework for the implementation of potable reuse in Florida – prepared for the Florida Potable Reuse Commission.
The extensive document outlines what is required, in regulation, stakeholder engagement and technology know-how, to help Florida increase the amount of water reused for potable applications.
Water quality assurances required
The Florida Potable Reuse Commission (PRC) was organised to create the framework to be used by the water industry, regulators and all stakeholders to help “advance the safe implementation of potable reuse in Florida”.
The Framework was prepared for the PRC, including the following collaborative partners:
Florida Section of the American Water Works Association Water Utility Council
Florida Water Environment Association Utility Council
Water Research Foundation
Water Reuse Association.
While it acknowledged that potable reuse has existed for decades as a proven way to deliver high quality, safe drinking water, PRC said the alternative water supply requires “appropriate treatment and water quality assurances”.
The guide added that treatment processes using a “multi-barrier approach”, include a combination of technologies to provide reliability and redundancy.
Current water use in Florida
More than 75 per cent of Florida’s water supply comes from aquifers. However, the availability of additional fresh groundwater is becoming limited in many areas of the state.
It’s estimated that an additional 1.1 billion gallons of water per day will be needed by 2035 to meet demand. This is against a current water use of 6.5 billion gallons used today.
Though much of the state receives an average of 50 or more inches of rain per year, most of that falls within a four-month period beginning in June and ending in September.
Florida adopted regulations for the use of reclaimed water more than 20 years ago, which set the stage for a successful statewide reuse program.
Today the US state reuses 48 per cent of its total domestic wastewater for non-potable uses, such as landscape irrigation and industrial uses.
Although current reclaimed water regulations exist in Florida for indirect potable reuse (IPR) for augmenting surface water, they do not address IPR involving groundwater replenishment, and the regulations do not address DPR.
As such, the PRC recommends a revision to Florida’s drinking water regulations to consider reclaimed water as a source water.
With this recommendation, drinking water produced from all potable reuse projects would be required to meet existing primary and secondary drinking water standards.
“Florida must have additional sustainable alternative water supplies to meet the future needs of its residents, agriculture, and industry, and to secure a robust economic future,” the Framework added.
Water reuse projects across the US
Potable reuse has been practised in the United States for a number of decades; however, it has evolved over the past 50 years.
The Orange County Water District (OCWD) is currently going through the third stage of an expansion to its flagship Groundwater Replenishment System (GWRS).
Meanwhile Californian city Santa Monica is moving ahead with plans to reuse brackish groundwater, wastewater and stormwater as part of its Sustainable Water Infrastructure Project.
In terms of DPR projects, severe drought conditions in the 2000s were a key driver for utilities, with
communities including Big Spring, Texas (2013) and Wichita Falls, Texas (2014) implementing projects.
DPR was essentially the only feasible solution to address the water resource challenges for these communities, the Framework added.
Public acceptance of alternative water supply sources has also increased as conventional sources have been adversely affected by recent severe droughts in states like Texas, California, and Arizona, and demand has increased amid rapid population growth.