Honolulu reuses its wastewater

Posted on 12 January 2017.

Veolia has built a wastewater recycling plant in Honolulu. Every day, 49 million liters are treated for direct reuse. It’s enough to solve the supply problem the city was facing a few years ago.

The plant treats over 49 million liters of wastewater per day.

Water is a precious resource - something they know all about in Honolulu. Over the past 40 years, the capital of Hawaii has enjoyed strong economic development: numerous businesses, residences and industries have been created on the island, resulting in a significant increase in water demand for both  production, and its residents.

So much so that in the 1990s, local aquifers - that is to say the underground water resources - became almost exhausted.

Given this alarming observation, the US Environmental Protection Agency, the Hawaii Department of Health and the City of Honolulu signed an agreement in 1995 to improve the city's wastewater network. A federal decree – which included with the threat of heavy financial penalties - stipulated that from 2001 Honolulu would have to re-use at least 38 million liters of water per day. Previously, effluent and wastewater were simply discharged straight into the Pacific...

To meet this challenge, in 1998 Honolulu called on Veolia to build a water recycling plant employing all the latest state-of-the-art technologies (microfiltration, UV disinfection, sand filter, reverse osmosis.

Since 2000 - the year it was commissioned - the plant processes more than 49 million liters of wastewater every day. It produces two types of water including high purity water sold to industry and local farmers.

This system has numerous advantages. Firstly, Honolulu has exceeded the target set by the federal decree but in addition, it saves the city more than $35 million: buying recycled water is cheaper than buying drinking water. And above all, the plant has a really positive impact on the environment: by reusing its wastewater, Honolulu is preserving its natural resources and not discharging polluted water into the ocean.

In 2003, the project received an award for its "exceptional contribution to the sustainable use of water" from the association WaterReuse which brings together various public and private actors.

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