Locale : Global (English)
1 / 2
2 / 2

Underpinning Auckland's growth

More than 1.5 million people live in Auckland and the population is forecast to be almost 1.9 million by 2035. As New Zealand’s most populace city grows its infrastructure needs to keep pace, and in a sustainable way.

Project Rosedale wastewater treatment plant, Auckland, New Zealand

ClientWatercare Services Ltd

ExpertiseConcept and detailed design

The Rosedale wastewater treatment plant (WWTP) serves about 17% of Aucklanders and is the region’s second largest. A programme of upgrades to the facility, will raise capacity by a third, enough to treat waste from 320,000 people, with peak flows of up to 4m3/s. Our original design included primary sedimentation and a modified activated sludge plant to increase liquid stream capacity as well as a new digester to improve the anaerobic digestion process. We have since developed the design for a thermal hydrolysis plant with partners Stantec. The upgrades to Rosedale will improve its resilience, reduce waste solids and greenhouse gases, and raise biogas yield to help power the plant.

The upgrade includes expanding the primary tanks, renewing the odour control equipment, modifying the bioreactor and digester, and improving the UV disinfection and associated electrical infrastructure – essential to ensuring the environment and waterways are kept clean, and drinking water is of the highest quality.


people served by upgraded plant

The new thermal hydrolysis plant will improve biogas yield and the destruction of solids. Electricity from biogas currently provides more than half the power needs of Rosedale. We are now supporting the integration of sustainable practices, including reducing aeration for biological nutrient removal, an energy-intensive process – helping Watercare achieve its goal of running the plant on 100% self-generated electricity by 2025. 

Rosedale is one of the top five most energy-efficient plants in Australasia. It also reuses treated water onsite, freeing up fresh supplies for Auckland’s burgeoning population. The thermal hydrolysis facility will be completed in 2022, enabling biosolids from the treatment process to be sterilised to create fertiliser that can be used by the agricultural sector.

expand-image mail-envelope icon-icon-linkedin-mmdv-green icon-close arrow-left icon-section icon-section-white arrow-down icon-arrow-down-sml icon-arrow-left-lrg icon-arrow-left-sml icon-arrow-right-lrg icon-arrow-right-sml icon-arrow-up-sml icon-champions icon-section icon-section-white icon-download icon-education icon-email icon-grid-view icon-language icon-link-to icon-list-view icon-location icon-login-register ec-icon-login-register icon-ec-apply-arrow icon-ar-apply-arrow icon-mm-icon-search-ec icon-minus icon-more icon-phone icon-plus icon-recently-viewed icon-search icon hash key-facts-corner-sash quote-underline social-icon-facebook social-icon-googleplus social-icon-linkedin social-icon-twitter social-share-icon-facebook social-share-icon-facebook social-share-icon-googleplus social-share-icon-googleplus social-share-icon-instagram social-share-icon-instagram social-share-icon-linkedin social-share-icon-linkedin social-share-icon-twitter social-share-icon-twitter social-share-icon-youtube social-share-icon-youtube sina-weibo MM-Shape01-Quote-Views MM-Shape03-Quote-Locations MM-Shape05-Quote-Projects MM-Shape12-Quote-Sectors MM-Shape13-Quote-Expertise MM-Shape14-Quote-About-Us MM-Shape14-Quote-Careers checkmark icon-expand-view icon-apply-now menu linkedin-mmdv-green icon-ad-close mail-mmdv-green icon-ad-menu menu-close ec-menu-close sphere icon-cookies icon-legal icon-registered-companies target rotate-screen video-replay-flat video-replay audio-mute audio-play
Mott MacDonald main logo

Would you like to hear more from us?

Sign up to receive notifications