Army Bay Sewage Treatment Plant, Rodney District, New Zealand

The expansion of Rodney District's Army Bay Sewage Treatment Plant, North Island, New Zealand was completed in 2007. The plant required an increase in treatment capacity because of the additional sewage wastewater from reticulated areas on the Hibiscus Coast, which includes Orewa and the Whangaparaoa Peninsula. Rodney District Council, which is responsible for the area, also considered the ability of the plant to protect the marine environment on the Hibiscus Coast.

There are currently 35,000 residents in the Rodney area with a projected population increase of 81,000 by 2051.

CONSULTATION AND CONSTRUCTION

The Rodney District Council asked Sinclair Merz Knight (SKM) to conduct a study on the plant and determine what could be done to increase its operational life. SKM recommended upgrading the plant.

The NZD$10m upgrade was approved and commissioned in March 2006. SKM produced a detailed design for the plant and provided civil, structural, mechanical and electrical engineering services, construction supervision, project management and commissioning of the plant. The design also formed the basis for the design of three new wastewater treatment plants for the neighbouring Thames-Coromandel District Council.

PLANT COMPONENTS

The plant was equipped with a new grit removal and handling system along with a new enhanced sequential batch reactor (ESBR) with a new decanted and aeration system. An ultraviolet light (UV) system was installed for the final disinfection of the treated effluent. The existing sequential batch reactors (SBRs) were also upgraded.

SILVER AWARD

The upgraded plant won a silver award for SKM at the Association of Consulting Engineers of New Zealand (ACENZ) INNOVATE NZ Awards of excellence in August 2007 for its environmental consideration and relationship management of the project.