Membrane Aerated Biofilm Reactor - First Full-scale Plant in New Zealand

Nadine Oschmann, Bronson Light (Veolia Water Technologies & Solutions), Kevan Brian and Hui Ian Tan (Watercare Services Ltd)

Membrane Aerated Biofilm Reactors or MABR’s are a new technology for the treatment of wastewater. The process is energy efficient and ideal for process intensification where additional total nitrogen removal or nitrification is required. MABR applications are very well suited to process upgrades in New Zealand where oxidation pond systems are required to meet tighter nitrogen consents year-round. Therefore, MABR technology was installed at the Helensville wastewater treatment plant and has been selected as the technology of choice for several future pond upgrades by Watercare.

The existing biological treatment process at Helensville WWTP included a 3 mm rotary drum with spiral sieve screen followed by two stage oxidation pond system and an Ultrafiltration (UF) Tertiary Membrane Plant, which discharges into a third pond, before the treated effluent is discharged to the Kaipara River. 

The WWTP has been historically non-compliant with resource consent requirements for several parameters. The WWTP has been upgraded with Membrane Aerated Biofilm Reactor (MABR), because of its ability to provide total nitrogen reduction in a compact footprint and the ease of integration with the rest of the treatment plant. The upgrade project included the installation of a new MABR system for nitrification, as well as installation of a third UF Membrane train. The objective of the MABR is to treat an average of 1,500m3/d of pond effluent to reduce ammonia nitrogen to meet the plant resource consent and to meet more stringent effluent quality targets. The MABR cassettes are installed in dedicated stainless-steel tanks upstream of the existing UF plant. Ammonia is removed by the nitrifier population on the inside of the biofilm. The plant was commissioned in March 2023. 

This paper presents the results of the start-up and first few months of operation of the Helensville MABR plant.