Developing National Wastewater Discharge Standards for New Zealand with an Indigenous Focus

BACKGROUND
New Zealand's publicly owned wastewater infrastructure is facing a major challenge. A significant proportion was built around 30-40 years ago, and upgrades or renewals are required for many wastewater treatment plants (WWTPs) and networks. Each WWTP has a consent/permit for the discharge of treated wastewater to either freshwater or estuarine/marine receiving waters, or to land by irrigation or other application systems. Since 1991, these consents, and the consenting process by which they are granted or renewed, have been authorized under New Zealand's Resource Management Act (the Act or RMA 1991).

The Act mandated extensive public and stakeholder participation in the consenting process by the applicants, as well as consideration of a number of alternative options. It was also very much focused on the 'effects of the activity on the environment' due to the abstraction or discharge, however, the Act was relatively silent on specific 'end of pipe' discharge standards for wastewater unlike in many other countries.

New Zealand's indigenous people — the Māori — are given primacy when it comes to RMA consenting and consultation, particularly for wastewater discharge consents. Māori have a very strong cultural aversion to discharge of any human sewage to fresh or marine waters.

THE CHALLENGE
Around 70 percent of the 326 public WWTPs will require reconsenting in the next decade, and 15 percent of all plants are currently operating on expired consents. Upgrading wastewater infrastructure is both resource intensive and a significant investment for councils, with many communities facing affordability challenges and competing demands on how rates should be spent.

To reduce the costs and legislative burden on WWTP owners, and to expedite this wave of new consents, plus achieve better environment outcomes for New Zealand, the Government decided to develop new National Wastewater Treatment Performance Standards which would apply to all WWTPs.

DEVELOPMENT OF STANDARDS
The Government department tasked with development of these new national standards was the Water Services Authority — Taumata Arowai (the Authority) whose functions and powers are set out in the Water Services Regulator Act 2020 and the Water Services Act 2021. The Water Services Act (2021) enables the Authority to make wastewater environmental performance standards following consultation with wastewater network operators, regional councils, and any other person considered appropriate. Standards may include requirements, limits, conditions, or prohibitions related to activities associated with wastewater networks, including:
- discharges to land, air or water
- biosolids and any other byproducts from wastewater
- energy use
- waste that is introduced by a third party into a wastewater network (for example, trade waste).

In late 2024, the Authority commenced a two-pronged investigation into what standards should be for treated wastewater discharges to water; to land; biosolids; and wastewater network overflows management. The two components were:
1. A technically focused review of international standards; current NZ consent standards for a range of sizes of WWTP; relevant treatment parameters; consideration of a single universal standard or a more targeted set of standards.
2. A series of case studies where Māori/mana whenua have been an integral part of recent wastewater consenting processes (see below).
[Mana whenua is a term that refers to the Māori people who have ancestral and territorial rights to a specific area of land. The term also refers to the customary authority that they exercise over the land]

INDIGENOUS/MANA WHENUA INPUTS
To inform the development of the standards, the Authority engaged with several mana whenua groups to understand perspectives on wastewater treatment arrangements. Some of the themes from this engagement were:
- Māori consider human waste to be tapu (prohibited) due to its impact on the health of people and the environment. This means that human waste must undergo a process of whakanoa (cleansing) before it can be safely integrated back into the environment.
- The preference is for the highest standard of treatment possible for both water and land-based approaches, at the point of discharge. Where wastewater is discharged to water, at minimum it should not have a detrimental impact on the health and quality of the taiao (receiving environment) or the people that use the environment.
- While iwi and hapu strongly prefer discharge to land, there are a number of examples where this option has not proved feasible. This has primarily been because nearby land is not suitable, is too productive and expensive, or the WWTP is too large for the land area required for disposal.
- There is a strong preference for ongoing 'at-place' decision-making to ensure that mana whenua are involved in decisions affecting them and can actively participate in all phases of the wastewater treatment processes.

CURRENT STATUS
The set of draft standards has now (January 2025) been completed and, after Government approval in principle, will be open for wider public consultation, including with Councils, regional water regulators, and with mana whenua. By September 2025 these Standards will be finalised and gazetted as the National Wastewater Standards for New Zealand, and these will be reported on in more detail at WEFTEC 25.