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Net Zero Discharge A key element/goal for Sustainable Water Cycle Management

IWRA 2021 Online Conference One Water, One Health
Theme 4: What are the synergies or trade-offs between ecosystem health and human health?
Author(s): Dr Charles Essery

Dr Charles Essery
Managing Director
Sustainable Water Solutions
Pty Ltd
Sydney, Australia

Keyword(s): Potable water recycling, Effluent Credits, Net zero discharge, Resource cycling


Water utilities and other water resource users need to resolve the conflicting demands from water consumption and subsequent discharges into receiving waters. Traditionally, regulatory/financial/political/community pressures have driven urban water utilities to deliver water as cheaply as possible and to dispose of the wastewater quickly and at minimal cost without breaching environmental/health regulations.

Given the increasing demand of “stakeholders/shareholders” (both public and private), financial performance still dominates. Yet increasingly communities want secure, reliable, healthy water services that have minimal environmental impact. Net zero discharge (NZD) may offer a pathway to achieve this long-term goal, but will require regulatory approaches that match the cyclic nature of water within the environment and our urban communities increasing demand. NZD gains little attention in these days of “net zero carbon emissions”, yet it is a goal that can deliver all the altruistic aspirations of low resource “footprints”.

Delivering NZD can be achieved by maximizing urban harvesting, minimizing wastage, recycling, decentralization of infrastructure and applying appropriate triple bottom line accounting and full lifecycle costing. Wastewater management and disposal has always been a point of conflict and compromise. Wastewater is 99+% water molecules, yet we continue to see this >1% of waste as an unsolvable issue. Effluent credits, environmental services, waste discharge licensing, potable recycling and waste recovery technologies can all be applied to this issue. Using existing statutory tools embedded in current NSW legislation, yet individually focused siloed bureaucracies instead use “their core legislative tools” to defend turf, position and powerbase.

In Australia, the longstanding resistance to potable recycling by health, environmental, resource, fiscal and policy “gatekeepers” makes the achievement of net zero discharge a distant, if not unachievable goal. Regulatory tools exist within current legislation to support an NZD outcome. This paper provides a framework that will enable water utilities to achieve this goal, while retaining their financial performance targets demand from their shareholders. This will be achieved by minimizing water extraction and other resources while delivering minimal impact on upstream and downstream communities.

The framework can be readily applied under other jurisdictions, assuming government policy and alignment of legislation can be applied consistently in a manner that matches community and environmental needs.

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