Wastewater challenge reframed

COLUMN

A WELL-functioning wastewater system is essential infrastructure for our city. To be well-functioning, and protect human health, comes at great cost to city dwellers.

A group of councillors and iwi leaders, enabled by council staff, are tasked with our wastewater challenge. They are responsible for our wastewater consent — containing 62 conditions/clauses — that the council is to comply with. We cannot focus solely on the tip of the iceberg; there are also challenges in the other 90 percent that lies below the surface — invisible to most.

Our wastewater challenge requires a strategic, holistic and integrated approach. At present, we are dedicated to finding three alternative treatment options to wastewater disinfection — options that must meet/exceed the consent discharge quality. We are discussing constructed ecosystems/wetlands, hybrid systems, and the consent default condition.

The “default” condition is to proceed immediately with wastewater disinfection. This requires an initial and expensive pre-disinfection step of solids (sludge) removal and management. Remembering the need for a strategic, holistic and integrated approach, we also need to be very cognisant of the many other clauses we need to comply with. Let me expand on a few of these so everyone can share in the depth, and hence unbudgeted costs, of this challenge.

We are dealing with sewage, or human waste: human excrement, grease/oil, chemicals, pharmaceuticals, illness-causing pathogens (viruses, bacteria) etc. The removal or bio-transformation of these components is needed to protect human health and safeguard natural environments (and their living organisms). We should not spread or shift the burden of substances harmful to human health from our confined wastewater system into rivers, oceans or other living organisms, eg shellfish. We want full and cost-effective treatment.

Our consent has a dedicated section on investigating alternative use and disposal (AUD) of waste-water. Depending on the level of treatment achieved, this treated water has re-use potential for irrigation via storage infrastructure (wetlands, ponds, aquifers etc), or it can be recycled for low-grade uses (eg toilets, laundry). This happens today in many countries (eg America, Israel, Spain), and in others, wastewater becomes human drinking water (eg Sydney, London).

This part of the consent opens our minds to wastewater-as-an-asset thinking (to see a valuable resource). Think of it this way: our homes receive treated drinking-quality water; we make it dirty in a variety of ways (toilets, kitchens, laundry,); we then treat this “dirty” water — again — to the highest standard possible; and then throw it away like it’s worthless! Looked at this way, and in the era of climate change, this could be classed as madness. And, add to this scenario, that we could have invested maybe $70-80 million on treatment, to then throw it away. Utter madness. Therefore, investigating AUD makes for wise expenditure of public money as we develop options.

Finally, the consent requires the council to search for alternative disposal locations to the marine outfall. This is a feature of extreme importance to local iwi (and many others). To achieve this would also create positive economic and environmental benefits via removal of many consent conditions such as plume monitoring, benthic and rocky reef surveys, and marine outfall water sampling (all ongoing and expensive requirements).

While the immediate goal is to provide the council with three wastewater management options, the scope of the consent requires a more strategic, holistic and integrated approach. We have to treat the waste to a high water quality standard. If we can re-value it and find productive uses for it, we also find new discharge locations (not the ocean). This upfront, win-win-win approach comes at a cost, but it also makes complete sense.

A WELL-functioning wastewater system is essential infrastructure for our city. To be well-functioning, and protect human health, comes at great cost to city dwellers.

A group of councillors and iwi leaders, enabled by council staff, are tasked with our wastewater challenge. They are responsible for our wastewater consent — containing 62 conditions/clauses — that the council is to comply with. We cannot focus solely on the tip of the iceberg; there are also challenges in the other 90 percent that lies below the surface — invisible to most.

Our wastewater challenge requires a strategic, holistic and integrated approach. At present, we are dedicated to finding three alternative treatment options to wastewater disinfection — options that must meet/exceed the consent discharge quality. We are discussing constructed ecosystems/wetlands, hybrid systems, and the consent default condition.

The “default” condition is to proceed immediately with wastewater disinfection. This requires an initial and expensive pre-disinfection step of solids (sludge) removal and management. Remembering the need for a strategic, holistic and integrated approach, we also need to be very cognisant of the many other clauses we need to comply with. Let me expand on a few of these so everyone can share in the depth, and hence unbudgeted costs, of this challenge.

We are dealing with sewage, or human waste: human excrement, grease/oil, chemicals, pharmaceuticals, illness-causing pathogens (viruses, bacteria) etc. The removal or bio-transformation of these components is needed to protect human health and safeguard natural environments (and their living organisms). We should not spread or shift the burden of substances harmful to human health from our confined wastewater system into rivers, oceans or other living organisms, eg shellfish. We want full and cost-effective treatment.

Our consent has a dedicated section on investigating alternative use and disposal (AUD) of waste-water. Depending on the level of treatment achieved, this treated water has re-use potential for irrigation via storage infrastructure (wetlands, ponds, aquifers etc), or it can be recycled for low-grade uses (eg toilets, laundry). This happens today in many countries (eg America, Israel, Spain), and in others, wastewater becomes human drinking water (eg Sydney, London).

This part of the consent opens our minds to wastewater-as-an-asset thinking (to see a valuable resource). Think of it this way: our homes receive treated drinking-quality water; we make it dirty in a variety of ways (toilets, kitchens, laundry,); we then treat this “dirty” water — again — to the highest standard possible; and then throw it away like it’s worthless! Looked at this way, and in the era of climate change, this could be classed as madness. And, add to this scenario, that we could have invested maybe $70-80 million on treatment, to then throw it away. Utter madness. Therefore, investigating AUD makes for wise expenditure of public money as we develop options.

Finally, the consent requires the council to search for alternative disposal locations to the marine outfall. This is a feature of extreme importance to local iwi (and many others). To achieve this would also create positive economic and environmental benefits via removal of many consent conditions such as plume monitoring, benthic and rocky reef surveys, and marine outfall water sampling (all ongoing and expensive requirements).

While the immediate goal is to provide the council with three wastewater management options, the scope of the consent requires a more strategic, holistic and integrated approach. We have to treat the waste to a high water quality standard. If we can re-value it and find productive uses for it, we also find new discharge locations (not the ocean). This upfront, win-win-win approach comes at a cost, but it also makes complete sense.

Your email address will not be published. Comments will display after being approved by a staff member. Comments may be edited for clarity.

Poll

  • Voting please wait...
    Your vote has been cast. Reloading page...
    Do you think the benefits of forestry to the region outweigh its negative impacts?
    See also: