Our Wastewater and The Manawatu River
Water infrastructure is vital to public health and safety. If the transportation infrastructure breaks down, travel will be slow and the slowdown will mean that businesses and households will incur costs. But travellers will eventually get to their destinations. Water infrastructure, however, is essential to sustain life. A well-maintained wastewater infrastructure is critical for public health, strong businesses and clean rivers.
Palmerston North wants local jobs and industry needs wastewater infrastructure to sustain growth. The city needs to provide appropriate infrastructure to support that growth. We are a growing agricultural and bio-research hub for which the city manages the wastewater.
Do we want to be a community that meets minimum standards with limited capacity for growth? Or can we be a community with future-proofed infrastructure that attracts industry and protects our environment?
We need to reduce the amount of wastewater and reduce harmful products that infiltrate into storm-water. We can set future building standards to recycle more grey water, such as for toilets, to significantly reduce the amount of wastewater produced by a household.
Mitigation options for improvements to the PNCC Wastewater Treatment Plant at Totara Rd, at the lower end of cost, treating for Total Particulate Phosphorus (TP) removal costing around $3m and treating for reducing Soluble Inorganic Nitrogen (SIN) at a capital cost of up to $18.6m ($21.5 for both options together). Both nitrogen and phosphorus levels are big problems for the river.
At the higher end of mitigation options for Totara Rd we could spend up to $42.2m for construction of a new biological nitrogen removal plant.
These options will all help reduce the long-term effects of excessive periphyton growth on the whole ecological system. However they can only ever ‘reduce’ the effect, not ‘remove’ the source of the problem.
Yet there is no guarantee that mitigation options will be successful. And consent standards are becoming more stringent all the time. For example, in 2002 PNCC spent $16m on treatment upgrade for phosphorus removal and UV treatment – but the standards are already out of date in terms of The PNCC’s current consent breaches. We are spending a lot of time and money trying to establish what aspect of our treated waste is causing the significant adverse effects on aquatic life. Is it the phosphorus, is it the nitrogen? Maybe if we treat the problem with a chlorine process it will solve things… or will that create a new issue. I actually don’t know. But nor do the scientists.
Moving on to Land-based Disposal….
In 1999 a Council investigation into treatment options outlined all-season land based options and three land and river options ranging in cost between $34 and $76million so the initial investment in moving to land-based disposal is expensive.
In balance, there are cost savings when we take into consideration the life extension of plant and the growing legal costs to defend antiquated plant breaking consents. Income from trade waste fees, alum savings and increased tourism around river and natural attractions reduce the burden to ratepayers all add positives to the economic equation.
Using our wastewater to grow things on a land-based closed loop system is the only thing that makes sense as a long-term solution.
In 1995 Taupo District Council implemented a new land disposal scheme, disposing of secondary treated municipal wastewater to land in a cut and carry farming operation. The council recently expanded its land disposal scheme to minimise nutrient inputs from point source discharges into the Lake Taupo and Waikato River catchments. A combined scheme now has the potential to irrigate up to 12,000 m3/d of treated wastewater effluent across almost 500 hectares of farmland around the periphery of the Taupo urban area. The cut and carry hay bailage crop is bailed and sold to farmers as part of this sustainable reuse initiative, and helps to fund the scheme. This represents the largest municipal wastewater irrigation scheme in New Zealand. Treated wastewater is irrigated to pasture where nutrients are stripped from the effluent by plant uptake and biological soil mechanisms, with excess nitrogen leaching to groundwater or volatising to the atmosphere. The associated nutrients are removed from the system during harvest when grass is cut, baled and taken off site.
If PNCC purchased suitable land based property and used that land for say, forestry, for every 50 hectares harvested would return $1m (in todays money at today’s commodity prices) once harvesting started. We could have already had a 13 year-old crop in the ground. Exploring farming a mix of cash crops and long-term crops would be interesting but the current council leadership has clearly signaled it is only interested in scoping mitigation options.
Wastewater upgrades have been built into financial models so the cost is not beyond the councils’ current financial modeling. As debt is refinanced to lower interest rates (PNCC is currently paying a high rate of around 7%) financing for infrastructure becomes more affordable.
Until very recently we had the Staces Rd Bridge project in our 10 Year Plan at an estimated cost over $100m (at 2012). This has now been removed and if we were indeed prepared to borrow for a project with dubious economic advantage, we should be prepared to borrow to create a long-term solution for wastewater. The fact that the bridge is no longer in our LTP means that we now have that financial headroom available.
Continuing to dispose into the river is like saying the river is a convenient drainpipe for washing all our waste out to the ocean, so let’s just make our waste less toxic and everything will be fine.
Under a river-based disposal system, our wastewater facilities will forever be required to meet more stringent environmental goals with expensive upgrades, operations and maintenance will become more expensive (with growing alum cost for example), yet the river will still be polluted.
Agriculture can no longer discharge waste directly into waterways, and if it’s good enough for us to enforce this onto them, then it’s good enough for us to consider that our discharge (consented or not) hardly gives us any moral ground to jump up and down about the quality of the river.
If we don’t make a plan to stop, who else is going to have incentive to, and then what does the River Leaders Accord and One Plan really mean?