9 December 2020
Media: Local Democracy Reporter
Topic: Terax project
Enquiry
I have some more questions that have arisen in the course of working on my story about Terax.
I also have some comments from Gerard Horgan I would like to invite the council to reply to if desired. Some of my questions cross over with Horgan's comments. I've left them in context. As well as right of reply, please respond to any inaccuracies in Horgan's comments.
Questions
- Why was Gardener's Gold composting no longer an option for the council? Is it still not an option?
- When did the council contract Ecocast to deal with its sewage sludge? How much is this contract worth, and does it remain ongoing today?
- If there was ever a contract with any other company for the disposal / processing of Rotorua's sewage sludge since the end of Gardener's Gold, please let me know the details of that also.
- How long did Rotorua District Council send sewage sludge to landfill and when was this? (if the exact day is not known, months is ok)
- If the council's contract with Ecocast crossed over with its continued pursuit of Terax, what was the reason for this?
- i.e. are other methods still being pursued, or is the council satisfied with this method for the foreseeable future?)
- Did the Terax pilot plant break down?
- If so, please provide details on any and all instances of this, including what the problem was, whether it was repaired - if so, how much did that cost. If problems were not repaired, why was this and how much was it expected to cost?
- Is the expected $5000 to wind down the Terax partnership included in that $6.7m total figure you gave me some months ago?
- If not can you please also provide me with the total cost of winding down the partnership and the company to add to that $6.7m figure.
- Tell me about the deal with Pacific Channel to commercialise the technology - how much of the profit (percentage wise) does the council expect to receive should the technology be successfully commercialised?
- Is it correct to say the demonstration plant was ultimately not viable because of the risk of nitrogen discharge into the lake as a result of the process? If not please clarify that point. When did the council become aware of this risk?
Horgan's comments:
[Terax is wet oxidation combined with standard anaerobic fermentation]
Horgan says wet oxidation has been around since the 1930s.
Even back then it was recognized [that] it could be a nice way of treating sewage sludge.
However, he says, that process has always been plagued with a cost problem due to the highly oxidising conditions and pressures that ravage the vessels holding the sludge.
It'll rust like nobody's business.
You have to use very expensive steels to stop your vessels oxidizing along with the process. That means that makes them highly expensive to build.
He says that came to fruition in Rotorua when the Terax pilot plant broke down.
In 2014 Horgan warned the council of the processes' expense and unreliability.
Proper and adequate testing of the commercial viability of Terax needs to be done - ideally not with Rotorua ratepayers acting as the test guinea pig, his submission read.
In 2016 he told the council other councils weren't taking up licenses to use Terax because it was an expensive process involving substantial risk, high maintenance costs and there were other ways of processing sewage sludge that were cheaper.
He called a council report titled Terax plant - approval to proceed' faulty and demonstrably wrong.
Talking with me at the cafe, Horgan says Scion had stepped forward in 2008 with a solution to the council's sludge issue - something Scion's chief executive, Julian Elder, would later dispute when I raise it with him, saying the approach was mutual.
[They] said, have we got a deal for you? We can solve your problem, Horgan tells me.
We've got this new wonderful never-before-seen technology,' it just needs a teensy-weensy bit of tweaking, needs a bit of money for research. The council said 'Oh! A solution! Where's the ratepayers' wallet?'
Horgan says that proposition was a lie - and says around the same time vermiculture was being investigated by Scion as a way to deal with Rotorua's sewage sludge - a composting process involving worms.
So you've got two competing technologies, Horgan says.
All [the council's] analysis of Terax was based on 'we can either use Terax and get rid of it, or we have to take it and put it in the dump'.They put it in the dump for about six months in 2008. Thereafter it went - and it's been going ever since - to Kawerau, to the vermiculture.
Response
The following was provided by Group Manager Infrastructure Stavros Michael:
- Why was Gardener's Gold composting no longer an option for the council? Is it still not an option?
It is my understanding that until about 2009/10 wastewater treatment plant biosolids were mixed on site with green waste to create compost. The operation called "gardener's gold" became unviable for three key reasons:
- The method of mixing in open air generated unacceptable odour effects with community objections
- Significant bulking agents were required (sawdust and shavings) that were becoming too costly and scarce
- There is no market for the product as users became averse to using it with the mixed sludge (biosolids), especially on applications to land that would generate food. Significant upgrade to the process was required to mitigate that emerging objection.Ecocast is a vermicomposting process and the use of worms to break down the biosolids into more natural constituents was seen as far more acceptable. Ecocast managed to secure all required permits to apply the product to land and in addition secured steady and reliable bulking agents (pulp) for the process. The facility is away from residential areas so odour is not an issue.
- When did the council contract Ecocast to deal with its sewage sludge? How much is this contract worth, and does it remain ongoing today?
- If there was ever a contract with any other company for the disposal / processing of Rotorua's sewage sludge since the end of Gardener's Gold, please let me know the details of that also.
When the Gardener's Gold operation became unviable, around 2010, Council was forced to send biosolids to the landfill until 2012.
This was problematic because sludge/biosolids were required to be mixed with general waste on a ratio of 1:4 and with 10,000 tonnes of bisolids per year, a minimum of 40,000 tonnes of waste was required at the landfill and the amount of waste to landfill was reducing to below 30,000 tonnes.
In addition, biosolids with high water content (about 80%) was a source of instability for the landfill face and was generating high leachate concentrate that needed to be re-treated at the WWTP. So landfilling was not viable for technical, environmental and financial reasons.
No other contract for the biosolids was entered into other than the landfilling.
While the cost of the Ecocast contracts and landfill were similar, operationally the landfilling was problematic (as outlined above) and it was important to find the best beneficial re-use option available.
The first contract with Ecocast started 1 November 2011 for an annual average cost of about $800,000 including transport and a second contract was awarded to Ecocast in 2016. This contract has been novated to Trility as part of the wastewater services contract. Trility is responsible, under that contract, for the beneficial use of biosolids and they have an ongoing contract with Ecocast on the same terms as the wastewater services contract i.e. at least 10 years. This is still seen as the most cost effective and environmentally viable option.
- How long did Rotorua District Council send sewage sludge to landfill and when was this? (if the exact day is not known, months is ok)
See above
- If the council's contract with Ecocast crossed over with its continued pursuit of Terax, what was the reason for this? (i.e. are other methods still being pursued, or is the council satisfied with this method for the foreseeable future?)
The TERAX proposal was an attempt to explore emerging technology to deal with biosolids instead of landfilling. In the context of the TERAX process being proven to be non-viable, vermicomposting through Ecocast is currently seen as the most beneficial and viable option for the foreseeable future, and the management of biosolids is now the responsibility of Trility.
- Did the Terax pilot plant break down? If so, please provide details on any and all instances of this, including what the problem was, whether it was repaired - if so, how much did that cost. If problems were not repaired, why was this and how much was it expected to cost?
In constructing a model there is always testing and modification and breakdowns during the pilot programme were not unexpected.
However, Council does not have the specifics about the breakdowns. This was managed by Scion.
- Is the expected $5000 to wind down the Terax partnership included in that $6.7m total figure you gave me some months ago?
Yes
- Tell me about the deal with Pacific Channel to commercialise the technology - how much of the profit (percentage wise) does the council expect to receive should the technology be successfully commercialised?
Re Pacific Channel: Pacific Channel provided services to the TERAX partnership to explore commercial options but are no longer involved as the partnership is being wound up.
Re profit share part of the above question: The Terax intellectual property has been transferred to Scion and any further/future developments would be led by Scion while any commercial value derived would be shared 50/50 between Council and Scion.
- Is it correct to say the demonstration plant was ultimately not viable because of the risk of nitrogen discharge into the lake as a result of the process? If not please clarify that point. When did the council become aware of this risk?
The pilot plant was not able to negate the by-product of biosolids treatment in a manner that would not add nutrients back into the wastewater treatment process. Council was alert to that requirement early on and monitored the results of the pilot plant's trials. But this was not the sole reason as the viability of the technology required a scaled up plant and that required more capital investment. Council was aware of the return nutrient risk but worked with the technology to see whether there were options to neutralise that risk.