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Muri lagoon problems ignored for 20 years

Saturday November 28, 2015 Written by Published in Weekend

 A potentially serious and alarming situation is looming for many of Rarotonga's accommodators, restaurateurs, bars, traders, public and private buildings as well as private residents.


And it’s all because of the sanitation requirements of new regulations.

By way of introduction, I quote below from my letter published in CINews on April 14, 2011, on a reticulation sewerage system..

"In the lead up to the last general election I endeavoured to interest those candidates who approached me to address this very question and urged them to seek out a report prepared for Government back in the 90s dealing with exactly that concept and which would be gathering dust somewhere.

“A group of consultants was here on an ADB funded technical assistance study to bring down a report, from memory largely focused on the landfill question and management of waste, and a group of us in Muri asked for a meeting with them to request that they widen the scope of their study and address the special case of the treatment of waste in the Muri area, because of our increasing concern for the health of the lagoon.

“It was called the Barrett's Report and it contained a chapter dealing with our area of concern. It was called something like, ‘Eastern Coastal Sewage Disposal System.’

“Basically what they recommended was to have a main pipe running from Parengaru to Pouara in Matavera and at right angles to that main trunkline feeder pipes to each property both residential and commercial and a vacuum arrangement that drew all the waste from a holding tank, which in most instances would be existing septic tanks, which would then be pumped to a primary treatment plant at Pouara, with eventual disposal across the reef to the ocean where it had been established the currents were conducive to rapid and safe dispersal.

“Some of my recollection could be faulty, but the point is this professional and engineering work has already been done and costed (albeit at 1990s values) and it just might be worthwhile locating it and determine whether there was any merit in re-examining the recommendations at least for the eastern coastal area but conceivably for adaption for wider application"

Governments have had the opportunity to address this issue of lagoon pollution now for over 20 years and, until the advent of WATSAN, totally ignored a mounting problem.

The generous overseas aid associated with the WATSAN project and the application of those funds, while admirable, is not the complete answer by any means and while attempting to reduce pollutants reaching the lagoon by improving the treatment of household waste some residents will be confronted by many of the same constraints as accommodators and those others affected however, in these latter cases, the implications and compliance options will be far more worrying and the consequences far more dire.

Who should be blamed for this state of affairs? Government of course. Not just this Government, but each Government over the last two decades that has been unable, or unwilling, for whatever reason, to come to grips with the real priorities.

Something like Te Mato Vai project was not the real priority, wastewater/sewage was. But now Te Mato Vai is underway we need some bold leadership and fiscal prudence which will retrieve some of the lost opportunity and recover some of the wastewater/sewage system progress that might have otherwise been made before we got our wires crossed.

Sure, there are people who go without water in times of drought. Te Mato Vai is not necessarily going to help them. Insufficient water and pressure in the pipes will still mean no water in their pipes.

Meanwhile those that get water still bathe, still flush the toilet and do their dishes and laundry and continue to pollute the lagoon and while the WATSAN sanitation upgrade effort is addressing part of that, it would be quick to acknowledge that it is only part of the solution. The other part is the commercial establishments which have probably yet to realise the draconian compliance demands that have been imposed upon them.

The Asian Development Bank in its Terms of Reference for the project preparation technical assistance study for a Cook Islands integrated urban infrastructure project as far back as 1993, identified the potential dangers and severe pressure on the environment and the tourist industry presented by an antiquated system of septic tanks and soakpits, only to be exacerbated if the uncontrolled management of septic waste continued unchecked.

That was when tourist numbers were less than half what they are now.

The Eastern Rarotonga Sewerage System, as it also later became known, was intended to be the first phase of an island-wide sewerage system.

Just the Eastern component was intended to capture 236 hotel rooms,10 commercial establishments and 70 Muri residences. That was back then. With significant further development in this same area since then, those numbers would have grown considerably.

The total estimated cost (in 1995 dollars) was $4.3 million. It was to be a user-pays service. Figures touted at the time were $4 a day per tourist room and $28-35 per month for a domestic residence.

Nowhere in ADB’s assessment of the priorities we faced, was there any mention of any water supply upgrade of any kind, let alone one of the magnitude of Te Mato Vai. Meanwhile, we now have this huge financial commitment to Te Mato Vai while the real, more pressing problem of sewage remains largely unresolved.

Let me repeat that. Twenty years ago water was not even on the radar. Water was not considered a priority. There were other more pressing problems. Certainly Rarotonga’s ageing water supply network, leakage etc has, in the intervening years, come more into focus, but had government being a little more responsive and possessed of a little more vision in 1995, we could have had a partial public reticulation system already in place well before we needed to turn our attention to a water supply upgrade which would have proven, or otherwise, that a public reticulation system was the way to go.

Now with Te Mato Vai at centre stage and dominating funding opportunities any public sewerage reticulation service is destined to slip further from attention unless some compelling new arguments can be advanced to revive it. 

So what we have now is the  WATSAN Sanitation Upgrade Programme and a new set of Regulations {Public Health (Sewage and Wastewater Treatment and Disposal) Regulations 2014} which repealed its predecessor the Public Health (Sewage) Regulations 2008 which were never effectively administered because of a clear lack of capacity, but promised the same challenge and potential grief.

LPZ stands for Lagoon Protection Zone and within this area secondary or better treatment of sewage is mandatory if the daily load is <.2000L/day but with a requirement of a land application system. If it is over 2000L/day advanced treatment, certain total nitrogen (TN) targets and a land application system (LAS) are standard.

Plain old septic tanks are no longer acceptable. Soakholes/soakpits, anywhere, in the LPZ or elsewhere, are prohibited. Those domestic residents within the LPZ and purchasing into the WATSAN programme will meet the requirements. Those who do not face penalties and the penalties are wicked.

What these penalties illustrate is the extreme insensitivity which attended upon the drafting of both the 2008 and the 2014 standards. This criticism is supported by the unrealistic, and many cases, unworkable, demands made upon property owners, both domestic and commercial, leaving one to wonder how much local input went into the exercise or whether we are, once again, the victims of consultants who breeze in and breeze out and suddenly are empowered with all the right answers which we blindly accept as gospel and pay big bucks for.

At the end of the day however, Regulations are made in Executive Council, which is Cabinet sitting with the Queen’s Representative, so if there is any criticism it should properly be directed to our political leaders who, too frequently (listen to Parliament sometime), approve legislation with no real understanding of what it contains nor its far-reaching consequences.

Outside the LPZ septic tanks alone but with a land application system can still be used but only for loads up to 2000L/day. Loads greater than this require advanced treatment (not available with regular septic tanks) TN monitoring to acceptable levels and a land application system.

Loads: Take a two bedroom home with standard fixtures and occupancy of four persons. Typical wastewater flow allowance is 200L/day/person = 800L/day (homes with superior fixtures are 220L). In the LPZ a minimum of secondary treatment would be required, as would a land application system in the form of an effluent bed or trench. Such a home outside the LPZ could still use the septic tank but the soakhole would have to be replaced by an effluent bed or trench.

Effluent beds or trenches alternative: the problem

Effluent beds or trenches consume valuable land and in tight situations with densely packed buildings on small sections this just might not be available. This is where the major problem emerges. If septic tanks are ruled out they will need to be decommissioned and a secondary treatment plant suitably sized installed to replace them.

Available space might prevent this and a commercial property may have to consider closing while it replaces the space occupied by a septic tank or tanks with an acceptable system. If space for that is a problem consider the larger problem of finding space for effluent beds.. Take a commercial property in the LPZ of say 10 rooms. 10 rooms equates to a minimum of 4400L/day (10 x 2 x 220L). An effluent bed of 88 sqm would be required (4400/50).

I know of some properties that could not even find 20 sqm let alone 88, especially when considering the setback requirements which are 15 m from any surface water (ie lagoon, waterway); 2m from any land boundary;3m from any house or building and 1m below the bed and above the water table.

If effluent beds will not work the alternative is drip irrigation but this is where the demands become ridiculously difficult. For this same hypothetical property the requirements would be 4400/4 or 1.1kilometres of drip line buried 250mm below the surface at 1.0m centres if the soil is category 1, sandy, with the same setback requirements operating. An impossibility in many instances.

The other alternative, which would be costly but would avoid the difficulties of a land application system, would be to pump the treated effluent into a holding tank and have it carted away. For busy properties or businesses however, this could mean several trips a week of the tanker at 7000L and at $700 a time the economics would kill it.

Is there a solution? I believe there is but it would require government to radically adjust its thinking and take some bold decisions. Now when it is digging up the road again and laying water pipes would this not be the perfect time to show some real leadership and review the sewage question and at least place the sewage pipes in the ground at the same time and proceed simultaneously with the treatment plant and ocean outfall at Matavera.?

Government will wring its hands and ask how to pay for all this. Well, if it had had enough vision 20 years ago it would have been a lot cheaper. But for starters, consult with your partners and get them to redirect the funding available to WATSAN to this more worthwhile, longer term permanent and convincing solution.

WATSAN has already spent $4.7m in the Muri Avana upgrade and it looks like another $2m or so for Titikaveka from a budget of $18m, so there are funds there. Maybe not enough at today’s prices, but enough to go a long way towards it. Remember the Barrett report costed it in the 90s at $4.3m, but admittedly that did not extend as far as Titikaveka.

I am informed that one of obstacles to a centralised treatment plant is the massive electricity running cost. Well it seems there is an answer out there for this as well which allegedly could reduce this expense by up to 90 per cent and produce valuable by-products.


TEXT IN BOX: Muri resident John Scott says a large number of businesses and private residents on Rarotonga face serious concerns in getting their properties to comply with new sanitation regulations. In this feature story, he makes the case for a public reticulation sewerage system on the island.