Landfill Survey Results
Back in October last year we reported on our landfill surveys using a drone. That was all well and good, but what we needed was to be able to do the survey again, so that we could see how the landfill changed over time, and then get a picture of how much waste is actually going to landfill and, just as importantly, how much time do we have before the landfill is full. The October article explained how we built local capacity to conduct the actual survey, so that all we needed from outside Kiribati was the ability to analyse the data with the right software. So at Easter we ran the drone over the three landfills again, following exactly the same flight path, using exactly the same benchmark levels. The time between surveys was eight months, so long enough that a reasonable picture should emerge, and this is what we found.
Betio Landfill is filling at the rate of around 5,500m³ per year: if we have a density of 500kg/m³ than that is around 2,750 tonnes; but at a more realistic 700 - 800kg/m³ we can expect 3,800 - 4,400 tonnes per year. Lifetime is not looking good though: to our benchmarks, Betio has just hit the 'Full' mark. So we'll just have to keep packing it in
somehow as we don't have any more landfill space, since we have rehabilitated 60% of the original area to build our new Materials Recovery Facility.
For Nanikaai Landfill the situation is perhaps worse, in that we are now 1,100m³ overfull, but we still took in approximately 1,250m³ of waste in 8 months, that means it is taking in around 1,300 - 1,500 tonnes per year. Compaction is probably better at Nanikaai as operation conditions are better. Nanikaai has a chipper taking the organic waste which helps.
Our third landfill is Bikenibeu, which still has about 70% of it with around 1.2m of water inside. The drone survey only shows the water level, not any waste beneath it, and as we work the landfill we push waste into the water. So the change here is quite small, as much of what went in 'disappears' under the water, and the survey showed only 600m³ of difference. Compaction at Bikenibeu is also not so good as the waste is still being pushed into the water and it is only once the entire landfill is filled above the water level that the waste will firm up and compaction will start to get better.
Overall, the drone is a wonderful tool that enables regular monitoring of the landfills, at about a hour's time at each landfill. The data gets sent via internet to our surveyor overseas who does the analysis, and set up the original benchmarks and flight plan. Something that took days can now be done in hours, and far more accurately.
Green Bag Truck Maintenance costs
You may recall last Real Rubbish News we had the Blues about our truck breakdowns. We have finally turned a corner with the arrival of two complete rear packer mechanisms from New Zealand, so that we can conduct major refurbishments of the trucks. But what does this cost compared to the value of the truck? Since 2016 we have good data on the money spent on maintenance. In the last year, a total of around A$75k has been spent on the two trucks in an effort to refurbish them for another ten years or so of use. The actual mileage of the trucks is low, of the order of 65,000km each, which is very little for a truck. But the corrosive environment, lack of fresh water to clean the truck out daily, and poor maintenance practices have contributed to these costs.
Overall, since 2016, both trucks have had $108k spent on them. How does this compare to capital cost and cost per year of operation? One truck started in 2014, and so cost for the first two years should have been low. The total truck years are 15,
and the capital cost was around $400k total. Since they started collecting bags, around 10 million Green Bags have been sold. The maintenance cost thus is around 1¢ per bag sold. Per year of truck use, mindful that only one truck has run at any time, so only ten years, the total maintenance cost works out at around $10,000/yr, or around 5% of the capital cost of a truck. (it is worth noting that if the trucks had been washed and greased regularly then the repairs cost would be very significantly lower.)
This is of course essential information to feed into any review of the Green Bag model, especially as we now want to run two trucks every day instead of one.
New MRF site and Landfill Rehabilitation
The rehabilitation of part of the Betio Landfill is nearing completion, and the foundation for our new Materials Recovery Facility (MRF) shed is now at the final preparation stage. The rehabilitated area is 1.6 hectares of the original 2.25 hectares, with 0.625 hectares now remaining of active landfill. Waste was taken from the active area to increase the height of the rehabilitated are to around 4m above sea level, which has created some of the highest land in Betio. This movement of waste also created more space in the active area. It has taken many months of spreading waste, levelling and compacting to do this, with the only available machine being the 12t Wheel Loader run by KSWMP.
The area will be split between the new MRF and shipping container parking for the Kiribati Ports Authority (KPA). The KPA have been a partner in this work, providing diesel, sand cover, fencing and gateway works, whilst KSWMP has provided the heavy machine & driver, and site management. The cost of the sand cover for the site is around $200k, and the new MRF shed, including a 40kWp grid-tie solar system, will come in at $450k. Machine time so far has cost around $15k including fuel and maintenance. The foundation for the 300m² shed has required digging down through 4m of landfill to reach the original beach, and then backfilling with sand and construction rubble to create a solid foundation. The new MRF will handle the existing cans, bottles and battery recycling, plus take on end-of-life vehicles, and e-waste.
The views expressed in this publication do not necessarily reflect those of the New Zealand Government.
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