The Solid Waste Disposal Solution for Guernsey

July 21st, 2009 by Dr Barrie Mealing

Summary

This paper presents a robust and complete solution to the Guernsey solid waste disposal problem.

This solution restricts use of landfill to materials which cannot reasonably be treated in any other way, eliminates unneighbourly commercial burning of timber, minimises the generation of problematic ash residues, and promotes best recycling practices.

This solution is feasible at a capital cost of £19 Million plus operating costs of £0.5 Million per year, including the costs of all residue disposal.

Cheaper variants are possible and would still do the job but even the suggested, more flexible, version remains highly economic.

At the proposed gate fee of £175 per tonne, this solution generates a contribution (after all operating costs, finance charges and capital repayments have been covered) well in excess of £3 Million per annum towards general tax revenues.

The relevant equipment could be in operation within 2 years and would in no way detract from ongoing efforts to achieve sustainable waste management in Guernsey through recycling and other initiatives which are already making a major contribution to the overall solution.

The solution comprises a 20,000-24,000 tonne per annum capacity twin-stream micro-incinerator together with an enhanced dry materials recovery facility (which it is assumed might best be operated privately under contract), improvements to domestic waste recycling arrangements and a small bio-plant producing high-quality compost from food waste separated at source and which would not suffer from the residue usability difficulties associated with bio-plants.

The main element of the solution would immediately achieve a sufficient step reduction in waste flow into Mont Cuet to remove all immediate pressure upon exhaustion of landfill capacity, allowing ample time for all elements of the solution to become effective. It would eliminate putrescible matter from waste being landfilled at Mont Cuet, thus addressing both the smell and the seagull problems.

The suggested solution is closely optimised to achieve a best result at minimum cost and there is every expectation that it would achieve the targeted results. The solution carries no fundamental long-term risk as there are no elements that could not affordably be augmented if this were ever to prove necessary. With the type and scale of solution recommended here there would not need to be any major contractual commitment by the States, other than for the relatively modest purchase cost of the plant. Importantly, there would be no need for the onerous 25-year operating contract involving irrevocable ongoing expenditure commitments and which would create major difficulties for ongoing development of environmentally sound waste-management practices.

The current States of Guernsey mandate requires the achievement by 2010 of recycling levels of 50% for both domestic and commercial waste, upstream of any tendered treatment facility. Means have been identified of achieving 62% domestic waste recycling and 60% for relevant commercial waste thus substantially exceeding the States target (which also happens to be the minimum recycling level which will become mandatory within the European Union).

It is regrettable that Public Services Department (PSD) has consistently refused even to examine solutions outside the current tender mandate, thereby potentially doing a great disservice to the people of Guernsey since the outcome of the current process has proved to involve unaffordably high costs and, as expected, onerous long-term contractual commitments.

The level of scrutiny which can be applied to the recommendation from PSD has been severely curtailed by virtue both of the reluctance of PSD to release timely and meaningful information on the tenders received and of the dismissal by PSD of the former Panel of experts and lay members whose purpose it was to provide such scrutiny on behalf of the people of Guernsey, on the spurious but convenient grounds that it had exceeded its mandate.

The people of Guernsey also need to be aware that the plant recommended by PSD to be acquired under the current tender (involving the creation of a special-purpose company to purchase the plant and pay operating costs using a loan to be granted by the States of Guernsey) will not be self-funding by any sensible interpretation of that term as it will not generate a new revenue stream and involves both the very substantial capital expenditure and increased ongoing costs, possibly implying either the need for the States to revisit the borrowing of additional funds (resulting in an increased future taxation burden) or to defer competing projects. Furthermore, the PSD solution will require significant further taxation increases to make up a shortfall in States revenues arising from the loss of some £3.7M per annum current profit from operations at Mont Cuet as well as the extremely high cost of the solution itself. The financial impact on each household over the next 25 years will be very substantial.

With the PSD/Suez proposal, correct identification of the tonnage to be incinerated is crucial because any upgrades are not covered by any legally-binding commitment by the tenderer and because any shortfall in the tonnage entering the plant would cause financial meltdown in terms of cost recovery, due to the overarching fixed costs. In contrast, the solution recommended here has both downward flexibility (due to its low capital cost and the twin-stream configuration) and upward flexibility (due to the easy affordability of adding additional capacity should that ultimately prove necessary whether through incorrect initial sizing or persisting failure to achieve recycling levels). With the recommended solution, it is not necessary to purchase up-front excess capacity which may never be needed but, if desired, enhanced initial capacity can be specified at very modest cost; permutations with and without the bio-plant are also possible and make little difference to the overall economics: obviously, incorporation of the bio-plant allows the environmentally-undesirable incineration stage to be minimised.

A final thought: the existing Guernsey State monopolies (Guernsey Electricity, Guernsey Water, Guernsey Post) which are run as independent operating companies at arms-length from direct States control but which are required to provide a monopoly service in the best interests of the people of Guernsey work rather well on the whole.

The waste treatment technologies suggested here are not difficult to implement and it is well within the competence of this Island to run all elements of the treatment plant without recourse to external expertise. If Guernsey Waste Treatment were formed and tasked (on a similar basis to Electricity, Water and Post) to own, staff and operate the main refuse treatment facilities this would mean that all operating profits would be returned as dividends to the people of Guernsey rather than being lost off-Island to the benefit of foreign shareholders: this would seem to be a much more attractive model than that currently being pursued by PSD.

Click on chart for full-sized version

THE SOLID WASTE DISPOSAL SOLUTION FOR GUERNSEY

Summary

Chart: The Residual Waste Stream in Guernsey

Index

1. The Current Tendering Exercise

2. Recycling Rates and Waste Flows

3. The Tender Inconsistencies

4. The Recycling Targets

5. Introduction of a Micro-incinerator

6. Extended Application of a Dry MRF to Commercial and Industrial Waste

7. Useful Application of Timber and Derivatives

8. A Small Bio-plant

9. MHT or MBT Compared with an Upstream Dry MRF

10. The Materials Recovery Facility

11. The End-treatment Process

12. Overall Costs

CONCLUSION

GLOSSARY

Chart: Pareto Elements of the Current Waste Stream

Chart: the effect of adding a micro-incinerator

Chart: showing the effects of a simple dry MRF and useful diversion of timber

Chart: + micro-incinerator, bio-plant, dry MRF, source separation & timber diversion

1. The Current Tendering Exercise

The current procurement exercise for a new solid waste treatment facility was based upon the requirement that it will receive and must be capable of dealing with 45,000 tonnes per annum initially, rising to 70,000 tonnes over the 25-year life of the plant, all assuming a “high-recycling” scenario according to which recycling rates of 50% are to be achieved (from 2010 onwards) upstream of the facility. However, possibly in recognition of the fact that the waste tonnages for the tendering process which Public Services Department (PSD) has consistently tried to defend are indefensible on this basis, it would appear, based upon the wording of a recently-issued document (PROPOSED AMENDMENTS Urban Area Plan – Review No.1, paragraph 1.2), that the ground is being laid to pervert the tendering process by now stating that “the most significant” route for achieving “a target for recycling 50%” is to be through “a major waste treatment plant … for which tenders have already been received”. In other words, the target of 50% recycling upstream of the new facility is perhaps quietly being abandoned to ensure that 45,000 tonnes of waste can be made available to the new plant, with whatever implications that may hold for costs and for existing operations.

The tender specification allows only combinations of Mechanical Biological Treatment (MBT) or Mechanical Heat Treatment (MHT) with Mass-burn Incineration (EfW) or Advanced Thermal Treatment (ATT) and therefore does not accommodate separation by a simple dry materials recovery facility (MRF) without MBT or MHT as part of the process of dealing with the 45,000 to 70,000 tonnes of waste to be accepted by the plant [see Glossary for explanation of these tenns).

A plant not capable of dealing with 45,000 rising to 70,000 tonnes through some combination of MBT, MHT, EfW and ATT processes would fail to meet the tender specification and any contract awarded on the basis of the tender requirements and draft contract would also not reward any recycling or other improvements in the waste management system upstream of the plant as there would be no reduction in the contract standing charges in the event of any reduction in throughput.

It would nevertheless appear possible (unless the States were to adopt coercive measures) for Parishes or waste collection organisations to reduce their inputs into the treatment plant by recycling means such as kerbside separation or a basic materials recovery facility or a small bioplant operated independently of the main treatment plant: which could potentially destroy the economic viability of any final treatment plant which needs high gate fees.

If any contract were to be awarded upon any basis other than the minimum 45,000 to maximum 70,000 tonne requirement processed by some combination of MBT, MHT, EfW and ATT it would constitute a fundamental deviation from the tender requirements and would therefore not only constitute unfair and improper procurement practice but would also seem unlikely to achieve best value, by virtue of having excluded potential suppliers of smaller-scale equipment and of

alternative (potentially cheaper) handling or treatment techniques.

2. Recycling Rates and Waste Flows

The current recycling rates are acknowledged to be of the order of 30% (PSD has suggested 31% for both domestic and commercial/industrial recycling and the work underlying this article suggests levels of approximately 29% for domestic and 28% for commercial/industrial recycling, giving some degree of confidence – subject to the caveat below – that these figures are reasonably indicative of current achievement).

The relevant current waste flows (all in tonnes per annum) can probably best be understood if grouped as follows:-

Click table to expand

*There is evidence that some commercial waste producers may illicitly be using bring banks for disposal of recyclable commercial waste, which means that domestic waste arisings as published by PSD will correspondingly overstate the

true figure and domestic recycling levels will also be overstated. This is not all bad news, however, since this commercial waste is at least being recycled. Beware that recycling rates are meaningful only when applied to waste streams relevant to the objective, such as landfill use reduction, and it is easy to derive spurious and irrelevant figures.

The “Arisings” figures relate to refuse flows which are of relevance to landfill capacity and to the proposed treatment facility and therefore exclude consideration of the much greater tonnages of inert materials used for land reclamation, of some 6,500 tonnes (and rising) of uncontaminated green waste very successfully recycled by PSD and returned for use as soil-improver, of home composting, of the (mainly) scrap metal exported by Guernsey Recycling and of all direct returns of packaging materials and containers by commerce and industry and also of agricultural or horticultural waste dealt-with on-site.

The tonnages shown as “Recycled” consist of the domestic waste collected by Mayside and PSD from the “bring” sites plus the commercial and industrial waste removed from the residual waste stream at Fontaine Vinery and in the Island Waste dry materials recovery facility at Pointes Lane plus some commercial (principally paper) source-segregated waste handled by Mayside. The “Other” category in the above table comprises the 5,000 tonnes of timber which is currently wasted by burning at Pointes Lane (and which therefore does not constitute material usefully diverted or recycled) plus an estimated 2,000 tonnes of material (being timber mainly – burnt in the open) now being disposed of outside the recognised waste streams. The above figures do not yet reflect the effects of new recycling initiatives now in progress (including window, polystyrene and milk-carton recycling) so some modest improvements in recycling levels should start to feed through.

3. The Tender Inconsistencies

If the 50% level of recycling mandated by the States of Guernsey were to be achieved (this mandate excludes green waste and happens also to be the level which nominally will apply within the EU, again excluding green waste) to relevant waste streams, upstream of the new facility, the above tonnages (with the illegal dumpinglburning allowance added back into the commercial and industrial waste arisings) would become:-

Click table to expand

Even acknowledging that the plant might eventually also have to accept some 1,200 tonnes of sewage treatment residues if a conventional sewage treatment plant were to be commissioned, It is clear that there is nevertheless a gross discrepancy (amounting to over 13,000 tonnes) between the initial residual waste flows requiring treatment or disposal corresponding to the mandated 50% recycling rate and the initial capacity figure of 45,000 tonnes forming the basis of the current tendering process which was supposed to have been based upon an assumed recycling rate of 50% upstream of the facility for which the tender has been issued. The current tender is thus seriously inconsistent with the current waste arisings taken in conjunction with the specified level of recycling performance upon which the tender is supposed to be based, when those recycling rates are applied to waste streams relevant to landfill usage.

In fact, the discrepancy between the tender requirements and the actual arisings which any MBT/MHT/EfW/ATT plant would be required to process is potentially even greater than the above figures show not only because growth projections upon which the tender is based have deliberately been inflated but also because straightforward and economic opportunities for further residual waste stream reduction upstream of the tendered facility have been disregarded, as will be seen.

4. The Recycling Targets

It is acknowledged that, whilst it ought to be possible to make further progress towards the 50% recycling target for domestic waste without resorting to partial separation at source (for example by improving access to bring banks in densely-populated areas), the only clearly-identified means of reducing the residual domestic waste stream feeding into any treatment plant by the full target figure of around 4,750 tonnes (needed to meet the agreed 50% domestic waste recycling level) may involve some form of separate kerbside collection of dry recyclables (in Appendix 4 of Billet I, 2007, consultants Enviros suggest that kerbside recyclate collection would divert 28.8% of Parish waste – amounting to some 4,500 tonnes). It would, however, probably be sensible to consider separation at source of both food waste and dry recyclables as this might cost little or nothing more to implement whilst potentially reducing the residual domestic waste stream by a further 4,500 tonnes, provided that a means were available of dealing with this food waste. On this latter basis, domestic recycling levels of at least 62% are demonstrably achievable.

Timber and timber derivatives may account for up to 9,000 tonnes out of the total of 36,500 tonnes of relevant commercial and industrial waste arisings. If none of this timber were diverted for useful application, the remaining commercial and industrial arisings of some 27,500 tonnes would need to show a recycling diversion rate of 66% in order to achieve diversion of the 18,250 tonnes required to meet a 50% recycling rate overall. Known, economic and practical means can be identified of achieving diversion of up to 14,800 tonnes (subject only to separation at source of wet or food waste in the commercial waste stream) but the extra 3,450 tonnes required would exceed the combined effects of the window and polystyrene initiatives not yet accounted for in these figures and further, as yet unidentified, initiatives would therefore be required to meet a 50% commercial and industrial recycling target if all scrap timber were to be included in the residual waste stream.

Fortunately, there are opportunities for useful and environmentally-sound diversion of much of the scrap timber and timber derivatives so this problem need not arise. Note that usefully diverting (instead of wasting) much of the timber currently burnt at Pointes Lane would cause the commercial and industrial recycling figure to jump substantially but there would be no corresponding reduction in the commercial and industrial waste flow into Mont Cuet in this particular instance since this timber has not hitherto entered landfill.

Implementation of a basic dry materials recovery facility (dry MRF – as discussed below) with a performance equal to that achieved at Pointes Lane for all of the dry commercial and industrial skip waste should improve recycling performance from 28% to 34% and diversion for useful application of around two thirds of all timber scrap would automatically increase the recycling diversion performance to 51%, thus meeting the required recycling target – and further improvement could be expected (subject to the separation at source of the wet or food waste in the commercial waste stream) even before the effects of other developments (such as the window and polystyrene recycling initiatives) are considered leading to achievement of approximately 60% recycling performance within the commercial and industrial waste stream and the curtain burner at Pointes Lane would also be eliminated.

The 50% domestic and commercial/ industrial recycling targets mandated by the States are thus realistic and achievable minima which can, in the event, be substantially improved upon, given the will to do so.

5. Introduction of a Micro-Incinerator

It can be seen that a micro-incinerator of 20,000 tonnes per annum nominal capacity, as recommended by the former Waste Disposal People’s Panel, (or a twin-stream 2×10,000 tonne unit) would immediately be capable of processing all refuse which may have any putrescible content (so no more smells at the landfill) and would promptly reduce residual waste flow to Mont Cuet to 21,000 tonnes per annum (including allowance for the 5,000 tonnes of bottom ash produced by the incinerator and which it is prudently assumed will have to be disposed of to controlled landfill), thus extending the life of Mont Cuet to year 2033 (for a 33m profile) even before further improvements are contemplated. This alone removes all immediate pressure upon landfill exhaustion and gives ample time to progress environmentally and economically sustainable initiatives without being forced into ill-considered acceptance of one of the current tenders. The cost, as quoted in the 2008 report of the former Panel, would have been £8.5M capital plus £0.43M per annum of operating costs and £0.17M per annum for ash handling and disposal, a grand total of £23.5M over 25 years operation; the recent collapse of Sterling against the Euro means that these costs would now be increased to £10M capital plus £0.5M per annum operating and up to £0.2M per annum for residue disposal, making a new grand total of £27.5M over the 25 year life of the plant for processing 540,000 tonnes of refuse. This corresponds to a cost of £51 per tonne of input, inclusive of capital, operating and residue disposal costs (in 2009 real-terms).

Nevertheless, this probably remains the cheapest means whereby an adequate step reduction in the waste flow to landfill can reliably and rapidly be achieved, allowing time for the other compatible and affordable measures suggested by the former Panel to be put in place to supplement the effect of the micro-incinerator and thus achieve a complete and sustainable solution. If, for reasons of flexibility and resilience, a twin-stream (2×1 0,000 tonne per annum) microincineration plant were adopted instead, the above costs would be increased by about 15% but this might be considered a worthwhile trade-off for the redundancy and flexibility which a twin-stream solution provides. It also transpires, as will be seen, that a 20,000 tonne per annum nominal capacity incinerator turns out to be the optimal size in the medium and longer term in the context of the further measures recommended here.

It is interesting to note that the Consultants who advised the States (Enviros, Appendix 4, Billet I, 2007) consider that mass-burn EfW facilities are not viable below about 50,000 tonnes per annum.

6. Extended Application of a Dry MRF to Commercial and Industrial Waste

Without any improvements whatsoever to the domestic residual waste stream, the application of a simple dry MRF to the whole of the commercial and industrial dry waste stream, and including capture of tonnages estimated currently to be outside the measured waste stream, together with diversion of a substantial proportion 2/3 ,say) of scrap timber for useful application would achieve the following result-

Click table to expand

The reduction in tonnage to landfill would superficially appear to be just 2,000 tonnes per annum but in fact the 5,000 tonnes per annum currently burnt at Pointes Lane would also have been dealt with as well as the estimated 2,000 tonnes per annum disposed of outside the system at present. The life of Mont Cuet would nominally be extended to 2024 by this measure in isolation.

Achievement of this result simply requires an enhanced simple dry MRF (which need not be at any cost to the States) together with some means (see below) of dealing with the aforementioned substantial proportion of scrap timber. The tonnage available to any treatment plant downstream of the enhanced dry MRF would theoretically be 16,000 + 5,500 + 12,500 + 1,000 = 35,000 tonnes per annum but at least 3,000 tonnes of this would be expected to be unsuitable for any treatment process and would therefore go straight to landfill, leaving up to 32,000 tonnes available to any treatment plant, plus possible sewage residues but less the reductions which will accrue from recycling initiatives currently in course of implementation but whose effects are not included in the above figures.

What this all means is that the 30,500 tonnes figure overall (or 31,700 tonnes including possible future sewage residues) for input to the treatment plant and corresponding to the States 50% recycling mandate when applied to the relevant elements of known current waste arisings rather than the spurious extrapolated historically-derived figures so vigorously defended by PSD, is very nearly achievable, in total, by known means, even without the benefit of any form of kerbside recycling.

7. Useful Application of Timber and Derivatives

Notwithstanding any legislation or regulations, not all of the 9,000 tonnes of timber and timber derivatives estimated to be present in commercial and industrial dry waste may in practice eventually appear in the “official” residual waste stream but it is reasonable to suppose that the 5,000 tonnes from Pointes Lane would at least be matched (pro-rata to input tonnages) by 2,000 tonnes extracted from the 6,000 tonnes of dry skip waste currently handled by operators other than Island Waste: it is a reasonable expectation therefore that the total tonnage of timber available for recycling or disposal upstream of any treatment plant would be at least 7,000 tonnes. For the purposes of this discussion, a “maximum” scenario involving 9,000 tonnes is, however, assumed.

The timber extracted from the commercial and industrial dry waste stream can be considered as falling into three categories:

primary (intact timber sections, treated or untreated, suitable for re-use or processing into as board);

secondary (timber shards, plywood, chipboard and paper-laminated chipboard suitable for heating use);

tertiary (plastic-laminated chipboard unsuitable for burning other than in a WID incinerator).

The actual breakdown of the residual timber into the above categories is not crucial but if it is assumed that the timber and timber derivatives likely to be available from the residual waste stream are split equally between the three categories then up to 3,000 tonnes might be available for recycling (a use which is rated highly in the waste hierarchy) whilst up to 3,000 tonnes could be made available for generating useful heat energy at a reasonably high efficiency (recovery as energy with an efficiency of at least 60% is accepted as being environmentally the next best option after recycling) leaving up to 3,000 tonnes for disposal (the least preferred option in the waste hierarchy): plastics or other contamination would render the use of this tertiary material non-feasible for heat generation because it would probably be uneconomic to incorporate the necessary flue gas treatment regimes in small-scale plant. In any case, the availability of an admixture of tertiary timber for a main incineration plant might be no bad thing as it would improve the average calorific value of the feedstock and should avoid or reduce any need for auxiliary fuel oil injection to achieve satisfactory combustion (an admixture of 2,500 to 3,000 tonnes of timber of calorific value 18MJ/kg would increase the average calorific value of the incinerator feedstock from a probable 10MJ/kg to a more desirable 11 MJ/kg).

3,000 tonnes per annum of secondary grade timber (shredded) would be sufficient to feed 8 small scale burners over a seven-month heating season of 5,000 hours. These burners typically cost £65,000 each and generate useful output of 300kW, based upon an overall thermal efficiency of 80% using timber with a calorific value of 18MJlkg. Assuming that heating oil at a cost of 35p per litre produces heat at a fuel cost of 3p per kWh, these 8 timber burners would save importation of a total of £360,000 worth of fuel per annum, eliminating the use of just over 1,000,000 litres of fossil fuel each year. There would be a useful saving in carbon emissions since the timber may be considered a bio-fuel. In contrast, use of the timber in an EfW plant would result in a very poor useful conversion efficiency: indeed, the use of the 3,000 tonnes of timber for heat production in the 8 small-scale burners saves as much or more fossil fuel than the electrical output from an EfW incinerator burning around 30,000 tonnes per annum. If a charge of £35 per tonne is allowed for shredding, storing, delivery and a profit margin in respect the recovered timber, the cost of fuel for the 8 timber burners would be £105,000 per annum to which would sensibly need to be added an annual charge of around £100,000 (to write off the burners over 5 years) which suggests that the energy cost for these units could be around 1.7p per kWh. Obviously, units of this type would be suitable only for major buildings (as a baseload heat source) or large glass-house complexes.

Whilst, from an overall ecological perspective, the use of primary grade timber for recycling into manufactured timber products is preferred under the waste hierarchy, the (local) economics should not be expected to be as attractive as the above figures suggest for use of secondary grade material (when used for local heating requirements) since it would probably be necessary to ship much of the primary grade material off-island for processing into OS board. Nevertheless realistic disposal routes for all three categories of timber and timber derivatives expected to be extracted from the waste stream have been identified.

8. A Small Bio-Plant

A further development, involving the separation at source of domestic refuse into dry recyclables, food waste and incinerable elements (and a parallel separation of food waste in the “Euro-bin” commercial waste stream) in conjunction with the introduction of a small and inexpensive (5,000 to 6,000 tonne) bio-plant (along with the dry MRF discussed above) would theoretically reduce the input to any end-stage thermal treatment plant (incinerator) to around 22,000 tonnes per annum (or 23,000 tonnes with sewage sludge). The size of micro-incinerator recommended by the Waste Disposal People’s Panel last year (8,OOOh/[email protected] 2.7t/hr) closely matches this level of input and would theoretically reduce inputs to Mont Cuet to as little as 8,000 tonnes per annum (comprising around 5,000 tonnes of bottom ash which it is assumed would need to be disposed of by controlled landfill and some 3,000 tonnes of untreatable waste). Depending upon how soon these arrangements could be introduced, the life of Mont Cuet would theoretically be extended to sometime around year 2065: this solution set would clearly remove all pressure upon any requirement to commission follow-on landfill capacity any time soon and would, in fact, achieve a much better life prolongation than any solutions involving larger-capacity end-stage thermal treatment plants such as those which have been promulgated by PSD: any projections purporting to show a longer life extension will have assumed ash disposal as “aggregate” or to Longue Hougue, both of which could prove unsafe or unsustainable assumptions.

Much emphasis is sometimes laid upon major additional costs which might be incurred to implement kerbside separation but that is not necessarily what is being suggested here: for example, the addition of one person to each collection team might allow collection of presegregated fractions at the existing speeds and frequencies (at an additional cost of some £0.3M per year) but separating putrescible matter at source commonly allows main collection frequencies to be reduced which might offer the potential to contain collection costs at or close to current levels if executed intelligently. At worst, Consultants (Integrated Skills), in a report dated July 2008, identified several options for separate collection which might incur additional collection costs of approximately £0.5M per annum, to which £0.1M for basic sorting offset by £0.2M bring bank savings need to be applied. It is particularly important, in order to avoid unnecessary marginal costs, that the detail should be thoroughly developed, hence the assumption here that, in the first instance, all domestic waste would go straight to the incinerator, thus allowing time to consider and possibly test various options and then adopt an optimised collection strategy most appropriate to the local circumstances: the compactness of Guernsey is helpful here since small-capacity vehicles are more viable when distances are short but optimising and de-bugging a new collection system may demand significant attention for a year or two.

The small (5,000 tonne) bio-plant suggested here for eventual incorporation into the waste management system would be expected to add between £2M and £3M to capital costs and operating costs would be relatively minor. The optimal process would probably comprise an anaerobic first stage followed by an open (aerobic) stage and air drying then grading to remove any minor amounts of foreign matter. The output from the process should be at least 1,000 tonnes of fertiliser in which it is understood the Nitrogen is compounded principally in a form which does not readily leach out: that being the case, the fertiliser should be safe for all domestic, horticultural and agricultural applications and would be saleable locally (or elsewhere), displacing imported chemical fertilisers and making a welcome, albeit small, contribution to the reduction of carbon emissions. If a price of £200 per tonne were achieved, some £200,000 per annum might be raised but it might be prudent to assume an average of only half that level as commercial users may not pay much if at all.

Note that the basic process can, if necessary, operate at up to 70 Celsius and may, in itself, be regarded as acceptable in respect of pathogen destruction but the costings here allow for the installation of an autoclave upstream of the main process in case it may be deemed necessary in order to achieve sterility and absolute protection against prion diseases.

9. MHT or MBT Compared with an Upstream Dry MRF

The application of a mechanical heat-treatment (MHT) plant to the dry commercial and industrial waste stream would not appear to make any sense as the mechanical separation element is anyway achieved by a simple dry MRF without any need to incur the cost and complexity of an initial heat treatment stage. Similarly, in the context of the dry commercial and industrial waste stream there is no obvious benefit from a biological first stage (MBT), given the likely paucity of bio-degradable material in that waste stream. MHT or MBT processes would offer an alternative first stage approach to the treatment of waste streams containing putrescible matter (essentially the Parish+Alderney and the Eurobin commercial/industrial waste streams) as an alternative to source separation of the dry and wet fractions. In this context, both MHT and MBT could recover much of the metal and glass for possible recycling but any paper or card content would not be recovered in any form fit for economic recycling and would in reality be suitable only for dumping or incineration (or other high temperature end-stage treatment process). Furthermore, the contamination of the foodstuff content of these waste streams by general refuse would probably render the digestate unacceptable for use as fertiliser and would result in the need to dispose of such by landfill or incineration, thus rather defeating the object of the exercise. Neither MBT nor MHT as applied to the Parish+Alderney and Eurobin waste streams would seem likely to be as effective as source separation of the dry recyclables and foodstuffs in terms of minimising the tonnage to be processed through a high-temperature end-stage process (incineration or ATT) and would require not only the mechanical separation plant element implicit in a dry MRF anyway but also the upstream biological or thermal process plant of some 21,500 tonnes per annum capacity.

The solution involving source separation of food waste and dry recyclates rather than use of MBT/MHT plant minimises the size of the end-stage incineration (or ATT) plant despite needing only a much smaller bio-plant (of 5,000 tonnes instead of 21 ,500 tonnes) whilst also providing better-quality recyclates and high-quality fertiliser as outputs.

10. The Materials Recovery Facility

The existing MRF at Pointes Lane is privately funded, does not constitute any drain upon public funds and does not involve any liability or contractual commitment by the States. The optimum waste management system discussed here requires either duplication of the Pointes Lane facility, presumably at Fontaine or Longue Hougue, or relocation and enlargement of the Pointes Lane facility, so as to increase the dry materials handling capacity from the existing figure of 15,500 tonnes at Pointes Lane (plus 4,000 tonnes at Fontaine) to a new total capacity of 30,200 tonnes.

In that the existing MRF is genuinely self-funding, as it generates sufficient income from the difference between the notional or actual fees charged upon entry and the (greater per tonne) fees paid for disposal to landfill (mainly) of the lesser quantity of residual waste to cover capital and operating costs and return a profit to the operator, it is reasonable to suppose that an enlarged similar type of facility (even with the addition of extra costs for an enclosure) should be achievable without States funding or anything other than a medium-term commitment: brief calculation of the likely economics of this type of operation confirms that this is a reasonable working assumption.

11. The End-treatment Process

High-temperature end-stage treatment processes [incineration (EfW), pyrolysis or gasification (AIT)] – produce noxious emissions to atmosphere, hazardous fly ash and considerable quantities of undesirable bottom ash (which may, at present, not be classified as hazardous waste but is likely nevertheless to contain, albeit in lower concentrations than the fly ash, similar eco-toxic, neuro-toxic or carcinogenic residues). It follows that the extent to which plants of this type have to be used should ideally be minimised (the smaller the plant, the less the problem). In the short term it is accepted that Guernsey probably has an unavoidable need to apply high-temperature end-stage treatment technology in order reliably to achieve a rapid and substantial reduction in the flow to landfill.

The combination of source separation, a small bio-plant and a dry MRF seems to offer the best prospect of achieving a more-than-adequate reduction in the residual waste flow to landfill whilst also minimising the size of the most environmentally-undesirable element of the solution.

Furthermore, provided that the cost of the high-temperature element does not require long-term (25-year) recovery of capital and operating costs or come accompanied by any long-term contractual commitment, there may be an opportunity to phase down the use of this type of technology as other opportunities become available or as improvements in waste management practices can be achieved. It cannot be over-emphasised that a long-term and inflexible contract along the lines of the published draft should be avoided as this would not only prove to be an escalating drain upon the Island resources but would seriously constrain progress in the development of sustainable waste management practices in the medium term. The type of end-stage treatment assumed here is incineration since this process is well-proven on mixed solid waste streams. The alternative, an “AIT” plant, using gasification or pyrolysis has to be regarded as rather developmental in the context of municipal waste (even though the fundamental processes are well-known in chemistry) and furthermore would require tightly controlled feedstock, implying that not only would more significant elements of the waste stream have to be diverted straight to landfill than would be the case for incineration plant but also that there might be serious risk of encountering difficulties in the commissioning or ongoing operation of the plant. It seems premature to expose Guernsey to such developing technologies even though there may be the prospect eventually of possibly lower noxious emission levels or a safer (vitrified) form of bottom ash produced. There is obvious merit in minimising expenditure upon any incineration plant in order to leave open the possibility, on a timescale within the potential maximum life of the plant, that it might become feasible to decommission such plant in favour of other environmentally more friendly technologies if these become proven, reliable, economically-viable and widespread. It is instructive to compare the relatively-affordable costs of the micro-incinerator based solution recommended here with the total likely cost of a 70,000 tonne mass-burn incinerator which has been the prime objective within the Civil Service and for at least some senior politicians in recent years and was stated as being the preferred option at the time of the recommendations underlying the current tender: the 2008 estimated capital cost of £90M would probably now be some £105M (mainly due to the recent depreciation of Sterling attributable in no small part to increasing public sector deficit spending) and the annual operating costs (excluding capital and finance costs but including maintenance, consumables and manning) would be around £3.5M, for throughput averaging 58,000 tonnes per annum, making for a total life cost (in 2009 real-terms) of some £193M even before the effects of the cost-escalation opportunities built into the draft contract are considered and excluding the costs associated with disposal of the fly ash and bottom ash residues which might add a further £22M (some £14M for export of the fly ash and at least £8M for dealing with the bottom ash), making for a frightening total of £215M in 2009 pounds, the vast majority of which would constitute an absolute and irrevocable liability upon the States from the moment the contract was signed. It seems likely that, recognising the outcry which would result from any attempt again to push through a solution with such serious adverse environmental impact and costs of this magnitude, PSD may well now be minded to recommend a somewhat smaller-scale initial solution and can probably be relied upon to claim (disingenuously) that landfill capacity will be down to a minimum 5-years remaining by the time the new facility becomes operational (so that an immediate go ahead must be given) and will probably also repeat the (false) mantra that the project will be self-funding whereas in reality its costs will bear heavily upon Island residents and local businesses for the next 30 years.

The costs, both immediate and long-term, the sustainability and the environmental impact of the solution which will be proposed by PSD must be tested at the very least against the solution discussed here but which, in essence, PSD has doggedly refused even to consider: there is a serious problem in this respect as there will probably be little opportunity for informed independent scrutiny of the PSD recommendation in what is a fairly complex issue and it is clear that PSD does not want any such scrutiny as it would not otherwise have dismissed the Waste Disposal People’s Panel which was originally set up to provide it.

The reader is warned that the nett-present-value formulae which will be used by PSD to evaluate the costs of the tendered solutions will substantially understate the real-terms costs over 25 years (probably by about 30%) whereas all costs discussed in this document are in 2009 real-terms.

12. Overall Costs

The nett costs of the waste treatment and disposal solution, based upon the suggested combination of micro-incineration, MRF and the small bio-plant could thus be (all in 2009 real terms):-

£16M capital cost for micro-incinerator plant and building etc (twin stream);

up to £3M capital cost of bio-plant and building (with autoclave);

£12 comprehensive total operating costs over 25 years;

£15M finance costs (ignoring inflation-related dilution effects)

-£3M possible revenue from fertiliser sales over 25 years (at £2 per 10kg bag x 50%);

£10M additional nett collection costs over 25 years;

-£4M saving on heating costs through use of secondary timber (but may not all accrue to States);

£12M assumed operating costs for Mont Cuet over 25 years (half of existing for 35% of tonnage);

-£12M “rent” charged to MRF operator (@£17 per tonnet).

£49M in total, nett (against £135M gate revenue)

The gate revenue is calculated as 22,100tpa for the incinerator plus 5,600tpa for the bio-plant and 2,500tpa for nonconforming/ untreatable waste, all at £175 per tonne plus 6,500tpa of commercial green waste at £16ft and ignores any possible revenue from sewage sludge acceptance.

Therefore contribution available towards general taxation revenue = £3.4M pa.

Note that in this analysis the MRF is assumed to be funded privately. If a publicly-funded MRF were required instead, the overall economics should be slightly improved in theory since the extra gate fee income ought more than to offset the overall costs of construction and operation of the MRF and the operating profit would then accrue to the States; however, the nature of the facility is such that it should probably best be set up as some form of arms-length or private-sector or contract operation. The comparable costs for the current procedure (landfill) would be £25M (£1M per annum direct costs of operating Mont Cuet) but gate revenue for the current procedure would theoretically be greater at £118M (@ current rates) by virtue of the greater tonnages entering the final disposal facility, resulting in a notional surplus towards general taxation revenues of £3.7M per annum, but obviously the current scenario is not sustainable. The total cost of around £49M (including the capital cost) would represent the real cost in 2009 Pounds Sterling of processing 27,700 tonnes of refuse per annum for 25 years (downstream of the MRF facilities) and disposal of 2,500 tonnes per annum of untreatable waste and effectively includes a £3M contribution towards the costs of windrow composting of the green waste. An amount of £30M for processing or disposal of 755,000 tonnes of waste is equivalent to a cost of £65 per tonne, which includes the cost of disposal of all residues and extra collection costs. Under this scenario, the only capital expenditure would be up to £19M and there would be no onerous contractual commitments to be entered into. The States would be free to implement and derive any benefits from any ongoing improvements or initiatives in the management of waste in Guernsey as opportunities arise. This is in contrast to the type of contract arrangements specified in the current tender process whereby the States would be locked into the agreed treatment arrangements and volumes with an irrevocable commitment on the part of the States to pay what would be likely to be very substantial and escalating charges for the next 25 years: such contract arrangements are increasingly frowned-upon and the proposition being circulated that the arrangements involving loans to a special-purpose company to cover what may be expected to be rather larger capital and operating costs under the tender submissions are entirely self-financing and involve no capital expenditure should be treated with the contempt which such suggestions deserve. Lower capital costs could be achieved by opting for a single-stream solution but this is not recommended if the more expensive but more reliable twin-stream solution is affordable.

CONCLUSION

The contractual arrangement according to the current tender, namely an absolute 25years commitment on the part of the States, should not be pursued unless the total real-terms costs are significantly lower than those for the model solution set suggested here, which seems unlikely.

Any tender having (2009 real-terms) capital or operating costs significantly in excess of the £19M capital and £0.5M pa operating costs (excluding capital and finance costs and the costs of the ongoing reduced tip operation but including residue disposal costs) shown to be achievable through adoption of a micro-incinerator, a simple dry MRF and a small bio-plant in this article should be rejected as representing needless expense: the solution analysed in this discussion probably achieves close to a best possible yet reasonably straightforward auditably achievable reduction in residual flow into Mont Cuet, is reliably capable of implementation more quickly (in part, at least) than any likely tender solution, in no way detracts fr om the freedom to pursue ongoing improvements to the management of the Island waste and does not paint Guernsey into a corner when the time comes to replace the treatment system.

Any end-stage high-temperature element materially in excess of 20,000 tonnes per annum capacity should be rejected as being unnecessary in the medium to long term and creating avoidable quantities of noxious atmospheric emissions and undesirable fly ash and bottom ash, the cost of and responsibility for disposing of which would fall to the States under the tender arrangements.

Finally, given the major problem the States now has of attempting to reconcile a growing wish-list of capital expenditure items with a diminishing or negative revenue surplus despite potentially damaging and increasingly oppressive increases in taxes and charges affecting Island residents and small local businesses, there should be a strong presumption in favour of a most economical solution when one has been identified, notwithstanding the absolute refusal of PSD to consider any modification of or alternatives to the current tendering process. It could be construed as negligent avoidably to commit the States of Guernsey to any contract involving irrevocable capital and ongoing expenditure totalling, in real terms, any amount materially in excess of the costs achievable by means outside the current tendering process, even acknowledging that the multipart solution identified here would require rather more effort on the part of PSD than simply signing a contract under the current tendering process. Unlike the situation for the new incinerator in Jersey or under the previous (Lurgi) contract in Guernsey, the current tender involves an absolute commitment for both the initial capital cost and 25 years of ongoing availability costs and even if a decision were to be taken to shut the plant down these costs would still have to be paid. The expenditure commitment incurred by signing a current tender would be the sum total of these amounts and may dwarf any other project cost commitments in the history of Guernsey.

Click on pareto elements of waste stream to download PDF file

A glossary of Solid Waste Treatment terms is available as a PDF file for download.

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