When a Contractor has excess topsoil, may it be sold and used off-site without it being classed as a waste and therefore needing to be classified as a waste material?

Based on existing European Court caselaw, there is absolutely no reason why uncontaminated soils excavated from one site cannot be reused on a different site – so long as you use only so much as you need, and the soils are suitable (and certain to be used) for the proposed end use. In those circumstances the soils cannot be regarded as having been discarded, and therefore cannot be waste.

Existing EA guidance suggests that only on-site reuse is permissible, but this does not (and, to be fair, is not intended to) represent an accurate statement of the legal position. The existing guidance is there simply to discourage off-site reuse, but without actually saying it is illegal (which it isn’t).

The WFD will, at the very least, provide that uncontaminated soils which are certain to be reused on the source site are not waste (thus superseding the existing guidance document). But if the European Parliament (intent on slashing needless red tape) gets its way, the above will apply both to the source site AND any other site.

View the original article here

It’s important to note, however, that even if the above Environmental Permit exclusion doesn’t get expanded to include other sites, the legal position (based on existing caselaw) will remain unaltered, meaning that off-site reuse (where the requirements of suitability and certainty are met) remains perfectly legal, notwithstanding the Agency’s reluctance to advertise that fact.

There are a lot of elements in the argument for and against phased restoration of a landfill. Well before making your decision, it’s going to be important and vital to make sure you know and fully grasp these pros and cons. This article explains some of the important plusses and minuses associated with the development, operation and restoration of landfills in a series of phases of sufficient size for efficient landfill operation.

The method of landfilling is known as phased restoration. It has many advantages, and in many national waste regulation regimes is considered to be a central requirement of sanitary landfill practice, and to show a well planned Restoration Phasing Plan is a pre-requesite of obtaining any site licence. In a number of the industrializing nations this does not apply which appears surprising when there are such huge benefits in:

• increase landfill gas yield
• reduced leachate production.

However, the requirements of pregressive restoration interact with other site aspects, and it is unlikely that all angles can be obtained perfectly at any given site. To be able to make the decision which is correct for you, you will need to know the following:

Benefits: Points In Favor Of phased restoration of a landfill

1. Landfill development should be based on the progressive use of the landfill area, such that at any given time parts of the site may be in the process of being:

- capped and restored
- capped
- actively filled
- prepared to receive waste, or as yet undisturbed,

and the aim of the restoration program is always designed to minimize incident rainfall soaking into the waste, and maximize early completion of discrete areas (Phases) to the final restoration profiles to allow maximum landfill gas extraction from full depth vertical landfill gas wells.

2. It allows progressive restoration. Progressive excavation of on-site materials, allows for efficient nearby storage of restoration materials, and minimisation of double handling of development and restoration soils.

One other good reason for the advance planning, development, operation and restoration of landfills in a series of phases, of sufficient size for efficient landfill operation, is minimisation of double handling of development and restoration soils.

This has the additional advantage of avoidance of unnecessary earthworks soils materials handling, that is certain to protect against making the mistake of large quantities of restoration materials being found to be needed toward the end of the landfill period, when otherwise useable material is then covered with waste and cannot be excavated and used.

3. It minimises the area required for active landfill operations and concentrates activities within a sequence of defined areas, reducing nuisance and polluting emissions.

And then there’s less visual intrusion caused by the landfill, and also site restoration funding requirements are more progressve and less peaky.

All these are advantages for the site that is continuously restored and each restoration work construction period is carried out by the site owner every year to 18months. It’s also very important as it could otherwise mean that without progressing restoration very large areas of only temporarily covered unsightly waste would be left for longer, for the alternative non-phased restoration of a landfill.

Also, perhaps all of us will agree that it must surely be best to plan full height restoration, and avoid large areas of waste left open and uncapped for long periods. Once you take that under consideration, then it makes sense to plan, and implement a plan, for phased landfill restoration using progressive restoration techniques.

The points above show the positive aspects of phased restoration of a landfill. There exists a down side also. Here’s a discussion of some of the drawbacks, but never overestimate the drawbacks!

Drawbacks: Arguments Against phased restoration of a landfill.

1. Physically excessively placing a limit on operational space

If you consider the phased restoration of a landfill, some parts may be too steep for the restoration works plant, within the phasing plan – especially for very deep landfills may limit operational space. That’s clearly a bad thingbut should be avoidable with good planning in most cases and all but the narrowest and deepest “quarry filling” landfills.

2. The direction of phasing usually needs to be resolved between screening for visual, wind and noise and allowing adequate flexibility for the passage of vehicles across the site.

Other factors to consider which will be present for the designers of many phased landfills will be

- potential instability in part-filled void, where support from future waste is absent
- need for protection of temporary edge of lining/capping
- need to protect against leachate overflow into unlined areas
- achievement of agreed final landscape plan after settlement.

3. Achieving the normal preference for leachate drainage to start at lowest point, may conflict with topographical requirements

The last pssible justification put forward to avoid phased restoration of a landfill is achieving the normal preference for leachate drainage to start at lowest point admittedly, this may conflict with topographical requirements. Everyone ought to consider this point very carefully, considering the fact that it can cause difficulties later with leachate wells in difficult to access or excessively deep locations if you decide to go for the phased restoration of a landfill. However, despite the complexities of phased landfill design, the fact is that it is genuinely the best option for probably about 90% of MSW landfills.

And so that’s that. There are the positives and negatives of phased restoration of a landfill. It may not be the right thing for some rare landfills, but it is most certainly beneficial to nearly all MSW landfill operations. So, you should carefully look at the above information and comparisons. Hopefully your final decision process will be aided in detail because of the pro and con info offered here.

Realize methods to understand local waste facilities by visiting my Waste Facilities web site at wastefacilities.org.

The most critical components of a landfill cap are the barrier layer and the drainage layer. The barrier (sealing) layer can be low-permeability soil (clay) and/or made from geosynthetic clay liners (GCLs).

A flexible geomembrane liner may also be required and if so, is placed on top of the barrier layer. In addition for stoney sub-soil materials a protection geotextile “blanket” may be needed, over and/or below the flexible geomembrane liner.

The soils used as barrier materials are usually clays that are compacted to a hydraulic conductivity no greater than 1 x 10-9 m/sec for UK landfills generally, but less stringent permeabilities may be justifiable and may be used where acceptable to the Environmental Regulator (UK – EA).

Compacted sealing layers are generally installed in 200mm minimum lifts to achieve a thickness of 600 mm or more.

Many people talk of using a composite capping system. A composite cap/barrier uses both soil (clay usually) and a geomembrane, and making best of the advantages of the properties of each. A geomembrane when installed is essentially if intact so impenetrable by water to be thought of as impermeable, but if it geomembrane barrier develops a leak, the soil component provides a second line of defence and prevents significant leakage into the underlying waste.

The purpose of landfill capping is to shield humans and the environment from the harmful effects of the landfill contents and limit the migration of the contents by reducing inflow of water from the surface, and greatly reducing gas escape. A cap will always restrict surface water infiltration into the contaminated landfill contents to reduce the possibility of contaminants leaching from the site after landfill closure.

A Landfill capping Landfill Capping is the most common form of remediation because it is generally less expensive than other technologies and effectively manages the human and environmental risks connected with a remediation place. That being said, the process of capping is still very expensive

Hydrogeological studies must be carried out to guarantee the drainage of any water that, by running between the membrane and soil mass, can reduce to zero the soil/membranes’ coefficient of friction. If such a situation was present the soil mass overlying the impermeable membrane would become unstable at many landfils subject to slippage in a veneer fashion.

The Geosynthetic material known as “Pozidrain” may be able to provide these functions with higher performance and lower cost than conventional crushed stone filters. Also, Pozidrain is also used by landfill operators who want to gain the revenue from every last once of waste into their landfill before landfill closure. The thickness of this material makes this possible as it is much thinner than a stone layer. This allows more waste to be put in the landfill before the planning consented top of site levels are attained.

Pozidrain has been specially designed to be compatible with both HDPE and clay liners and to give the optimum performance over the whole life of the landfill closure capping. Pozidrain will enhance the performance of the GCL or HDPE liners by providing an additional barrier that prevents the majority of the water or gas reaching the liner.

The often proposed alternative landfill liner system to Low Permeability Clay Layer or HDPE Lining Membrane consists of replacing the default design of compacted clay liner (CCL) with a Geosynthetic Clay Liner (GCL).

There are currently two major types of commercially available GCLs. One type consists of bentonite encased between two geotextile fabrics and the second type consists of bentonite glued to a HDPE geomembrane.

The type of clay typically used in GCLs is sodium bentonite. Sodium bentonite is the name given to the highly plastic clay mineral montmorillonite, with sodium as the primary exchangeable cation.

Bentonites used to fabricate GCLs are processed in an unhydrated state such that they appear to have a granular consistency. However, upon hydration with water, the bentonite swells to form a continuous clay layer.

GCLs are shipped in rolls typically 3.7 to 5.3 meters wide and 25 to 60 meters long. They are installed by unrolling to form panels. Adjacent panels are overlapped, and for some products, powdered bentonite is placed between the panels at overlaps.

Large-scale laboratory testing has shown that, when installed in accordance with the manufacturer’s specifications, GCL overlaps are self-sealing and do not create a preferential pathway for liquid flow.

GCLs have been used in liner systems and cover systems for landfills, surface impoundments, and tank farms, as well as in other structures. When used in landfills, GCLs are often substituted for the compacted low-permeability soil component of a composite liner. The function of the GCL in the composite liner is identical to that of a compacted soil liner, which is to provide a low-permeability barrier to liquid flow through any defect in the overlying geomembrane.

The GCL material is manufactured under strict quality control (QC) guidelines. The QC requirements include conducting index and performance testing on both the supplied materials and finished product at specified frequencies. After the material is approved at the manufacturing plant, care is taken to keep the rolls dry, not stack them too high, and keep them from damage during handling.

Prior to acceptance in the field, information concerning the manufacturer’s name, product name, lot and roll number, and length, width, and weight must be submitted to the on-site CQA representative, who will verify all records.

To analyze the leakage through a composite liner utilizing a GCL instead of a CCL, D’Arcy’s equation is utilized based upon an assumed design hydraulic head over the liner.

The leakage through a membrane liner has been found to be closely correlated with the hole defects. In a recent paper a defect size per acre of 1 cm2 was assumed, however assessments of defects and their likely frequency and size vary widely.

The US Fabricated Geomembrane Institute (FGI) offers its popular short course, “Constructing with Fabricated Geomembranes“, on 23 October 2009 in Lakewood, Colorado at the Sheraton Denver West Hotel. This course will be presented by Timothy D. Stark, Stan Slifer, John Heap, Daren L. Laine, Bill Shehane, Stuart Lange, Andrew Mills, Gary Kolbasuk and other speakers. Course participants are eligible for 6 PDHs.

Those involved with the design, construction, operation and closure of potable water and irrigation ponds, floating covers, canals, landfills, waste water lagoons, secondary containment, golf course ponds, decorative applications, corrective action activities at closed sites, etc. are encouraged to attend this course. Participants will gain a broad knowledge of what is required to properly design, specify and construct with fabricated geomembranes and advantages of fabricated products over rolled geomembranes.

The fabricated geomembrane information will cover manufacturing, formulation, fabrication, shipping, installation, long-term performance, wedge welding, testing of field geomembrane seams, updated ASTM testing of geomembranes, and design and installation of various applications, such as floating covers, canals, decorative and irrigation ponds, and secondary containment.

AGENDA

The 23 October short course will unfold as follows:

7:30 – 8:00 am Registration / Continental Breakfast
8:00 – 8:20 am FGI Introduction, Activities, and Research
8:20 – 8:40 am Fabricated Geomembranes vs. “Rolled Goods”
8:40 – 9:30 am Manufacturing Fabricated Geomembranes
9:30 – 9:45 am Break
9:45 – 11:00 am Fabrication and Installation
11:00 – 11:30 am Leak Location with Fabricated Geomembranes
11:30 am – 12:30 pm Lunch on Your Own
12:30 – 1:30 pm Floating Covers and Potable Water
1:30 – 2:00 pm Canals, Decorative and Irrigation Ponds
2:00 – 2:30 pm Wastewater Ponds
2:30 – 3:00 pm Break
3:00 – 3:30 pm Secondary Containment
3:30 – 4:30 pm Case Histories
4:30 – 5:00 pm Summary and Questions
5:00 pm Geomembrane Welding Demonstration

REGISTRATION

The registration fee for industry professionals is $100 and the course is free for government employees and students. All receive one day of instruction, short course notes, refreshments and lunch. Industry professionals should register by 25 September 2009 to get the best rate. See the online event registration page to start the process: http://fgi.eventbrite.com/

The following applies to the typical RCRA Subtitle C Landfill Cap System

Landfill Capping is the most widespread type of remediation since it is in general less pricey than other technologies and actually manages the human being and environmental risks allied with a remediation site.

Landfill caps can be used to:

* Reduce exposure on the surface of the rubbish facility.
* Avert vertical infiltration of water into wastes that would create contaminated leachate.
* Contain waste while treatment is being applied.
* Manage gas emissions from underlying garbage.
* Generate a terrain surface that can maintain plants and/or be used for additional purposes.

The plan of landfill caps is location specific and depends resting on the proposed functions of the system. Landfill Caps can range from a one-layer system of vegetated soil to a multifaceted multi-stratum technique of soils and geosynthetics. In general, less complicated systems are necessary in arid climates and more intricate systems are essential in damp climates. The fabric used during the assembly of landfill caps involve low-permeability and high-permeability soils and low-permeability geosynthetic products. The low-permeability materials reroute water and preclude its path into the rubbish. The high permeability materials move water away that percolates into the cap. Further materials could be used to increase slope stability.

The most significant components of a landfill cap are the barrier layer and the drainage layer. The barrier layer can be low-permeability soil (clay) and/or geosynthetic clay liners (GCLs). A flexible geomembrane liner is placed on top of the barrier layer. Geomembranes are usually supplied in large rolls and are available in several thickness (20 to 140 mil), widths (15 to 100 ft), and lengths (180 to 840 ft). The candidate list of polymers commonly used is lengthy, which includes polyvinyl chloride (PVC), polyethylenes of various densities, reinforced chlorosulfonated polyethylene (CSPE-R), polypropylene, ethylene interpolymer alloy (EIA), and many newcomers. Soils used as barrier materials generally are clays that are compacted to a hydraulic conductivity no greater than 1 x 10-6 cm/sec. Compacted soil barriers are generally installed in 6-inch minimum lifts to achieve a thickness of 2 feet or more. A composite barrier uses both soil and a geomembrane, taking advantage of the properties of each. The geomembrane is fundamentally impermeable, but, if it develops a leak, the soil component prevents significant leakage into the underlying waste.

For facilities on top of putrescible wastes, the collection and control of methane and carbon dioxide, potent greenhouse gases, must be part of facility design and operation.

More…

Landfill reclamation in varies guises is becoming more popular in many areas. The most common form of landfill reclamation seldom gets reported is such, and it comprises the removal of waste from brownfield sites where old landfills were present. These are usually quite small tips, and quite often due to there age there are very few problems in moving them, into new lined areas. Odours that might have caused distress to neighbours are gone and it is simply a matter of clearing and cleaning the land for development, removing a constraint which would otherwise have prevented redevelopment of the land This may be either due to regulatory requirements or risks of foundation settlement, and/or possible landfill gas present.

Reclamation can make sense economically too, for shallow and very old landfills. In addition to raising the land value once it can again be used for development the continuing liability to the owner of any old landfill will also be reduced by reclamation. It is easy to forget that old landfill sites must be monitored on a regular basis to make sure they are not causing pollution and are safe from such matters as gas migration iot nearby houses and factories.

The responsibility for this monitoring rests with the local Environmental Protection Authority (Environment Agency England and Wales) (EPA/EA) and landfill operators themselves. Landfill gas removal diminishes the potential for landfill contaminants to travel as a gas and dissolve into the groundwater. The regulatory aim is always to protect the public’s health and safety from the potential for the landfill gases to concentrate in enclosed areas where harmful vapours could be inhaled or an explosive atmosphere could occur.

Landfill mining also achieves landfill reclamation and is carried out for a slightly different purpose. Landfill mining is all about recovering valuable metals, producing high quality fertiliser and retrieving construction materials. In some nations carrying out this sort of reclamation is used to make available real-estate that was once considered lost forever.

However, concerns arise about the release of landfill gas and odours during reclamation works. Landfill gas has an unpleasant odour that can cause headaches or nausea. The odour, however, is more irritating than a hazard to health as it can contain carcinogenic compounds. Landfill gas escapes should be monitored at least quarterly at agreed points around the site perimeter to check for migration. A gas collection system may be installed that will enable gas to be sucked out of the wastes and collected and the collected gas be converted into energy.

During landfill reclamation it has been reported that waste material has proved much harder to sort, and the actual productivity has been much lower than originally estimated in feasibility studies.

Gas Plasma technology is being sold to carry out landfill reclamation projects in the US, and the most favoured technologies will not require manual sorting. In gas plasma plants, waste material is fed into a specially designed chamber and the intense heat of the plasma breaks down organic molecules (such as oil, solvents, and paint) into their elemental atoms. In a carefully controlled process, these atoms recombine into harmless gases such as carbon dioxide. This is why gas plasma is described as a mass destruction method.

Landfill reclamation can remediate groundwater contamination problems. Groundwater moves slowly and continuously through the open spaces in soil and rock below ground. If a landfill contaminates groundwater, a plume of contamination will occur. Groundwater, surface water, soils and sediments ons ite become contaminated. In most cases, and routinely, monitoring wells have to be provided around landfills in areas likely to detect leakage (e.g., downstream of the groundwater flow).

It is a sad fact that in many countries environmental contamination from landfills is entering watercourses and underground aquifers at alarming rates. Liner breaches, if indeed the landfill was even lined to start, are not uncommon. Landfill reclamation can at as stroke return land to normal uses especially housing, and by placing the existing waste in a new environmentally sound landfill also remove pollution.

Space is becoming the biggest issue. We have little enough space in most cities already, so we can hardly afford to effectively sterilise land above landfills forever. Space is even seen as becoming increasingly scarce throughout the United States, particularly in the more densely populated urban and coastal areas. Old closed landfills as time goes on will eventually take up massive tracts of land, and the use of that land will be very limited unless extension reclamation of these old landfills can be carried out.

One of the most common locations for landfills are worked out quarries and quarries suitable for landfill are an increasingly valuable resource for this reason.

In a growing number of cases suitable sites include rare geological exposures of mineral bearing rock, or strata of regional importance which need to be kept exposed after landfilling for educational and also often for historical reasons.  In the United Kingdom these features are identified at planning permission stage and usually allocated Special Scientific Interest (SSI) status.

These SSI’s can result in conflict between conservation and waste disposal interests. The geological feature is usually below the intended restoration level and results in a low point being left in the restoration profile where the SSI is present.

Where quarries used for waste disposal contain Sites of Special Scientific Interest, it is necessary to maintain safe long term access to the geological exposure. The landfill operators will wish to minimise sterilisation of void space for the waste. These objectives can be met by the construction of a structure which limits land take and which maintains a safe barrier to the waste material.

However, it is possible to minimise the conflict and to provide for these geological SSI’s without undue difficulty, as we will describe.

The following list of considerations is broadly based on research described funded by the Nature Conservancy Council in the early 1990s, and has led to the identification of engineering measures designed to optimise landfill void in quarries whilst protecting, in the long term, geological Sites of Special Scientific Interest.

1.    To provide long term, safe, unhindered access to the geological exposure with minimal sterilisation of landfill void space for waste, it is necessary to provide an engineered structure which limits land-take and which maintains a safe and  secure perimeter barrier to the waste material. Long term slope stability must be checked by geotechnical analysis, but it is not the sole design consideration since the access to the exposure must remain drained, be free of leachate and free of significant concentrations of landfill gas.

2.   The presence of a geological exposure in a quarry used as a landfill may have a significant effect on the design and operation of the landfill particularly with respect to leachate management. In some cases in nations where leachate levels are not controlled by landfill site licenses it will be necessary to maintain leachate in the landfill at a much lower level than if a geological Site of Special Scientific Interest was not present.

3.   Natural drainage should be provided where possible to prevent the accumulation of surface water adjacent to the geological exposure. Where this is not possible or the base of the geological exposure is below the water table, pumping may be necessary to facilitate access to the exposure. In such cases it will be necessary to maintain the level of accumulated water below that at which it  will flow into the landfill to prevent the generation of unacceptable volumes of leachate. In addition, it will be necessary to minimise the volume of water which may become contaminated by leachate so rendering it unsuitable for discharge to the surface water system.

4.    It may be necessary to take measures to prevent the movement of leachate from the landfill site through or beneath the waste retaining structure towards the Site of Special Scientific Interest where it  may contaminate accumulating surface and groundwater. The measures may include excavation of the base of the landfill site to a lower level and maintaining leachate below the level of the  base of the geological exposure, reducing the leachate level by pumping and the construction of a low permeability leachate retaining structure keyed into the low permeability materials forming the base of the site.

5.     Landfill gas is flammable, is explosive if ignited in an enclosed space, and can also create an asphyxiating atmosphere. In Europe gas hazard sites (such as landfills) are controlled by the ATEX Directive and national regulations, such as the UK’s Dangerous Substances and Explosive Atmospheres Regulations. Landfill sites in most nations now have gas control systems, and with adequate control it is considered unlikely that landfill gas will accumulate in significant concentrations adjacent to a Site of Special Scientific Interest. However, this may not always be the case and especially if no landfill gas extraction is provided on the site, the area should be monitored for the presence of methane and carbon dioxide prior to access, and ATEX Rules applied as appropriate.

6.   Where the landfill perimeter slopes adjacent to the geological exposure are engineered and graded to a profile of less than 1:3 access by visitors on foot across mown ground should present no significant problems if all visitors wear suitable footwear. Where steeper landfill perimeter slopes are designed an engineered access route may be necessary in the form of a graded path across the landfill or the geological exposure or a purpose made staircase from original ground level to the floor of the exposure.

However, if the above criteria are met, there is no reason why a geological SSI and a landfill cannot co-exist without a significant conflict of interest.

The closest you can get to a list of the top contractors doing Construction Quality Control (CQC) work on landfill developments (basal development and capping/restoration) is probably the following list.

New Civil eEngineer Magazine, which is the weekly news magazine of the Chartered Institution of Civil Engineers, provides through eMapInform an annual contractor listing and ranking report across all civil engineering construction disciplines.

This years edition provides the following list for “waste” contractors. these are the top twenty waste contractors by turnover. These companies normally also work in building recycling facilities and composting plants.

1. Ascot Environmental
2. J N Bentley
3. Edmund Nuttall
4. Fitzpatrick Contractors
5. Balfour Beatty
6. Norwest Hoist Civil Engineering Division
7. North Midland Construction
8. J Breheny Contractors
9. Fox Owmby
10. Amalgamated Construction Company
11. Dean and Dyball
12. Raymond Brown Construction
13. Alun Griffiths Contractors
14. Forkers
15. UCS Civils
16. Wrenco Contractors
17. Highland Quality Construction
18. Interserve Project Services
19. Barhale Construction
20. Buckingham Croup Contracting

Although the top listed players above, are well known and respected within the waste industry they are not household names outside the waste industry, and the really large national contractors are under-represented with only Balfour Beatty present. This is a very specialist area of work and has the large value contracts have the past been dominated by landfill development and restoration works, with some work also in waste facility construction.

The split of the value of the work will soon reverse with increasing demand for waste treatment and processing facilities rising fast to eventually exceed landfill type projects. This will happen as the largest of the UK’s planned PFI integrated waste management contracts move into the construction phase and the start of their operational contract periods.

The UK government plans to pump a lot of money into this sector, to have the necessary effect on the redirection of waste away from landfills in a big way, over the next few years.

Whether the name Dean and Dyball will be around for very long, or even next year in this list, is unknown as they were taken over by Balfour Beatty in March 2008.
Archive information etc on the top contractors of past years is available at the Landfill Site Top Twenty Contractors.

Dense Asphaltic Concrete can be an extremely versatile product, suitable for many types of applications.

The ancient civilizations of Egypt, Babylon and Assyria all used bituminous lining materials and mortars for waterproofing and building, some more than 5,000 years ago, and many examples of their work remains intact even today.

More recently with the advances in hydraulic technology, asphalt has been shown to be an effective material for sealing Dams, Reservoirs, Canals, Water Catchments, Sea Defences, Coastal Groins, River banks and importantly for us - Landfill Sites.

WALO is a main UK supplier.