Old Landfills and New Disposal Sites
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| License | No Open Access License: German copyright law applies. This film may be used for your own use but it may not be distributed via the internet or passed on to external parties. This film contains music to which the collecting society GEMA holds the rights. | |
| Identifiers | 10.3203/IWF/C-1920eng (DOI) | |
| IWF Signature | C 1920 | |
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| Production Year | 1995 |
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| IWF Technical Data | Film, 16 mm, LT, 329 m ; F, 30 1/2 min |
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00:00
Computer animation
00:34
Hydraulic engineering
01:00
Hydraulic engineering
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Computer animation
01:54
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02:37
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Map
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Computer animation
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Computer animation
07:45
Hydraulic engineering
08:31
Hydraulic engineering
09:03
Aerial photography
09:53
Hydraulic engineering
11:07
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11:33
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12:27
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12:53
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MapLecture/Conference
14:32
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Computer animation
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Map
17:31
Meeting/Interview
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Computer animation
19:26
Computer animation
20:37
MapHydraulic engineering
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Hydraulic engineering
21:42
Computer animation
23:12
Satellite imagery
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24:25
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25:25
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25:50
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Computer animationEngineering drawing
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Computer animation
Transcript: English(auto-generated)
00:23
Industrial countries produce large quantities of refuse and waste. 1.5 million cubic meters of waste are produced in the city of Chemnitz every year. This large volume is disposed of by composting or landfill dumping. Today waste has to be disposed of in a safe way to prevent the contamination of air, groundwater and soil.
00:47
In the past, refuse was deposited at random. Its remnants are a threat to our environment because of the emission of toxic gases and fluids into the atmosphere, groundwater and soil. Waste dumping in Chemnitz started around 1900.
01:03
Medical, chemical, military and domestic wastes were dumped without regulation in disused quarries. The most dangerous garbage was deposited in old leaking clay polders on the periphery of the recent landfill. Various toxic fluids were dumped through pipes or poured from barrels.
01:23
Some of them are mutually ignitable.
01:45
Old landfills and new disposal sites. All available data on this hazardous waste site and its geology have been collated and evaluated.
02:03
And on the basis of these data, a study of the impact on the air, groundwater and soil was implemented. Three problematical areas became evident. The smoldering fires inside the disposal site, the fact that the site lies on top of a geologically highly complicated rock series
02:28
and that this exhibits a strong degree of faulting. Only about one kilometer from the city limits of Chemnitz, the landfill is located on a rounded hillock above porous Permian tuffs.
02:47
The fractured tuffs, colored yellow here, lie over less permeable strata of Permian origin. The contaminated plume from the waste site spreads along this discontinuity. At the quarry wall, the fracturing and porosity of the tuffs is clearly evident.
03:10
This stone was used in the building of the city of Chemnitz. The landfill will continue to be used after being sealed with watertight plastic lining foil to prevent leaking into the groundwater.
03:29
The foil is topped with soil and humus to promote revegetation. By 1990, some 80,000 areas of suspected contamination had been registered in Germany.
03:41
A further 180,000 are thought to exist. It will not be possible to investigate or remediate all of them. The scientific community is therefore challenged to evolve lean methods for assessing the danger potential of such sites. This film aims to show examples of various old landfill sites as well as methods of investigation and supervision.
04:06
Following the Chemnitz landfill, we now present the Mansfeld copper mine. These extensive tips have been covered with black plastic foil to reduce heavy metallic dust and leachate formation.
04:27
Many other metals besides copper were mined in these copper shales. The overall mining waste produced by the Mansfeld ore field is distributed over a far larger area than we see in this aerial view.
04:50
The former ore treatment plant is also scheduled for demolition and partial disposal as special waste.
05:01
Dismantling also includes disposal of asbestos insulation material. Soil contaminated with heavy metals has to be stripped, packed in leak-proof bags and placed in interim storage.
05:21
The metallic contaminants will later be reclaimed from the soil by smelting in shaft kilns. The hazardous wastes also occur in close proximity to the residential areas of the former mining community. From the end of World War II up until 1991, around 220,000 tons of uranium were mined by the Soviet-Russian Vismut AG in Saxony and Thuringia.
05:48
The operations were responsible for extensive environmental depletion. The impact on the region of Ronneburg and Auer was particularly strong. In Europe's richest uranium deposit, the fissile material urgently needed for nuclear power generation
06:05
and weapons was mined in large quantities in both open-cast and underground workings. The waste piles are to be used to fill in the remaining open-cast pit.
06:26
Decay of the naturally occurring uranium isotope begins with uranium-238. The decay chain finally leads to the formation of the only gaseous decay product, radon. It in turn decays after a short half-life of 3.8 days.
06:44
Radon emanates in mine adits and above ore veins. It rises in the open-cast pit and can even penetrate into houses. In large desiges, it represents a health hazard. Radon levels underground are reduced by intensive mine ventilation. Therefore, the health hazard to the miners who are removing reusable machinery, piping and wiring from the mine workings is minimized.
07:08
After stripping, the adits will be backfilled with spoil from the waste piles and sealed with concrete. This will prevent seepage circulation in the flooded mine.
07:27
Overflowing floodwater contaminated with chemicals and radioactivity will be treated in water purification plants until the contaminant levels have fallen below the threshold values.
07:47
The waste piles in the uranium mining area near Auer are already reforested. Their danger potential is not only due to their residual radioactivity, but also because they contaminate the freshwater resources with arsenic and lead.
08:01
To prevent transport of the contaminants by wind and water, the piles are now being covered in layers of clay soil. Afterwards, they can be seeded with vegetation.
08:23
Other waste piles are excavated and the spoil is used for backfilling the settling basins or sludge lagoons. The management of these ponds presents the greatest engineering challenge.
08:40
The sludge lagoons were used for the sedimentation of the fine tailings from uranium extraction. The banks or littorals first have to be overspread to prevent aeolian transport of fine radioactive dust.
09:09
The cost of the entire rehabilitation operation at Vismut has been estimated at around 9 billion US dollars. The aim is to complete the project within the space of roughly 15 years.
09:21
To dry out the sludge lagoons, the water first has to be pumped out and treated.
09:46
After backfilling with spoil from the waste piles, the basins will be covered with plastic foil and then dried out with so-called capillary wicks. The foil is used to prevent the penetration of rainwater and hence formation of contaminated seepage.
10:05
The contaminated seepage water that continues to flow from the sludge lagoons is retained in wells and drainage trenches. A total of around 2 million cubic meters of seepage water are collected annually and returned to the sludge lagoons.
10:32
The uranium extraction plant is also contaminated by radiation and has to be dismantled. The scrap is put into interim surface storage on the site.
10:46
Studies are being conducted to test the feasibility of storing contaminated scrap in the sludge lagoons. Outside the mining and smelting facilities, the soil is also investigated radiometrically to map the incidence of radioactive dust.
11:07
Gamma radiation is registered by scintillometers in 20 by 20 meter grid squares. An extensive survey grid allows the long-term results of the remediation measures in the mining area to be controlled.
11:20
By the end of 1992, a total of 1300 surveillance points were set up. The files are to be stored in an environmental data bank.
11:51
At a reference point, the scintillometers are calibrated and equalized.
12:08
Non-radioactive wastes can, for example, be investigated by using geo-electrical methods. In the electromagnetic technique, a large transmission coil induces an electromagnetic field in the soil.
12:22
Highly conductive pollution plumes modify the field. Two long receiving coils pick up the modified field. The readings are digitalized for later evaluation by computer.
12:51
One possible result is a three-dimensional representation of the conductivity of an old subterranean pollution source. Higher conductivity is expressed by peaks.
13:06
Besides electromagnetic detection, vertical electric soundings can reveal the thickness, depth and extent of waste deposits and pollutant plumes in detail. In the riverine forests of the Upper Rhine-Graben, deep saline groundwater is being investigated by geo-electrical techniques.
13:28
Vertical electric soundings with arrays up to 12 kilometres in length allow detection of saline contamination down to a depth of over 1000 metres. For this purpose, an electrode connecting cable must be laid out straight for several kilometres.
13:45
Left and right of the centre of the array, two non-polarizable electrodes are grounded. Between them, the voltage is measured.
14:05
Two move-away current electrodes are grounded simultaneously. Their equal distances to the centre of the array are increased by logarithmical spacing until the ultimate distance of two times six kilometres is reached. The potential between the two electrodes is digitally measured, filtered and stored.
14:25
In this way, the electrical resistivity of the ground can be computed. An old Rhine tributary standing in the way of the electrode array is bridged with an angler's cast.
14:56
In a north-south geological section from the Kaiserstuhl left to Strasbourg right,
15:01
the tertiary strata at the dip faults of the Rhine-Graben have been downthrust to a depth of more than 1500 metres. This is revealed by deep drilling. When saline was drilled there at a depth of 200 metres, there was first no plausible geological explanation. It was geo-electricity that showed that this salinity, or rather its extremely low electrical resistances,
15:24
reached down to a depth below 1500 metres, that is, to the base of the tertiary. The original supposition that the salt had been leached out of old salt dumps could be refuted. Such large-scale salinisation could only originate in tertiary salt deposits,
15:40
which have been leached out in the course of several million years. Wherever possible, geophysical findings should be verified by individual drillings. A drill hammer is sufficient for shallow depths up to 10 metres.
16:24
For greater depths, the method of choice is rotary drilling, allowing exploration down to several hundred metres.
16:45
Disused gravel pits near Heidelberg-Eppelheim have been used for a period of years to dispose of chlorinated hydrocarbons. The groundwater downwash from this site has given rise to a pollution plume. Rising gases damaged vegetation and drew attention to this hazardous, hidden site.
17:06
Within the context of the model program for Baden-Württemberg, the remediation was initiated with a pilot plant. At the Eppelheim disposal site, we have tested two processes in parallel,
17:20
mainly for extracting chlorinated hydrocarbons from the water, soil and air by microbiological remediation. This is done in two ways. First, by an on-site plant. This means that all the pollutants removed from or still present in the soil itself, as well as the groundwater, are extracted and dealt with above ground.
17:46
Besides this, we also have an in-situ plant, where the water and soil are left where they are and are treated on the spot. In the case of the on-site procedure, the contaminated soil is excavated, cycloned in the terra nox plant,
18:05
ventilated and provided with a bacteriological nutrient medium. The bacteria decompose the chlorinated hydrocarbons. Following sanitization, the soil is returned to its original location. The groundwater treatment cycle is elucidated in a cycle diagram published by the sanitizing company.
18:26
In the first stage, the contaminated water is pumped up from the groundwater aquifer and denitrified. The next stage is chlorine reduction in an anaerobic microbiological reactor.
18:43
Then the water passes over sand filters to the erogenic reactor where the remaining chlorinated hydrocarbons are removed. After a final filtration by activated carbon filters, the water finally seeps into drainage wells.
19:17
As they separate off, the contaminated gases are piped through this humus biofilter plant and bacteriologically cleaned.
19:27
The in-situ remediation process involves the ground emplacement of five large steel cylinders each with a diameter of 2.4 meters and a length of 10 meters. Three of the cylinders serve to assess the efficiency of various microbiological processes.
19:44
A central shaft serves to test the processes. Because of gas emissions, the shaft may not be entered without breathing equipment. Steel portholes allow samples to be taken at various depths to follow the progress of bacteriological degradation of the chlorinated hydrocarbons.
20:04
Having shown up to now the exploration, risk assessment and remediation of hazardous waste sites,
20:37
the two concluding examples both show cases of exemplary new disposal sites.
20:43
The first is already operating, the domestic refuse site at Ormusheim in Saarland. It is scheduled for extension. First, a new base barrier has to be constructed. The material used is outcropping Kuiper clay that also functions as a geological barrier.
21:04
For the base barrier, the Kuiper clays are broken up and sifted.
21:27
After homogenization, the material is worked into a 75 centimeter thick mineral barrier. A vibrating roller compacts the emplaced material.
21:41
The mineral seal is topped by a plastic liner three millimeters thick. The sheets are then welded together. The welding joints can be tested for leaks by built-in air channels. Any leak in the plastic liner allows leachate to spread rapidly between the foil and the mineral seal.
22:05
In an experimental leak, measurements of the electrical resistance showed that seepage water advanced at about 1.5 meters a day. For additional protection, the plastic liner is entirely covered with a geotextile carpet
22:23
on top of which a 20 centimeter thick layer of surface filter gravel is spread. The gravel will collect all contaminated seepages. Through a system of drainage pipes, the leachate will be conducted to a central water treatment plant.
22:45
A section through the bottom barrier in diagram. In the central water treatment plant, the seepage water from the landfill drainage is purified almost to potable quality.
23:13
First, the foam is filtered out. Oxygenation then follows in the regeneration tank.
23:23
Aerobic and anaerobic bacteria reduce the pollution potential. A special feature of the Ormesheim water treatment process is the microfiltration plant which ensures that even the finest clouding particles are removed.
23:43
Inside the landfill, biological decomposition and compression producing temperatures up to 70 degrees Celsius cause formation of gases particularly methane and hydrogen sulfide. For this reason, a new landfill site has to make provision for a gas collection system.
24:02
Chimneys serve to flare off the gases or these can be used for thermal energy conversion. Special waste dumps require higher safety standards than domestic sites. A good example is the special dump at Rondershagen in North Germany. At this exemplary site for the disposal of certain types of special wastes,
24:30
the incoming materials are sampled, analyzed and the future emplacement site is registered.
24:55
Wind sifting is a simple way of classifying the grain size of the material.
25:13
To prevent rainwater infiltration, the special waste is stored on arrival in a series of large movable sheds until it is due for final covering on site.
25:25
The special waste site is bedded on a thick almost impervious layer of marl. The groundwater table is at a sufficient depth beneath the base of the landfill.
25:58
The special wastes are assigned to appropriate dumping areas or polders.
26:09
Approximately 60,000 tons of special wastes are deposited here annually.
26:21
The subsoil of this special waste site has been very carefully and extensively sealed off as evidenced by the blueprints drawn up by the Society for the Disposal of Special Wastes.
26:48
The seepage is guided via irrigation pipes to the pumping sumps. Here it is pumped to interim storage tanks. In an external plant, the collected seepage water is treated thermally.
27:03
Its remnants are again deposited. When filled with special wastes, the polders are covered with a three meter thick impermeable top lining and then cultivated. In this way, even highly contaminated wastes can be safeguarded so that they present no hazard to future generations.
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