Project Description Hunan (China)
„Waste Disposal Plant Hoefer,
City and County of Celle”
Author:
IBE Dr Born – Dr Ermel GmbH
Ingenierbüro für Verfahrenstechnik
Finienweg 7
D - 28832 Achim
Germany
Phone: 04202/7 58-0
Fax: 04202/7 58-500
E-Mail:
Web:
Table of contentPage
1.Initial situation......
2.Technical implementation......
2.1Entrance area......
2.2Disposal site......
2.3Leachate water treatment facility......
2.4Surface water drainage......
2.5Gas treatment and disposal......
2.6Recultivation......
2.7Compensation area......
3.Course of construction measures......
3.1Traffic routes and places......
3.2Disposal site......
3.3Leachate water treatment plant......
3.4Surface drainage......
4.Summary of operational data......
5.Conclusion......
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1.Initial situation
“Where can we dispose our waste in future?” was the question of the responsible politicians in the City and County of Celle at the beginning of the eighties. Step by step all of the nearly one hundred smaller landfills were shut down and remediated. Only two landfill were remaining which are very limited in remaining disposal capacity.
The long-drawn-out search for a suitable solution of the disposal problem of City and County of Celle started with an intensive discussion about the future location of a new landfill. Not only the location was under discussion among politicians and citizens but also for what purposes the new landfill should be designed. It was understood that the new plant should comply with the latest state of the art and technique and that the landfill must be completed by recycling and leachate water treatment facilities. Co-ordination of all demands took a certain time until the final decision taking process to construct the new Hoefer waste disposal plant.
At the end of the year 1989 approval was given by the responsible authority at Lueneburg. Start of construction was in early 1991, approximately 10 years after initial planning steps of the new landfill. In September 1992 the facility was put into operation.
The Waste Disposal Plant Hoefer represents a sanitary landfill according to the latest state of the science and technique. Extended constructive securing elements together with effective control systems make sure that the created disposal capacity could be used on a long –term scale.
2.Technical implementation
2.1Entrance area
The entrance area surrounds a space of approx. 6 ha (equal to 60,000 m²) and is dedicated to host all main technical facilities for operation of the landfill. Another 11 ha (equal to 110,000 m²) are taken by streets, drains and plantations.
The entrance control consist of a separate control building with weigh bridge for registration and weighing of delivering vehicles. For handling of the entrance data registration and accounting procedure a modern IT-solution is set up. This computer system also co-ordinates the operation of main facilities of the plant and serves as well as a register for waste disposal for exact location. Picture 1 shows an aerial view of the plant in form of a layout plan.
Administration building
The administration building which was set up separately from the entrance area building to avoid any pestering by noise accommodates three main functional areas:
- Office and social rooms
- Sanitary facilities and dressing room
- Rooms of the central laboratory of the County of Celle.
Information centre
An information centre was set up for documentation of disposal technique and waste management measure in the County which is dedicated to the interested public.
Container facility
A special container facility is installed for private delivery of non-recyclable waste and bulk waste as well as recyclable material like cardboard, metal, garden waste, tyres, construction waste and polystyrene.
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Picture 1: Aerial view (layout plan) of waste disposal plant Hoefer
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Reception station for toxic waste
Reception station for toxic waste is installed for such waste occurring in private households, smaller shops and small trade. Examples of toxic wastes are solvents, batteries, mercury lamps, acids, pesticides etc. All public bodies in Germany are responsible for proper disposal of toxic waste up to 500 kg/producer.
The reception station for toxic waste is located in the southern part of the entrance area of the Waste Disposal Plant Hoefer. The station is structured into the areas of reception, sorting and storage. Treatment of toxic waste on site is not intended. Storage of toxic waste happens in special transport containers made of high-grade steel until transportation by private disposal companies to specialized treatment plants.
Machine building
Directly adjacent to the landfill site (polder) the machine building is located. In a hall with workshop and storage area vehicles used on the landfill are maintained and parked.
Sorting facility
A sorting facility for light wastes like plastics, metals and packaging material is also installed near the landfill site.
Composting facility
Additionally a composting facility for garden waste separately collected from private households and small trade in the City and County of Celle is implemented.
2.2Disposal site
The landfill was build section wise. The disposal site (approx. 39 ha, equal to 390,000 m²) is divided into seven sectors (polder 1 to 7). The first sector in polder 1 comprises a capacity of about 6,33 ha (equal to 63,300 m²).
The corresponding “Technical Guideline Waste” makes high demands to basic sealing of the landfill. Contamination of groundwater and soil needs to be avoided anyway. The basic sealing system consists of a combined sealing in the form of a mineral sealing layer in three parts and a plastic sealing layer of PEHD. Strata of sand and gravel are protecting the system against mechanical stress. Above the top sand layer an area drainage is installed to grasp leachate water and drain it without any backwater.
A scheme of the basic sealing system is shown in Picture 2. Surveillance of any groundwater contamination is achieved by a system of control wells around the disposal site. Systematic analysis of groundwater extracted from these wells enables permanent quality surveillance.
Picture 2:Scheme of structure of combined basic sealing system
Prior to installation of the basic sealing system an experimental field for prove of construction method needs to be established according to the corresponding regulation. Based on these experiments quality instructions for proper installation were set up and approved by the relevant authority.
The installation instructions (quality safeguarding plan) for installation of the basic sealing system comprises the following:
- Definition of special indices to be kept during installation (i.e. water content, density, k-value etc.)
- Determination of method of crushing and homogenization of construction material
- Extension of mix of fine gravel or mixing of different materials
- Addition of water / drying / interim storage
- Thickness of compressed layers
- in case of mill and mixing for homogenization of construction material: determination of necessary depth and number
- Method of compression and type/weight of compressing facilities
- Number and rate of compressions
- Determination of production of basic layer of mineral sealing (quality safeguarding)
- Extension of necessary drainage system including lowering of surface water impact during installation of sealing system as well as information about protection against any weather impact and which securing measures have to be taken during construction
- Quality information about behaviour in case of any deviation from installation manual and repairs of weak spots
- Frequency of verification by external inspectors
Picture 3: Picture 4:
Surveillance of quality during connection Controlled installation of sealing elements
plastic layers by welding for basic sealing system
2.3Leachate water treatment facility
Escaping leachate water from the disposal site is collected by special open drain pipes which are installed in a area drain system above the combined sealing system. Connected closed transport pipes are leading the leachate water through embankment of the landfill to the leachate water treatment facility.
Leachate water is high contaminated by contact with disposed waste as well as by activities from microbes inside the waste body. That is why cleaning of leachate water needs a special treatment facility. High demands on treatment quality only could be achieved with combination of different processing stages. For the waste disposal plant Hoefer a two-stage leachate water treatment facility with the following treatment steps is installed:
After storage organically easily degradable pollutants as well as nitrogen compounds were transformed into elementary compounds like water and carbon dioxide in the first treatment step, the aeration facility. Subsequently – after another interim storage – hard degradable organic substances, halogen organic compounds and salts are held back in a second treatment step, the reverse osmosis facility. Leachate water is pressed under high pressure through semi-permeable membranes. Pollutants are held back in concentrate (approx. 20 % of original amount) and afterwards sprinkled on the disposal site. Flow (permeate, approx. 80 % of original amount) is led to storage tanks for analysis. Only after analysis and clearance by laboratory cleaned water is given to the nearest river by pressure pipe.
Picture 5: Flow scheme of leachate water treatment facility
2.4Surface water drainage
The occurring surface water on the waste disposal facility is collected by a special sewer system. After interim storage in a rain water retention tank and analysis the surface water is led to the nearest river. Rain water from building roofs is led to a special underground tank and afterwards introduced to the aquifer.
2.5Gas treatment and disposal
Rotting processes are producing gas inside the waste body. For collection of gas an extended gas collection system is implemented in the waste body. In a first step gas is collected in open PEHD pipes in three horizontal layers.
After completion of each disposal polder (1 to 7) the horizontal collection system is complemented sector-wise by vertical gas wells as well as by surface drainage during construction of the surface sealing system.
Gas collection shafts
The gas collection system inside the waste body is lead to gas collection shafts where a separation into recyclable and non-recyclable gas according to composition of gas could be managed. Connected to gas collection shafts is a high temperature torch. All polluting substances in the non-recyclable gas are destroyed using temperatures of > 1,200 °C and a dwell time of about 0.3 seconds. It is intended to use the recyclable part of gas energetically, for example by gas motor to generate electricity and/or heat.
2.6Recultivation
After completion of the first two polder on the disposal site a surface sealing system consisting of a 50 cm mineral clay sealing with corresponding gas drainage and compensation layers as well as plastic protection and water drainage layer is applied. Highest layer in this system is a one meter recultivation layer. This layer serves as water and nutrient storage as well as root space for plantations and therefore for re-integration of the plant into landscape.
In final stage the waste disposal plant will reach a height of about +100 metres above sea level. This will result in a raise of about 30 metres above surrounding terrain. Maximum disposal capacity of the plant will be around 5 million m³.
2.7Compensation area
Because of lost of an area being undeveloped a compensation area in a nearby marshy land was prepared for nature reserve purposes.
3.Course of construction measures
The relevant construction measures for the waste disposal plant Hoefer could be divided into five main sections:
- Traffic routes and places
- Disposal site
- Leachate water treatment facility
- Surface drainage
- Operational equipment
Before start of construction in summer and autumn 1990 extended preparing measures as clearing and removal of approx. 10 ha (equal to 100,000 m²) of pinewood as well as inspection of the whole site by ammunition clearing service.
In March 1991 construction of buildings and disposal site was started. In September 1992 the waste disposal plant was completed and ready for operation.
3.1Traffic routes and places
In total three kilometres of streets and approx. 4,800 m² of pavement as path to buildings, to parking lots and to container station were new constructed.
3.2Disposal site
The disposal site of polder 1 comprises an area of about 55,000 m2. The following construction material was used:
- ca. 180,000 m³filling soil (approx. 7,500 truck loads)
- ca. 30,000 m³gravel (approx. 1,800 truck loads)
- ca. 41,000 m³clay material (approx. 5,800 truck loads)
- ca. 55,000 m²separating fleece 450 g/m2
- ca. 55,000 m²protecting fleece 1.200 g/m2
- ca. 55,000 m²plastic sealing layer
- ca. 2,400 mgas pipes
- ca. 1.950 mleachate water drainage pipes
The plastic sealing layer of the basic sealing system were connected together by welding on a length of approx. 15 km. The welded joints were investigated and checked by pressure analysis.
3.3Leachate water treatment plant
The leachate water treatment plant consists of diverse storage tanks, aeration tank as well as reverse osmosis facility and centralized pumping station.
For the storage and treatment tanks overall 1,500 m³ of concrete and 250 Mg of concrete steal have been used. In the centralized pumping station all necessary pumps, pipes and fittings have been placed.
Inside the building of the reverse osmosis facility the control room, low voltage main distribution and the reverse osmosis itself are located.
3.4Surface drainage
To secure the drainage of surface water approx. 1,000 metres of pipes and about 600 metres of trapeze shells have to be installed.
For the surface water retention tank approx. 1,600 m³ of concrete and 135 Mg of concrete steal have been used.
4.Summary of operational data
The following table summarizes exemplary data of the Waste Disposal Plant Hoefer for the City and County of Celle being in operation:
No / Topic / Unit / Parameter1 / Availability
1.1 / Operating time / hours/year / 8,700
1.2 / Time for
revisions / hours/year / none, redundant system
1.3 / Overall availability / % / 100
2 / Quantities
2.1 / Total amount of disposed waste at plant / Mg/year / 40,000
2.2 / Total amount of treated leachate water / Mg/day / 60
3 / Quality of leachate water treatment
(emission, spot check from 2-hour mixed test)
3.1 / Chemical oxygen demand (COD) / mg/l / 200
3.2 / Biochemical oxygen demand in 5 days (BOD5) / mg/l / 20
3.3 / Nitrogen, total, as sum of ammonia, nitrite and nitrate nitrogen (Ntot) / mg/l / 70
3.4 / Phosphorous, total / mg/l / 3
3.5 / Hydrocarbon, total / mg/l / 10
3.6 / Nitrogen from nitrite (NO2-N) / mg/l / 2
3.7 / Fish toxicity (FT) / - / 2
No / Topic / Unit / Parameter
4 / Investment Costs
4.1 / Development / Euro (€), net / 2.05 million
4.2 / Entrance area building / Euro (€), net / 174,000
4.3 / Container station / Euro (€), net / 102,000
4.4 / Administration building / Euro (€), net / 665,000
4.5 / Machine house / Euro (€), net / 390,000
4.6 / Surface water retention tank / Euro (€), net / 940,000
4.6 / Leachate water treatment facility / Euro (€), net / 4.5 million
4.7 / Basic sealing system / Euro (€), net / 5.6 million
4.8 / Exterior area / Euro (€), net / 380,000
4.9 / Construction site facilities / Euro (€), net / 580,000
4.10 / External surveillance / Euro (€), net / 235,000
4.11 / Other / Euro (€), net / 220,000
Overall investment / Euro (€), net / 15.8 million
5.Conclusion
The waste disposal plant Hoefer is an important component to secure proper waste disposal and management on a long-term scale for the City and County of Celle. According to the principal waste management guidelines several measures for recycling of waste could be carried out on site of the plant.. In addition all necessary facilities and equipment are installed to minimize possible emissions and impacts to the environment. With construction and operation of the waste disposal plant Hoefer a safeguarding step was made for all citizens of the City and County of Celle.
In the meantime (year 2003) all prepared disposal sites of the plant are almost filled. Further operation of the plant actually is under investigation, i.e. operation as special landfill for inert waste fractions like construction waste and contaminated soil. Operation of the plant like in the past no longer will be possible because of changed demand of relevant regulations forbidding disposal of untreated waste after the year 2005. The City and County of Celle are now co-operating with neighbouring County of Uelzen to develop future form of economical operation of the landfill and it´s periphery.
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