Stefan Melchior

• Dr. rer. nat. habil.
• Beratender Ingenieur und Bodenkundler at melchior + wittpohl Beratende Ingenieure PartmbB

The water balances and the long-term performance of different landfill cover systems have been measured in situ in large-scale lysimeters on the landfill Hamburg-Georgswerder, Germany since 1988. The cover systems including different barrier components for water transport were constructed with state-of-the-art technology and have been excavated at...

Since 1988 the water balances and the long-term performance of landfill cover systems with different liners have been measured in-situ in large-scale lysimeters (test fields) on the landfill Hamburg-Georgswerder, Germany. The lysimeters were constructed with the same state-of-the-art technology as the whole cover of the landfill to obtain represent...

Die Deponie Georgswerder wurde auf 45 ha durch ein Oberflächenabdichtungs- system, dessen erster Teil ("Obere Abdeckung") 1988 fertiggestellt wurde, und eine Sicker- flüssigkeitsfassung gesichert. Nun können Nachsorge- und Überwachungsergebnisse aus einem zwanzigjährigen Zeitraum vorgestellt werden. Die jährlichen Sickerflüssigkeitsförder- mengen l...

Trisoplast is a mineral barrier material composed of sand, bentonite (> 10.7%) and a non-biodegradable polymer. Its permeability is less than 3 x 10 -11 m/s , which in general is not seriously affected by external physico-chemical influences. Trisoplast barriers, installed in 1995-1996 were excavated to check the occurrence and potential effects of...

In situ test fields were installed within a landfill surface lining system in order to investigate the desiccation risk of the combined liner (clay liner under a geomembrane) due to temperature induced water movement. Temperature conditions in the combined liner were modified in order to enhance the temperature-dependent flow processes. Analysis of...

In dem Beitrag werden zunächst Prozesse beschrieben, die die Austrocknung und Rissbildung in mineralischen Dichtschichten unter dem Einfluss von erhöhten Temperaturgradienten herbeiführen können. Danach wird aufgezeigt, wie sich die Austrocknungs- und Rissgefährdung aufgrund der Forschungsarbeiten darstellt. Schließlich werden Empfehlungen für Depo...

Sediment dredged from the port of Hamburg is treated and stored upland in a storage facility. The site is covered by a system of topsoil above a sand drainage layer and a barrier layer made of processed harbour sludge in order to minimize the input of water after completion of the site. In 1995 in-situ investigations have started to study the hydra...

Sediment dredged from the port of Hamburg is treated and stored upland in a storage facility. The site is covered by a system of topsoil above a sand drainage layer and a barrier layer made of processed harbour sludge in order to minimize the input of water after completion of the site. In 1995 in-situ investigations have started to study the hydra...

Since 1986 different types of landfill covers have been studied in situ on the Georgswerder landfill in Hamburg, Germany. Water balance data are available for eight years. The performance of different barriers has been measured by collecting the leakage on areas ranging from 100 m2 to 500 m2. Composite liners with geomembranes performed best, showi...

 Cover systems are widely used to safeguard landfills and contaminated sites. The evaluation of the water balance is crucial for the design of landfill covers. The Hydrologic Evaluation of Landfill Performance (HELP) model of the US Environmental Protection Agency was developed for this purpose. This paper discusses some limitations of version 2 of...

Capillary barriers are used to seal the slopes of landfills. Hydrological experiments in a 10 m long tilt-gutter demonstrate the principles of lateral flow in the capillary layer above the capillary block and can be used to test materials. Very well sorted sands provide a sufficiently high unsaturated conductivity of the capillary layer. The capill...

Composite liners (geomembranes above compacted, cohesive soil liners) are used in landfill covers. They are subjected to a number of risks that might reduce their efficiency. Desiccation and shrinkage of the compacted soil liner below the geomembrane due‘ to thermally induced water transport is one of the major threats. This study presents an in—si...

Landfill covers and base liners are constructed according to the latest technology as combined systems with plastic liners (High Density Polyethylene, HDPE) on top of compacted cohesive soil material (often referred to as “clay liners”). In case of a failure of the plastic liner the concept of combined liners solely relies on the efficiency of the...

The long-term performance of different covers has been monitored on the Georgswerder landfill (Hamburg, FRG) since 1988. The compacted soil liners have lost their efficiency due to desiccation and shrinkage. The flexible membrane liners and an extended capillary barrier perform very well. A slight periodical desiccation due to thermally induced liq...

The physical isolation of the disposed waste material by encapsulation is a major strategy to safeguard landfills. To design a landfill cover properly, its water balance must be evaluated. For this purpose a model called “Hydrologie Evaluation of Landfill Performance” (HELP) has been developed in the USA in order of the Environmental Protection Age...

Seit 1987 werden auf der Deponie Georgswerder in Hamburg sechs Testfelder mit unterschiedlichen Deponieabdecksystemen untersucht. Neben Kombinationsdichtungen mit Kunststoffdichtungsbahnen über bindigen mineralischen Dichtschichten und einer erweiterten Kapillarsperre werden bindige mineralische Dichtschichten ohne bedeckende Kunststoffdichtungsbah...

Since 1987 six test fields with different types of covering systems are being studied on the Georgswerder landfill in Hamburg. Besides combined systems with plastic liners on top of compacted cohesive soil liners, and an extended capillary barrier design, compacted cohesive soil liners without superjacent plastic liners are being tested. The measur...

Für die Oberflächenabdichtung von Deponien und Altlasten stehen verschiedene technische Systeme zur Verfügung. Am häufigsten werden verdichtete bindige Sedimente als sogenannte mineralische Dichtschichten und Kunststoffdichtungsbahnen aus Polyethylen hoher Dichte (PEHD) eingesetzt. Beide, oft auch kombiniert eingesetzte Dichtverfahren weisen spezif...

Different technical systems are available to cover disposal sites. Compacted soil liners and plastic liners (high density polyethylen, HDPE) are most commonly used to construct barriers. Both systems, often used in combination, have specific advantages and disadvantages. The latter essentially are: construction controlled by weather conditions, the...

Im Rahmen der Sanierung der durch Dioxinfunde in ihrem Sickerwasser in die Schlagzeilen geratenen Mülldeponie Georgswerder in Hamburg werden eine Reihe von Forschungs- und Entwicklungsvorhaben zur Entwicklung von Sanierungstechniken und zur Kontrolle der Wirksamkeit der ergriffenen Sicherungs- und Sanierungsmaßnahmen durchgeführt. Das hier vorgeste...

Along with the remediation activities on the waste disposal site Georgswerder in Hamburg a research and development program with regard to the water balance of several multilayered surface sealing systems is being carried out. For this purpose six large-scale test fields with a size of 500 m2 each were installed in the landfill surface sealing, whi...

Austrocknungsverhalten von mineralischen Abdichtungsschichten in Deponie-Oberflächenabdichtungssystemen Fachhochschule Lippe und Höxter, Abteilung Höxter 31. Januar/01. Februar 2002 veranstaltet von der Arbeitsgruppe 7 – Oberflächenabdichtungssysteme des Arbeitskreises 6.