Project Developement and Plants Services

The Basic idea of this method is the lasting reduction of hazardous proper-ties by the physical and chemical alteration of the waste. The method is economical and an-swers all the relevant legal requirements.

The waste treatment plant in Vienna has obtained official approval for a large number of wastes, under the strict provisions of the Austrian and European waste management law.
By the physical mixing of the waste with matrix made up of latent-hydraulic binders for so-lidification, permeability and porosity are reduced so as to lessen the mobility of contami-nants.

Chemical reaction, i.e. immobilisation, between binder constituents and mineral contaminants lead to the formation of new stable phases (e.g. calciumsilicate-hydrate-matrix). This patented method is particulary suited for toxic heavy metal residues from industrial processes (e.g. fil-ter dusts, fly ash or sewage sludges) as well as for materials from contaminated sites.

It is also possible to treat various liquid and pasty wastes for subsequent direct disposal. The great number of incoming treatment contracts help to demonstrate the effectiveness and econ-omy of this innovative method.

Even years after they have been closed, for lack of oxygen in the waste body, landfills gener-ate malodorous, sometimes toxic, and explosive gases. These gases consist mostly of meth-ane, carbon dioxide and nitrogen, with traces of hydrogen sulfide, mercaptan, perchloro-ethylen and vinyl chloride.

These trace gases are well known to be toxic and carcinogenic. Additionally, leachates heavily polluted with organic contaminants pose a threat to the ground water. So during excavation of an old landfill a considerable threat to the personnel as well as a massive odour nuisance are to be expected.

To avoid these harmful effects an aerobe treatment of the waste body is necessary, the aim of which is to change the anaerobe conditions into aerobe ones. To achieve this, oxygen enriched air has to be injected into the material and distributed evenly.

So during the BIOPUSTER® treatment air or oxygen enriched air is injected with pressure impulses of 2 to 6 bar. The resulting flow behaviour ensures that cracks and pores as well as closely packed areas of the waste body are equally supplied with oxygen. Thus methane pro-ducing anaerobe processes are stopped, and microbiological aerobe decomposition can take place instead. The products of these aerobe decomposition processes are mainly carbon diox-ide and water. To encourage and speed the aerobe decomposition oxygen enriched air is used, whereby the concentration of oxygen can be adjusted to circumstances on-site and usually varies between 30 and 35%.

Paralleling the aeration, the produced decomposition gases are sucked off and subsequently cleaned by a filter device. The extracted gas amount usually exceeds the amount of injected air/oxygen mixture by approximately 30%, thus ensuring low pressure conditions in the waste body. This way, unchecked gas emissions on the landfill surface can be avoided.

The adequate duration of this aerobe pre-treatment is crucial for the success of the condition-ing of any waste body. As our tests clearly showed, a pre-treatment period of only a few days would mean that after some hours anaerobe processes will take over again, which in turn lead to the renewed production of harmful landfill gas by anaerobe conditions. From the many successful applications of the BIOPUSTER® a necessary treatment period of at least 3 to 4 weeks can be estimated, thus ensuring the aerobe stabilisation of the waste to be completed, and the material being fit to be excavated, sorted, transported to other facilities and subjected to further treatment.

The utilisation of the BIOPUSTER®technique prior to excavation of a landfill is an essential precondition for professional remediation of old waste dump sites.

PORR Umwelttechnik GmbH designs, constructs and operates Landfills, especially for con-struction waste materials and mineral waste. PORR Umwelttechnik GmbH also offers comprehensive solutions for site assessment, design, funding, construction and operation of landfills and waste dumps of all kind.

Due to constructional advantages asbestos was used for many years in construction industry and plant engineering. The field of application included fire protection and noise insul

Well known asbestos products are spray asbestos, light weight construction panels and sealing materials as well as corrugated asbestos and asbestos cement pipes. Today it is generally known that wear, climatic influences or ageing of the asbestos products may all lead to unforeseen and intermittent release of respirable fibres into the surrounding atmosphere.

Evidence shows clearly that breathing of respirable fibres represents a serious health risk. Therefore, years ago the introduction into circulation and usage of asbestos products was prohibited by federal law. Step by step even weak asbestos bound products, such as spray asbes-tos, were removed from contaminated buildings or at least properly sealed to protect the envi-ronment.

Because of the high risk that personnel is exposed to during sanitation of an asbestos contaminated site, restrictive safety requirements are mandatory. Two points have to be considered carefully: to minimise health risks for the sanitation personnel, the workers have to be equipped adequately, and asbestos fibres must not escape into the environment in any way.

In the contaminated area, the trained staff is obliged to wear gas mask and breathing equipment with an adequate particle filter, and an encapsulating suit with hood, protective gloves and safety boots.

For environmental protection the site is sealed hermetically from the surroundings and kept at low pressure by a local exhaust system. Access and exit are solely possible by passing a personnel lock system.

The remediation itself has to be as dust free as possible. Spray asbestos is removed directly from the working site by a high-vacuum exhaust device and then transported by an encapsulated system. In a state of the art solidification plant this asbestos can be solidified with cement, packed, and eventually disposed of on a controlled landfill.

As a terminal examination an airborne-fibre measurement makes sure that the sanitation was successful.

Since there is no doubt that asbestos is a hazardous material the handling of it requires a great deal of consideration. The successful remediation of a contaminated site without danger to the environment demands professional planning and implementation. To ensure this, the remedia-tion has to take place according to legal requirements and in coordination with the local government, and has to be supervised and documented by an independent expert.

ation, heat protection and damp proofing.