Reinhaltungsverband Region Neusiedler See-Westufer- Accident Information

The wastewater treatment plant Schützen am Gebirge is according to § 2 Zi. 6 lit. b StlV due to the plant size of 66.500 EW an information-liable plant in the sense of the Störfallverordnung.

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Monday to Thursday, 07:00 to 16:00 hrs, Friday: 07:00 to 12:00 hrs

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for external disturbances and perceptions concerning the regional sewage treatment plant

facility description

The wastewater treatment plant Schützen/Geb. is used for the mechanical/biological treatment of municipal and industrial wastewater from 9 municipalities and all industrial and commercial enterprises located in this region, as well as for the proper treatment and disposal of the resulting sewage sludge.

The Schützen/Geb. wastewater treatment plant covers an area of 2.5 ha and currently employs 8 professionally trained staff.

The wastewater treatment plant essentially consists of the following plant components:

• Mechanical cleaning stage (intake structure, rake house, grit chamber)
• Biological treatment stage (aeration tank, final clarifier, blower station and phosphorus precipitation) and subsequent discharge into the wulka
• Sludge treatment (thickener and storage tank, sludge dewatering, intermediate sludge storage)

Description of potential hazards, assessment by accident analysis

A comprehensive internal accident analysis was carried out and, based on this, measures for handling such incidents were defined. The following possible internal and external incidents were considered:

Internal disturbances:

• Incident during manipulation and the use of equipment
• car accident
• gangrene
• gas leakage
• pipe breakage

External failures:

• high tide
• power failure
• Penetration of flammable, explosive, water-polluting pollutants into the sewer system upstream of the wastewater treatment plant
• in particular: design basis accidents involving the relevant industrial and commercial dischargers with the ingress of hazardous substances into the sewer system

Potential Hazard Areas

• ground water
• ambience
• Upstream sewer system
• Wulka receiving water - Neusiedler See

Possible effects on a public possibly affected by it were raised and behavioural measures were determined.

This safety analysis showed that the"Wulka receiving water" area in particular could be affected by only partial or untreated wastewater. In such cases, there is primarily an environmental hazard. Fishing and water sports in the area of the discharge into the Wulka and in the sewage plume area are to be omitted in such cases. A direct endangerment of persons can be largely excluded.

It can be ruled out with a very high probability that the"groundwater" hazard area is affected. Consequently, it can be assumed that groundwater and its use are neither endangered to the environment nor to persons.

In the event of fire, the"atmosphere" hazard area could be affected by fumes. Odour nuisances cannot be excluded.

In the event of fire, the windows and doors must be kept closed by residents in the immediate vicinity of the sewage treatment plant and paths outside the buildings must be avoided if possible in the affected area.

The"adjoining sewer system" hazard area could be affected by backwater in the event of failure of the inlet pumping stations of the sewage treatment plant in the case of mixed water (i.e. in rainy weather) with an increase in the wastewater level (up to the level of the emergency overflow plus overflow height). This could result in flooding of areas below the backflow level in the event of malfunctioning or missing backflow flaps in house duct connections. However, an environmental hazard or a hazard to persons is not to be expected.

Measures to ensure trouble-free operation

The following organisational and technical precautions have been taken to prevent design basis accidents.

Organization:

Our qualified personnel (8 employees) regularly maintain the sewage treatment plant and monitor it 7 days a week, 24 hours a day. A shift and call availability and alarm service has been set up for times outside normal working hours.

Automated warning devices monitor the essential parts of the wastewater treatment plant around the clock (see below).

Regular training, instruction and operating instructions (emergency plans, etc.) ensure that the employees have the necessary knowledge to be able to react correctly even in the event of a malfunction.

Plant equipment:

The entire structural and mechanical system as well as the electrical, measurement, control and instrumentation technology is state of the art and has provided the corresponding redundancies and reserve units, so that operation is always safe.

Technical monitoring systems and technical equipment:

The entire wastewater treatment plant operation is automated and monitored online. In general, all plant components and units were installed with the necessary reserves and redundancies.

An automatic alarm and information system is installed for secure monitoring. In the event of operational disruptions of a general nature, but also in the event of malfunctions, two shift employees or two employees on call are informed by SMS. These employees rectify the fault and, if necessary, carry out a further alarm according to the alarm plan and emergency plans. Should this SMS alerting system fail, employees on call are alerted by telephone.

In addition, a gas warning system is installed which automatically switches off the relevant system components in the event of gas leaks or gas formation in closed system components and is also linked to alarm targets.

A fire protection concept was developed and implemented for the wastewater treatment plant, which provides for numerous clearly separated fire compartments and escape routes. This largely prevents or makes it more difficult to spread fires and spread to other parts of the plant and building. Fire protection plans are available from the fire brigade Schützen am Gebirge.

In accordance with the Ordinance of the Federal Government on the Protection of Employees from Explosive Atmospheres (BGBI. II No. 309/2004), an analysis was carried out in this regard with the assistance of external experts and the required explosion protection document was drawn up.

With all these measures for the preventive protection of our personnel and the plants against operational disturbances and their effects, the potential possibilities of the effects on a possibly affected public are largely reduced. A certain residual risk of disruptions to the operation of the sewage treatment plant, in particular due to events outside the sphere of influence of the Schützen/Gebirge wastewater treatment plant, cannot be completely ruled out despite all the technical and organisational measures mentioned above.

Information flow in the event of malfunctions

In the event of a malfunction within the meaning of the design basis accident concept, the information is sent to the following places (the following listings in alphabetical order):

• district administrative authority
• Firefighters
• fishing rights
• Municipalities of Schützen am Gebirge, Oggau and Donnerskirchen

Transmission and publication of this incident information:

• Edition in the municipal offices of Schützen am Gebirge, Oggau and Donnerskirchen
• Posting at the entrance gate of the wastewater treatment plant Schützen am Gebirge
• Bezirkshauptmannschaft Eisenstadt- Surroundings
• Water supervision of the office of the BGLD state government
• state fire department command
• state security headquarters
• Water Law Authority of the Office of the BGLD State Government
• Firefighters
• state fire department command
• state security headquarters
• Publication on the Internet: www.rhv-nsw.at Subpage Emergency information
• Water Law Authority of the Office of the BGLD State Government