case studies

The picturesque village of Rosedale Abbey lies deep within the North York Moors National Park – an area of great natural beauty and environmental sensitivity. Very popular with holidaymakers, the village contains peaceful caravan parks and several restaurants and pubs. The population varies greatly between winter and summer.

The village is situated alongside the river Seven and is in a steep sided valley. In the past, inadequate sewerage within the village meant that the risk of polluting the river was always present, particularly so in the summer months.

Having made the decision to install a mains sewerage system to serve the village, Ryedale District Council designers were faced with some difficult problems to overcome. The river and a tributary stream had to be crossed by the sewers and the environmental impact of the construction work had to be kept to an absolute minimum. This meant that fixing pipes to the existing bridges was not acceptable – the pipes had to cross under the deeply cut stream and river.

To use conventional sewerage techniques would have meant pumping stations at each crossing together with some deep trenching works in difficult ground. Iseki were asked to assess the possibility of using The Vacuum Way and were able to offer a cost-effective and well engineered sewerage system. This enabled the environmental impact to be kept to a minimum with shallow, narrow trenches and a single pumping station located away from the attractive village centre.

Vacuum Pipework
Vacuum sewers in polyethylene, sized from 110mm to 160mm diameter, with electro-fusion joints.

Vacuum Station Equipment
2 liquid ring vacuum pumps each rated at 370 cubic metres/hr.

2 No dry well discharge pumps each rated at
10.5 l/sec duty-assist.

Vacuum collection vessel volume 4.5 cubic metre fully protected with suitable paint and tested to Lloyds certification

Motor control cabinet – fully automatic with programmable PLC. All pumps start in rotation and all conditions are remotely monitored via station telemetry in a central control office, which minimises personnel attendance.

Bespoke valve monitoring system which monitors the open / closed mode of each interface valve located around the village, such that each valve within the village can be individually observed from the collection station.

Exhaust gases are filtered by passing them through a biological filtration unit situated close to the collection station which is within the sewage treatment works site

Summary
The ‘Vacuum Way’ enabled the river and streams to be crossed without the need for separate pumping stations. The shallow trenches offered specific construction advantages on the steep streets of the village. The system is sufficiently flexible to cope well with the wide seasonal variety in sewerage flows.

Possible Applications for Iseki Redivac’s Technology
Rural community sewerage schemes
Industrial developments
Supply bases
Housing developments / compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

The village of Csorna is situated some 150km north of Budapest and 30 km east of the nearest town, Gyor. The landscape in and around Csorna is flat with a high water table making a vacuum sewerage system an obvious choice due to the ground conditions. The system was installed during 1997 by Hungarian civil contractor Mestermernok. The day to day running of the vacuum system is the responsibility of the local water company operating from a nearby sewage treatment works. A computer link between the vacuum station and treatment works enables the maintenance crew to monitor and control the vacuum system’s operation from their control room at the treatment works.

Mestermernok have installed equipment to the main control panel which allows the PLC logic to be reprogrammed from the town of Gyor via use of a telephone/modem link. The Csorna vacuum system is very efficient and economical to operate with an electricity consumption of less than 0.5kwh per cubic metre of sewage collected.

Vacuum Pipework
There are some 34km of vacuum sewers in PN10 polyethylene pipe from Ø90mm to Ø160mm with electrofusion joints laid at an average depth of 1.2m.

Vacuum Station Equipment
22m³ steel horizontal vacuum vessel.

Three Nash SC4 liquid ring vacuum pumps each producing some 700m³/hr. The vacuum pumps operate on a duty/assist/assist basis.

Two dry well discharge pumps operating on a duty/ standby basis each with a capacity of 24l/s.

Control panel with programmable PLC which controls all pump operations and automatic recovery systems to assist with the efficient running of the vacuum system.

Valve Chambers
The valve chambers (designed by civil contractor Mestermernok) were constructed from pre-cast concrete rings complete with conical base unit and intermediate landing platform. 420 chambers have been installed to date serving some 1100 houses making the vacuum system one of the largest in Europe.

Summary
The village combines difficult geographical conditions – flat land with a high water table and covering many square kilometres. Many conventional gravity pumping stations would have been required whereas only one vacuum station was needed allowing minimal disruption to the village and providing the most cost-effective solution.

Applications for Iseki Redivac’s Technology
Rural community sewerage systems
Industrial developments
Supply bases
Housing development/compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

Vacuum Pipework
Vacuum sewers in polyethylene sized from Ø90mm to Ø160mm with electro fusion joints.Vacuum Station EquipmentTwo rotary vane air cooled vacuum pumps with a capacity of 200m³/hr.Two dry well discharge pumps rated at 5l/s, duty and standby.
Vacuum vessel has a 4m³ volume and is epoxy coated inside and out and tested to Lloyds Certification. The motor control cabinet is fully automatic with a programmable PLC. All pumps start in rotation. The valve monitoring system which monitors the open/closed mode of each interface valve located around the village can be individually observed from the vacuum station.

Exhaust gases are filtered by passing them through a Biological Filtration Unit situated adjacent to the vacuum station.

Summary
Poor ground conditions, challenging topography, river crossings and the need for installation to take place over a short time span, causing minimal impact to the normal life of the village, made Iseki Redivac the only realistic choice.

Applications for Iseki Redivac’s Technology
Applications for Iseki Redivac’s Technology
Rural community sewerage systems
Industrial developments
Supply bases
Housing development/compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages