Posts

Prestons Residential Development Vacuum Sewer

/0 Comments/in , /by

The Flovac Vacuum Pump Station was installed in 2015 to service the Prestons residential development in Marshlands Christchurch and has continued to grow with house sales in the area ahead of schedule.

Every effort has been made by the developer Ngai Tahu to ensure that this medium priced housing development for 8,000 residents is world class.

Environmentally Sensitive Development at Prestons

 

Right next to the vacuum pump station, the Marshland School for children aged 5-13 has been completed. When Master Planning a vacuum sewer system it is always important to consider that any flows from schools will be interrupted during school holidays and weekends. So to ensure that plenty of air is entering

Marshlands School

the system, especially close to the station the system needs to be tuned correctly or have an automatic air inlet system that can be programmed to take the change into account.

 

The vacuum sewerage system is the ideal technology for a development like this as it can be very flexible with new additions over time and is resilient to damage from earthquakes. Unlike low pressure pump systems, the only power requirement is at the vacuum pump station, so if an earthquake interrupts power supply the vacuum sewerage network at Prestons will continue to work as there is a back up generator located at the station.

Another resilient feature of the Flovac system is that if any of the vacuum mains break or rupture during an earthquake, the negative pressure in the pipe ensures that no sewage will leak out. A low pressure pump system operates on positive pressure, so if a pipeline breaks sewage will surcharge from the pipe into the surrounding area. In an environmentally sensitive area like Prestons, that could be a disaster.

Another benefit of the vacuum sewer system is its ability to handle high flows into the collection system. A large supermarket complex is being planned in the neighborhood complete with a Foodstuffs supermarket, cafe’s and restaurants. Already built is a large BP service station which houses a cafe and a Jetwash. The Flovac system handles the commercial premises and can handle any flows from the car washing facility.

On the right side of the BP Jetwash you can see three of the Flovac pillars that house the air vents that are required to admit air into the vacuum sewer. These are connected to three separate valve pits which are served via a splitter to handle the high flows. The pillars will also house the wireless monitoring system that is being rolled out. The monitoring system will alert operators to any valve faults or potential overflows from the pit.

The operators looking after the system have been very happy with the operational benefits and have had very few callouts. As the operators have little to no contact with sewage and have no requirements to enter the property of the residents they see real benefits relative to how the low pressure pumps have performed. Many low pressure pumps are located on the property of the resident and any maintenance often leaves residual sewage on the lawns of the residents.

 

Largest Vacuum Sewerage Project in Slovenia has Commenced Operation

/0 Comments/in , /by

One of Europe’s largest vacuum systems and certainly the largest vacuum sewerage system in Slovenia has commenced operation in the Municipality of Brezovica. The system will have 6 Vacuum Pump Stations and over 1,500 Flovac valves.

The municipality is located just south of the capital  Ljubljana, in central Slovenia. It has a population of about 9,500 people. It is known for its famous marshlands which is why a vacuum system was chosen as the principal form of sewage collection for the region.

As all vacuum pipework is installed in shallow trenches, contractors were able to avoid dewatering to a large extent allowing construction time to be shortened extensively. This meant that there was a lot less impact on local residents who could still go on with their daily chores without disruption. It also meant that when severe cold weather occurred then workers were not impacted for long periods of time.

A gravity system would have required dozens of gravity pump stations due to the high water table while only 6 Vacuum Pump Stations were needed. This has reduced the energy cost of the system and also reduced the maintenance cost. As the area sometimes suffers power outages the ability to have backup generators at each station allowed for unrestricted service for homeowners. The Vacuum Pump Stations have both duty and standby pumps and are fully monitored back to base.

All 6 stations and all 1,500 vacuum valves are also monitored via the Flovac Monitoring System using a cable FLbus system which allows operators to see exactly which valves are operating in the network and if any infiltration is occurring.

Flovac Adria was established in 2006 and is based in  Zalec, Slovenia and has done a number of projects in Slovenia and the region. It is the largest designer and supplier of vacuum systems in the Adriatic region and the groups Managing Director Mr Dejan Pušnik is considered one of the most experienced Vacuum Sewer professionals in Europe.

Preston’s Housing Development in Christchurch

/in , /by

It’s a case of one down and 2599 to go at the biggest subdivision in Christchurch.

The single house under construction in the Prestons housing development in Christchurch will not be alone for long.

The milestone of Prestons’ first house was marked by a visit from Prime Minister John Key this week, five years after the giant housing development was first launched. That first house is owned by 87-year-old Cliff Mitten. Since sections in the Marshland subdivision first went on sale last year, about 330 have been sold.

Of the 200 sections in the first stage, known as Korowai, only four remain unsold. Those buyers now have titles to their sections and more construction is due to get underway soon.

In the second stage, Harakeke, 130 of the 230 sections have sold without being officially released to the market. Titles in that stage will be ready for buyers in June next year.

Prestons is the city’s biggest subdivision, designed for 2600 homes and 8000 residents. It is being developed by CDL Land NZ, Ngai Tahu and Foodstuffs South Island.

Section sizes are from 450sqm to 650sqm, and those in stage two are priced at $210,000 to $244,000.

The developers first released their plans for Prestons in 2008.

They were in the process of trying to get the farmland rezoned for housing, in the face of opposition from Environment Canterbury and other parties, when the earthquakes hit.

The decision was put on hold and then the project was given the green light in 2011 under the Canterbury Earthquake Recovery Act.

At 203 hectares, Prestons is on a site bigger than Hagley Park. It is next to the Bottle Lake Forest reserve, and the Waitikiri and Windsor Golf Courses.

The development has been designed to include a shopping area with cafes and restaurants, a New World supermarket, a primary school and parks. David Schwartfeger, development manager for Ngai Tahu Property, says the section buyers so far have come from across the board in both age and location.

He believes the geotechnical report that comes with each section is helping attract buyers.

Most of the land in the development has been classed as TC1, the least earthquake damage- prone of the government’s technical categories, while the remaining TC2 land has been brought up to TC1 level.

As part of that work, the developers did a soil swap with the Waitikiri Golf Club, removing and giving the club 70,000 cubic metres of peat in exchange for 70,000 cubic metres of sand. The subdivision was then stabilised with a 40-tonne elliptical roller which has been used overseas for mining work.

The Flovac vacuum sewerage system was chosen due to concerns about future earthquakes and due to the high water table in the area. This is Flovac’s second project in Christchurch, which is at Shirley.