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Award Winning Vacuum Pump Station Design

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The Hunua Views Flovac vacuum pump station located between Drury and Ramarama south of Auckland in New Zealand has taken out the highly commended award in the 2021 ADNZ Resene Architectual Awards. The design was done by Madushin Amarasekera of Construkt Associated for Classic Homes, a major developer in New Zealand.

The Hunua Views residential development , is serviced by a vacuum sewer system after deep gravity sewers and low pressure pumps were rejected by Watercare, the main utility looking after the Auckland area. Up to 1,000 houses will be connected to the new vacuum pump station.

The comment at the awards

A beautifully bold and intriguingly sculptural project by Madushin Amarasekera of Construkt Associates NZ took out a Commercial/Industrial accolade in the 2021 ADNZ Resene Architectural Design Awards. With a need to accommodate very specific engineering functions, Madushin took the opportunity to create not only a functional home to the pump station, but also a building to act as a site marker within its residential context. We love the irregular roof geometry which perfectly accompanies the textured precast concrete panels.
🏆 2021 ADNZ Resene Architectural Design Highly Commended for Commercial/Industrial Award.
Watercare are naturally very proud of the new infrastructure and were very involved in the coordination of everyone involved. When designing and creating the structure, specific engineering functions needed to be met and there was a lot of coordination between the architect, civil, structural, services & acoustic engineers, precast fabricator and Flovac, the vacuum system specialist. In fact, it’s so detailed that all the vents were acoustic rated while the control room is positioned on the south side, providing an acoustic buffer for nearby residential dwellings.

Flovac is the largest vacuum system supplier in New Zealand and has established a production facility on the north island of NZ to handle the business growth within the country.

Photos by Calvin Hui

Versatility for Developers

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A “Plug N Play” Temporary Solution.

Installing infrastructure at the early stages of a residential housing development can often disrupt the staging process and the cash flow of the project. Vacuum sewerage systems can make it easier.

At Flovac, our engineers have used deployable engineering solutions that will be incorporated into long term projects.

The town of Clevedon in Auckland New Zealand is finally beginning the process of eradicating septic tanks which have been causing environmental problems and will install a new Flovac vacuum sewerage system. Growth in the town had been on hold due to the lack of a proper municipal sewerage system. This has impacted on the restaurants and commercial premises and the increased demand on housing which is just a short drive to Auckland City.

Gravity sewers were looked at for the area, but a very high water table made that a very expensive and disruptive alternative. Low pressure Grinder pumps were also looked at but with an ultimate population of more than 6,000 people costs made that prohibitive. There were also other downsides with looking at grinder pumps where the local utility has had some terrible experiences. An increasing number of severe storms meant that power outages left communities with no access to sewer services. Also off sewage during low flow periods put added pressure onto Treatment Plants. The main issue was also the reluctance of the community in having sewerage infrastructure on their properties which would need to be accessed whenever problems arose.

The proposed vacuum sewer system will require only a single vacuum pump station and all sewage infrastructure will be outside the property boundaries. There will also be far less impact on residents as installation can be a lot faster than a gravity installation as all pipework will be shallow in the ground and so less de-watering will be required.

Watercare who are the water and wastewater service provider for the greater Auckland area is leading the project and has had a lot of experience with the successful Flovac vacuum sewerage system at the town of Kawakawa Bay which has won a number of engineering and environmental awards. members of the project team have also visited the successful projects that were installed in Christchurch NZ which replaced systems impacted by large earthquakes. Auckland is also in an earthquake zone, making vacuum systems an even better solution.

As the township of Clevedon connects up to the sewer network a number of new residential developments will also be built and will connect to the system. The vacuum sewerage system is versatile enough to cope with developers adding on new houses as they are built over the coming 10-15 years.

As there are multiple developers involved in the project, the timing of infrastructure installation can be difficult. What roads need to be built first, which group of houses need to be serviced first.

One well know developer with a small block of 26 houses positioned at the very end of the catchment wanted to develop their land well ahead of the infrastructure being ready for connection. As it is a major project it will take over two years to complete and possibly longer before the pipework reaches all the way to the end of the catchment. Working with Flovacs engineers an interim solution was proposed and Watercare was flexible enough to allow the developer the opportunity of utilising short term infrastructure.

Flovac’s deployable sewerage systems have been used in a variety of projects around the world, including at the London Olympics. You can see details of the projects here.

The developer installed the vacuum mains and house connections as well as the Flovac collection pits. A plug and play containerized vacuum pump station was positioned next to a temporary treatment plant and the system was connected up. Once houses are built, local plumbers can connect to the vacuum pits. The system will be operated and maintained by a local operator with support from Flovac. As the station and all of the collection pits have wireless monitoring, Flovac’s operations center in Sydney Australia can provide 24 hour support.

When the time comes, the deployable system can be moved on to the next project and the vacuum mains connected up to the main Clevedon project mains and vacuum pump station 4 km away. The developer has spent a minimal amount of money which allowed them to start selling houses significantly faster than traditional methods would have allowed for.

Prestons Residential Development Vacuum Sewer

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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.

 

NZ’s First Vacuum System Wins Major Environmental Award

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wastewater system at Kawakawa Bay, Auckland, New Zealand has been awarded an Environmental and Sustainability Award at the Arthur Mead Awards Function. Flovac’s system was awarded one of three prizes, which was presented by IPENZ, Auckland Branch.

The awards are named after Auckland City Waterworks Engineer, Arthur Mead, who performed the initial survey and created the designs for Upper Nihotupu and Hia Dams. They are awarded every year to projects that use sustainable features, deal with waste management, avoid negative environmental effects and promote community involvement.

As well as fulfilling the requirements of the rewards, Watercare’s project highlighted the close relationship the company maintained with residents and community groups throughout Auckland. Raveen Jaduram, acting chief executive of Watercare, said that one of the company’s main objectives was to improve wastewater treatment services in order to continue to better Auckland’s estuaries, harbours and waterways.

The celebrated project was designed by engineering consultancy Harrison Grierson with Flovac Systems and constructed by Fulton Hogan. Watercare took over the operation of the Kawakawa Bay system after it had been in operation for a year. Following the implementation of the system, ageing septic tanks in the area could be removed, helping to reduce pollution to local streams and groundwater. The pollution caused by the septic tanks resulted in the Bay being unsafe for swimming in 2002. The safe-for-swimming status was restored at the end of 2012.

The wastewater project makes use of a Flovac vacuum collection system, which is a first for New Zealand. This allowed for the fast construction of shallow pipelines, reducing the impact on residents in the area.

Vacuum collection systems allow wastewater from each individual property to drain into a pit before going through a vacuum pipe network. This is controlled through the use of a pneumatically controlled vacuum interface valve in the pit.

Once the wastewater is in the network, it moves to the vacuum pump station through by differential pressure created by opening and closing valves throughout the network. The wastewater is then moved from a collection tank at the pump station to a treatment plant.

– See more at: http://www.envirotech-online.com/news/water-wastewater/9/breaking_news/auckland_wastewater_system_wins_award/31129/#sthash.eTXiUt4g.dpuf
Kawakawa Bay NZ Case Study

Preston’s Housing Development in Christchurch

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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.

Earthquake Sewer System for Christchurch NZ

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Vacuum Sewers prove to be the best Earthquake sewer system for Christchurch Shirley vacuum sewer a first for the South Island.

SCIRT partner McConnell Dowell is more than halfway through a big project to build a Flovac vacuum wastewater system in the Christchurch residential suburb of Shirley – the first area of the South Island to use such technology.

The catchment includes about 750 houses, with 7km of vacuum main pipes in streets as well as lateral/ side connecting pipes to homes and businesses. About 6km of mains and 150 out of 195 collection chambers have been built, with a pump station and lateral pipes still in progress. It will take just over a year to complete the project, which began April 2013.

The area targeted for the Flovac vacuum system was badly affected by earthquakes with lateral spread and land-level changes. Previously, the city’s wastewater network has relied totally on a gravity system with pipelines at a gradient to support downhill flow.

After the earthquakes, the slope changed in many parts of the city, so wastewater was running in the wrong direction. The Flovac vacuum system will offer much greater resilience if there are further large earthquakes, especially in areas considered prone to liquefaction.

A further reason for using vacuum in Shirley was to keep excavation depths to a minimum because of the high ground water table and running sand. The system allowed McConnell Dowell to lay the pipes mostly at depths between one and 1.5 metres deep.

This is shallow compared to the traditional gravity system which has pipes plunging to several metres deep to maintain the gravity-feedwhich takes a lot longer to access for maintenance or repair work with subsequent traffic and residential disruption.

Wastewater will arrive at the Shirley catchments new pumping station, on Golf Links Road, from small collection chambers, usually located on the grass berm of a street, each serving up to four properties. The only visible parts in most streets will be collection chamber lids and man-holes at ground-level, while vent stacks will sit against property boundaries.

Like in other parts of the city, wastewater from the new pumping station will go via the normal gravity system southeast to the wastewater treatment plant at Bromley.Shirley NZ Flovac Project

Residents will not notice any change

Shirley residents will not notice any difference when they flush their toilets or see their kitchen and bathroom wastewater draining to the collection chamber on the street via the gully trap/ lateral pipe. There is no additional cost to them for becoming part of this modern system.