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What are your thoughts about the recommendations within the summary report?

This discussion is now closed
by Project Team 09 Mar 2012, 02:08 PM
Sean 14 Mar 2012, 08:27 AM
I am strongly opposed to the pressure drainage system, due to:
1. the potential for significant damage due to a failure in the pumping and/or backflow prevention devices.
2. my property already has an easement within it for the future provision of sewer drainage. If this is not used for the pressure system (it uses the street) then this easement should be removed and all costs borne by YVW
3. Personal costs to connect to a pressure system will far outweight the costs to connect to an equivalent gravity system, due to the location of the systems in our location. This would be a 5-fold increase (at least) and require more significant external works within our property, as all drainage currently falls to the grey water and septic systems on the opposite side of the property to the street and proposed pressure main (in preparation for the future gravity drainage through the easement).
Gmi 14 Mar 2012, 04:24 PM
I am sceptical about the pressure drainage as well.

1.Root systems will create havoc
2.regular power outage will be a problem
3. personal costs
4. Intrusive
Project Team 14 Mar 2012, 05:49 PM
Hi Gmi,

Thanks for your post.

Pressure Sewer Systems (while a comparatively new technology to traditional sewers) are becoming increasingly preferred. I will elaborate further on the points you raised:

1. Root systems. Pressure Systems use Polyehtylene pipes that use a jointing method that is more robust than that used for a gravity sewer. This means it is in fact more difficult for tree roots to intrude into the sewerage network in Pressure Systems, than it is for Gravity Systems.

2. Regular power outage. I understand that power outages are more frequent in North Warrandyte than other areas of Melbourne. The good news is that the on-property Pressure Sewer Units that Yarra Valley Water use have more than one day's emergency storage within them. This means that if the power goes out, wastewater will continue to be stored in the storage tank. One power is restored, the Pressure Sewer Unit will automatically restart and resume pumping operation.

3. Personal costs. There is a diagram included in the Summary Report that shows the ownership of Pressure Sewer Assets. Yarra Valley Water pays for the supply and installation of the on-property Pressure Sewer Pumping Unit; however, it is the landowner's responsiblity to cover the on-property plumbing costs to connect into this tank from the house. Further details of costs are included here:

4. Intrusive. Agreed there will be some level of on-property intrusion; however, the disturbance associated with the installation of these pumping units is aimed to be as minimal as possible. The location of the pumping unit is agreed upon between the landowner and Yarra Valley Water’s accredited installation contractor. During later stages of design, each property that has a pressure connection will have an individual on-property design undertaken. The location of the unit will be agreed upon based on the functional requirements for the pumping unit, but also based on landowner’s preferences (e.g. to minimise on-property disturbance, reduce the costs of their plumbing, or to locate it to avoid gardens or lawn areas, etc.). Furthermore, the land is reinstated to its previous state once installation is complete (or as near as possible to it).

I hope this helps! Thanks for participating in the forum.


Project Team 14 Mar 2012, 05:28 PM
Hi Sean,

Thanks for your feedback on this project. I’ll address your points as below:

1.Regarding the failure of:

a. The pumping equipment. In the event of mechanical failure of the equipment, property owners are notified of failures by an audible and visual alarm that is sounded from a control panel located on their premises (either on an outside wall of their house, shed, or a standalone panel). The storage tanks have more than one day’s emergency storage within the unit, so Yarra Valley Water’s maintenance contractors can respond to fix the problem prior to a spill occurring.

b. Backflow prevention devices. Yarra Valley Water installs two backflow prevention devices on each pressure property. There is one located at the Boundary Valve Kit, to prevent sewage from flowing back into the property from the pipe in the street. The other is located within the Pumping Unit, and serves as a backup in the event of failure of the other backflow prevention valve. So in this regard, the risk for on-property damage is minimised.

2. Existing easements may or may not be used by Yarra Valley Water for this project. Final pipe alignments are only confirmed during later design stages, so the alignments shown on the plans are only conceptual at this point in time and are subject to change. Having said that, Yarra Valley Water’s preference for Sewerage Backlog works is to locate pipes in the road reserve where possible to minimise disturbance to customers during construction, operation and maintenance of the system.

3. The location of the pumping unit is agreed upon between the landowner and Yarra Valley Water’s accredited installation contractor. During later stages of design, each property that has a pressure connection will have an individual on-property design undertaken. The location of the unit will be agreed upon based on the functional requirements for the pumping unit, but also based on landowner’s preferences (e.g. to reduce the costs of their plumbing, or to locate it to avoid gardens or lawn areas, etc.)

I hope this helps, feel free to post again if you have any other concerns.


midge64 14 Mar 2012, 11:20 AM
I am surprised the report recommends a pressure system and not the gravity or hybrid system.
Each system requires a number of pump stations with the pressure system requiring the most.
With every property requiring a storage tank and pump and valve pit I cant imagine this to be more economical than the hybrid system when around 40% of properties would not require the tanks/pits.
As our treatment plant is only 18 months old and serviced regularly is draining the effluent to the sewer system an option as it would already have been treated. Could this reduce fees, charges to the property owners as we already pay for quarterly services?
With the pressure system would the in line booster pump stations be concealed? underground?
With the gravity and hybrid system pump stations be concealed? underground?
Any visible pump stations would impact on property values nearby.
Thank you
Project Team 14 Mar 2012, 05:35 PM
Hi Midge64,

First of all, thanks for your post and interest in the project. I’ll address your points as below:

1. The report recommends a pressure system due to the approach used to compare options. This option came out most favourably when considering the Multi Criteria Assessment (i.e. comparing against a range of customer, environment, culture/social, and efficiency (cost) factors). Having said that, the scores between the Pressure and Hybrid were not vastly different, so a Hybrid system could be preferred based on further investigations and feedback received on this forum. Two of the reasons this came out more favourably than the gravity or hybrid are:
- Reduced impact on the existing sewerage system. All three reticulated options require to connect to the existing system over the Kangaroo Ground-Warrandyte Bridge. The pressure system has a lower design flow rate and therefore less impact on the capacity of the existing system.
- Reduced costs to customers. Costs to the customer can often be lower with Pressure Systems, as there is more flexibility with current on-property plumbing arrangements.

2. Economics of Hybrid and Pressure systems. Agreed there will be additional costs for the Pressure System in procuring and installing the on-property pumping units; however, there are also cost savings associated with adopting such a system. For example:
- Constructing less larger Sewage Pump Stations. Larger Sewage Pump Stations will be more expensive than the ‘booster pump stations’ that are proposed by GHD. Although there are more pump stations in the Pressure than the Hybrid system, the cost per station will be less.
- The Pressure System has smaller diameter sewers, and these can be run shallower. Both of these factors will reduce the cost of the sewers.

3.Your treatment plant system draining the treated effluent to the sewer to reduce costs. I agree with your reasoning here, as theoretically it could reduce Yarra Valley Water’s costs in treating the sewage. However, it is a matter that would need to be considered at later stages of design and implementation, given that the type of sewerage system is still being decided upon. It’s also a policy decision that would need to be considered at a wider level at Yarra Valley Water.

Failing that, should these cost savings not be passed on, you could avoid paying the Sewage Disposal Charges (which account for the treatment at Sewage Treatment Plants) by electing to not connect to the system. Note to do this you will need to demonstrate that your treatment plant system is an EPA approved product, is serviced regularly, and treats all of your wastewater to an acceptable standard.

However, please also note that current Yarra Valley Water policy is to still charge the $500 Sewerage Backlog Contribution Fee (as detailed here, given that the properties can opt to connect to the system at a later stage and avoid building the reticulation sewers required to connect to the system (depending on the size, depth, and ground conditions this can be many hundreds of dollars per metre of sewer pipe required).

4. Regarding your queries on pump stations, the design of all pump stations will attempt to reduce visual impact. All of Yarra Valley Water’s Sewage Pump Stations include a below ground wet well, but also an above ground control panel and cabinet. The visual impact of these are minimised by putting them in locations that are less conspicuous, however, there will be some visible parts of each. Having said that, the current indicative locations are conceptual locations and are only confirmed at later stages of design once issues such as visual impact are considered in greater detail.

I hope this answers your queries, please post again if you have any further questions.


Meeka 06 Apr 2012, 02:26 PM
With regards to the visual impact of these pump stations, the simple answer then is that yes they will be visible and yes they will be an eyesore for those who delight in gardens whether natural or exotic.
Project Team 18 Apr 2012, 03:35 PM
Hi Meeka,

Thanks for your contribution to this forum.

There are two types of pump stations that may be used for the North Warrandyte Sewerage Backlog Area; On-Property Pressure Sewer Units, and larger centrally located Sewage Pump Stations.

On-Property Pressure Sewer Units are small pump units that are installed on a customer’s property. They are much smaller than the more traditional type of Sewage Pump Stations, which are centrally located and collect and pump sewage from a large number of houses. The visual impact of On-Property Pressure Sewer Units is quite small, as the resident will only see the lid of the storage tank and the control panel. The lid is made from moulded polyethylene, and comes in a range of colours. Typically, residents prefer the natural green colour which is used in most of Yarra Valley Water’s pressure sewer installations. The lid is circular and is 600mm in diameter, and sits above the ground surface by about 50-100mm. The control panel is installed on the outside wall of a resident’s house or shed and is approximately 300mm by 250mm in size. Given that these visible parts are small and they get installed in consultation with the landowner (where the resident can seek to install these in a location that is less visible), the visual impact of On-Property Pressure Sewer Units is generally quite small.

Larger centrally located Sewage Pump Stations are installed either in road reserves, or on land purchased by Yarra Valley Water. The visible parts of these are the top of the concrete wet well, and the control cabinet. The lid of the wet well is circular and will vary in size depending on how many houses are serviced by the pump station. As a rough guide, they could be between 2.5m and 5m in diameter if used in North Warrandyte. While their visual impact is larger than On-Property Pressure Sewer Units, you should note they are never installed on a customer’s property.

The forum has now closed and you won’t be able to reply back to this post, so feel free to email me if you have any further questions.


Mark 14 Mar 2012, 08:12 PM
Black water pumping systems must present a significant maintenance effort and cost. Who will bear this ongoing maintenance burden? Power cost for operation - a burden for the property owner? Pump failure effect on service (sorry can't use the toilet or take a shower because the pump has failed - again). As the owner of an electric treatment plant who is amazed at the actual operating cost (power, maintenance and the high incidence of failure) I wonder how any electric up-hill solution could be anything but big trouble. Show us the precedent of a delighted community with this proposed wizardry - or come up with something that is not a cure far worse than the disease.
Project Team 16 Mar 2012, 03:35 PM
Hi Mark,

Thanks for your interest in this project and your contribution to the forum. You raised a number of concerns, so I’ll summarise our response here:
- Maintenance. The ongoing maintenance of on-property Pumping Units and larger centralised Sewage Pump Stations is Yarra Valley Water’s responsibility. The on-property Pumping Units used by Yarra Valley Water are designed to operate automatically, and maintenance is only required when there is a blockage or a mechanical failure that causes the pump to stop operating. The Pumping Units that have been supplied to Yarra Valley Water over the past five years have proven to be reliable, with maintenance callouts well within acceptable levels.
- Power. The power costs are paid by the resident. The systems are designed to pump for a few short periods of time each day, meaning that power use is not excessive. To date, residential usage of On-Property Pressure Sewer Pumping Units has cost no more than $30 in electricity per year.
- Effect on service of pump failure. The Pumping Units used by Yarra Valley Water have an emergency storage in excess of 600L, which is more than the average volume of wastewater generated by a typical house in a day. If there is a problem in the unit, property owners are alerted by both a visual and audible alarm that is located on the Control Panel of the Pumping Unit. This small Control Panel is installed in a location on the property agreed to by the landowner, typically on an outside wall of the house or a shed. If this alarm sounds, it is the landowner’s responsibility to call Yarra Valley Water who will send a maintenance crew to fix the problem. Response times during business hours are generally less than 6 hours, which is significantly less than the 24 hours (or more) of storage contained within the unit. Therefore the lifestyle of the resident should not be impacted by whether the property is serviced by pressure, or a conventional gravity system.
- Uphill solutions. Given the topography of the area, it would be unrealistic to build a gravity sewer system in North Warrandyte without some kind of electricity powered pumping station. Also, the slope and ground conditions in some areas can make on-site solutions difficult to install, and more importantly they can be ineffective in terms of treatment of wastewater. The adopted solution for the North Warrandyte Sewerage Backlog Area will be the best overall solution in terms of financial aspects, environmental considerations, while also taking into account impacts on the customer and the wider community.
- Other Pressure Sewer Areas. Yarra Valley Water has already serviced a number of its Sewerage Backlog Areas using this Pressure Sewer technology. Examples of these areas are in Gembrook, Donvale, and Heathmont to name a few. Overall the feedback from these communities has been largely positive. If you would like more specific information, please feel free to contact me to discuss directly.

I hope this addresses your concerns, please post again if you have any more questions. Thanks!


Meeka 06 Apr 2012, 02:32 PM
@ Matt. Statistics on satisfaction levels of existing installations should be mandatory information provided to all Nth Warrandyte residents rather than an optional extra provided to individuals on demand.
Project Team 18 Apr 2012, 03:37 PM
Hi Meeka,

Thanks for your numerous contributions to this forum.

I assume you are referring to my part of the post that said ‘If you would like more specific information, please feel free to contact me to discuss directly.’ This was regarding the operation of the units and impacts on residents’ lifestyle, not on satisfaction levels of existing pressure sewer customers. One of the key requirements for Yarra Valley Water’s Pressure Sewer Products is that a customer’s lifestyle should not be impacted by whether they are serviced by gravity or pressure. What this means is that a customer doesn’t have to change their water use behaviour as a result of having a pressure sewer unit on their property (i.e. they can use their washing machine, showers, toilets etc. in the same manner in which a gravity property could).

While I don’t have statistics on hand along the lines of ‘X% of Pressure Sewer customers are happy with their Pressure Sewer System’, I can tell you that Yarra Valley Water wouldn’t continue to install these systems if our customers were not happy with them. Maintaining customer satisfaction is a key area of focus for Yarra Valley Water.

I hope this helps. The forum has now closed and you won’t be able to reply back to this post, so feel free to email me if you have any further questions.


Meeka 06 Apr 2012, 02:28 PM
@ Mark. As I am thinking of not connecting to the sewer but instead putting in a treatment plant I would be grateful for some idea of maintenance costs.
Don_2 16 Mar 2012, 10:12 PM
Unfortunately there is insufficient information in the report to allow any view to be formed as to the recommendations, although I do appreciate a system which allows smaller pipes would have a significant advantage. But the description of the hybrid system is quite vague. My house and the two adjacent houses are on a steep hill above the road, where the sewer is proposed to run. Do we need a pressure pump each, when gravity feed would be more than reliable? Just curious.

More importantly, I'm wondering if this project could embrace a look at the water supply. We have had more than one interruption to service in my street in recent times due to rusty mains, plus several of us are alleged to depend on old 'private' mains, in some cases quite vulnerable - plastic and near the surface. While we're digging up the road reserves, would it make sense to consider other underground opportunities? Come to think of it, powerlines and trees don't mix that well either!
Project Team 22 Mar 2012, 11:52 AM
Hi Don,

Thanks for your comment on this forum and your interest in the project.

The intention of the Summary Report was to disseminate the main findings of this project into a short, succinct document. The document summarises the findings of two larger technical documents (both in the order of 100 pages in length), that will be uploaded to the site later this week. If you require further information about anything contained within the Summary Report, please refer to these larger documents or post some questions on this forum.

You had a couple of queries about the Hybrid and Pressure Systems, so I’ll address them here:
- If properties are designated to be serviced by pressure, all single density properties will be serviced by their own individual On-Property Pumping Unit installed on their property. Larger residential properties, i.e. multi-unit Body Corporate arrangements, may share a single, larger, centrally located unit, but this is considered on a case-by-case basis at a later stage of design.
- Pressure units are sometimes installed on properties even when wastewater could potentially flow via gravity. This may be because there is a hill somewhere further down the path of the reticulation sewer that requires flows to be pumped over. Another reason may be that the best option for your street or area (when considering the wider network) is for the entire street or area to be serviced via pressure. In this case, your property would need to pump flows in order for the reticulation pipe to operate under pressure.

Regarding the potential for other services to be improved during the construction of this project, this is a matter that will be considered in the next phase of this project. If a reticulated sewer service is provided (as opposed to on-site treatment systems), discussions will be held with the other authorities who own services in the area. This will include discussion with the other divisions within Yarra Valley Water to potentially align sewer construction schedules with any programmed works for water main upgrades. I can’t promise anything will happen as this will depend on the cooperation of authorities outside of Yarra Valley Water’s control, but these issues will certainly be considered during the next stage of design for this project.

I hope this answers your queries, feel free to post again if you need further information.


Don_2 22 Mar 2012, 02:20 PM
Hi Matt,

Thanks for your answer. I should say that I accept that sewering the area is a good thing even though I don't personally have a problem with the current arrangement.

But I would like to understand the pressure/gravity situation better. At the end of Hamilton Road there are certainly 3 and maybe 5 properties that could gravity feed into a shared pressure pump. What are the pros and cons?
Project Team 30 Mar 2012, 12:42 PM
Hi Don,

No problem at all with the response, I’m glad it was helpful.

If a pump was used to service more than one gravity property, it would need to be a larger type of Sewage Pump Station, located somewhere in the road reserve. This would contain a large concrete wet well (built below ground but with a large concrete roof at the ground surface level), and would need to be installed in a location that would allow access for maintenance personnel. The Pressure Sewer Units that are shown in the Summary Report could not be used to service a group of properties, as these are designed and sized to service a single property.

The benefit of doing as you suggested would be that flows from the properties could be conveyed via gravity instead of being pumped by the unit on each property. But these would then need to be pumped from this larger, centrally located Sewage Pump Station to get over the hill further down Hamilton Road. This represents the more traditional way that sewerage services have been delivered in the past, before Pressure Sewer Units were an option.

Pressure Sewer Units are preferred in this location because it avoids the need to construct the larger Sewage Pump Station in the street. This is more economical and has less impact on the property owners in the street during construction, and also when the system is operational.

Thanks for your interest in the project and your posts to this forum. Please feel free to write again if you have any further questions.


Andrew 21 Mar 2012, 10:27 AM
Whatever method is chosen, the property owner should bear minimal cost. Anything over $500 is onsite plumbing costs is unacceptable and unafforable to me. I don't intend on taking out a loan either.
Project Team 22 Mar 2012, 11:53 AM
Hi Andrew,

Thanks for your post and your interest in the project.

As I have indicated elsewhere in this forum so far, residents who have a system that complies with EPA requirements for the on-site management of wastewater are not required to connect to the system. There is a useful flow chart on the third page of the ‘Backlog Program Explained’ Fact Sheet that has been provided under the ‘Documents’ section of this site. This flow chart demonstrates whether properties are required to connect to the new system once it is provided. To summarise this, every property that cannot demonstrate that their on-site system meets EPA requirements will be required to connect to the new system once it is provided.

If a resident connects to the system within the first twelve months of the sewer being declared available for connection, the $500 Backlog Contribution Fee is waived. Sometimes residents do not connect to the system within this first twelve month period because they cannot afford to do so. It is for this reason Yarra Valley Water tries to provide as much notice as possible to local residents (by way of the first letter you received last year, advising that design work in the North Warrandyte Sewerage Backlog Area had commenced), to give local residents time to save up for on-property works. Based on current estimates, the new sewerage system isn’t expected to be available to all of North Warrandyte until 2014, meaning Yarra Valley Water has provided residents with up to three years’ notice.

In extreme cases of financial hardship, residents may apply for a grant for on-property plumbing works that is available through the Department of Health Services. To be eligible for this, the applicant must:
- Hold a valid pension or concession card;
- Be the owner of the property;
- Primarily reside at the property (i.e. this is the principal place of residence); and
- Be able to demonstrate they cannot afford the costs in connecting to the sewer.

I hope this information is helpful, please let me know if you have any further questions.


blackcat 30 Mar 2012, 12:44 PM
There is insufficient information for me to make any decision about what methods should be used. Our septic tank is old, but, as I am a pensioner, I cannot afford to connect to a costly sewerage system and also pay for plumber's fees and a pump.
Perhaps Yarra Valley Water should be spending more time on maintaining what they have and regularly cleaning out the storm gutters in the "oh so costly" kerb and channelling put in half way along Kangaroo Ground Road.
Project Team 04 Apr 2012, 04:16 PM
Hi BlackCat,

Thanks for your contribution to this forum and your interest in the project.

If the reticulated service is the option that is carried forward in design, properties that cannot demonstrate compliance with Environment Protection Authority (EPA) Victoria requirements for on-site containment of wastewater will need to connect to the sewer once it has been provided. These are indicated in the Flow Chart on Page 3 of the Fact Sheet included in the ‘Documents’ section of this website. In short, these requirements are to treat wastewater to the required standard, and contain it on the property all year round. Many existing septic tank systems in the area cannot contain treated wastewater on the property during winter months in particular as the soil is saturated from rainfall. If this is the case for your property, you will need to connect to the scheme once it is provided.

The Department of Human Services provides assistance to eligible customers experiencing hardship with a once off grant. This covers the cost of connecting to a compulsory water and sewerage scheme.

To be eligible for this, you must:
- Hold a valid pension or concession card;
- Be the owner of the property;
- Primarily reside at the property (i.e. this is the principal place of residence); and
- Be able to demonstrate you cannot afford the costs in connecting to the sewer.

If you can meet the above criteria, you will not need to pay for the plumbing costs. Please be advised that you will not need to engage a plumber until the sewer has been constructed. Based on where your property is located, this could be anywhere from 1-2.5 years from now.

It should be noted that residents aren’t required to pay for any pumps if a reticulated sewerage service is provided. Yarra Valley Water pays for the supply, installation and maintenance of any On-Property Pressure Sewer Pumping Units that are installed on a customer’s property. The resident’s costs are in connecting their existing plumbing to this Pumping Unit, and in supplying electricity to the unit (typically less than $30/annum).

Unfortunately stormwater infrastructure is a service that is provided by local Councils, who are also responsible for its maintenance. So while Yarra Valley Water can provide this feedback to Council, unforunately we cannot directly do anything about it.

I hope this helps! Feel free to post again if you have any further questions.


Ian Penrose 04 Apr 2012, 06:20 PM
Tackling pollution from waste water is important, but it is only one of several important environmental goals. Another is water recycling. Water is a precious resource for both people and the natural environment, and any opportunity to recycle it should be pursued with all water projects. Our suffering rivers deserve nothing less.

$25+million ($24,000+ per property) of public funds will likely be spent on this project to reduce water pollution but the reported analysis attributes no tangible benefit to those options that allow treated water to be reused on site or returned to the environment. In particular I would like further consideration of on-site treatment-reuse systems (properly maintained) for those properties that could accommodate them. Some systems may be more economic (particularly if water recycling is fully valued) and more environmentally friendly (lower energy costs and less destruction of vegetation if sewers are not installed).

North Warrandyte is blessed with valuable indigenous vegetation and wildlife, and a community that not only cares about the natural environment but is prepared to take action to protect and restore it (eg native gardens, water tanks, solar panels, recycling, environmental groups…). I ask the relevant authorities, Yarra Valley Water, EPA and Shire of Nillumbik to be more innovative in considering other options for this project.
Project Team 18 Apr 2012, 04:51 PM
Hi Ian,

Thanks for your post on the forum. You raised a number of points, so I’ll address them in turn under the below headings.

Water Recycling.

Yarra Valley Water is aware of the importance of recycling water where possible, particularly in the recent periods of drought.

The Concept Design Report provides further information on the Triple Bottom Line (TBL) assessment that was used to score each option. This approach uses a number of sub-measures from the following broad categories to score each option:
- Customer
- Environment
- Culture / Social
- Efficiency

The ability of each option to save potable water (e.g. recycle water) was considered under sub-measure 4 of the ‘environment’ category. Therefore the TBL assessment approach did consider the importance of recycling water, in addition to all the other competing measures (e.g. impact on customers, cost of the project, impact on receiving waterways, etc). The options that scored the best with respect to all the sub-measures were the on-site STEP/STEG systems and the reticulated Pressure scheme.

As is mentioned in the report, in general, properties using on-site greywater and blackwater treatment systems cannot contain wastewater on-site during winter months. Given that soils are saturated during these months, there is reduced demand for treated greywater (i.e. people don’t water their gardens during winter) and therefore more flows are generated by each property than can be used on-site. These overflows must be conveyed somewhere, and therefore a piped network is required. The costs of these options become highly prohibitive as the on-site systems must be installed in conjunction to a sewer network.

Other project aims other than reducing water pollution.

The Sewerage Backlog Program exists to provide sewerage services to those properties using on-site systems that cannot meet Environment Protection Authority (EPA) Victoria on-site containment requirements. These EPA requirements exist to:
- Improve the health of receiving waterways (as you have pointed out)
- Reduce risks to public health.

So while it would be ideal for a project to achieve these goals and also enable water recycling, the main driver for this program remains the above two goals. While other environmental benefits such as water recycling are considered in a servicing strategy, if the cost to do so significantly exceeds the funds that have been allocated to the program, it will not go ahead. This opportunity was explored extensively for the Wonga Park Sewerage Backlog Project, but ultimately it did not proceed because there was insufficient demand for the water from the community.

On-site treatment-reuse systems for those that can accommodate them.

The EPA require that on-site treatment systems treat wastewater to the required standard, but also that treated wastewater is contained on-site all year round. This second part of the requirement is not influenced by the type of system that is installed, rather it depends on the physical characteristics of the property, including:
- The size of the block
- The slope on the block
- The soil profile on the property (i.e. if it is rock, clay, etc.).

An initial assessment of the Land Capability of the North Warrandyte Area indicates that the overwhelming majority of properties in the area will struggle to contain wastewater on-site all year round.

Therefore properties that cannot contain treated wastewater on-site all year round will be required to connect to a sewerage scheme once it has been provided. There is further information on this available in the Fact Sheet that has been included in the ‘Documents’ section of this website.

I hope this information helps. The forum has now closed and you won’t be able to reply back to this post, so feel free to email me if you have any further questions.


Meeka 06 Apr 2012, 02:44 PM
Is this all just a PR whitewash? The more I read on these forums the more concerned I become. The YVW preferred system is going to be an expensive eyesore and potentially more dangerous than the septic systems we have now. When it works it will take water away from a very dry area. When it fails it could be disastrous. The stated 6 hour callout time on blocked pumping stations is only applicable during business hours. So what happens when the pumping stations block after 5pm on a Friday night? And why is the customer satisfaction data from existing installations in Donvale, Heathmont etc not made available as a matter of course instead of just 'on demand'? Finally, at a time when we are all trying to conserve energy why is YVW intent on installing something that will collectively use a great deal of energy? Warrandyte is nothing but hills so even with an intermittent pump that's a lot of effluent getting pumped UP HILL. Isn't it time we started planning for the future and a /lower/ carbon footprint?
Project Team 18 Apr 2012, 04:09 PM
Hi Meeka,

Thanks for your continued contribution to this forum. You raised a number of concerns in this post which I will address in turn.

PR Whitewash.

I can assure you that this forum is not a ‘PR whitewash’. Yarra Valley Water is using this online forum as an extra way to gather input from the community on the proposed sewerage services. Other means of gathering this feedback include letters we have received about the project, phone calls, emails, and face to face contact at the recent Warrandyte Festival. The feedback received is taken seriously by Yarra Valley Water and is used to help decide on the sewerage system to be carried forward into design. The community input can also be used to inform the design of the system, as the residents of North Warrandyte are aware of local issues.

Expensive eyesore.

You mentioned the preferred system would be an ‘expensive eyesore’. The system will be expensive, but being an expensive system does not negate the need for the system to be installed. This project exists in North Warrandyte because the majority of septic tank systems throughout the study area can no longer treat and contain wastewater to the standard required by the Environment Protection Authority (EPA) Victoria. This poses risks to the environment and public health, and the removal of these risks is the driver for this project. Even though the project is expensive, the vast majority of the project is funded by Yarra Valley Water, with residents requiring to connect to the infrastructure provided by Yarra Valley Water once it has been constructed. Please refer to Yarra Valley Water’s website for information on what costs are payable by the customer for this scheme using this link

Regarding the ‘eyesore’ part of your comment, the visual impact of the system is not anywhere near as significant as people might think. Please refer to my reply to the comment you made on 6 Apr 2012 at 2:26 PM.

Potentially more dangerous than the current septic systems.

Assuming you mean ‘dangerous’ as in risks to the public in terms of safety, I can assure you that reticulated sewerage systems are inherently safe for a number of reasons:
- The pipe network is built underground.
- Sewage flows are conveyed away from a resident’s property, instead of contained on it. Because flows are taken away from a resident’s property, there is less opportunity for contact with sewage with a reticulated scheme than a septic system.
- Access to the system is only required by Yarra Valley Water maintenance personnel. Systems are designed to operate automatically, so access is only required periodically for the purposes of maintenance.
- Access to the system is restricted to Yarra Valley Water maintenance personnel.

Taking water away from a dry area.

If a reticulated sewerage scheme is provided to the North Warrandyte Area, residents may still opt to use their greywater on their property. The property must still connect to the scheme, but greywater can be used on-site with any excess flows directed to the sewerage network.

Failure of systems and response times.

The ‘stated 6 hour call out time’ was an approximate figure I gave. It varies depending on the priority of the works (i.e. if a job is urgent it gets assigned a higher priority) and how many other jobs the maintenance crew are required to attend at that time. So the response time is often far less than 6 hours. You are referencing a post I made elsewhere in this forum, where I also mentioned the on-property Pressure Sewer Pumping Units have an emergency storage volume in excess of 24 hours during normal water use. The response times of our maintenance crews are well within the required timeframes.

My post mentioned the time was ‘during business hours’ because if the pump blocked during the evening there would generally not be the need for our maintenance crews to come out to immediately fix the problem. Given that the units have 24 hours storage, and there is no water use in a house while people are sleeping (meaning the level of wastewater in the tank would not rise at all during this time), the maintenance crew could respond first thing in the morning.

If a problem is called in at 5:00pm on a Friday night, Yarra Valley Water will send a maintenance crew who are on call after hours and on weekends to attend to the problem. Depending on the urgency of the works they will either attend the site that night, or on Saturday morning. As I mentioned earlier, the storage tanks have more than 24 hours emergency storage volume, so there may not be the need to respond immediately.

Customer satisfaction data.

Please see my response to this under your comment on 6 Apr 2012, 2:32 PM. Please let me know if you have any further questions.

Environmental impact.

Power use is but one indicator of environmental impact. As discussed earlier in this forum, the environmental impact of each option was considered in the Triple Bottom Line assessment for each option. Other environmental impacts include:
- Impact on biodiversity
- Waste to landfill
- Discharge to environment
- Potable water consumption
- Energy consumption.

As you have correctly pointed out, the Pressure System scored worse than the Gravity System with respect to energy consumption. But in terms of discharge to the environment, the Pressure System performs better as there are less opportunities for excess flows to be spilled from the system. There is also less waste to landfill with a Pressure System, due to the increased excavation associated with the Gravity System. In a Gravity Sewer, pipes must be laid progressively deeper to allow flows to be conveyed via gravity. In parts of the system, Gravity Sewers may be constructed at depths exceeding 6m, whereas in a Pressure System pipes are typically laid at 1m depth.

So even though the Pressure System has ongoing power use, its impact on the environment is less than a Gravity System based on the other indicators of environmental impact. A gravity system would also require a greater length of pipe to be constructed, as every property must convey flows via gravity. In a street where one side of the street falls towards the road, and the other falls away from the road, two pipes must be constructed to service the street in a Gravity System whereas in a Pressure System only one pipe would be needed.

I hope this information helps. The forum has now closed and you won’t be able to reply back to this post, so feel free to email me if you have any further questions.