New Zealand’s Garden City has the opportunity to re-invent itself from the bottom up.
I’m talking sewage.
Consider the large amount of clean water that is used to carry even a small quantity of human excreta. With each flush, over 10 litres of clean water goes down the drain. This clean water which is flushed down the toilet goes into a traditional sewage system. We reticulate all sewage solids and wastewater in a big network of ceramic pipes for centralised treatment. The Romans had the idea for that first and it was perfected by the British almost 200 years ago. It’s ancient.
In the absence of government support or massive rates, traditional sewage solutions threaten to bankrupt communities. Especially if sewer networks need to be rebuilt.
Traditional sewage systems are atrociously expensive to build today primarily because of the labour intensive drainage network. Sewage treatment plants themselves are relatively cheap. It’s the thousands of kilometres of pipes that cost seriously big money. And where pipes are laid in ground that moves – forget shakes – cracks open up in the pipes letting rainwater in and causing overflows, and letting sewage out polluting more water — invariably rivers and ponds and beachwater.
For more than a decade – as a Councillor - I have immersed myself in Auckland’s sewage problems, projects and costs. I chaired North Shore City Council’s Works & Environment Committee’s recommendation ten years ago to impose a fixed charge per ratepayer of $500 annually to reduce leaks from the city’s fragile sewer network. We debated the issue at length. I suggested – half in jest – that we’d be better off with old style night-cart collection of excreta, central composting, and recycling back to land. At least we’d know it was being collected, and we’d also know it wouldn’t end up on the beaches.
North Shore City ratepayers have invested close to a billion dollars in its sewage system. And it still leaks. Much of Auckland is built on soft Waitemata clays and sandstone. It’s shifting slowly all the time, cracking the sewer network. The damage is slow but it’s relentless. And so are the repairs and the costs.
Much of Christchurch is built on alluvial gravels and sand. Its sewer networks lie in ditches dug into this substrate which liquefies in even a small earthquake. Given the choice of developing Christchurch today as a greenfield site – subject to earthquakes from time to time - engineers today would surely advise against a ceramic pipe based wastewater network.
Ten years ago the Auditor General concluded that “it is difficult for Thames Coromandel District Council to demonstrate that the sewage reticulation option is indeed the best use of ratepayer’s funds.” That report was part of a long running battle between the majority of Cooks Beach lot owners and a Council determined to fix septic tank problems by imposing a traditional reticulated sewage scheme. I know Christchurch City is not like Cooks Beach.
My interest in sewage alternatives has taken me round the world and times have changed, as Sydney Water found when it investigated developments in the United States and Europe, after facing estimates of between $16,000 and $70,000 per lot to connect houses to new centralised sewage systems.
They found that on site wastewater services are used in 50% of lots in Norway and 25% of all lots in the USA. On-site servicing is no longer seen as a temporary measure in the USA where 35% of new city housing developments are now on-site serviced. Beverley Hills in LA is all on-site, and Barbra Streisand was one who lobbied the council to keep it that way. The US Environmental Protection Agency has advised the US government that “decentralised systems, where properly managed, could protect water quality over the long term and do so at lower cost than conventional systems in many communities.”
The most modern systems used in US urban environments combine sophisticated on-site primary treatment tanks, which retain and biodigest solids and need emptying every ten years or so, and small-gauge leak-proof pipes which reticulate the liquid effluent only, to either a centralised treatment plant, or to small local treatment facilities. Some of these use vacuum systems or small pumps to send effluent through leak-proof plastic pipes which can bend and move with ground movement.
While modern centralised wastewater treatment plants in New Zealand are using cleaner technology, the fact is that traditional sewage reticulation pipe networks are dreadfully leaky, and environmental disasters in themselves. Even without an earthquake.
It is difficult to justify their construction and use in coastal environments if the goal is to protect and preserve water quality in the long term.
It is no longer flush it and forget it in Christchurch. Every day people are faced with the personal challenge of what to do with their own, and their children’s excrement. Call it human bio-solids. Right now a system of Portaloos and regular collection is being rolled out across Christchurch.
The collected bio-solids will contain toilet paper and some sterile urine. But will not be contaminated with heavy metal trade wastes that get tipped into the sewer. It will not be diluted with thousands of litres of water. It will be pure. Ripe for composting and re-use. It can be developed into a modern, resilient and responsible sanitation system.
Christchurch has the opportunity to re-invent itself from the bottom up.
Wednesday, March 2, 2011
Garden City’s Cheeky Opportunity
New Zealand’s Garden City has the opportunity to re-invent itself from the bottom up.
I’m talking sewage.
Consider the large amount of clean water that is used to carry even a small quantity of human excreta. With each flush, over 10 litres of clean water goes down the drain. This clean water which is flushed down the toilet goes into a traditional sewage system. We reticulate all sewage solids and wastewater in a big network of ceramic pipes for centralised treatment. The Romans had the idea for that first and it was perfected by the British almost 200 years ago. It’s ancient.
In the absence of government support or massive rates, traditional sewage solutions threaten to bankrupt communities. Especially if sewer networks need to be rebuilt.
Traditional sewage systems are atrociously expensive to build today primarily because of the labour intensive drainage network. Sewage treatment plants themselves are relatively cheap. It’s the thousands of kilometres of pipes that cost seriously big money. And where pipes are laid in ground that moves – forget shakes – cracks open up in the pipes letting rainwater in and causing overflows, and letting sewage out polluting more water — invariably rivers and ponds and beachwater.
For more than a decade – as a Councillor - I have immersed myself in Auckland’s sewage problems, projects and costs. I chaired North Shore City Council’s Works & Environment Committee’s recommendation ten years ago to impose a fixed charge per ratepayer of $500 annually to reduce leaks from the city’s fragile sewer network. We debated the issue at length. I suggested – half in jest – that we’d be better off with old style night-cart collection of excreta, central composting, and recycling back to land. At least we’d know it was being collected, and we’d also know it wouldn’t end up on the beaches.
North Shore City ratepayers have invested close to a billion dollars in its sewage system. And it still leaks. Much of Auckland is built on soft Waitemata clays and sandstone. It’s shifting slowly all the time, cracking the sewer network. The damage is slow but it’s relentless. And so are the repairs and the costs.
Much of Christchurch is built on alluvial gravels and sand. Its sewer networks lie in ditches dug into this substrate which liquefies in even a small earthquake. Given the choice of developing Christchurch today as a greenfield site – subject to earthquakes from time to time - engineers today would surely advise against a ceramic pipe based wastewater network.
Ten years ago the Auditor General concluded that “it is difficult for Thames Coromandel District Council to demonstrate that the sewage reticulation option is indeed the best use of ratepayer’s funds.” That report was part of a long running battle between the majority of Cooks Beach lot owners and a Council determined to fix septic tank problems by imposing a traditional reticulated sewage scheme. I know Christchurch City is not like Cooks Beach.
My interest in sewage alternatives has taken me round the world and times have changed, as Sydney Water found when it investigated developments in the United States and Europe, after facing estimates of between $16,000 and $70,000 per lot to connect houses to new centralised sewage systems.
They found that on site wastewater services are used in 50% of lots in Norway and 25% of all lots in the USA. On-site servicing is no longer seen as a temporary measure in the USA where 35% of new city housing developments are now on-site serviced. Beverley Hills in LA is all on-site, and Barbra Streisand was one who lobbied the council to keep it that way. The US Environmental Protection Agency has advised the US government that “decentralised systems, where properly managed, could protect water quality over the long term and do so at lower cost than conventional systems in many communities.”
The most modern systems used in US urban environments combine sophisticated on-site primary treatment tanks, which retain and biodigest solids and need emptying every ten years or so, and small-gauge leak-proof pipes which reticulate the liquid effluent only, to either a centralised treatment plant, or to small local treatment facilities. Some of these use vacuum systems or small pumps to send effluent through leak-proof plastic pipes which can bend and move with ground movement.
While modern centralised wastewater treatment plants in New Zealand are using cleaner technology, the fact is that traditional sewage reticulation pipe networks are dreadfully leaky, and environmental disasters in themselves. Even without an earthquake.
It is difficult to justify their construction and use in coastal environments if the goal is to protect and preserve water quality in the long term.
It is no longer flush it and forget it in Christchurch. Every day people are faced with the personal challenge of what to do with their own, and their children’s excrement. Call it human bio-solids. Right now a system of Portaloos and regular collection is being rolled out across Christchurch.
The collected bio-solids will contain toilet paper and some sterile urine. But will not be contaminated with heavy metal trade wastes that get tipped into the sewer. It will not be diluted with thousands of litres of water. It will be pure. Ripe for composting and re-use. It can be developed into a modern, resilient and responsible sanitation system.
Christchurch has the opportunity to re-invent itself from the bottom up.
I’m talking sewage.
Consider the large amount of clean water that is used to carry even a small quantity of human excreta. With each flush, over 10 litres of clean water goes down the drain. This clean water which is flushed down the toilet goes into a traditional sewage system. We reticulate all sewage solids and wastewater in a big network of ceramic pipes for centralised treatment. The Romans had the idea for that first and it was perfected by the British almost 200 years ago. It’s ancient.
In the absence of government support or massive rates, traditional sewage solutions threaten to bankrupt communities. Especially if sewer networks need to be rebuilt.
Traditional sewage systems are atrociously expensive to build today primarily because of the labour intensive drainage network. Sewage treatment plants themselves are relatively cheap. It’s the thousands of kilometres of pipes that cost seriously big money. And where pipes are laid in ground that moves – forget shakes – cracks open up in the pipes letting rainwater in and causing overflows, and letting sewage out polluting more water — invariably rivers and ponds and beachwater.
For more than a decade – as a Councillor - I have immersed myself in Auckland’s sewage problems, projects and costs. I chaired North Shore City Council’s Works & Environment Committee’s recommendation ten years ago to impose a fixed charge per ratepayer of $500 annually to reduce leaks from the city’s fragile sewer network. We debated the issue at length. I suggested – half in jest – that we’d be better off with old style night-cart collection of excreta, central composting, and recycling back to land. At least we’d know it was being collected, and we’d also know it wouldn’t end up on the beaches.
North Shore City ratepayers have invested close to a billion dollars in its sewage system. And it still leaks. Much of Auckland is built on soft Waitemata clays and sandstone. It’s shifting slowly all the time, cracking the sewer network. The damage is slow but it’s relentless. And so are the repairs and the costs.
Much of Christchurch is built on alluvial gravels and sand. Its sewer networks lie in ditches dug into this substrate which liquefies in even a small earthquake. Given the choice of developing Christchurch today as a greenfield site – subject to earthquakes from time to time - engineers today would surely advise against a ceramic pipe based wastewater network.
Ten years ago the Auditor General concluded that “it is difficult for Thames Coromandel District Council to demonstrate that the sewage reticulation option is indeed the best use of ratepayer’s funds.” That report was part of a long running battle between the majority of Cooks Beach lot owners and a Council determined to fix septic tank problems by imposing a traditional reticulated sewage scheme. I know Christchurch City is not like Cooks Beach.
My interest in sewage alternatives has taken me round the world and times have changed, as Sydney Water found when it investigated developments in the United States and Europe, after facing estimates of between $16,000 and $70,000 per lot to connect houses to new centralised sewage systems.
They found that on site wastewater services are used in 50% of lots in Norway and 25% of all lots in the USA. On-site servicing is no longer seen as a temporary measure in the USA where 35% of new city housing developments are now on-site serviced. Beverley Hills in LA is all on-site, and Barbra Streisand was one who lobbied the council to keep it that way. The US Environmental Protection Agency has advised the US government that “decentralised systems, where properly managed, could protect water quality over the long term and do so at lower cost than conventional systems in many communities.”
The most modern systems used in US urban environments combine sophisticated on-site primary treatment tanks, which retain and biodigest solids and need emptying every ten years or so, and small-gauge leak-proof pipes which reticulate the liquid effluent only, to either a centralised treatment plant, or to small local treatment facilities. Some of these use vacuum systems or small pumps to send effluent through leak-proof plastic pipes which can bend and move with ground movement.
While modern centralised wastewater treatment plants in New Zealand are using cleaner technology, the fact is that traditional sewage reticulation pipe networks are dreadfully leaky, and environmental disasters in themselves. Even without an earthquake.
It is difficult to justify their construction and use in coastal environments if the goal is to protect and preserve water quality in the long term.
It is no longer flush it and forget it in Christchurch. Every day people are faced with the personal challenge of what to do with their own, and their children’s excrement. Call it human bio-solids. Right now a system of Portaloos and regular collection is being rolled out across Christchurch.
The collected bio-solids will contain toilet paper and some sterile urine. But will not be contaminated with heavy metal trade wastes that get tipped into the sewer. It will not be diluted with thousands of litres of water. It will be pure. Ripe for composting and re-use. It can be developed into a modern, resilient and responsible sanitation system.
Christchurch has the opportunity to re-invent itself from the bottom up.
3 comments:
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Greetings Joel,
Just a few questions about your blog on "Garden City's Cheeky Opportunity"
1. Granted it will not be contaminated with heavy metal trade wastes dumped into the system. What are these levels of contaminants from non domestic sources and how does that compare with heavy metals from domestic sources ?
2. Pure ?? Isn't the waste contaminated with pathogens such as Giardia, E coli, Cryptosporidium, Helminth ova from domestic sources ?
3. Pure ?? Isn't the waste contaminated with heavy metals from shampoo, underarm deodorants, soaps, detergents, makeup, and other personal care products from domestic sources ?
4. Pure ?? Isn't the waste contaminated by heavy metals from estrogens and pharmaceuticals such as Panadol, steroid creams, drugs that help people with psychotic disorders etc. ? Also what are the effects on the environment of these pharmaceutical residuals that enter the system ?
5. Ripe for composting and reuse - yes that is possible, but what are the methods of composting and what are the reuse options ?
6. Are you saying that the "collected bio-solids" are what comes out of portaloos and via collection services -
August 10, 2011 at 11:14 AM
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Thank you for this set of informed and interesting questions which I will quickly respond to here. In some cases more detailed information is required....
Q 1. Granted it will not be contaminated with heavy metal trade wastes dumped into the system. What are these levels of contaminants from non domestic sources and how does that compare with heavy metals from domestic sources ?
A 1. I only know about these levels from my experience in Auckland and North Shore Cities. Non-domestic sources are responsible for the great majority of heavy metal contaminants: esp nickel and zinc from platers, some mercury from dentists, various dusts and oils from washing down machinery and factory floors. Really depends on the nature of commercial and light industrial activities carried out in the catchment.
Q 2. Pure ?? Isn't the waste contaminated with pathogens such as Giardia, E coli, Cryptosporidium, Helminth ova from domestic sources ?
A 2. What I mean is that human sewage - without non-domestic contaminants - is mainly "pure" organic material. I accept that it contains lots of bacteria and bugs which can have very serious health effects unless killed in processing. But it contains very little in the way of heavy metals and active toxic chemicals because we don't tend to eat these things.
Q 3. Pure ?? Isn't the waste contaminated with heavy metals from shampoo, underarm deodorants, soaps, detergents, makeup, and other personal care products from domestic sources ?
A 3: It is contaminated with chemicals that are ingested. The pharmaceutical products you mention get into the water when you wash, shower etc. But you don't ingest those, so they are not in your biosolids. These chemicals would be washed - without biosolids - in small pipe networks for treatment.
Q 4. Pure ?? Isn't the waste contaminated by heavy metals from estrogens and pharmaceuticals such as Panadol, steroid creams, drugs that help people with psychotic disorders etc. ? Also what are the effects on the environment of these pharmaceutical residuals that enter the system ?
A 4: It does contain the left-overs from drugs that are ingested, including the ones you list. Caffeine goes through the human system almost unchanged. Other drugs are changed. Their fate - after aerobic or anerobic decompostion of biosolids (or whichever process is adopted) needs to be known and understood before deciding how the treated biosolids are finally used, buried or applied to land. I'm not saying it's straightforward. Other Western countries have experience. We need to learn from them. Adapt their ideas to NZ. We can do much better than simply flushing and hoping it all goes away.
Q 5. Ripe for composting and reuse - yes that is possible, but what are the methods of composting and what are the reuse options ?
A 5: There are many examples in other Western countries (Germany, USA, Australia). Wellington operated a combined green waste biosolids compost operation at Moa Point till just a few years ago. There were issues with that, partly because Wgtn could not separate trade wastes from the sewer stream.
Q 6. Are you saying that the "collected bio-solids" are what comes out of portaloos and via collection services
A 6: Absolutely. The ideal solution to the current hole we are in, is to decide to do something different from mixing all our different wastes, reticulating them through an expensive and fragile and leaky network, and then giving up on separating them at the other end because it's all too dilute and too contaminated.
Chch is in the unique position of having to change its sanitation system. I am advocating that Chch designs and builds its wastewater system to suit the seismic nature of the land it is built upon. -
August 10, 2011 at 12:20 PM
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As far as I know sewage treatment plant will be very beneficial to a City as it cost-effective and use to threat waste water and reuse in other purpose or make a useful products.
-
September 6, 2011 at 8:32 PM
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3 comments:
Greetings Joel,
Just a few questions about your blog on "Garden City's Cheeky Opportunity"
1. Granted it will not be contaminated with heavy metal trade wastes dumped into the system. What are these levels of contaminants from non domestic sources and how does that compare with heavy metals from domestic sources ?
2. Pure ?? Isn't the waste contaminated with pathogens such as Giardia, E coli, Cryptosporidium, Helminth ova from domestic sources ?
3. Pure ?? Isn't the waste contaminated with heavy metals from shampoo, underarm deodorants, soaps, detergents, makeup, and other personal care products from domestic sources ?
4. Pure ?? Isn't the waste contaminated by heavy metals from estrogens and pharmaceuticals such as Panadol, steroid creams, drugs that help people with psychotic disorders etc. ? Also what are the effects on the environment of these pharmaceutical residuals that enter the system ?
5. Ripe for composting and reuse - yes that is possible, but what are the methods of composting and what are the reuse options ?
6. Are you saying that the "collected bio-solids" are what comes out of portaloos and via collection services
Thank you for this set of informed and interesting questions which I will quickly respond to here. In some cases more detailed information is required....
Q 1. Granted it will not be contaminated with heavy metal trade wastes dumped into the system. What are these levels of contaminants from non domestic sources and how does that compare with heavy metals from domestic sources ?
A 1. I only know about these levels from my experience in Auckland and North Shore Cities. Non-domestic sources are responsible for the great majority of heavy metal contaminants: esp nickel and zinc from platers, some mercury from dentists, various dusts and oils from washing down machinery and factory floors. Really depends on the nature of commercial and light industrial activities carried out in the catchment.
Q 2. Pure ?? Isn't the waste contaminated with pathogens such as Giardia, E coli, Cryptosporidium, Helminth ova from domestic sources ?
A 2. What I mean is that human sewage - without non-domestic contaminants - is mainly "pure" organic material. I accept that it contains lots of bacteria and bugs which can have very serious health effects unless killed in processing. But it contains very little in the way of heavy metals and active toxic chemicals because we don't tend to eat these things.
Q 3. Pure ?? Isn't the waste contaminated with heavy metals from shampoo, underarm deodorants, soaps, detergents, makeup, and other personal care products from domestic sources ?
A 3: It is contaminated with chemicals that are ingested. The pharmaceutical products you mention get into the water when you wash, shower etc. But you don't ingest those, so they are not in your biosolids. These chemicals would be washed - without biosolids - in small pipe networks for treatment.
Q 4. Pure ?? Isn't the waste contaminated by heavy metals from estrogens and pharmaceuticals such as Panadol, steroid creams, drugs that help people with psychotic disorders etc. ? Also what are the effects on the environment of these pharmaceutical residuals that enter the system ?
A 4: It does contain the left-overs from drugs that are ingested, including the ones you list. Caffeine goes through the human system almost unchanged. Other drugs are changed. Their fate - after aerobic or anerobic decompostion of biosolids (or whichever process is adopted) needs to be known and understood before deciding how the treated biosolids are finally used, buried or applied to land. I'm not saying it's straightforward. Other Western countries have experience. We need to learn from them. Adapt their ideas to NZ. We can do much better than simply flushing and hoping it all goes away.
Q 5. Ripe for composting and reuse - yes that is possible, but what are the methods of composting and what are the reuse options ?
A 5: There are many examples in other Western countries (Germany, USA, Australia). Wellington operated a combined green waste biosolids compost operation at Moa Point till just a few years ago. There were issues with that, partly because Wgtn could not separate trade wastes from the sewer stream.
Q 6. Are you saying that the "collected bio-solids" are what comes out of portaloos and via collection services
A 6: Absolutely. The ideal solution to the current hole we are in, is to decide to do something different from mixing all our different wastes, reticulating them through an expensive and fragile and leaky network, and then giving up on separating them at the other end because it's all too dilute and too contaminated.
Chch is in the unique position of having to change its sanitation system. I am advocating that Chch designs and builds its wastewater system to suit the seismic nature of the land it is built upon.
As far as I know sewage treatment plant will be very beneficial to a City as it cost-effective and use to threat waste water and reuse in other purpose or make a useful products.
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