Based on your inputs, the optimum end-of-life scenario for your used membrane is:
Disposal in local landfill
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Yes |
| Available in Australia |
Yes |
| Available globally |
Yes |
| Manual disassembly required |
No |
Landfill is currently the industry standard for disposal of end-of-life reverse osmosis membranes. Due to their mostly polymeric composition, membranes are considered inert municipal solid waste in the case of landfill disposal, with no degradation over a measureable time period. Therefore, disposal in landfill has the highest environmental impact of all the considered options, and should be avoided where possible; however, it is the simplest option, with minimal cost.
Energy recovery through incineration
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Yes |
| Available in Australia |
Limited |
| Available globally |
Yes |
| Manual disassembly required |
No |
Incineration is a thermal waste treatment method that involves the combustion of materials to produce ash, gas emissions and heat. It is attractive because of the reduction in volume of garbage over 90% and the generation of usable energy
[1], and therefore is commonly used in countries with strict land use requirements, such as Singapore and Japan
[2]. However, while current technology makes it possible to operate incineration plants with significantly reduced emissions, the environmental impact is still high, and there is a large public and political resistance against incineration in Australia
[3]. Due to these factors, there is currently no large scale industrial waste incineration industry in Australia.
References
- ↑ Saikia, N.; de Brito, J. Construction and Building Materials (2012), 34, 385-401.
- ↑ Tan, R. B. H.; Khoo, H. H. "Impact Assessment of Waste Management Options
in Singapore." Journal of the Air & Waste Management Association (2006), 56, 244–254.
- ↑ Australian Bureau of Statistics. Australia’s Environment: Issues and Trends. (2010). Available at www.abs.gov.au.
Energy recovery though syngas production
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
No |
| Available in Australia |
Emerging |
| Available globally |
Yes |
| Manual disassembly required |
Yes |
Syngas (synthetic gas), otherwise known as gasification, which involves the production of fuel from solid plastic waste
[1]. Gasification is the partial oxidation of carbon-based feedstock to generate syngas, which is often directly combusted onsite in an internal combustion engine generator to produce electricity
[2]. Oxygen is added to maintain a reducing atmosphere, but the quantity is maintained lower than the stoichiometric ratio for complete combustion. This process has a number of advantages over traditional incineration including reduced air emissions and the production of a usable fuel product. Due to these advantages, this type of tertiary treatment of plastic waste is seen as an environmentally favourable option with the advantage of significant landfill waste adversion
[3]. As there is a growing number of companies in Australia (and around the world) that use this process with plastic waste, with many small scale trial plants opening. Australian companies using this or similar technology include,
Bioplant,
Pacific Pyrolysis Pty Ltd, and
New Energy Corp.
References
- ↑ Wu, C.; Williams, P. T. Fuel (2010), 89, 3022-3032.
- ↑ Al-Salem, S. M.; Lettieri, P.; Baeyens, J. Waste Management (2009), 56, 244–254.
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. Desalination (2014), 357, 45-54.
Energy recovery through use as a coke substitute in Electric Arc Furnaces
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
No |
| Available in Australia |
Emerging |
| Available globally |
Emerging |
| Manual disassembly required |
Yes |
The use of polymeric membrane components as a substitute carbon source in electric arc furnace steel making process is a new end-of-life approach with many financial and environmental benefits, specifically in terms of diverting waste from landfill
[1]. The use of waste plastic and rubber as a substitute for metallurgical coke has been extensively tested in recent years and has also seen commercial use
[2]. This method has been specifically tested with membrane components and the results show that 64% by weight of membrane modules are compatible, including the membrane sheets, as well as the feed and permeate spacers
[3].
A partial waste polymeric material substitute actually improves the process though increased energy retainment and promotion of the foamy slag, which help protects the electrodes and walls of the furnace. There are however strict requirements for feed quality for this process and any type of contamination can lead to a negative impact on steel quality. Therefore, after the membrane components have been grown to the required size, the material needs to be thoroughly washed to remove any contamination from membrane use. This end-of-life option is most suitable for membrane users with a large number of membranes, or when constant replacement is required.
While a number of electric arc furnace plants around the world are now using this technology, there is no streamlined recycling program for additional waste streams. Therefore, membrane users with a large number of membranes should contact companies willing to participate. Companies in Australia that are currently using this technique include Bluescope Steel.
References
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. Desalination (2014), 357, 45-54.
- ↑ Sahajwalla, V.; Zaharia, M.; Kongkarat, S.; Khanna, R.; Rahman, M.; Saha-Chaudhury, N.; O’Kane, P.; Dicker, J.; Skidmore, C.; Knights, D. Energy & Fuels (2012), 26, 58-66.
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. "Assessment of End-of-Life Opportunities for Reverse Osmosis Membranes." The University of New South Wales (2015).
Material recycling
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Possible but limited |
| Available in Australia |
Yes |
| Available globally |
Yes |
| Manual disassembly required |
Yes |
Recycling of the polymeric membrane components using standard methods has been shown to be one of the most environmentally favourable end-of-life options, with an extremely positive public perception
[1].
The primary recycling method for end-of-life plastic components is mechanical recycling[2], which involves the components being shredded into plastic flakes, which are melted and reformed via melt-extrusion, to produce uniformly-sized pellets which can be used as a raw material for new products[3]. This process requires the module to be disassembled and sorted prior to the plastic washing and grinding stages. Due to the requirements of mechanical recycling, only the ABS components, including the tube and end caps, and the spacers are suitable for this method, with all other components being sent to landfill or other end-of-life application[4].
In Australia, the overall plastic recycling rate was 20.1% (in 2011), with the majority of plastics being mechanically reprocessed into durable (non-packaging) products[5]. There are a wide range of companies and programs available for this standard type of plastic recycling currently available in Australia, including SITA and AP Recycling.
As manual disassembly is required for mechanical recycling, there is also an opportunity to directly reuse some of the membrane components, saving on the cost of processing. These opportunities include, the use of ground plastic components as an aggregate for use in concrete[6]; the use of membrane sheets and spaces as geotextiles, which are used to separate and retain soils or gravel in landscaping or construction application[7]; and their use in wood plastic composites, which are produced by mixing recycled plastics with ground wood particles to produce decking, roof tiles, cladding, landscaping timbers etc[8].
References
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. "Assessment of End-of-Life Opportunities for Reverse Osmosis Membranes." The University of New South Wales (2015).
- ↑ A’Vard, D.; O’Farrell, K. National Recycling Survey Final Report; Plastics and Chemicals Industries Association: Carlton, VIC (2013)
- ↑ Brulliard, C.; Cain, R.; Do, D.; Dornom, T.; Lim, B.; Olesson, E.; Young, S. "The Australian recycling sector." Department of Sustainability, Environment, Water, Population and Communities (2012). Available at www.environment.gov.au
- ↑ Goodship, V. "Introduction to Plastic Recycling". Smithers Rapra Technology Limited: Shawbury UK (2007)
- ↑ PACIA. "Plastic recycling in Australia remains strong" (2012)
- ↑ Saikia, N.; de Brito, J. Construction and Building Materials (2012), 34, 385-401.
- ↑ Ould Mohamedou, E.; Penate Suarez, D. B.; Vince, F.; Jaouen, P.; Pontie, M. Desalination (2010), 253, 62–70.
- ↑ Kazemi Najafi, S. Waste management; New York (2013)
Chemical conversion to an ultrafiltration membrane and then reuse
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Yes |
| Available in Australia |
Yes |
| Available globally |
Yes |
| Manual disassembly required |
No |
Given the nature of the composite construction used in RO production, relatively simple conversion from an RO to ultrafiltration (UF) membrane is possible
[1]. The structure of an RO membrane can be seen in the image below, and flat sheet UF membranes have an extremely similar construction, but are just missing the top polyamide layer. By chemically degrading the polyamide active layer with sodium hypochlorite (NaClO), the polysulfone layer is exposed, resulting in a membrane with properties extremely similar to commercially available UF membranes
[2].
The method for chemical conversion of RO membranes has been optimised, with controlled exposure to 300,000 ppm.hr of NaOCl resulting in organic and virus removal properties, and hydraulic performance, comparable to commercially available 10 – 30 kDa molecular weight cut off UF membranes. Potential applications for the converted RO membranes include use in pre-treatment filtration in desalination plant, waste water treatment or for low cost water treatment in developing areas.
This promising end-of-life application how now been extensively validated, and is ready for a trial application. If you require a series of extremely low cost, environmentally friendly, spiral wound UF membranes, please contact Pierre Le-Clech (mailto:p.le-clech@unsw.edu.au) for further information.
References
- ↑ Lawler, W.; Antony, A.; Cran, M.; Duke, M.; Leslie, G.; Le-Clech, P. Journal of Membrane Science (2013), 447, 203-211
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. "Assessment of End-of-Life Opportunities for Reverse Osmosis Membranes." The University of New South Wales (2015).
Direct membrane reuse
Direct reuse as a high quality seawater RO membranes
Direct reuse as a high quality brackishwater RO membranes
Direct reuse as a medium quality brackishwater RO membranes
Direct reuse as a low quality brackishwater RO membranes
Direct reuse as a medium quality nanofiltration membranes
| NaCl rejection range (%) |
Permeability range (l.m-2.h-1.bar-1) |
Designation |
Action |
Estimated reuse lifespan (yrs) |
| 99.9 - 99.6 |
> 0.45 |
High quality SWRO |
Direct reuse as SWRO possible in normal applications |
2 –5 |
| 99.7 - 99.2 |
> 1.6 |
High quality BWRO |
Direct reuse as BWRO possible in normal applications |
2 – 3 |
| 99.2 – 98 |
> 1.6 |
Medium quality BWRO |
Direct reuse as BWRO in standard applications possible |
1 – 2 |
| 98 – 96 |
> 1 |
Low quality BWRO |
Direct reuse as BWRO in harsh applications where regular replacement is required |
1 |
| 96 – 80 |
> 5 |
Medium quality NF |
Direct reuse as NF membrane possible |
- |
| < 96 |
< 5 |
Unsuitable for RO or NF |
Membrane suitable for UF conversion. |
- |
Disposal in local landfill
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Yes |
| Available in Australia |
Yes |
| Available globally |
Yes |
| Manual disassembly required |
No |
Landfill is currently the industry standard for disposal of end-of-life reverse osmosis membranes. Due to their mostly polymeric composition, membranes are considered inert municipal solid waste in the case of landfill disposal, with no degradation over a measureable time period. Therefore, disposal in landfill has the highest environmental impact of all the considered options, and should be avoided where possible; however, it is the simplest option, with minimal cost.
Energy recovery through incineration
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Yes |
| Available in Australia |
Limited |
| Available globally |
Yes |
| Manual disassembly required |
No |
Incineration is a thermal waste treatment method that involves the combustion of materials to produce ash, gas emissions and heat. It is attractive because of the reduction in volume of garbage over 90% and the generation of usable energy
[1], and therefore is commonly used in countries with strict land use requirements, such as Singapore and Japan
[2]. However, while current technology makes it possible to operate incineration plants with significantly reduced emissions, the environmental impact is still high, and there is a large public and political resistance against incineration in Australia
[3]. Due to these factors, there is currently no large scale industrial waste incineration industry in Australia.
References
- ↑ Saikia, N.; de Brito, J. Construction and Building Materials (2012), 34, 385-401.
- ↑ Tan, R. B. H.; Khoo, H. H. "Impact Assessment of Waste Management Options
in Singapore." Journal of the Air & Waste Management Association (2006), 56, 244–254.
- ↑ Australian Bureau of Statistics. Australia’s Environment: Issues and Trends. (2010). Available at www.abs.gov.au.
Energy recovery though syngas production
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
No |
| Available in Australia |
Emerging |
| Available globally |
Yes |
| Manual disassembly required |
Yes |
Syngas (synthetic gas), otherwise known as gasification, which involves the production of fuel from solid plastic waste
[1]. Gasification is the partial oxidation of carbon-based feedstock to generate syngas, which is often directly combusted onsite in an internal combustion engine generator to produce electricity
[2]. Oxygen is added to maintain a reducing atmosphere, but the quantity is maintained lower than the stoichiometric ratio for complete combustion. This process has a number of advantages over traditional incineration including reduced air emissions and the production of a usable fuel product. Due to these advantages, this type of tertiary treatment of plastic waste is seen as an environmentally favourable option with the advantage of significant landfill waste adversion
[3]. As there is a growing number of companies in Australia (and around the world) that use this process with plastic waste, with many small scale trial plants opening. Australian companies using this or similar technology include,
Bioplant,
Pacific Pyrolysis Pty Ltd, and
New Energy Corp.
References
- ↑ Wu, C.; Williams, P. T. Fuel (2010), 89, 3022-3032.
- ↑ Al-Salem, S. M.; Lettieri, P.; Baeyens, J. Waste Management (2009), 56, 244–254.
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. Desalination (2014), 357, 45-54.
Energy recovery through use as a coke substitute in Electric Arc Furnaces
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
No |
| Available in Australia |
Emerging |
| Available globally |
Emerging |
| Manual disassembly required |
Yes |
The use of polymeric membrane components as a substitute carbon source in electric arc furnace steel making process is a new end-of-life approach with many financial and environmental benefits, specifically in terms of diverting waste from landfill
[1]. The use of waste plastic and rubber as a substitute for metallurgical coke has been extensively tested in recent years and has also seen commercial use
[2]. This method has been specifically tested with membrane components and the results show that 64% by weight of membrane modules are compatible, including the membrane sheets, as well as the feed and permeate spacers
[3].
A partial waste polymeric material substitute actually improves the process though increased energy retainment and promotion of the foamy slag, which help protects the electrodes and walls of the furnace. There are however strict requirements for feed quality for this process and any type of contamination can lead to a negative impact on steel quality. Therefore, after the membrane components have been grown to the required size, the material needs to be thoroughly washed to remove any contamination from membrane use. This end-of-life option is most suitable for membrane users with a large number of membranes, or when constant replacement is required.
While a number of electric arc furnace plants around the world are now using this technology, there is no streamlined recycling program for additional waste streams. Therefore, membrane users with a large number of membranes should contact companies willing to participate. Companies in Australia that are currently using this technique include Bluescope Steel.
References
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. Desalination (2014), 357, 45-54.
- ↑ Sahajwalla, V.; Zaharia, M.; Kongkarat, S.; Khanna, R.; Rahman, M.; Saha-Chaudhury, N.; O’Kane, P.; Dicker, J.; Skidmore, C.; Knights, D. Energy & Fuels (2012), 26, 58-66.
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. "Assessment of End-of-Life Opportunities for Reverse Osmosis Membranes." The University of New South Wales (2015).
Material recycling
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Possible but limited |
| Available in Australia |
Yes |
| Available globally |
Yes |
| Manual disassembly required |
Yes |
Recycling of the polymeric membrane components using standard methods has been shown to be one of the most environmentally favourable end-of-life options, with an extremely positive public perception
[1].
The primary recycling method for end-of-life plastic components is mechanical recycling[2], which involves the components being shredded into plastic flakes, which are melted and reformed via melt-extrusion, to produce uniformly-sized pellets which can be used as a raw material for new products[3]. This process requires the module to be disassembled and sorted prior to the plastic washing and grinding stages. Due to the requirements of mechanical recycling, only the ABS components, including the tube and end caps, and the spacers are suitable for this method, with all other components being sent to landfill or other end-of-life application[4].
In Australia, the overall plastic recycling rate was 20.1% (in 2011), with the majority of plastics being mechanically reprocessed into durable (non-packaging) products[5]. There are a wide range of companies and programs available for this standard type of plastic recycling currently available in Australia, including SITA and AP Recycling.
As manual disassembly is required for mechanical recycling, there is also an opportunity to directly reuse some of the membrane components, saving on the cost of processing. These opportunities include, the use of ground plastic components as an aggregate for use in concrete[6]; the use of membrane sheets and spaces as geotextiles, which are used to separate and retain soils or gravel in landscaping or construction application[7]; and their use in wood plastic composites, which are produced by mixing recycled plastics with ground wood particles to produce decking, roof tiles, cladding, landscaping timbers etc[8].
References
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. "Assessment of End-of-Life Opportunities for Reverse Osmosis Membranes." The University of New South Wales (2015).
- ↑ A’Vard, D.; O’Farrell, K. National Recycling Survey Final Report; Plastics and Chemicals Industries Association: Carlton, VIC (2013)
- ↑ Brulliard, C.; Cain, R.; Do, D.; Dornom, T.; Lim, B.; Olesson, E.; Young, S. "The Australian recycling sector." Department of Sustainability, Environment, Water, Population and Communities (2012). Available at www.environment.gov.au
- ↑ Goodship, V. "Introduction to Plastic Recycling". Smithers Rapra Technology Limited: Shawbury UK (2007)
- ↑ PACIA. "Plastic recycling in Australia remains strong" (2012)
- ↑ Saikia, N.; de Brito, J. Construction and Building Materials (2012), 34, 385-401.
- ↑ Ould Mohamedou, E.; Penate Suarez, D. B.; Vince, F.; Jaouen, P.; Pontie, M. Desalination (2010), 253, 62–70.
- ↑ Kazemi Najafi, S. Waste management; New York (2013)
Chemical conversion to an ultrafiltration membrane and then reuse
| Compatible with plastic components |
Yes |
| Compatible with fibreglass components |
Yes |
| Available in Australia |
Yes |
| Available globally |
Yes |
| Manual disassembly required |
No |
Given the nature of the composite construction used in RO production, relatively simple conversion from an RO to ultrafiltration (UF) membrane is possible
[1]. The structure of an RO membrane can be seen in the image below, and flat sheet UF membranes have an extremely similar construction, but are just missing the top polyamide layer. By chemically degrading the polyamide active layer with sodium hypochlorite (NaClO), the polysulfone layer is exposed, resulting in a membrane with properties extremely similar to commercially available UF membranes
[2].
The method for chemical conversion of RO membranes has been optimised, with controlled exposure to 300,000 ppm.hr of NaOCl resulting in organic and virus removal properties, and hydraulic performance, comparable to commercially available 10 – 30 kDa molecular weight cut off UF membranes. Potential applications for the converted RO membranes include use in pre-treatment filtration in desalination plant, waste water treatment or for low cost water treatment in developing areas.
This promising end-of-life application how now been extensively validated, and is ready for a trial application. If you require a series of extremely low cost, environmentally friendly, spiral wound UF membranes, please contact Pierre Le-Clech (mailto:p.le-clech@unsw.edu.au) for further information.
References
- ↑ Lawler, W.; Antony, A.; Cran, M.; Duke, M.; Leslie, G.; Le-Clech, P. Journal of Membrane Science (2013), 447, 203-211
- ↑ Lawler, W.; Alvarez-Gaitan, J.; Leslie, G.; Le-Clech, P. "Assessment of End-of-Life Opportunities for Reverse Osmosis Membranes." The University of New South Wales (2015).
Direct membrane reuse
Direct reuse as a high quality seawater RO membranes
Direct reuse as a high quality brackishwater RO membranes
Direct reuse as a medium quality brackishwater RO membranes
Direct reuse as a low quality brackishwater RO membranes
Direct reuse as a medium quality nanofiltration membranes
| NaCl rejection range (%) |
Permeability range (l.m-2.h-1.bar-1) |
Designation |
Action |
Estimated reuse lifespan (yrs) |
| 99.9 - 99.6 |
> 0.45 |
High quality SWRO |
Direct reuse as SWRO possible in normal applications |
2 –5 |
| 99.7 - 99.2 |
> 1.6 |
High quality BWRO |
Direct reuse as BWRO possible in normal applications |
2 – 3 |
| 99.2 – 98 |
> 1.6 |
Medium quality BWRO |
Direct reuse as BWRO in standard applications possible |
1 – 2 |
| 98 – 96 |
> 1 |
Low quality BWRO |
Direct reuse as BWRO in harsh applications where regular replacement is required |
1 |
| 96 – 80 |
> 5 |
Medium quality NF |
Direct reuse as NF membrane possible |
- |
| < 96 |
< 5 |
Unsuitable for RO or NF |
Membrane suitable for UF conversion. |
- |