(projects i'm involved in)
Mae Taeng, Chiang Mai, TH
(projects i'm following)
Posted by Richard Perkins about 6 years ago
The road leads East as we head across the country to Hampshire, home of theSustainability Centre where Permanent Publications and the Permaculture Magazineare based. We have come to speak with Maddy and Tim Harland whose dedication has established an extensive collection of temperate Permaculture and related publications in the last 25- 30 years. The Permaculture mag goes out to over 100 000 readers across the world, bringing positive solutions and strategies in all areas of our lives. We arrived with only a few days left before the next edition of the magazine needed to be delivered to the printers and so were very grateful to steal Maddy away from the office for a few hours!
The Sustainability Centre has a lot going on, functioning as a hub for different businesses, a natural woodland burial site, publishing HQs as well as a center for learning and education particularly with younger marginalized folks. Set aside the highest peak on the South Downs way, this site is a former Naval base established in the 40s when Portsmouth was being bombed. Now nature is regenerating this chalky downland and all manner of species are taking refuge. Predator bird species are regularly nesting and visiting, a good sign of balanced and flourishing ecology.
One of the center pieces to the site is the beautiful woodland classroom built by Ben Law and his team which was built with wood either from the site or sourced very locally in the area. The organic and graceful design sit gently in this setting, indeed the building has no foundations other than slab footings making this building very low impact. In fact Maddy comments there was no waste in the construction, offcuts from the timber construction boiled the tea that kept the workers going. The building is unusual in that the back wall has a hearth and cordwood and adobe wall, which actually really creates a heart and sense of home to what would otherwise probably feel like a much more simple shelter in the woods.
Perhaps the most interesting aspect for us at the center was the WET system. With a decommissioned naval sewage system as its backdrop, this biological treatment system is a testimony to good Permaculture Design and actually produces useful yields from human “waste”. In Permaculture systems we always try to look at wastes as unused resources, and here gray and black water are being utilized as nutrient rich resources that can produce a yield with the added benefit of remaining “off grid” in terms of sewerage as well as ensuring water leaving the site is cleaner than when it came in.
WET systems, Wetland Ecosystem Treatment systems, are a very important regenerative strategy for dealing with various waste effluents, and have broad- reaching implications for industrial, agricultural as well as human landscapes. This system was designed and built by Jay Abrahams from Biologic Design, who has pioneered this system and created large systems for dairy cattle yards and Sheppys brewery that kicks out a lot of highly acidic discharge at the time of pressings. The same principles could be applied to a regular household and scaled and replicated through understanding of the “waste” inputs and ecosystemic services of soil and plants.
Traditional sewage takes huge infrastructure, financial and energy inputs, usually involving degenerative infrastructure that in big cities could never actually be fully repaired due to the sheer cost and magnitude. An incredible amount of water (already treated) goes into working our conventional sewage systems at huge cost on many levels. This solution has impacts across various climates and could be a very low cost and low maintenance solution for a lot of developing countries where health problems arise form poor sewage management. Treated and bottled water has cost more than refined petroleum since the 1980s and is already a huge factor in land prices, indeed will likely be the main element in pricing land in the future- the ability to capture and store potable water. The degenerative water, sewage and treatment systems of our water is something we will look at deeper another time, and a most important topic. WET Systems are ‘low-entropy systems’ in that they use no fossil fuels or electricity to purify the wastewater and they are ‘solar powered’ by the ability of plants to absorb solar energy during photosynthesis. Micro-organisms in the root-zone mineralise the nutrients found in wastewater making them available to the plants.
The system works by connecting a series of ponds built on contour with piping that regulate and ensure water movement is slowed right down and controlled in the landscape. This allows soil microbiology and plants to utilize the high levels of nutrients and transform a “waste” stream into biomass. In this example willow is grown on the berms, the mounds shaped from the pond digging that form the downhill bank for the pond. This water loving plant thrives in the moist soils and can be cropped annually either for crafts of biomass heaters if chipped or turned into faggots. It takes around 0.8 acres of annual willow coppice to meet the heating needs of a well-insulated family of four, so you can start to see the multiple benefits of a system like this. Unlike conventional Reedbed Treatment Systems, no gravel or plastic aeration/distribution pipes are used in their construction; thus gravel does not need to be quarried and transported to site, and because plastics are not routinely used in WET Systems they have a very low embedded energy - soil in the root-zone, not imported gravel, is the filtration medium and this is already on-site.
The ponds themselves are lined with a geo- synthetic textile, usually a bentonite clay impregnated liner that swells and seals the pond when it comes into contact with water. This is covered with 20- 30 cm of topsoil to weight it all down and help seal the joins in the liner, and is then planted out with water edge species such as Carex and Phragmites families, with perhaps different 40- 50 species in the planting to ensure diverse, stable and resilience in the system. There are some design considerations, mainly around understanding level and contour to ensure water moves as slowly through the system as possible. Allowing the plants to establish is also important. There are likely planning conditions with a system of this nature, which must be considered, and hence the use of liners to ensure no seepage occurs into watercourses. Increased edge to allow greater densities of plantings are easily achieved through multiple ponds, which obviously have far more surface area than a single pond of the same total surface area. The complex aspect of designing these systems revolves around the BOD, or Biological Oxygen Demand, which it is necessary to explore and understand to know what size treatment area is required for the expected load.
Perhaps the most important design aspect for me is the fact that these systems have a huge tolerance in terms of their loads compared to comparable systems such as reed beds. In fact that is why this very system was designed. During the spring and summer the center has high numbers of visitors which peak at over 3000 for the annual Green Fair. That’s really what makes WET systems so remarkable a solution for dealing with effluent waste streams. Reed beds and biogas systems need regular inputs to run efficiently and effectively, whereas in this thriving ecosystem will tolerate large loads and spells of no inputs in a way that makes it unique.
With the diverse applications of WET systems, the ecosystem services and multiple functions offered it is clear this is a truly regenerative system that will surely become widespread in the future. It feels incredibly important, and with this system being the first in the South of England we would hope to find it becomes easier and easier to get planning for establishments such as this now there is a great example to compare it with.
It was P A Yeomans pioneering work on Keyline Design that led to his 1971 book The City Forest in which Yeomans presents logical ways to go about establishing cities according to the Scale of Permanence. His notions of using gravity to feed effluent out of cities to forest strips growing lumber and biomass have never really been seriously explored by town and city planners and my design brain cannot help but think of the synergy that could emerge with multiple strategies of dealing with our waste waters biologically, responsibly and regeneratively. Farms that left water exiting the farm cleaner than it came in, and businesses rewarded for how well their ecosystems treatments are functioning.
Another element of Permaculture thinking we try to share is that its often the small things that would make a huge difference if everyone adopted them. Putting a brick or 2l bottle in the cistern of the toilet, connecting up the sink to the toilet cistern or using urine (N source) to fertilise the garden. With various solutions existing to minimize our impact on a personal level its perhaps time to consider how to apply biological solutions to wider communities to create functional and thriving habitats that deal with resources locally and beneficially.
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