Notes from Piers, No 172 - How should a real Jedi Master treat their sewage?
Friday, 19 January 2018
Anyone who has seen the recent Star Wars movie can´t fail to have noticed the scene where the Rebel heroes are trapped in a sticky situation on the Death Star and conveniently escape through a man-entry sewer. I love the idea that, across the universe, sewage is captured via a capex-heavy water-based collection system. I particularly like the idea that Darth Vader defecates: I imagine him going into a toilet cubicle, removing his mask and carefully hanging his long black cape on the back of the toilet door, being extra diligent to not to let it touch the floor (for obvious reasons, ….well, for anyone who has been in a male public toilet that is). I imagine him squatting down to business, just like every other human. Imperial Overlord or not, when nature calls, you answer.
Sewage treatment on the Death Star is, I assume, via a UASB1 (since conventional aeration-based systems would be prohibitively uneconomic due to the lack of oxygen in space). The biosolids generated must surely be treated via SCWO2 , as this would enable them to recover and reuse the precious water in the sludge. This would not be a cheap solution, but the one thing everyone knows about the Imperial Empire is they are not short of cash. Just look at how much they spend on their fancy suits.
For the Rebel Alliance however such gold plated treatment would be uneconomical. Fortunately the Alliance tend to be based on green lush planets where land availability is not an issue. The exception to this is obviously the ice planet Hoth (see Empire Strikes Back), but who wouldn’t want to live on Takodana (‘I have never seen so much green’ – Rey). Having space and sunshine creates treatment opportunities that the evil Empire simply cannot entertain on their dark and foreboding Death Star.
Back in 2016 I had the honour of presenting a paper at the IWA conference on the conversion of wastewater to energy via the production of algae (see Note, No 154). I was not presenting work that I had done personally but rather I was a last minute stand-in for my good friend Frank Rogalla (Director of Innovation at Aqualia). There is nothing I enjoy more than stealing the limelight, but doing it legitimately for once only made it sweeter. Earlier this week I met with Frank in Madrid for an update on the project.
Aqualia, as part of the ‘All-Gas’ project within the EU FP 7, have built a 2 hectare demonstration facility which can treat the sewage of 10,000 people. It is a thing of beauty. No odour and fantastically low power usage (0.15kWh/m3, compared to conventional nutrient removal methods which are typically 3 times this). It is actually a significant net energy generator – each ha (the surface of one football field) can provide fuel for 20 cars. Compared to conventional biofuels (eg Palm-oil-diesel, or sugarcane-ethanol) this is 4 times better. For more details please click: https://we.tl/pzcOTIakRC
Unlike other algae biofuel projects the AllGas team have kept the process gloriously simple, not complicating it with specialist algae species or the extraction of unique oils. Instead the AllGas project, as the name implies, simply grows whatever algae is naturally occurring, harvests it, and then converts it to biogas via a conventional anaerobic digester – while achieving free nutrient removal. The innate simplicity of the system is part of its beauty. No wonder it is the obvious treatment method of choice for the Rebel Alliance. Bearing in mind all the environmental and economic benefits you would think the Alliance would make a bigger noise about it but, apparently, in space no one can hear you scream (oops, wrong film).
Sadly Star Wars is not the only Hollywood movie to get confused about sanitation systems. The 1990s film ‘Robin Hood: Prince of Thieves’ has a scene near the start (where Kevin Costner first bonds with Morgan Freeman) where they escape from a medieval dungeon in an ancient Middle Eastern city via a Victorian sewer. It even has a manhole cover for crying out loud. I am tempted to conclude that powerful Hollywood moguls rate storytelling above the accurate representation of sanitation practices. Surely not?!
I feel the need to create a definitive list of water sector mis
-representations in major films. When I finally get to meet Spielberg, Lucas and Nolan I will ensure they stand corrected. All suggestions welcomed.
Note 1: UASB = Upflow Anerobic Sludge Blanket;
Note 2: SCWO – Super Critical Wet Oxidation)