When I graduated University - two degrees, all fancy on paper, green as i'll ever get, no experience, and hoping for a better future. I'd think my first job was just at a LEGO Brand retail store, but the first real Engineering job was a civil service position at the Department of Environmental Protection in New York City. They stuck me with the Wastewater treatment division.
New York City has a mixed sewage system, with all rain water and sewage from houses eventually converging before going to the treatment plants. Thirteen plants in all, and I was able to visit all of them in my short stay there. It didn't take long before I made the decision to leave. I was on top of a sludge tank on the fourth day, I knew I wouldn't last long there. There were tours of old sludge pipes, three and four meter tall pipes of old sewage tracks, and small cracked pipe replacements due to erosion from the inside.. think about that one. And some of the normal HVAC replacements, new installations, simple replacements, site inspections just could not compare to the smell. They say smell is the sense closest to memory, and believe me, I'll never forget.
Can you imagine my horror of doing a site visit to a water treatment plant, twelve years later and eventually deciding that the big complex model would be a water treatment plant? It made so much sense to do, being one of the most complex parts of the human water cycle. It also leaned a bit on that experience from that long ago.
The model itself, going down to details, has a fun function. You need to flush the toilet, and hold it down to activate the treatment plant, where once completed clean water and a sludge cake would come out. So one action, with a delay, to release two objects over the span of a meter of axles with ramps running over those axles. There's counterweights, locks, long axles with U joints, a non dual locked model and some clever design choices to match what would be part of the real thing.
You can see the counterweight should be sludge tanks, the fly wheel is an oxygenation or chemical treatment tank, and then the sludge release actually mimics the solid separation tank skimmer. The water is released under everything via the skimmer as well. The rest of the mechanism works via a clutch and release through the long pipe activated by the toilet. When you flush, the mechanism can start, but if you don't hold down long enough, the model will lock itself again. I mean its the real thing, you should flush a bit longer to get the solids out.
It took forever to get it to work, the timing was wrong, or there was an unknown friction somewhere in the system. So many of my sketch models worked and then it came to testing. The balance between time and weight was an issue. Down to seconds and grams ! It felt like I had gone back to the shit back then. I never thought i'd have to go back to it, but its funny how life goes in that cycle.
I remember when I left that job, it would actually begin an 18 day road trip around the US, by myself. The life risk was there, and I was young enough to take it. I told myself I'd look back at it and laugh. It took some years, but maybe it came back to laugh at me. I'm proud of the model, and I hope all the FLL kids enjoy it too. You get another piece of me here, how rare is it that we get to put that in our work.
*photo from the Building instructions and setup of FLL Hydro Dynamics, courtesy of firstlegoleague.org*
