parallel treatment trains here, and an impressive record. The Water Authority mandates less than thirty parts per million total suspended solids; we average eight. The biological oxygen demand needs only be reduced to twelve ppm, but even with extremely polluted influent, our effluent rarely tests out at over seven.”
I had learned at age twelve, from my uncle Willem, that in a properly run plant the average BOD should never be higher than two ppm, but I didn’t say anything. Hepple hadn’t mentioned heavy metals or any of the volatile organic compounds, either, and I wondered what the plant’s record was like on those.
We walked among enormous translucent vats filled with swimming fish and floating duckweed. Pipes ran everywhere: transparent and opaque, plastic and metallic, finger-thin and bigger around than a human torso. I could feel the vibration of larger pipes running under our feet.
“The fish graze on this weed,” he said, “and if we have overgrowth we can harvest for animal feed. Further on we grow the lilies that are the real commercial backbone. But nothing, nothing at all, is wasted.” He came to an abrupt halt. “According to your employment file you’ve worked at the Immingham Petroleum Refinery. What was your speciality?”
“Continuous emission monitoring,” I said, knowing full well that in this solar aquatics and bioremediation wastewater plant there was no such job.
“You’ll be assigned something suitable, of course, but whatever your role, the one thing to bear in mind is that this plant—the four and a half million gallons coming in, the thirty-five million gallons on the premises, and the four and a half million going out—is one giant homeostatic system.” He waited for me to nod. Probably wondered if I knew what homeostatic meant. “The more polluted the influent, the more plants we grow and the more fish we harvest, but the effluent is always the same: clean, clean, clean. The only way this can be achieved is through attention to detail. As you’re used to a monitoring post, we might start you off in TOC analysis.”
I asked, because Sal Bird would have. “What’s TOC?”
“Total organic carbon analysis. Of the influent.”
At the initial stage, where none of the workers wore masks. One of the dirty jobs.
We stepped through what looked like an airlock into another closed corridor. Hepple fussed with the seals and we started walking again. “It’s not for you to worry about what a given reading may mean, but you’d better know what the parameters of any substrate are, and know what to do if they rise above or fall below that level. When you’re assigned, your section supervisor will give you more precise details.” We stopped at another air-sealed door. Hepple opened a panel in the corridor wall and took out a pair of dark goggles for me. He pulled up his own pair. “Goggles must be worn in the tertiary sector at all times.” With his eyes covered, his mouth seemed plump and soft. “Even though you will not be assigned to the tertiary sector immediately, the possession of eye protection is mandatory.” He ticked some thing off his chart. “The cost of those will come out of your first wage credit.”
It seemed I had the job. I pulled on the goggles.
Hepple opened the door. The light was blinding: huge arc lights hung from a metal latticework near the glass roof; bank after bank of full-spectrum spots shone from upright partitions between vats. It was incredibly hot and the air was full of the hiss of aerators and mixers and the rich aroma of green growing things. I had forgotten how much a person sweated in a skinny. “This is where the heavy metals are taken out by the moss.” I watched as a man and a woman lifted a sieved tray out of a vat and scraped off the greenery. “It’s recycled, of course.” A woman carrying a heavy-looking tray of tiny snails walked toward us. I started to move aside to let her pass, but Hepple pretended not to notice and the woman had to detour. A little tin god, lording it over his tiny domain. He wouldn’t have lasted more than a day on one of my projects.
“Zooplankton and snails do a lot of cleaning up at this stage, along with the algae, of course.” Women and men moved back and forth, harvesting zooplankton; checking nitrogen levels; monitoring fecal coliforms. Hard and busy work in the tertiary sector, but not dangerous.