Rieckermann seems unfazed. Moving with hunched urgency, the athletic 34-year-old pops open the top on the corrugated-plastic robot. The contraption uses a vacuum pump and a long hose to siphon samples from the sewage and then fill a carousel of plastic flasks with a mechanical arm. Apparently the battery has died, because half the flasks are empty. "At least it didn't malfunction and overflow, like last time," Rieckermann says, adjusting his rimless eyeglasses. He punches a keypad to recalibrate the draw. The robot beeps and gurgles and then spits up 100 millimeters of brown water. "Now, that's a nice sample," he says, holding up a plastic test tube full of sewage to the morning sun. "Liquid, plus particles—toilet paper, feces, sludge, slime." Not to mention traces of cocaine, methamphetamine, marijuana, heroin and any number of other illicit substances ingested, digested, and then flushed down the toilet. This spiked refuse is why we're here.