A skeptical young Metropolitan Water District chemist explained it to me 10 years ago. Over a dinner of Montana Avenue pasta, she laid it out straight: “In the environment, there are no solutions. There are only trade-offs.”I noted the remark and filed it away. At that precise time, though, we believed in solutions. I was writing a long piece about Los Angeles wastewater, and city officials were then agog with optimism that solutions to long-standing sewage problems were finally within reach. We were about to stop pouring the stuff into the increasingly desolated Santa Monica Bay. Instead, the city’s wastes would be transformed into a human-sourced, harmless hydrocarbon through the magic of a special, federally funded multimillion-dollar refinery. The hydrocarbon, in turn, would be burned to make electricity. It was so simple. My skeptical friend was right, though: It was too simple. It turns out you can’t make sewage literally disappear into clean air. Oh, after a court order, the first part went well enough — so much so that one seldom worries about Santa Monica Bay pollution, except when heavy rain fouls the storm drains. But the waste-to-energy burner became the biggest scientific flop since cold fusion.