Chris Gidez - Producer

I really didn’t know what to expect when I descended with my camera crew and host into the depths of the Los Angeles sewer system. Would the odor be overpowering? Would we see every conceivable variety of human waste? And most of all, would we be able to film in this dangerous environment?

Every precaution is taken. Before we enter, the safety officer makes each of us don a white, full-body, haz-mat suit, rubber wading boots, protective eyewear, hard-hats, and latex gloves. The safety briefing is short and succinct: the biggest risk while walking through a sewer pipe is slipping on wet sediment, and falling into the stream of wastewater. The solution: walk bow-legged, with the toes of each foot angled up the sides of the pipe. That way, there will be no twisted ankles, biohazard bathing, or bruised egos.

We walk down a ramp, into the tunnel entrance. From the sunny, cloudless Southern California day, we enter a dark, dank and surprisingly fascinating underworld. It is a work-site where an 80-year-old section of 10-foot diameter sewer pipe has been re-lined with new concrete and a durable, corrosion resistant PVC plastic material. The reason for all this work is invisible, but definitely evident in the form of a subtle rotten-egg aroma. It is the smell of hydrogen sulfide. Combined with the moisture inside the pipe’s enclosed environment, it

Exploring underneath the streets is no easy task.

becomes corrosive to the concrete pipes, eating away the structure over time. Rather than dig up the entire community that had been built above, engineers have diverted the wastewater flow through smaller pipes, and are working from within. It’s an innovative way to keep subterranean sewage separated from our lives above ground.

Most of us take the sewage system for granted. We don’t want to think about where human waste goes. Or as one expert told me, we “flush it and forget it.” Like most cities, Los Angeles’ has a network of sewer pipes that channels wastewater from our homes and businesses, under our streets and communities to a treatment plant. This is where the sewage waste – or what the sewage treatment people called “bio-solid” – is taken out of the water, rendering it harmless to the environment. In LA, the treated water is then pumped into Santa Monica Bay – which is where it would naturally end up. The same treatment process is used throughout the nation, but at varying scales depending on the size of the sewer system.

LA's waste treatment facility the Hyperion

LA’s major treatment plant, called Hyperion, deals with about 450 million gallons of wastewater a day. To see – and of course, smell – this river of sewage entering the treatment process is quite an experience: at first disgusting, but then somewhat surreal when put in the context our everyday lives. First, it flows into the “headworks,” through a bank of sieve-like grates called “bar screens.” This separates any large, solid objects floating in the wastewater. And, when I say “large, solid objects,” that means everything from used condoms and tampons, to an array of unusual items like bowling balls and bicycle frames. But, I was even more surprised to learn that the workers at the headworks find cash in various denominations. The workers sanitize the dirty money – which is quite resilient – and then fill out an official claim form in order to take it as their own.

But I digress. The rest of Hyperion’s treatment process happens at a more microscopic level, inside covered tanks. After solid objects are taken out of the wastewater, it flows into the “primary treatment” part of the plant – which is comprised of huge, football field length tanks. Here chemical coagulants are added to the water, which binds to the organic waste, causing it to settle to the bottom. The wastewater is then channeled into an area called “secondary treatment,” where oxygen-charged, aerobic bacteria devour the dissolved bio-solids. The beneficial bacteria then settles out of the water, leaving it 95% cleaner than when it entered the system. From here, the treated effluent flows through an outfall pipe five miles from shore, where it’s released into Santa Monica Bay.

One can only imagine what our oceans, rivers and streams would be like if it weren’t for sewage treatment. Our lives certainly wouldn’t be pleasant. And we wouldn’t be able to take for granted the amazing feat of environmental engineering accomplished by sewer systems like the one in Los Angeles.