This is always the sort of topic that makes me want to talk like Homer Simpson. When you treat sewage and spit the water out one side, a spongy, sterilized byproduct comes out the other. That's "biosolids," and for the last 5 years, LA has been testing a new way to deal with them...a way that is, in fact, "the nation’s first full scale application of deep well injection technology." Explaining what that means is complicated but cool.
All of the crap we send into sewers produces 1 million pounds of biosolids in southern California. The City of Los Angeles and specifically its Hyperion Treatment Plant can raise its hand and take credit for a quarter of that..."pathogen free, exceptional quality, Grade A biosolids." Some of those biosolids get composted in Griffith Park. And for 11 years much of those high-quality biosolids have been trucked to a field in Kern County and spread over non-food farmland. They serve as fertilizer for Green Acres Farm, a 4-thousand acre property near Bakersfield that LA bought specifically so that it could have land on which to spread solid waste. LA farms alfalfa and other feedstock grains that the city sells locally in Kern County.
As you might guess, Kern County isn't in love with LA trucking biosolids up to its county and letting them offgas on lands within their county borders. They have enough bad air as it is. A local ordinance aims to shot down operations like the one LA has (it's not the only one, bot by a long stretch); a legal fight is wending its way through federal courts.
So LA engineers had another idea.
One of the first stories I covered when I moved to LA was the groundbreaking for the Terminal Island Renewable Energy Project. Three years ago, LA started shoving the biosolids it produces into underground reservoirs, spaces between rocks, once occupied by oil and gas. The space they chose at Terminal Island is a mile and a half from the nearest house; the capital cost was 8 million dollars, which isn't huge by municipal waste standards.
Putting the biosolids down there, LA can let the earth do the work for them. The higher temperature of the earth breaks them down; using the byproduct methane gas, LA can produce energy for 3000 homes. LA Sanitation has been monitoring the pressure, the temperature, the material amount, and the seismicity of the injection site. And it's working:
So far, TIRE has successfully injected over 120 million gallons of bio-slurry material, which includes, brine, treated effluent, digested sludge and re-slurried biosolids. Currently all 50 tons of biosolids produced at TIWRP is being managed at the TIRE facility and 150 tons from the Hyperion Treatment Plant. The injection well is accepting the material and formation response is good.
The project's been saving LA more than a million and a half dollars annually in trucking costs; keeping those truck trips off the road, incidentally, cuts emissions in the region too. LA's been doing this with the permission of the federal Environmental Protection Agency as a full-scale demonstration. Now the city wants to keep going, so they're seeking to re-up that permit. They're taking public comment about this through December 27th.
The advantage of this project if it succeeds is that it keeps tons of carbon dioxide out of the air. City documents say that at the end of 5 years, the demo project will have cut the same amount of carbon as taking 16-thousand cars off the street would. And so far, they seem to be saying the project is succeeding.
Today the Board of Public Works meets to talk about re-upping the permit. It's an item I barely caught in an agenda I don't always read. I wonder why nobody else is as interested in human waste as I am. Where's Greig Smith when you need him?