LA’s Sewage Sludge

Laudably sustainable or dangerous?

by Sarah (Steve) Mosko, PhD

Appeared in:

  • Vall-E-Vents, Sierra Club Newsletter, Jan 2012
  • E-Magazine, 08 Aug 2011

People flush the toilet maybe five to 10 times a day. Ever wonder where it all goes?

Los Angeles(LA) is representative of the challenge a large metropolis faces in managing its sewage waste.  LA area residents generate roughly 90 gallons per person per day of raw sewage from toilet flushing, bathing, housekeeping and discharging industrial waste into drains.

Most of us care not to think about sewage once it’s out of sight.

However, thinking about sewage is exactly what wastewater treatment facilities do. The Hyperion treatment plant in Playa Del Ray is by far LA’s largest, managing a daily wastewater inflow averaging 330 million gallons generated by over four million people in LA and 29 surrounding cities. That’s enough to fill 500 Olympic-sized pools.

Hyperion’s task is to separate the water from the solid components – aka sewage sludge – and recycle both in a sustainable fashion.

For three decades through the 1980s, the disposal of sewage from the LA area into theSanta MonicaBaycreated a dead zone, prompting LA to launch a Biosolids Environmental Management System (EMS) embodying environmentally sound alternatives. Since 1994, Hyperion has achieved 100 percent “beneficial reuse” of sewage sludge by converting it into “biosolids” which are being used as soil amendment or as an energy source.

LA’s Biosolids EMS has won awards for innovation and environmental stewardship while also eliciting opposition from parties claiming it is unsafe because of the contaminants still present. The City is even in a protracted legal battle over the safety of some aspects of its Biosolids EMS.

What are biosolids?
At Hyperion, the liquid is separated from the solids and incubated so bacteria can digest the disease-causing pathogens before the water is discharged five miles offshore deep intoSanta MonicaBay. Sewage sludge is the black slurry left behind.

Biosolids are sewage sludge which has been “stabilized” to reduce odors and pathogens by extended incubation in enclosed vessels at 128°F to encourage anaerobic bacteria to break it down. At Hyperion, the resulting biosolids meet U.S. Environmental Protection Agency (EPA) standards for “Class A” biosolids, a nearly pathogen-free product supposedly safe, as is, for human contact and application to agricultural land or for further processing into garden compost.

Hyperion produced 650 wet tons of biosolids per day in 2010.  Nearly four-fifths were spread on a 4,688-acre farm inKernCountycalled Green Acres where, because of a local ordinance, only animal feed crops are grown and sold to local dairies.  LA purchased Green Acres in 2000 to insure a reliable location for recycling its biosolids.

Another nine percent were composted at aGriffithParkfacility along with “zoo poo” and green park trimmings, yielding a registered trademark product, TOPGRO®, owned by the City ofLA.TOPGRO® is utilized inGriffithParkor sold to landscapers and nurseries.  It is considered non-toxic by the EPA so not subject to any hazardous waste regulations.

Since 2008, LA’s biosolids are also being diverted to a first-in-the-nation, five-year pilot project overseen by the EPA wherein they are injected a mile underground into depleted, abandoned oil and gas reservoirs at Terminal Island.

This so-named Terminal Island Renewable Energy Project, or TIRE, capitalizes on the high temperatures at such depths which foster biodegradation by anaerobic bacteria, producing methane gas and carbon dioxide as byproducts. The carbon dioxide remains permanently sequestered underground in a brine solution, whereas the methane is captured topside as a renewable energy source.

Thirteen percent of LA’s biosolids in 2010 were processed at TIRE.  TIRE has enhanced the prestige of the Biosolids EMS through recent awards for innovation from the National Association of Clean Water Agencies, the National League of Cities and the California Association of Sanitation Agencies. The Biosolids EMS also has Platinum Level Certification (highest possible) from the National Biosolids Partnership, a non-profit alliance of water quality organizations that recognizes biosolids programs for sustainable practices that go beyond regulatory compliance.

But are biosolids safe?
Despite such accolades, not everyone is thrilled about what LA is doing with its sewage waste.

KernCountyvoters passed an “anti-sludge ordinance” (Measure E) in 2006 to block Southland jurisdictions from dumping biosolids inKernCounty, reflecting concerns about threats to human health and groundwater. Implementation of Measure E has been delayed, however, by court battles led by the City ofLA.A federal case against Measure E was dismissed in late 2010, but LA is suing again, now in state court, to block the ordinance which is scheduled to be implemented in October.

ShouldKernCountyultimately prevail, LA still plans to find beneficial reuses for all its biosolids by calling upon contingency contracts like land application inArizonaand more composting inCaliforniaandArizona.

Another stink over biosolids erupted in 2009 inSan Franciscowhen “organic compost,” given away for free to the public by the Public Utilities Commission, tested positive for several endocrine-disrupting chemicals. The giveaway is now on temporary hold, and Food Rights Network, a nonprofit research group that oversaw the testing, has called for a permanent end to the program which it accuses of using home gardens as a dumping ground for the sewage waste industry.

The controversy over recycling biosolids on farmland and gardens has generally heated up following release in 2009 of an EPA survey in which biosolids from water treatment agencies in 35 states all tested positive for, at minimum, several flame retardants, heavy metals and pharmaceuticals.

The EPA report did not comment on the implications for the safety of applying biosolids to home gardens or lands used for crops or grazing. However, the Organic Consumers Association (OCA) has launched a campaign against all such practices, emphasizing that biosolids regulations cover only certain pathogens and heavy metals and neglect the wide spectrum of other chemical pollutants.

Hyperion’s biosolids undergo monthly testing which exceeds EPA requirements because more pathogens and more high priority pollutants, like dioxins, cyanide and pesticides, are covered. Furthermore, Diane Gilbert Jones, an environmental engineer representing LA’s Biosolids EMS, stated that there is no evidence that anyone has ever been harmed by LA’s biosolids and that the level of contaminants is lower than what people are exposed to through interaction with everyday consumer products.

Nevertheless, both the OCA and Food Rights Network object that there is no labeling requirement for compost derived from sewage sludge. They want the public to know that the term biosolids was coined in a 1991 contest orchestrated by the Water Environment Federation – an association of water quality professionals – to find a marketable euphemism for sewage sludge.

Adding to the debate, very little is known about the extent to which contaminants from biosolids might build up in soil over time or enter the food chain. Furthermore, articles recently appearing in the New York Times outlined concerns raised by federal regulators that radioactive waste from drilling for natural gas is turning up in wastewater and could end up on farmlands treated with biosolids.

The OCA urges consumers to look for foods labeled “USDA Organic” because, since 1998, organic standards have prohibited use of sewage sludge as fertilizer in food production.

The OCA and the Food Rights Network are among the more strident opponents of biosolids recycling programs who want all sewage sludge handled as toxic waste and contained for disposal, which could mean landfilling or incineration. Others have called for more nuanced approaches.

Congressman Jose Serrano ofNew York, for example, has recently introduced federal legislation to prohibit grazing or growing crops and animal feed for a full year on land spread with biosolids and to require any foods grown on such land be labeled as such (HR 254).

Whatever future tacks LA might take to improve on the sustainability and public acceptance of its biosolids program, homeowners, businesses and industry also must move beyond “out of sight out, out of mind” and give due attention to the toxicity of what is being flushed down drains and in whose backyard that waste ends up. LA’s ongoing “No Drugs Down the Drain” public education campaign is a positive step in this direction.

Perhaps a debate over the safety of recycling sewage waste is just the wakeup callAmericaneeds to force it to rethink the reckless approach to chemicals regulation which has allowed some 80,000 chemicals into commerce, most without any health or environmental safety testing, let alone plans for how to best handle the tainted sewage that inevitably results.

One Response to LA’s Sewage Sludge

  1. I agree that the public needs to be educated that out of sight and out of mind does not mean out of danger. We all have an unconscious belief that we can simply “flush it away.” The sooner we realize that there is no “away” — at least on this planet earth — the better off we will be and the sooner we will effectively address the problem of sewage disposal.

    While I applaud LA treatment plants’ seeming vigilance and creativity, it’s entirely too easy to fall into the “fluoride trap” of conveniently coming up with uses for an industrial byproduct and touting its supposed benefit even though we have subsequently learned of its unheralded health dangers.

    The sheer volume of sewage sludge is enough to make a person want to get wasted.

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