Biosolids Management Program

When you flush or wash water down the drain, LA Sanitation & Environment (LASAN) cleans that water to protect public health, local rivers, and ocean beaches. During the wastewater treatment process, beneficial microorganisms break down organic matter into nutrient-rich solids called biosolids.  

Biosolids are not raw waste, garbage, or hazardous chemicals. Instead, they are a valuable, recycled resource rich in essential plant nutrients like nitrogen and phosphorus. We are committed to 100% beneficial reuse of our biosolids, processing over 250,000 tons annually without sending any material to landfills. Our two main solids treatment facilities, the Hyperion Water Reclamation Plant (HWRP) and the Terminal Island Water Reclamation Plant (TIWRP), produce Exceptional Quality (EQ) Class A biosolids that meet the highest environmental safety standards set by the U.S. Environmental Protection Agency (US EPA). 

Recycling nutrients back into the soil improves land health and supports sustainable farming. Through land application, we use biosolids as an organic soil conditioner and fertilizer on agricultural lands.  

Applying biosolids restores organic matter to the soil, improves moisture retention, and reduces reliance on synthetic chemical fertilizers. At sites like Green Acres Farm, biosolids nourish non-food crops such as alfalfa, wheat, corn, milo, and Sudan grass which are harvested as feed for local dairies, the Los Angeles Police Department (LAPD) Mounted Platoon Stables, and the Los Angeles Zoo in Griffith Park.

Composting converts organic materials into rich, dark soil amendments that boost plant growth. At the Griffith Park Compost Facility, biosolids from the Hyperion Water Reclamation Plant are blended with green materials and naturally decomposed into high-grade compost.  

This nutrient-rich compost is used on City-owned property and supplied to local landscape companies, nourishing Los Angeles parks while supporting a circular local economy. To guarantee public safety, compost samples are routinely tested at our Environmental Monitoring Division laboratories in Playa Del Rey to verify that the final product is free of harmful pathogens.

In addition to farming and composting, LASAN turns organic wastewater solids into clean, green power.  

At our Terminal Island Water Reclamation Plant (TIWRP), we operate the Terminal Island Renewable Energy (TIRE) project, which is the first deep-well injection facility of its kind in the nation. Operating under a US EPA Underground Injection Control permit, TIRE places bio-slurry 5,300 feet underground into depleted geological formations. The earth's natural heat breaks down the organic material to produce renewable methane gas for energy, while permanently sequestering carbon dioxide ($CO_2$) deep subsurface.

Protecting public health and natural ecosystems guides every decision in our biosolids management program. Our operations strictly adhere to federal, state, and regional regulations, including the US EPA Part 503 Rule, California General Orders, and regional air and water quality control rules.  

To ensure complete transparency and operational quality, LASAN maintains a Biosolids Environmental Management System (EMS). Certified at the Platinum level (the highest honor awarded by the National Biosolids Partnership) our management system and contractor operations undergo regular independent third-party audits to verify environmental performance, safety, and continuous improvement.