2024 BACWA Report Summarizes Bay Area Biosolids Trends

Written By John Almazan

Image Source: BACWA 2024 Biosolids Trends Survey Report

In September 2024, the Bay Area Clean Water Agencies (BACWA) published the 2024 Biosolids Trends Survey Report summarizing the biosolids treatment, disposal, and beneficial use survey results collected from 32 Bay Area wastewater agencies. The survey covers the time period of 2021 to 2023. The BACWA Biosolids Trends survey is conducted every few years, with the previous survey conducted in 2021. The purpose of the surveys is to collect specific Bay Area biosolids information and track industry trends on the following topics:

  • Biosolids production volumes.

  • Treatment and dewatering technologies.

  • End use and disposal options.

  • Biosolids management technologies and destinations.

  • Hauling and tipping costs.

  • Agency challenges.

  • Strategies for SB 1383 compliance.

  • Public outreach.

The 2024 report summarizes survey responses from 31 agencies, representing more than 95 percent of the total flow of BACWA member agencies, plus the City of Santa Rosa which is not a BACWA member. The report notes the following trends compared to previous surveys:

  • Treatment: The majority of Bay Area facilities treat biosolids using mesophilic and/or thermophilic digestion. Compared to the previous survey, an increasing number of agencies sent their biosolids to another facility for additional treatment, such as composting or thermal hydrolysis.

  • Changes in Landfill Practices: Since BACWA’s first biosolids survey in 2015, most agencies have stopped sending biosolids to landfills for use as Alternative Daily Cover (ADC). This change likely reflects efforts to divert organics from landfills to reduce methane emissions per SB 1383. Despite the reduction in the number of agencies that use landfill ADC to manage their biosolids, 57% of the Bay Area survey respondents’ total biosolids were sent to landfills for disposal or use as ADC in 2023.

  • Cost Increases: Between 2020 and 2023, region-wide total hauling and tipping costs for biosolids increased by more than 50%. This likely reflects increased unit costs for hauling and end use management, as well as changes in biosolids practices at each individual agency, such as hauling biosolids further or providing additional treatment.

  • Planned changes: Some agencies are planning additional changes to their biosolids management practices, such as major dewatering and treatment projects. Also, agencies are planning projects to accept diverted organic waste for co-digestion, improve onsite biosolids treatment, and send more biosolids offsite for additional treatment.

More detailed information can be found in the 2024 Biosolids Trends Survey Results posted on the BACWA website.

2024 Biosolids Trends Survey Results : https://bacwa.org/wp-content/uploads/2024/09/BACWA-2024-Biosolids-Trends-Survey-Report-2024-09-10.pdf

BACWA website – biosolids page: https://bacwa.org/committees/biosolids/

John Almazan
Next

Biosolids PFAS Resources