Sanitation Districts of Los Angeles County and Kennedy/Jenks Consultants

Primary Filtration (PF) using a pile cloth-depth filter (PCDF) is an emerging treatment process that may provide significant benefits to the wastewater treatment industry. Rather than using a primary clarifier, a PCDF is used after screening and grit removal prior to the activated sludge process. To evaluate this technology as a potential option for replacement of the existing primary clarifiers at the Lancaster Water Reclamation Plant (WRP), a one year pilot-scale study was conducted. During the study, over ten million gallons of screened and de-gritted raw sewage was treated without any significant operational or maintenance issues. The results from this study demonstrate some of the key reported benefits of PF including enhanced removal of particulates and organics and a related reduction in activated sludge process aeration energy requirements, as well as the potential for increased digester gas production if implemented full-scale.