Rehabilitation of a Classic Trickling Filter Secondary Treatment Plant to Meet Current NPDES Permit Requirements

The Camuy Regional Wastewater Treatment Plant (CRWWTP) is a 0.13 m3/s (3.02 MGD) Secondary treatment facility owned and operated by the Puerto Rico Aqueduct and Sewer Authority (PRASA). The core treatment process is composed of two separate treatment trains, each with a dedicated primary clarifier, two-stage trickling filter with intermediate clarifier, and final clarifier. The facility was not in compliance its final NPDES permit limits. As part of a Consent Decree with regulatory agencies, a capital improvement rehabilitation project and a compliance evaluation were undertaken to improve performance and assess options for compliance. The capital improvement rehabilitation project was completed successfully. All noncompliant parameters were identified and both short-term immediate actions and long-term capital improvement options for compliance were identified. Upon completion of the capital rehabilitation project and implementation of selected operational improvements, plant effluent was brought into compliance with secondary effluent limits. Compliance with all other noncompliant parameters will be addressed through modification of the NPDES permit to include a marine discharge mixing zone.