Brown and Caldwell Home Page
Technical Papers RECENT PAPERS    ALL PAPERS      LOG IN

Brown and Caldwell engineers and scientists are technical and thought leaders in the environmental sector. Meet the people who have been advancing innovation for more than 70 years.
Author      Title/Abstract      

Have Your Cake and Pump It Too: Lessons learned from the San Diego Metro Biosolids Center Cake Pumping Operations
Author: Ken Fonda; Banko Rupik (City of San Diego Metropolitan Wastewater Department)
Date: 3/106
Residuals Conference 2006

The City of San Diego started operation of its new 175 dry ton per day biosolids processing facility, The Metro Biosolids Center (MBC) in 1997. This facility was designed to dewater and dispose of all the anaerobic ally digested wastewater solids produced from the Point Loma Wastewater Treatment Plant as well as solids digested on site received from satellite water reclamation plants in Northern San Diego. These facilities were designed to replace an air drying and belt press dewatering facility located in Mission Bay Park on Fiesta Island. Because odors had been a perceived problem at the Fiesta Island facilities, the new facility was designed to be a “Good Neighbor Facility” by conveying dewatered cake to the enclosed storage and truck load out facilities using dual piston high pressure cake pumps rather than open conveyors to minimize odor emissions. For the first several years of operation these pumps required more frequent maintenance than was expected. Therefore, operations and plant engineering staff sought to solve this problem by changing the control logic of the cake pumping system. After making these changes there was a noticeable increase in time between maintenance cycles that has significantly improved equipment reliability and reduced maintenance costs. This paper described how the system was originally designed to operate and the changes made to improve the process. This paper is a follow up to previous papers presented on startup experience of the centrifuge thickening and dewatering facilities. Additional information on the startup and initial operations can be found in “Startup Experience of the San Diego Metro Biosolids Center Centrifuge Dewatering Process”, Fonda, K. et. al., presented at the WEF Biosolids Specialty Conference, Austin, Texas, 2002.