GrokSurf's San Diego

Local observations on water, environment, technology, law & politics

Posts Tagged ‘Wastewater treatment’

Ecologically integrated water management: the Da Vinci challenge

Posted by George J Janczyn on March 21, 2011

(Norman Allenby wrote this guest column)

Leonardo Da Vinci had a relevant thought on this subject. His Ideal City postulate #6 states, “ Require that each house have its own sewerage system and be built on aesthetic and environmental principles with access at ground level.” The Da Vinci challenge is to design such a system, not just for homes, but buildings, subdivisions, shopping centers and micro watersheds that comprise greater San Diego. Homes, buildings, subdivisions, shopping centers are all parts of our urban water shed. They each take in water and give back wastewater. With each having its “own sewerage system,” the Da Vinci challenge would be met and the opportunity for onsite recycling created.

Under our present integrated water management system there is insufficient recognition of the potential for on site reuse of water. We have done a great job in corralling water from Imperial County to augment waters received from the Metropolitan Water District. We largely ignore storm water allowing it to contaminate our beaches. We discharge 180 MGD of wastewater into the Pacific Ocean at our Point Loma treatment facility. We continue to delay the intended use of the North County reclamation plant’s reclaimed water, augmenting San Vicente reservoir. We do distribute a modest amount of reclaimed water for irrigation through our purple pipe system, but our wastewater is largely wasted. That waste can be avoided through an ecological approach to water management.

Ecologically integrated water management utilizes process water, storm water and “waste water”. It first calculates how much water a facility needs, how much storm water is site available and how much “waste water” is site available. Any deficit between site available water and needs is met by process water purchased from the local provider. The focus of ecological water management is conservation and reuse and, yes, more reuse.

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San Diego ocean monitoring program to be renewed

Posted by George J Janczyn on May 18, 2010

San Diego’s waiver from having to provide secondary treatment of its wastewater at the Point Loma Wastewater Treatment Plant and the South Bay Water Reclamation Plant requires that an Ocean Monitoring Program be conducted. The monitoring program has been underway for years now. That program is now to be renewed and expanded.

The San Diego City Council votes today to adopt an ordinance approving a phase-funded Second Amendment to the Agreement with the University of California, San Diego for the Evaluation of San Diego’s Coastal Ecosystem for an amount not to exceed $1,499,721, and to authorize an FY 2010 expenditure of $344,516 from Wastewater Fund 700001 for Phase 5 of the aforementioned Amendment (council docket item 51:

Excerpt from the executive summary:

“Continued monitoring and protection of the coastal marine environment are the main objectives of the City’s Ocean Monitoring Program…Under this Second Amendment, Scripps Institution of Oceanography (SIO) will conduct studies monitoring the status of the San Diego region’s kelp forests as part of the City’s enhanced ocean monitoring requirements for the PLWTP and SBWRP. Specifically, SIO scientists will continue long-term monitoring studies to define the impacts or potential impacts of treated wastewater discharge on the health and stability of the local kelp forest ecosystem off Point Loma, La Jolla and in North County relative to other environmental parameters.”


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Council adopts resolution for upgrade at Point Loma Wastewater Treatment Plant

Posted by George J Janczyn on May 11, 2010

Grit processing equipment at the Point Loma plant

The San Diego City Council adopted a resolution at today’s (Tuesday) meeting approving the plans and specifications for the construction of the Point Loma Wastewater Treatment Plant Grit Processing Improvements Project (Project).

Quoting from the project description from the council docket:

The Grit Processing Improvements Project (GIP) is located at the existing Point Loma Wastewater Treatment Plant (PLWTP). Presently, the PLWTP has six aerated grit basins constructed between 1962 and 1988. The south grit tanks were part of the original PLWTP construction. The central and north pair of grit tanks was added in 1983 and 1988, respectively. This project will reconstruct the south grit tanks and its adjacent pump gallery; replace the head works building with a drive through facility and new grit processing equipment. It also includes an interim grit processing facility to allow processing to continue during construction.

Adequacy of the grit removal is a major issue because of the wear and tear the material causes on the downstream equipment and the decrease in treatment capacity and efficiency. It is estimated that PLWTP spends $1,000,000 a year on grit removal from plant digesters. The material also affects the operations, maintenance and performance of the Metro Bio-solids Center.

The total estimated cost of this project is $33,453,006.75. Project cost may be reimbursed approximately 80% with current or future debt financing. The project is scheduled to be funded in four phases Fiscal Year 2011 thru Fiscal Year 2014.

Click here for full supporting materials for the project.


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