The Delta as an Ecosystem Laboratory

Gurmukh Grewal testing Delta water for appropriate PH-water levels in treated wastewater discharge.

When you think of the average workday for a local chemist, you may imagine sterile laboratories, protective clothing and intricate laboratory equipment. However, don’t be surprised if the next time you are boating or fishing in the Delta you meet one of the chemists from the Delta Diablo Sanitation District (DDSD) going about their work safeguarding the environment where protection means a life vest and sunscreen.

DDSD is responsible for collecting and treating wastewater from all homes, businesses, industries in Antioch. After we flush a toilet, shower, run the dishwasher or do a load of laundry, our domestic waste begins a process of physical and biological treatments to remove bacteria’s, chemicals, and other harmful substances before being released back into the Delta.

It is the role of wastewater chemists to perform and or review the laboratory tests necessary to ensure that processed wastewater meets all standards set by the National Pollutant Discharge Elimination (NPDES) permit. The NPDES permit details all the federal and state government guidelines DDSD is required to achieve before treated wastewater can be discharged back into the Delta.

Meeting these regulations requires a range of tests and reporting which are required daily, monthly, quarterly or semi-annually. Failure to meet these guidelines can result in violations and large fines.

Gurmukh Grewal has been a chemist at DDSD since 1990. Recently awarded the Grade IV Laboratory Analyst certification, the highest qualification bestowed by the California Water Environment Association, he is responsible for collecting and processing samples of the wastewater during all stages of the process to ensure that DDSD is in full compliance with its NPDES permit.

Tests are undertaken to determine specific levels of pollutants such as ammonia, pesticides, metals and bacteria. Tests are undertaken at the Plant, but also in sections of the Delta which are only accessible by boat. Testing done on the Delta is to ensure treated wastewater discharge doesn’t have any negative impact on our local ecosystems.

According to Grewal, “Even after 21 years, every test I undertake is challenging to ensure we are fully protecting the Delta”.

Treating wastewater requires the commitment of highly skilled worked to continually meet the increasing stringent regulations. This past summer DDSD was awarded the National Association of Clean Water Agencies (NACWA), Platinum 7 Peak Performance Awards recognizing zero discharge violations over seven consecutive years. Achieved by only 1% of wastewater treatment operations nation-wide, this award acknowledges public wastewater treatment facilities for 100% operating compliance with its NPDES permit.


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Gurmukh Grewal Delta Testing 2011


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