HomeMy WebLinkAbout2020-02-20; Exceedance of Sodium Limits at the Carlsbad Water Recycling Facility; Gomez, PazTo the members of the:
-~ PTY COUNCIL
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Feb.20,2020
Council Memorandum
To: Honorable Mayor Hall and Members of the City Council
From: Paz Gomez, Deputy City Manager, Public Works
Vicki Quiram, Utilities Director q
Via: Elaine Lu key, Chief Operations Officer ~
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Carlsbad
Memo ID# 2020015
Re: Exceedance of Sodium Limits at the Carlsbad Water Recycling Facility
This memorandum provides updated information related to an exceedance of the sodium limit
at the Carlsbad Recycled Water Facility (CWRF), which was previously provided to City Council
on Jan . 30, 2020, in Memo ID #2020009.
Background
As per the agreement between Encina Wastewater Authority (EWA) and the City of Carlsbad,
EWA staff notified city staff that the 60% sodium limit for calen~ar year 2019 has been
exceeded at the CWRF. The 60% sodium annual limitation is based on a percentage of dissolved
cations.
Discussion
The water is still safe to serve to recycled water customers. Specialty plants can be sensitive to
higher sodium water. However, the exceedances are very small, 1-2%, and there have been no
complaints. Because of the violation, the current quarterly monitoring frequency will increase
to monthly until compliance is achieved for three consecutive months.
The San Diego Regional Water Quality Control Board (SDRWQCB) has been notified. EWA and
city staff are investigating the cause. In discussing this issue with a water quality expert, staff
has been informed that it is likely that the desalination plant's water could be the cause. The
desalination plant decreases hardness in the water, i.e., calcium and magnesium, which results
in an increase in the percent of sodium.
Next Steps
Staff will be working with EWA, the water quality expert and the SDRWQCB on an action plan
should we not receive three consecutive months under the sodium limit. In the meantime, the
city could receive a letter of non-compliance from the SDRWQCB. However, according to the
water quality expert, it is unlikely that the city will receive a fine since the cause of the problem
is the source water. Staff will keep City Council informed as we move forward and complete the
action plan.
Public Works Branch
Utilities Department
Carlsbad Municipal Water District 5950 El Camino Real I Carlsbad, CA 92008 I 760-438-2722
'· , "Honorable Mayor Hall and Members of the City Council
Feb.20,2020
Page 2
cc: Scott Chadwick, City Manager
Celia Brewer, City Attorney
Laura Rocha, Deputy City Manager, Administrative Services
Cindie McMahon, Assistant City Attorney