Innovations and Energy

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Zeolite-Anammox Pilot

In partnership with Calpine, the District will be embarking on a pilot test of a new ammonia removal treatment process known as Zeolite-Anammox (Ze-An). Ze-An combines the high affinity for zeolite, a porous rock, to adsorb ammonium, with the ability of the anammox bacteria to combine ammonium and nitrite to create nitrogen gas and regenerate the zeolite. Advantages of this process include reduced energy usage (nitrogen removal is normally a very energy intensive process), no chemical use requirements, and simplicity of operation. We will be testing the process on the District’s centrate as well as our secondary effluent. Each pilot will be housed in a trailer, so be on the lookout for two trailers appearing in the next month or so. One will be located at the southeast corner of the Cogen Building and the other will be on the west side of the Recycled Water MCC.


After a prolonged hiatus, the CANDO pilot will be starting operation again in March. After a successful bench-scale test in the lab during 2013, a pilot scale test was run during most of 2014, but replication of the bench-scale results were never fully achieved. As a refresher, the Coupled Aerobic-anoxic Nitrous Decomposition Operation, or CANDO, is a new treatment process that removes and recovers energy from ammonia nitrogen in sidestreams, specifically the centrate from sludge dewatering devices such as centrifuges. The goal of the pilot is to use lessons learned during the first run to achieve three months of stable operation so that we can gather enough data to evaluate the technology against other sidestream treatment processes.

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