Proving BioCord cold-weather nitrification under highly variable conditions

DATE POSTED: December 11, 2019

St Henry pilot

What happens when a BioCord™ pilot system experiences operating conditions that are much different than what was expected? Is the data still useful? Is the pilot project considered a success? 

These are some of the questions we asked ourselves after looking at the results from a BioCord pilot study performed under highly variable conditions. In the end, we learned that the data was very valuable and proved not only that BioCord can achieve nitrification at temperatures below 1°C, but it can do it under some pretty tough conditions. 

The BioCord pilot project was conducted at the wastewater treatment lagoons serving the small town of St. Henry, Ohio, USA. The village was facing serious operational challenges at its four-cell lagoon system, which treats municipal wastewater and effluent from a food processing plant. Despite adding aerators and a mixing unit, the plant was struggling to maintain sufficient ammonia removal during the winter months. 

With little space to expand the treatment plant, the community was also concerned about potentially complying with more stringent ammonia limits (1 mg/L) and handling increased hydraulic flows of up to 2x the plant’s rated capacity. 

St Henry pilot

A 1.4 m x 1.4 m x 1.4 m BioCord Reactor was used in the St Henry Pilot Project.

A BioCord pilot system was installed to test its ability to provide a scalable, low-energy, fixed-film technology that could upgrade lagoon performance and increase treatment capacity without expanding plant footprint. 

The BioCord pilot system was designed to handle influent ammonia concentrations of about 20-25 mg/L and BOD of 50 -75 mg/L, drawn from Cell 2 of the lagoon system. The pilot ran from September 2017 to May 2018. 

BioCord deals with unexpected conditions

But influent concentrations of ammonia and BOD often exceeded the design specifications, especially in the colder months – between November and February. Ammonia was often above 40 and BOD climbed as high as 300 mg/L at times. Our team was concerned that the BioCord system was undersized to handle the higher influent levels. 

Yet despite the higher than anticipated influent concentrations and undersized reactor, the BioCord system performed very well. Nitrification was achieved at temperatures as low as 0.5°C and BOD levels were also dramatically reduced. Based on the data and BioCord performance, the team concluded that additional BioCord reactors would have enabled the pilot system to handle the higher-than-expected loading rates and provide desired nitrification. 

St Henry BOD reductionsSt Henry BOD Reductions

Learn more about simple, low-energy BioCord Reactors for cold-weather ammonia and BOD removal.

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