EOSi’s MicroC® products and services can help landfill operators remove ammonia and other nitrogen compounds from leachate. MicroC® supports the microbial populations needed for biological nitrogen removal (BNR), which converts the nitrogen compounds into harmless nitrogen gas.


Leachate from municipal solid waste landfills is a complex, high-strength wastewater. Leachate typically has high concentrations of organic compounds, ammonia and other forms of nitrogen, metals, and dissolved solids. The composition of leachate changes markedly over the lifetime of a landfill. Materials in younger landfills have not yet been extensively biodegraded, so the leachate still contains higher concentrations of readily biodegradable organic compounds and lower concentrations of ammonia. As the landfill ages and biodegradation proceeds, the concentration of biodegradable organic compounds decreases and the concentration of ammonia increases.

Leachate has traditionally been discharged to POTWs for processing. However, as discharge standards for POTWs have become stricter, particularly for nitrogen, it’s become more common for POTWs to require onsite pretreatment of the leachate. Alternatively, some landfills fully treat the leachate onsite prior to discharging it to the environment.

Biological treatment is a proven technology for removing organic compounds and ammonia from leachate. Biological treatment is often more cost-effective than physical or chemical treatment technologies, and has the advantage of breaking down the contaminants into harmless components.

For leachate, a typical biological treatment system would have an aerobic zone followed by an anoxic zone. Microbes in the aerobic zone degrade organic compounds into carbon dioxide and water, and oxidize ammonia and ammonium into nitrite and nitrate in a process called nitrification. Microbes in the anoxic zone then convert the nitrite and nitrate into water, nitrogen gas and carbon dioxide in a process called denitrification.

How EOSi can help

MicroC®  helps establish and maintain the healthy biomass needed for BNR. Leachate from older landfills may not have enough biodegradable organic compounds to support the biomass needed for nitrification in the aerobic zone. And regardless of the age of the landfill, denitrification in the anoxic zone occurs after the aerobic bacteria have already oxidized any biodegradable organic compounds. In both cases, the biomass will need a supplemental carbon source such as MicroC® that provides readily-available food and energy. MicroC® can be custom blended to provide other essential microbial nutrients, such as phosphorus, that may not be present in sufficient quantities in the leachate.

EOSi’s services help landfill operators design and implement MicroC® programs. EOSi offers optimization services, bench-scale treatability studies, modeling and simulations, and equipment selection and procurement for supplemental carbon programs. EOSi also delivers solutions through our Objective Based Programs such as ongoing technical and application support, remote process monitoring, troubleshooting and optimization programs to our MicroC® customers. For landfills, EOSi refines the MicroC® program as needed as the leachate characteristics change over time.