Hi all,
A client approached us and wants a treatment solution for water contaminated with arsenic and nitrate. Kanchan Arsenic Filter removes arsenic but we wanted to do some research on Nitrate removal.
I found one study on BSF (Biosand Filter) knowledgebase, which says BSF removes nitrate- https://www.biosandfilters.info/research/dbe0985d/biological-denitrification-of-drinking-water-in-a-slow-sand-filter.
However, another study mentions that both nitrification and denitrification is happening inside a BSF - https://pubmed.ncbi.nlm.nih.gov/20705990/
Upon further research, I found the following analysis,
· Nitrification and denitrification occur in soils
· Nitrification and denitrification occur in BSFs
· Under very high ammonia loading, nitrites may increase beyond WHO limit in BSF
· Source water concentrations highly variable
· If there is a risk that source water is very high in ammonia, BSF may not be appropriate (but ceramic filters may have a similar problem…)
Literature says that activated carbon does not remove nitrates from water either.
Two types of systems that will remove nitrates from your water are: (https://www.epa.gov/sites/default/files/2017-12/documents/lower-yakima-valley-groundwater-faq-october-2012.pdf )
• Reverse Osmosis (RO) unit
• Distillation unit
RO units are not that affordable, requires energy, skills and funding to operate and maintain. Distillation is also not that common and consume energy as well.
HOWEVER, WHO emphasizes need for microbiologically safe drinking water and even within the nitrate/nitrite guidelines, emphasizes priority for microbiological quality.
I welcome comments from the experts in the group about the possible solutions to problem faced by our client with high levels of arsenic and nitrate.