Filter backwash water (FBW) is a prominent residue from water treatment plants (WTPs) that is often disposed into water bodies or recycled within the WTP without due disinfection. FBW usually contains particles within a size range that includes pathogenic protozoa. as the infective forms of Giardia and Cryptosporidium. parasites responsible for waterborne diseases outbreaks. https://www.freaknleather.com/product-category/flint-lighter/