Source of Giardia LambliaGiardia is a protozoan which can exist as a trophozoite, usually 9 to 21 .tm long, or as an ovoid cyst, approximately 10 um long and 6 um wide. Protozoans are unicellular and colorless organisms that lack a cell wall. When Giardia are ingested by humans, symptoms include diarrhea, fatigue, and cramps. The US EPA has a treatment technique in effect for Giardia.
Treatment of Giardia LambliaSlow sand filtration or a diatomaceous earth filter can remove up to 99 % of the cysts when proper pretreatment is utilized. Chemical, ultrafiltration, and reverse osmosis all effectively remove Giardia cysts. Ozone appears to be very effective against the cysts when utilized in the chemical oxidation - disinfection process instead of chlorine. The most economical and widely used method of removing Giardia is mechanical filtration. Because of the size of the parasite, it can easily be removed with precoat, solid block carbon, ceramic, pleated membrane, and spun wrapped filter cartridges.