AWWA WQTC58902

Arsenic naturally occurs in more than 200 minerals of the earth's crust. Its dissolution in water resources essentially depends on pH and on oxidation-reduction potential. Over the world, the greatest number of humans exposed to high arsenic concentration in groundwater is mainly located in Bangladesh, India and Taiwan. Recent epidemiological studies on these populations have shown that daily ingestion of water with high arsenic content could lead to specific diseases like skin loss of pigmentation, keratosis, skin cancer or cancers of internal organs as lung, liver or bladder. Following these studies, the last US and European regulations decreased the acceptable limit of arsenic in drinking water from 50 to 10 ug/L. Consequently, improvement of existing treatment processes and evaluation of new technologies are needed to comply with the regulation on arsenic. Several efficient treatments are available. The best treatment choice for one site mainly depends on the following conditions: arsenic chemical state in relation with pH and oxidation-reduction potential values in the resource; presence of other pollutants to be removed (iron, manganese, hardness, etc.); implementation of an arsenic removal process in already existing treatment plant; and, design of a full scale treatment on a new site. Includes 15 references, tables.