Development of household arsenic removal system using local adsorbent

Abstract

The arsenic contamination in the groundwater in Cambodia is a problem for rural people since they are st ill drinking the arsenic contaminated water from their tube well s during the dry season when the rainwater is used up. The village scale arsenic water treatment systems in Cambodia were sustainable in schools but not applicable in villages due to the lack of system of distribution of treated water to each household. Thus, we developed the household arsenic water treatment system by combining the bio- sand filter with the local arsenic adsorbent. Nine filters were tested in three location s using 1 Kg of adsorbent for each filter, where the concentrations of arsenic in the groundwater sources are ranging between 600 - 800 ppb. The kinetics of bio-sand filters and combined bio-sand and adsorbent filters were studied for six months. The filters removed the arsenic from 95 to 99% which provided the treated water with the arsenic concentration conformed to the Cambodian standard for drinking water « 50 ppb) for the period of six months corresponding to a volume of treated water of 7,000 L. The filters removed also iron, manganese, phosphate and turbidity 99.5, 60, 85 and 99% respectively. The filters also removed total plate count, coliforms and . E. coli with efficiency of 98, 100 and 100% respectively. For a long term arsenic treatment, the system should consist of a combined bio-sand and 10 Kg of adsorbent for the material cost of USD 18.With this set-up, the filter could provide treated water of about 70,000 L for the period of several years.