The Shapla filter is an earthen household arsenic removal technology developed by International Development Enterprises (IDE), Bangladesh. It is based on adsorption (adhesion or sticking together) of the arsenic to the iron on the coated brick chips, which works as well as iron coated sand. The bricks are coated by treatment with a ferrous sulphate solution (Ahmed, 2005). The filter can hold up to 30 litres of water. As water passes through the filter, arsenic from the water is rapidly adsorbed by the iron on the brick chips. The media (20 kg) filters 4,000 litres of arsenic-contaminated water reducing arsenic concentrations to undetectable levels and supplying an average family with 25-32 litres of safe drinking water per day.
'''Coagulation-Flocculation: Bucket Treatment Unit (BTU) and 2-Kolshi Filterfilter'''<br>
The Bucket Treatment Unit has been developed within the DPHE-Danida project. It consists of oxidation (loss of electrons of As(III) to form As(V)) and coagulation (clumping of particles to promote sedimentation) processes using potassium permanganate and aluminum sulphate respectively. The water is then filtered through cloth into a second bucket that contains a sand filter. The BTU can be constructed from locally available materials.
'''Surface complexation: Sono Filterfilter'''<br>
The Sono Filter is a three bucket system with a composite iron matrix (CIM) as the active arsenic removal component. It creates surface complexation of arsenic on the CIM followed by a filtration. The filter is manufactured from indigenous materials and it works without chemical treatment, without regeneration, and without producing toxic waste. It is efficient to remove arsenic and 22 other heavy metals as well as bacteria.
'''Kanchan Arsenic Filterfilter'''<br>
The Kanchan Arsenic Filter (KAF) is an adaptation of the biosand filter. The KAF has been designed to remove arsenic from drinking water, in addition to providing microbiological water treatment. Arsenic removal is achieved by incorporating a layer of rusty nails in the diffuser basin of the filter.
==Construction, operations and maintenance==
'''Adsorption: Magc-Alcan filter'''<br>
* Place two buckets (with taps) filled with activated alumina media in series using a stand.