ABSTRACT
ABSTRACT: This work was part of a project on technology partnership for innovative treatment of drinking and industrial water (INNOWA) dealing with innovative treatment of drinking and industrial water in Bangladesh and China. The aim of the project was amongst others to find out an appropriate, reliable, simple and cost-effective technology for removal of arsenic from ground water. Several million people world wide are exposed to high arsenic levels due to contaminated groundwater. In Bangladesh an estimated population of 35 million people-nearly one fourth of the population of the country is at risk. Hence cost-effective and viable arsenic removal techniques for drinking water are badly needed. Recently a new generation of energy efficient so called low pressure reverse osmosis (RO)membranes for brackish and tap water application has been emerged on the market. It is the purpose of this work to investigate the performance of these membranes on arsenic removal. All of the experiments were carried out on laboratory scale using local tap water spiked with As(III) and As(V), respectively. The membrane screening experiments were conducted depending on pH, temperature, pressure and concentration. As(V) rejection exceeds 95%, whereas As(III) rejection is only in the range of 60-80%. The permeate quality of the tested membranes can comply with the recommended Maximum Contaminant Level (MCL) of 10 μg/L up to feed concentration of 2000 μg/L for As(V) and 50 μg/L for As(V), respectively. In the examined pH range (5-9) and temperature range (15-30◦C) no considerable change of arsenic rejection has been found. Finally the experimental data have been analysed using the solution-diffusion model. This preliminary screening test provides a basis for subsequent experiments using technical modules.
34.1 INTRODUCTION
