Adsorptive removal of manganese, arsenic and iron from groundwater

Abstract

To determine the scale of the problem of arsenic, iron and manganese contamination of groundwater in Ghana a survey was performed in the first phase of the research to provide in depth information with respect to these contaminants. Presence of these mentioned contaminants in groundwater is not peculiar to Ghana alone. Many countries in the world have similar problems with their groundwater. Establishing the existence of the problem also calls for the need to find remedies. Over the years much studies have been done in the Unesco-ihe on the adsorptive mechanisms and techniques for iron and arsenic removal from groundwater. Therefore in this study much emphasis is placed on the adsorptive removal of manganese from groundwater. This research has the following as it objectives: 1. The conduction of a survey for the arsenic, iron and manganese content in selected groundwater aquifers in Ghana. 2. Determination of the arsenic, manganese and iron adsorption capacities of different locally available filter media. 3. Determination of the effect of pH on adsorption capacities of the selected media for arsenic, manganese and iron. To determine the effect of iron (II), manganese (II) presence on arsenic adsorption capacity of selected media – (competition). 4. Studies on the rate of oxidation of Fe (II) and Mn (II) adsorbed onto one or more selected media under different conditions (e.g. dissolved oxygen, pH etc.). 5. Determination of the rate of adsorption of Mn (II) onto one or more selected media under different oxic conditions. 6. To develop a conceptual model that describes the processes involved in adsorptive arsenic, manganese and iron removal. To investigate to what extent these processes can be described in a quantitative way with one or more mathematical models . Generally the study has the following relevance: 1. Provide a base line data on the arsenic and manganese content of selected groundwater aquifers in Ghana. 2. Provide information on the adsorption capacities of locally available filter media for manganese. 3. Contribute to the knowledge on the kinetics and mechanisms of catalytic adsorptive iron, manganese removal. 4. Provide an efficient backwashing procedure for regeneration of adsorptive sites in iron-oxide coated filters operating in the oxidative adsorption mode