Direct use of agricultural bio-waste in water treatment

Abstract: The existence and maintenance of life are associated with the use of water. Water is used by all beings every day to meet their metabolic needs, as well as in various agricultural and industrial activities. Globally, there is growing concern about the low water quality that is available to consumers. In underdeveloped or developing countries, the lack of adequate treatments means that water of dubious quality is available to consumers [1]. This work presents some preliminary results on the direct use of untreated biomasses from agricultural activities as adsorbents for water treatment. The efficacy of agricultural wastes, such as stubble, sawdust from teak (Tectona grandis), fibres from Imbondeiro (Adansonia digitata L.), bamboo flowers, and other regional plants was tested using Methylene Blue (MB) removal from the aqueous phase. Adsorption studies were conducted in a batch system and the influence of solution pH, MB initial concentration, adsorbent granulometry, contact time and temperature was evaluated. The adsorption performance of the natural adsorbents was significantly high, and Imbondeiro presented a maximum removal capacity of 188.3 mg of MB per gram [2]. This amount is higher than published values obtained on diverse activated carbons considered excellent adsorbents for this purpose. Imbondeiro exists in rural areas of some poor countries. The possibility of using these natural adsorbents in the treatment of water before it is consumed is of particular importance. This study was finished by constructing filters containing natural adsorbents. The maximum amounts of MB removed on a continuous flux were lower than those obtained on a batch system. However, these quantities were in line with other results that have been published and were obtained in batch mode from a variety of untreated biomasses.

[1] Water Supply Overview (worldbank.org) (consulted on 14-02-2024)