Abstract
Silica scaling of reverse osmosis (RO) membranes in water desalination poses a worldwide problematic issue in the cost-effective operations in seawater desalination plants. Underground water is one of the main water resources in the Kingdom of Saudi Arabia. Most of the inland cities and remote villages rely entirely on this supply mode for their domestic, industrial and agricultural purposes. However, this water resource is characterized by its relatively high silica contents. Therefore, pretreatment for silica removal from the RO feed is crucial in a system running on high silica waters. In this preliminary work, we investigated the effectiveness of advanced Fenton process ( using hydrogen peroxide and zero valent metal iron Fe-0 as source of Fe3+) for the silica pretreatment of water from the Buwaib deep aquifer by its co- precipitation with ferric hydroxide. The influences of several reaction parameters, i.e., iron powder dosage, hydrogen peroxide concentration, pH effect, were investigated. In the optimum conditions, up to 70% of silica was removed. This preliminary study showed that this environmentally friendly process is an effective silica mitigation strategy prior to the RO desalination.