Innovative Wastewater Treatment Processes

Abstract

This PhD thesis covers a range of research topics particularly in water and wastewater treatment, copper recovery from a mining company effluent, slime dewatering, drug synthesis, and a fire suppressing material. Pollution of drinking water by toxic heavy metal ions is a matter of concern worldwide. These pollutions may occur naturally or from industrial wastes. Surfactants have been used to remove organic and inorganic contaminants from water. After usage, the residual surfactants are discharged into surface waters or sewage systems. This can cause environmental pollution. In this work, a biodegradable surfactant was synthesised and used to treat contaminated water containing PFAS and heavy metal ions. Moreover, the effectiveness of the synthesised green surfactant was examined through recovery of copper ions presenting in the effluent produced by a mining company located in Australia. To achieve a better result, a pre-treatment phase was applied before the main ion flotation process. The term slime typically refers to a water-based colloidal dispersion that resists dewatering. Dewatering is a process in which water from the slime is separated from the dispersed solids to thicken up the waste for disposal or further processes. In this work, a novel method was developed and studied using a Bubble Column Evaporator (BCE). Based on this method, dewatering was undertaken in sub-boiling conditions using hot air and hot helium bubbling. The obtained results show that this is a promising method for dewatering slimes and using hot helium was found to be more efficient than using hot air. IV N-acetylcysteine is a drug which is used to treat paracetamol overdose. The molecular structure of this drug is similar to the molecular structure of the surfactant which was synthesised in this work for use in ion flotation. Therefore, synthesis of N-acetylcysteine was also studied with this synthesis method. Moreover, a new water-saving method is proposed to extinguish fires. This fire suppressant material, which is based on the use of a zeolite, can release large amounts of carbon dioxide when exposed to raised temperatures. This material can be used in roof cavities to protect properties against fires caused by, for example, electrical faults or ember attacks.