This research explores the potential effect of Subsurface Iron removal (SIR) on the removal of organic micropollutants (OMPs). The presence of OMPs and their transformation products in the water environments globally, have raised concerns due to the potential environmental and human health risks they are posing. Recent technologies often fail to remove OMPs completely or require high energy levels and costs. Previous findings by Vitens water company have indicated that SIR application resulted in the attenuation of certain OMPs. Therefore, the effect of SIR as an alternative, cost-effective removal method of OMPs was investigated.

A continuous flow column experiment was conducted in order to simulate the processes which take place under oxic conditions at SIR for the removal of 5 targeted OMPs (bentazone, metformin, caffeine, carbamazepine and atrazine). Two columns were filled with iron oxides (FeOx) coated sand and manganese oxides (MnOx) coated sand respectively, in order to simulate the two precipitation zones created in the subsurface. The aim of the study was to investigate the removal efficiencies of the selected OMPs in both columns in order to understand if the SIR environment is favourable for the
removal of OMPs.

Results indicated that for most compounds there was removal observed after 65 pore volumes of continuous flow. Metformin was hardly removed (<10% removal rate) in both materials. A higher removal efficiency was observed at the FeOx column for bentazone (65%), caffeine (54%) and carbamazepine (29%), while atrazine was the only compound which had a greater affinity for MnOx, with a removal rate of 87%.

These findings suggest that SIR has a potential on the removal of certain OMPs. It is suggested that during SIR the OMPs existing in the subsurface, pass through the two precipitation zones and undergo removal processes within both zones. However, based on their respective affinities to each of these zones, their removal extents vary accordingly. Ultimately, the water extracted from the undergoing SIR exhibits a reduced concentration of OMPs, which is a result of the combined removal mechanisms operating within both precipitation zones.

Globally, drinking water sources are polluted with poly- and perfluoroalkyl substances (PFAS). The toxicity and persistent properties of these industrial chemicals raised concerns about environmental and public health. As a result, drinking water companies are removing PFAS from drinking water using separation technologies. Anion exchange and nanofiltration membranes have been proven to be effective drinking water treatment methods for the removal of PFAS. However, these drinking water technologies produce large volumes of PFAS-containing waste streams, which poses new challenges for the drinking water industry. To prevent toxic PFAS from re-entering the environment, these waste streams must be treated. This can be done by PFAS destruction, however, due to the large volumes of the waste streams, this is very expensive and energy-intensive. Therefore, concentrating the drinking water waste streams before destruction is desired. This research examined existing PFAS-concentration technologies and compared their PFAS removal efficiency, volume reduction, and cost-effectiveness in concentrating the PFAS waste streams produced during drinking water treatment. These waste streams include the concentrate of nanofiltration and the brine from anion exchange. The analysed concentration technologies are foam fractionation, adsorption of PFAS onto DEXSORB+ and all-silica BEA zeolites, and nanofiltration.
Foam fractionation removes PFAS from the waste stream by injecting air bubbles. Two laboratory setups were made for the injection mechanism of the air bubbles. First, by passing pressurized air through an air stone, and second, by adding pressurized water (i.e. white water) to the waste stream. The adsorbents were tested in the laboratory by conducting equilibrium batch experiments with different adsorbent dosages. The laboratory experiments were performed on both drinking water waste streams. The performance of concentrating the anion exchange brine solution with nanofiltration membranes was evaluated with the use of IMS Design models.

Over the last decade, a wide range of organic micropollutants (OMP) has been regularly detected in surface water, groundwater and wastewater treatment plant (WWTP) effluent. These OMPs consist mainly of synthetic organic compounds (SOC) such as pharmaceuticals and pesticides. Although their concentrations in water bodies are usually low, they can cause potential risks to disturbance and affect human as well as environmental health, which has attracted the attention of governments and institutions to search for reliable and simple methods with low cost to remove them. Powdered activated carbon (PAC) adsorption is considered to be an efficient, convenient and cheap method to remove OMPs with low concentrations. However, the adsorption capacity of PAC is not fully used due to a short contact time in the traditional adsorption treatment of dosing PAC into water directly. Therefore, some processes such as the Actiflo Carb or PAC membrane reactors, recirculate PAC in order to increase the contact time. Predicting the performance of older, recirculated PAC is difficult. The objective of this project was to simulate performance of aged PAC using a simple lab-scale experiment. Three different water matrices (tap water, WWTP effluent and diluted WWTP effluent) were used to make the OMPs solutions with 18 selected OMPs of 10 ug/L. PAC was added into the OMPs solutions to make two concentrations of PAC suspension (0.5 g/L and 0.25 g/L). Samples were collected at fixed time intervals. The breakthrough behavior of selected OMPs for aged PAC was then investigated and determined by analyzing the OMPs concentration, UV254 and DOC of samples. The setup was successfully used to record breakthrough curves of 5 different OMPs (Gabapentin, Sulfadimethoxine, Sulfamethoxazole, Metformin and Clofibric acid) and UV254 in 3 different water matrices. Gabapentin was the least adsorbable in tap water and the breakthrough occurred after 10 hours, while in WWTP effluent, Sulfadimethoxine was the least adsorbable OMP with the complete breakthrough time of 14 hours. Propranolol was the most adsorbable compound in both tap water and WWTP effluent. The breakthrough of UV254 was observed later in tap water and WWTP effluent, about 24 hours and 22 hours, respectively. However, parameter DOC can not be used to predicate the breakthrough of OMPs accurately. Model fitting based on the experimental adsorption data was also included.