Organic micropollutants (OMPs) originate from organic chemicals such as drugs and pesticides that are widely used in human activities. OMPs are difficult to remove by conventional water treatment techniques, and hence continue to accumulate in natural water bodies. More effective methods need to be investigated for the removal of OMPs in drinking water treatment because of their toxicity and carcinogenicity, which may pose potential risks to human health. Previous studies have suggested that the use of activated peroxymonosulfate (PMS) catalyzed by Palladium (Pd) immobilized in ultrafiltration (UF) membranes can effectively degrade 1,4-dioxane and p-nitrophenol, while its removal efficiency for other OMPs, limiting factors and reaction mechanism still require for more research. In this study, PMS-Pd/UF system was established by coating Pd on the surface and 20 nm pores of the ultrafiltration membrane. The effectiveness of PMS-Pd/UF in the removal of OMPs from ultrapure water under various flux, pH, PMS dosages and ions presence was examined, as well as the performance in other water matrices including simulated brackish water, simulated brine water and river water. The results showed that PMS-Pd/UF achieved more than 95% of OMPs removal in 1 and 12-hour filtration tests at a flux of 30 LMH, while removal efficiency decreased with the increased flux due to the reduced contact time. The pH tests indicated that the system was more efficient under a neutral pH environment. The presence of 1 mM of various ions (Cl⁻, HCO3⁻, SO₄²⁻, and ClO⁻) had limited effects on the degradation of OMPs. However, the removal of OMPs was inhibited when OMPs coexisted with NOM in river water and, in combination with high salt concentrations simulated brine water (e.g., with 250mM of total anions). From specific scavenger dosing experiments, it was concluded that SO₄^•–, ^•OH, and O₂^•– were the main reactive species induced from Pd/UF-activated PMS for the removal of OMPs.

Reusing water is a crucial part of the solution for addressing the growing concern regarding the risk of water scarcity in industrialized and urbanized areas. This study introduces a tool for the design of water networks, focusing on water reuse in industrial parks. Utilizing a mixed-integer nonlinear programming (MINLP) model developed earlier, this tool is the first in water network design models that operates with open-source software, while considering water treatment systems and multiple constituents. A literature study is conducted to discover shortcomings in water network design models and to find a foundational model to use to develop the tool. The developed tool creates a water network based on the optimization of the costs of water obtained from water sources, the costs of treatment systems, and optionally the piping costs. The treatment systems are used to regenerate the water for reuse in industrial plants and to meet environmental discharge limits. The tool develops local optimal solutions as an output. Additionally, this study is the first to integrate a water treatment systems database into a water network design model. However, this database needs to be expanded before it is usable. This study demonstrates the tool through three case studies.

Membrane technology is widely used as an effective water treatment or pretreatment technology, especially in the filtration of oil-in-water (O/W) emulsions. Ceramic membranes have shown excellent performance in this regard. However, due to the complex composition of real wastewater, laboratory studies are limited to the filtration of simulated O/W emulsions, and there is little research on the favorable conditions for filtering real wastewater. Additionally, since actual devices operate as constant flux units, previous studies have been conducted under constant pressure conditions, thus further understanding of the effect of membrane pore size on constant flow membrane filtration is required to better understand the situation in real plant applications.

Ceramic ultrafiltration is a promising technology for water reclamation, but issues with membrane fouling and the removal of organic micro-pollutants have limited its development. Recent research has shown that catalysis-based ultrafiltration has the potential to address these problems. In this study, catalysis-modified (CuFe2O4 and Pd) ultrafiltration was investigated for fouling mitigation and organic micro-pollutant removal.

The membranes were successfully synthesized and it was found that using Fenton oxidation (a combination of CuFe2O4 membrane with H2O2 backwash) had a 93.9% higher cleaning efficiency than applying demi-water. Besides, it was found that the backwash flux and backwash time were crucial in determining the cleaning efficiency of Fenton oxidation, with a smaller backwash flux or longer backwash time resulting in better permeability recovery.

However, the application of Fenton oxidation was also found to be limited by the instability of the CuFe2O4 catalyst in acidic environment, and the problem of catalyst leaching led to a decrease in cleaning efficiency. Additionally, it was discovered that using PMS oxidation was more effective for OMPs removal compared to Fenton oxidation, with a removal efficiency of up to
90%. Overall, this work demonstrated the potential of catalyst-coated ultrafiltration for water treatment and highlighted the benefits of combining membrane filtration with advanced oxidation processes.

With the development of industry, there is an increasing focus on environmental issues, while organic micro-pollutants (OMPs) have garnered significant attention as emerging contaminants in water. Due to the low concentration and small size, OMPs pose a challenge to retain in traditional low-pressure membrane filtration systems. Prior researches found that membrane coupled advance oxidation processes (AOPs) could effectively degrade OMPs. However, membrane fouling caused by natural organic matter still remains an issue. In this study, the feasibility of simultaneous OMPs removal and fouling mitigation was validated in such a membrane coupled AOPs system, where the peroxymonosulfate (PMS) worked as the oxidants and palladium was immobilized on the ceramic ultrafiltration membrane surface to activate the PMS. In a continuous four-cycle experiment, the Pd-coated membrane maintained over 60% removal for 4 OMPs and improved the hydraulic clean efficiency significantly. Furthermore, the factors related to experimental conditions were also explored. The research
found that OMP removal rates were reduced by fouling due to the competitive effect of PMS. Take Trimethoprim as an example, its kinetics constant decreased from 22.491 to 0.916 s−1. PMS dosage also played an important role in both fouling alleviation and OMP removal. The improved performances were observed with increasing PMS dosage.

Trials of surface modifications using low pressure chemical vapor deposition (LPCVD) has successfully decreased the high temperature needed for the fabrication of SiC membrane from 2000°C to below 900 °C. With this great success on the reduction of the energy con-sumption, however, further studies on the chemical stability and the fouling features of this kind of membrane were necessary. In this research, experiments were done on the SiC-Al2O3 UF membrane fabricated by LPCVD to study its chemical stability in a NaClO solution and its fouling features when filtrating sodium alginate and surface water under constant flux cross-flow mode. The backwash efficiency and the fouling resistance were analysed as well to further elucidate the fouling composition.
According to the results, the SiC-Al2O3 membrane coated under higher temperature (860°C) remained stable in the NaClO solution for 200 h, (1% for 100 h and then 5% for 100 h) while the membrane coated under lower temperature (750°C) showed a water permeability increase during chlorine treatment, indicating the dissolution of the SiC layer. The high temperature coated membrane (860°C) had a better antifouling ability than low temperature coated mem-brane (750°C) and the pristine membrane especially when filtrating the pure sodium alginate (SA) solution without Ca2+ under normal flux (170 LMH) or the surface water under lower flux (65 LMH). Cake filtration was observed in the fouling curves when the critical flux was not exceeded. The addition of Ca2+ into the pure SA solution resulted in the decrease of elec-trical repulsion and the increase of bridging between foulants and membrane surface. These led to the severe fouling of the high temperature coated membrane. The low temperature coated membrane had better antifouling ability than high temperature coated membrane and the pristine membrane when 2 mmol/L of Ca2+ was added. However, the backwash (back-wash flux of around 340 LMH for normal flux condition and around 195 LMH for lower flux condition) was not efficient for all the membranes and should be improved in the future ex-periments.

Water scarcity and uneven distribution of water resources pose a significant challenge globally. Searching for alternative water resources could alleviate this issue. Municipal sewage reclamation with ceramic NF membrane has gained momentum nowadays. However, the inevitable fouling, especially organic fouling during membrane filtration, is the major limitation of the application. To mitigate the fouling issues and protect the membrane from frequent sodium hypochlorite cleaning, a reaction-based CaCO3 pre-coating method, which could prevent the direct contact of foulant and ceramic NF surface was developed. Acid cleaning was applied to initiate the reaction between CaCO3, which was attached with foulants (sodium alginate) and acid. Lastly, forward flush was implemented to remove the loosened CaCO3 and sodium alginate layers.

The effectiveness of hydrochloric acid cleaning, formic acid cleaning and citric acid cleaning was studied in this paper. Citric acid was found to be the most effective way of cleaning because of the highest permeability recovery rate obtained and the lowest consumption rate of the pre-coating layer. This could be ascribed to the carboxyl groups chelation with calcium ions and the ‘peeled’ chelates adsorbed with more foulants were flushed away. Formic acid was less efficient showing moderate efficiency. Besides, HCl cleaning restored the lowest extent of membrane permeability. Additionally, experiments of increasing the pre-coated CaCO3 amount (7655 mg/m2) to apply for more filtration/acid cleaning cycles were executed. The effectiveness increases in the order of HCl, formic acid and citric acid. The pre-coated membrane cleaned with citric acid could last for the whole six cycles, while the membrane cleaned with HCl only worked in the first three cycles. Lastly, the effect of bubbles generated during the reaction was explored using CaHPO4 as a pre-coating layer. However, the hypothesized positive impact of bubbles was not verified.

Ultrafiltration (UF) is an efficient and effective method of filtrating oil-in-water (O/W) emulsions. However, the favorable conditions of filtrating nano-sized O/W emulsions have not been investigated. This study investigated the influence of four different parameters including membrane pore size, cross flow velocity, pH and salinity on membrane fouling as well as oil rejection. Alumina UF membranes were employed to filtrate nano-sized O/W emulsions. O/W emulsions were synthesized using soybean oil and stabilized by surfactants. The filtration experiments were conducted under constant flux for multi cycles. The results showed that 200nm was recommended to filtrate nano-sized O/W emulsions (average droplet size -100nm) based on the high oil rejection (95% ~ 99%) and low irreversible fouling resistance. Besides, alumina membranes were proved to be more effective in fouling mitigation at low salinity, high pH, and high cross flow velocities.

Natural organic matter is one of the key components to remove from source water during drinking water production. NOM not only negatively influences the colour, taste and smell of the water, it also decreases the effectiveness of common water treatment steps such as (membrane) filtration and UV desinfectation. A big fraction of natural organic matter is negatively charged and because of that it can be removed from water with ion exchange.

Suspended ion exchange is a relatively new type of ion exchange, invented and developed by drinking water company PWN in the Netherlands. The trademark aspect of this process is that ion exchange resin gets dosed directly into the influent in suspension, followed by a filtration and a regeneration step instead of fixed bed reactors. The big advantage of this way of operating is that it can operate raw surface water, it is not prone to clogging and can operate continuously. Therefore it is much easier to implement towards the beginning of the water treatment chain, allowing it to positively impact later treatment steps.

PHREEQC is a computer program developed to do geochemical calculations. It is designed to take into account different chemical processes happening simultaneously in complex ground or water matrices.

This report is about the research done to see if the removal of natural organic matter through SIX can be simulated with a modeling program such as PHREEQC. Therefore a series of jar tests and titrations have been done to determine the relevant chemical properties of four different NOM samples, the influence of pH on ion exchange and the influence of competition between different target anions.

The counter anion exchange equivalence of NOM has shown to be varying from around 1.8 to 8. This can explain why it is observed that the adsorption of natural organic matter is almost unaffected by the presence of competing anions such as sulfate, as this high counter anion exchange equivalence suggests that NOM sits high in the anion selectivity range. Additionally, the adsorption of NOM has been constantly high over a wide pH range. This is remarkable, especially at low pH values where titrations show that the charge of NOM decrease drastically. The release of chloride by the resin does get affected by pH a lot however, although this is minimally related to the changing charge of NOM and rather by the increasing amount of bicarbonate in the system adsorbing to the resin at neutral or high pH ranges.

Using the equilibrium constants calculated with results from the jar tests in PHREEQC give quite accurate results when a system of two anions is simulated. When a system with more than two anions is introduced however, the program values the equilibrium constants too much, resulting in vastly underestimating the adsorption of whichever anion has the lower selectivity in the system.
NOM is currently too complex to accurately represent in a computer model compared to other, more common anions such as chloride, nitrate and sulfate. On top of that PHREEQC needs more parameters beyond exchange equilibria to properly model the exchange reactions in a model.

The aim of this research was to evaluate the feasibility of direct hollow fiber nanofiltration membranes for drinking water purposes. The experiments were performed on the dNF40 pilot provided by NXF. The fouling potential and the ion retention of the dNF40 pilot were determined by continuous filtration experiments using raw IJssellake water under different operational conditions. The performances (ion retention and fouling potential) of the dNF40 on raw IJssellake water were compared with the dNF40 performances on pre-treated water from Waterwinstation Prinses Juliana (WPJ) (previously done at PWNT). The WPJ pre-treated water has undergone extensive pre-treatment consisting of drum screens, flocculation, sedimentation, rapid sand filtration (RSF) and granular activated carbon (GAC). The OMP retention of the dNF40 pilot was determined by full recirculation experiments using WPJ pre-treated water under two different operational conditions with elevated concentrations 'spiked solution'.
Limited to no fouling impact was observed on the membrane performance when feeding the pilot with raw IJssellake water. The membrane performance parameters (mass transfer coefficient (MTC), trans membrane pressure (TMP) and normalized pressure drop (NPD)) were stable over time. In addition, limited to no fouling impact was observed on the membrane when feeding the pilot with WPJ pre-treated water. However, membrane performance (i.e. MTC) was better for raw IJssellake water (1 year old membrane) compared to WPJ pre-treated water (virgin membrane). This implies that the active outer layer of the membrane has undergone a change in properties leading to these higher MTC values.
An increase in recovery, flux and crossflow velocity resulted in a decrease in ion retention. However, a decrease in ion retention with elevated crossflow velocity is unusual. Higher crossflow velocities should actually lead to an increase in ion retention due to reduced ion build-up next to the membrane surface (i.e. lower concentration polarization effect). However, the lower ion retention can be attributed to the elevated MTC during experiments. The removal of natural organic matter (NOM) was consistently above 90% and was not influenced by a change in operational condition. Ion retention was higher for WPJ pre-treated water (virgin membrane) compared to raw IJssellake water (1 year old membrane). This can be attributed to the increase in MTC of 1.5 LMH/bar in raw IJssellake water (compared to WPJ pre-treated water) potentially caused by a change in the properties of the active outer layer.
For determining the OMP retention of the dNF40 membrane, a spiked solution containing per- and polyfluoroalkyl substances (PFAS) and pharmaceutical compounds was analyzed. The PFAS compounds of the spiked solution were retained very well (above 80%). As expected, the retention increased with increasing MW. The adsorption percentage of PFAS was between 40%-90%. The pharmaceutical retention was around 30%, although all pharmaceuticals analyzed had a MW below the MWCO of the membrane.
A 5-stage full-scale dNF40 plant was designed based on a permeate flow of 15 M m3/year, a total hardness concentration in the permeate stream below 1.4 mmol/L and a recovery percentage of 85%. Based on the 5-stage full-scale dNF40 plant an economical analysis was performed and compared to the full-scale UF-RO in Heemskerk. The total cost (OPEX and CAPEX) were cheapest for the full-scale dNF40 plant fed with raw IJssellake water (12 ct/m3), followed by the dNF40 plant fed with WPJ pre-treated water (32 ct/m3) and most expensive for the UF-RO plant (35 ct/m3). The major factors in the OPEX was the membrane replacement cost for the dNF40 plant and the energy and chemical cost for the UF-RO plant.

In this research, a few initiatives were completed with practical industrial information and water samples from Heineken®. A Python model was built for an imaginary bottle washer, and tested with difference operational variables under the four testing scenarios. Based on the operational information fromthe Spanish brewery, a second Python model was built for the real-life case study, which was then optimised with several operational variables to reduce either WFP or CFP as caustic soda in five optimisation scenarios. With three water samples from three caustic baths from another bottle washer operated in a Belgian brewery, a composition analysis on significant water parameters was carried out in the Water Lab in TU Delft. This lab analysis gave a basic insight of the compositions of caustic wastewater from bottle washers, and provided possibility to discuss the treatment methods.

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.

An increasing trend of urbanization, land shortages and frequent floodings have created unfavorable living circumstances for Philippine inhabitants. Finch Floating Homes aims to repurpose the permanently flooded ricefields in Hagonoy into flood-proof, typhoon-resilient, affordable housing. The floating neighborhood will serve as storm-resilient living and have an educational purpose on circular living and recovering resources. The pilot floating home is equipped according to current sanitation practices, a septic tank. The septic tanks are usually emptied in drainage fields or surface water. With the aim of circularity in mind, an alternative sanitation had to be designed.

The neighborhood aspects and social implications were analyzed after which a set of eight design criteria were drafted. With the design criteria a framework was set up for selecting a flexible sanitation system that fits a range of desired effluent qualities. The framework offered treatment compartments that can be combined depending upon the location and effluent requirements. Three different treatment scenarios were compared based on the effluent qualities and costs. Scenario 2 containing a UASB-septic tank as primary treatment and a polishing step with water hyacinths, was found to be the most cost-effective. A final effluent concentration of 3 g/L COD, 0,05 mg/L NH3 and between 53 and 134 mg/L P was reached. And based on the die-off of E.coli, a pathogen removal of 5 log units was achieved.

Next, the conceptualization was laid out. The platforms on which the houses float, were made up of standard modules that were prefabricated and assembled on-site. Rainbarrels in wooden frames provided floating ability. The UASB-septic tank had similar dimensions as the rainbarrels, meaning no specialized treatment platform had to be built since the reactor could take the place of a rainbarrel. The disinfection tubes are placed on top of the platform and could be added at any time if the effluent quality demands a low pathogen level.
The final polishing pond was constructed from locally sourced materials and can be built in any shape that suits the neighborhood as long as the surface area is 17 m2.

The treatment system also offered possibilities for resource recovery in the form of biogas, irrigation water, fertilizer and reuse of the plant mass (food, extra COD, fabric raw materials). The residents could benefit from the biogas in the form of a communal kitchen suitable for social gatherings. The fertilizer and irrigation water were applied in communal gardens. Communal areas aided in improving relations between neighbors which created a pleasant environment.

The final treatment design was a scalable, affordable and sustainable treatment system with a range of resource recovery possibilities.

Climate change, population growth and urbanisation contribute to an increasing demand for freshwater resources. In order to face this challenge, stormwater harvesting for aquifer storage and recovery has gained interest over the past decades. However, pollutants from various surfaces are transported with the runoff, posing a threat for receiving groundwater upon aquifer infiltration. Biofiltration is a low-cost and low-energy technology that uses natural processes to improve the stormwater quality. Heavy metals are a contaminant of concern, because of their lack of degradability and toxicity at low levels. So far, removal potential has been shown in lab and column tests, but field research is limited. Furthermore, most biofiltration studies focused on removal of total metals, whereas dissolved metals are known to have higher bioavailibilities and thus toxicities. This research aims to gain more insight in the processes in field scale biofilters, by monitoring and analysing the concentrations of metals (Fe, Mn, As, Co, Cr, Cu, Ni, Pb, Zn) in the inlet and the outlet of a stormwater biofilter in Spangen, Rotterdam. In the analysis, a distinction was made between the total metal concentrations, consisting of dissolved and suspended metals, and dissolved metal concentrations. The main chemical water composition was also monitored, to get a better picture of the conditions in which the biofilter was operated. This information was used to identify how the design and operation of the system can be improved with regards to metal removal. Additionally, a transport model in PHREEQC was used to estimate the lifetime of the biofilter before breakthrough occurs, and how operational choices affect this lifetime. Preferential flows and short-circuiting as a result of design- and operational choices were uncovered by analysis of the electrical conductivity. Heterogeneous distribution of water on the filter and the inlet located closely to the outlet contributed to this. A great variation in hydraulic conductivity supported these observations. The hydraulic conductivity was generally much higher than is recommended for biofilters. Additionally, the system was irrigated with recovered water from the aquifer to avoid a foul smell of extracted water and keep the biofilter wet during longer dry periods. This means that the system was not only fed with stormwater, but also with water from the aquifer. Feeding of two different water sources with different compositions lead to the increase of total and dissolved concentrations of As, Co, Cu, Ni \& Pb in the outlet, as well as higher dissolved Zn concentrations. Phoshate, ammonium, and total and dissolved concentrations of Fe, Mn, and Cr on the other hand decreased. The effect of mixing of two different waters was accounted for, by estimating the expected concentration of each pollutant if mixing was the only mechanism effecting their concentration. This was done using mixing fractions based on the electrical conductivity. Differences in estimated and measured concentrations showed that the release and removal of various pollutants was not a mere result of mixing only. The change in water composition and subsequent competition for sorption spots was found to be the main mechanism involved. The transport model showed that preferential flows resulted in C/C0 = 0.8 breakthrough of metals occurring much faster than in a plug flow. These observations show that the current design and operation of the biofilter do not provide adequate removal of metals in the biofilter.

There are more than 160,000 recreational crafts in the Netherlands with a toilet on board. It is forbidden to discharge blackwater into the environment from these crafts. Stricter enforcement of the law by the sealing of the valves of the external drain, leaves the owners of these crafts with a major problem. It is allowed, however, to treat the blackwater on board and then discharge it if the following two boundary conditions for fecal indicators are met: a maximum concentration of 330 cfu per100 ml of Intestinal enterococci and a maximum concentration of 900 cfu per 100 ml of E. coli. The overall objective of this research was to find and test a proof-of-concept (PoC) method to reach these boundary conditions. The method consisted of a series of conventional wastewater techniques: first a coagulation and flocculation step, then the filtration and subsequent dewatering of the TSS and lastly the filtrate was disinfected using UV-C irradiation. Bench scale experimental setups were used to get the data for this research. Results demonstrated that TSS was most efficiently removed by a combination of polyaluminnium chloride and a cationic polyacrylamide copolymer with a low charge density. Furthermore, polyaluminium chloride demonstrated to be highly effective at removing the fecal indicators. Dewatering experiments proved that increasing the polymer dosage did not affect the total dry solid content of the final sludge cake. Also, under the most ideal circumstances a dry solid content of the filter cake of 30% was achieved. Lastly, UV-C experiments were conducted on the filtrates of two different samples, with values for UV254 absorbance of 1.34 cm−1 and 11.85 cm−1 respectively. The first of which was sufficiently disinfected after a total irradiated UV-C dose of 180 mJ/cm2, of which the effective dose was 54.9 mJ/cm2. The fecal indicators in the second sample were not sufficiently removed after a total UV-C dose of 1100 mJ/cm2. The absorbance of UV254 of the filtrate was so large that the effective dose was only 40.0 mJ/cm2. The PoC method showed to have potential for implementation, but adjustments need to be made to make it more sufficient and viable for use of on board disinfection of black-water. Preliminary screening can extract most of the fecal material, which is already high in dry solid content, before homogenising with the liquid fraction. The quantity of conditioning agents need to be adapted to the specific blackwater, and if necessary the pH will need to be adjusted to ensure the right coagulation mechanism for efficient TSS removal. Finally, humic matter in the filtrate will have to be reduced for UV-disinfection to be an effective treatment method. This could possibly be achieved by mechanisms such as adsorptive coagulation or by implementing an intermediate ozonation step after filtration of the TSS, which would also help in the removal of fecal indicators.

Zeolites can be used for the adsorption of organic micropollutants (OMPs) from water. In this research, the potential applications of zeolite granules for OMP removal in wastewater treatment plants (WWTPs) were discovered. The adsorption of 18 target OMPs by zeolite granules was fully studied in batch and column experiments. The adsorption capacity and kinetics of OMPs in demineralised water (DW) and secondary effluent from WWTP (WW matrix) were investigated. A prediction model of OMP breakthrough curves in zeolite packed columns was established and evaluated.
It was found that the adsorption of OMPs by zeolite granules in batch and column experiments was influenced by OMP species, water matrices and operational parameters (e.g., superficial velocity and contact time). Positively charged OMPs were better adsorbed by zeolite granules than neutral and negatively charged OMPs. In most cases, the adsorption capacity and kinetics of OMPs were reduced in WW matrix, which led to an earlier breakthrough in columns. On the contrary, WW matrix enhanced the adsorption capacity and kinetics of a few negatively charged OMPs, such as diclofenac and clofibric acid.
Higher zeolite dosage resulted in faster OMP adsorption kinetics.
Column experiments showed that 12 of the 18 target OMPs could be effectively removed at the EBCT of 12 min, achieving removal efficiencies of 50% over 10 days. The mathematic model for the prediction of OMP breakthrough curves was optimized by applying larger kinetic constants obtained from the batch experiment. It was predicted an EBCT of 15 min is an alternative for a 7-day operation to remove OMPs sufficiently by zeolite packed columns.

Pressure on fresh water resources has led to water scarcity and increasing demand for alternative water resources, such as rainwater. Nevertheless, heavy metal contamination is a limiting factor for re-use of urban stormwater. This research focusses on the adsorption of heavy metal contaminants by biofiltration systems, specifically on the Bluebloqs Biofilter, to fulfil the water quality requirements for infiltration. The effect of various physical and chemical conditions on HM adsorption were assessed.A field experiment was built in the summer of 2019 and operated during 5 months. A range of low to high heavy metal concentrations was synthetically dosed to functional prototype of the Bluebloqs Biofilter, with the aim to characterise both the removal efficiency as well as geochemical processes in the filter media. Results showed that due to saturation of the filter media, Cd and Zn concentrations in the effluent rose above the Dutch infiltration standards after 74 bed volumes. Ni, Cd and Zn were most susceptible for bed saturation as average concentrations over biofilter depth increased by operation. Highest removal of all heavy metals happened in the top 5 cm of the filter bed. A surface complexation sorption model was developed in PHREEQC to evaluate adsorption of Cd, Cu, Ni and Zn. The model was established by calibration on batch adsorption experiment data of the same heavy metals. With this modelling tool, various physical and chemical conditions in stormwater could be easily simulated and extrapolated, as well as characteristics of filter media that could be modified. Surface complexation modelling showed a reasonable fit compared to the Freundlich isotherm.The order of adsorption to the filter media was Cu>Cd>Zn>Ni. Batch simulations showed that by raising solution pH, adsorption of each HM was increased for both quartz sand and iron oxide coated sand. For pH 7.0, the partition coefficient for iron oxide coated sand was 1.34, 16.8, 19.9 and 23.9 for Ni, Cd, Cu and Zn respectively. For pH 8.0, the partition coefficient rose to 12.9, 2.15*103, 282 and 698 in the same order. In the case of quartz sand and pH 7.0, partition coefficient was found 4.7 *10-2, 1.18, 1.41 and 14.8 for Ni, Zn, Cd and Cu respectively. When increased to pH 8.0, partition coefficients rose to 0.7, 34.0, 228 and 201 in the same order.To a lower extent, increase of ionic strength of the solution had a negative effect on the adsorption of Cu and Cd. By increasing the Zn and Cu proportion by a factor 5.0 in the influent stormwater, adsorption of Ni and Cd was negatively affected, but only for unrealistic high concentrations.One dimensional transport simulations were performed for the average stormwater compositions found at the field experiment. Ni showed first breakthrough in the filter due to lower affinity, followed by Zn, Cd and Cu. Increase of the pH from 7.0 to 8.0 delayed breakthrough by a factor 9.2, 15.8, 25.9 and 135.1 for Cu, Ni, Zn and Cd respectively, despite the type of media used in simulations. By changing the 20% of the top layer of the total filter length from quartz sand to iron oxide coated sand in the model, the adsorption capacity increased and delayed the breakthrough of heavy metals by a factor ±2.36 at all pH conditions.Comparison of the established sorption model with field experiment data showed underestimation of Ni adsorption, while Cd and Cu were overestimated. Zn adsorption showed the most similarity between model results and field data. The model cannot provide an accurate prediction on HM adsorption, but it can be used to compare in between HMs.For the first mature system of the Bluebloqs biofilter, operational in Spangen, Rotterdam since the summer of 2018, the first exceedance of the Zn for the infiltration standards was predicted after 410 bed volumes, due to saturation of filter media. This resulted in elevated Zn concentration in the effluent. Further improvement of the sorption model could be established by additional batch adsorption experiments to obtain more trustworthy results.

Microorganisms may cause problems in drinking water distribution system (DWDS). It is hard to control and always forms the biofilm, which can result in the deterioration of drinking water quality. At household’s tap, due to the favorable conditions, which incurs an easier formation of biofilm. Therefore, the idea of secondary disinfection at households to control the drinking water quality has come up. Ultrasound disinfection provides an easy-operated way for point-of-use disinfection, which can be influenced by the local hydraulic conditions. Previous studies have monitored the spatial and temporal variations in the microbial community in DWDS but most of cases were based on long-term effect. In this study, a simulated household piping system was sampled intensively over short time scales. Several parameters on the dynamics of microbiological processes such as tATP, cATP, TOC and total cell concentration of drinking water samples were examined at four sampling points under various flow rate at different disinfection time. The results highlighted that ultrasound disinfection can restrain cell activity but the effect was also influenced by flow rate. Both FCM and ATP data described the microbiological dynamics in the drinking water samples. The cell concentrations decreased when the flow rate was lower. Moreover, operation time of the ultrasonic device showed significant influence on the disinfection efficiency. At the same sampling point, when the system was operated at a constant flow rate, the cell activity decreased with the increase of the operation time of ultrasonic device. Considering the time that a cell travel through the system subjected to ultrasonic effects, the so called exposure time, it is observed that the cell activity decreased with the increase of time that the cell experienced ultrasound. As a result, the cell at the furthest sampling point under the most significant flow rate with longest ultrasound disinfection time showed the lowest activity.

New techniques are urgently demanded to remove organic micropollutants (OMPs) such as endocrine disrupting compounds, pharmaceuticals and pesticides from our drinking water sources. With increasing salinity of surface waters in coastal regions, salt removal has also become an issue in the production of drinking water. When advanced oxidation processes are combined they are capable to remove OMPs to a large extent, but without the removal of salts. Dense membranes like reverse osmosis (RO) or flat-sheet nanofiltration (NF) membranes – which require an extensive pretreatment – can sufficiently remove OMPs and salts, but only at low permeabilities and by producing a saline waste stream. Hollow fiber NF membranes seem very promising in this respect as they have higher permeabilities, lower energy consumptions and can be applied directly. In this study, the removal of salts and OMPs from synthetic surface water and real lake water from the Valkenburgse Meer (VM) by the polyelectrolyte multilayer (PEM) coated dNF40 membrane was studied in order to make it suitable for dune infiltration water. This type of membrane is fabricated by depositing polycations and polyanions alternately on a porous support medium, also known as the layer by layer (LbL) technique, which enables control of the membrane’s surface charge and permeability. Hollow fiber NF membranes have the ability to separate ions or solutes with smaller sizes and hydraulic radii than the pore size of the membrane due to electrostatic repulsion. The membrane is negatively charged at neutral pH.

The dNF40 membrane showed ion retentions of up to 27% for Cl-, 98% for SO42-, 87% for Mg2+, 76% for Ca2+ and 17% for Na+ in once-through configuration with a hydraulic permeability of 5.8 Lm-2h-1 and molecular weight cut-off (MWCO) of ~200 Da. However, lower ion retention values were observed for filtration of real lake water, except for SO42-. Retentions were unaffected by cross-flow velocity, but increased with increasing permeate flux. Moreover, the ion retentions reduced considerably when the system recovery increased to 75%. In addition to the salt retentions, the retention of a mix of 20 distinctively different pharmaceuticals, both positively charged, negatively charged and neutral OMPs with molecular weights between 119 and 748 gmol−1, was investigated. An average retention as high as 79% and 89% was reached for SW (no natural organic matter (NOM)) and VM water (11.6 mgL-1 of NOM), respectively. As expected, the negatively charged pharmaceuticals were retained best as a result of electrostatic interactions with the negatively charged membrane, followed by the positively charged compounds, of which repulsion is probably promoted by underlying polycation layers in the membrane structure. Neutral compounds were retained less.

The dNF40 membrane showed to be resistant to fouling, while no extensive pretreatment was applied, making it suitable for direct treatment of surface water. Furthermore, OMPs were largely removed, hardness was partially reduced and NOM was almost completely removed, but insufficient NaCl was retained to meet dune infiltration water standards. Therefore, an additional step becomes necessary in the pretreatment of surface water. Four suggestions were provided.

Our use of pharmaceuticals, pesticides and personal care products leads to an increase of organic micropollutants (OMPs) into the aquatic environment. Conventional wastewater treatment plants are not designed for the removal of OMPs and need to be upgraded to reduce OMP contamination. The adsorption of OMPs to zeolites is proposed as an alternative treatment method. Zeolites are synthesized as powders, however they need to be shaped into pellets to be used in water treatment practice. This research focussed on engineering zeolite pellets and which properties of these pellets are important for the adsorption of OMPs.
First the influence of the calcination temperature and binder content on the mechanical stability and porosity of the pellets was analysed. Second, the influence of two different preparation techniques (extrusion and high-shear granulation) and the introduction of a polymer on the mechanical stability, porosity and adsorption kinetics of the pellets was assessed. Third, the effect of the porosity on the breakthrough for an empty bed contact time (EBCT) of 20, 5 and 1 minute(s) was determined according to the linear driving force (LDF) model. It was found that an increasing binder content and calcination temperature increased the wear resistance and porosity of the pellets. However, the effect on the porosity is minimal. The introduction of the polymer had opposite effect on extruded and granulated pellets. For extruded pellets, the introduction of the polymer increased the porosity. However, the granulated pellets showed a decrease in porosity. A relation was found between the porosity and the wear resistance and between the porosity and adsorption kinetics. A larger porosity decreased the wear resistance of the pellets and increased the kinetic rate constant. The porosity was of great importance in relation to the breakthrough. First, the porosity in the zeolite pellets determined to a great extent the bulk density of the filter bed. A higher bulk density resulted in a later breakthrough point. The bulk density was also influenced by the shape of the pellet. Spherically-shaped (granulated) pellets had a higher bulk density than rod-shaped (extruded) pellets. Second, the porosity was related to the kinetic rate constant. At lower EBCTs (5 and 1 minute), the kinetic rate constant had an influence on the breakthrough point. For these EBCTs, a higher kinetic rate constant led to a later breakthrough point. It was recommended to optimize the zeolite pellets by making the extruded pellets in a more spherically-shaped form and to start column experiments to validate the LDF-model.