DOC and Ammonium Removal Processes in Slow Sand FIlters - Influence of Grain Size and Flow Rate

Slow sand filters (SSFs) are essential for ensuring microbial quality and biological stability of drinking water in the Netherlands. However, gaps exist in understanding of removal processes of dissolved organic carbon (DOC) and ammonium and the effects of grain size, loading rate, and backwashing on removal in SSFs.<br/>Four lab-scale SSF...

One-Step Reverse Osmosis Based on Riverbank Filtration for Future Drinking Water Purification

The presence of newly emerging pollutants in the aquatic environment poses great challenges for drinking water treatment plants. Due to their low concentrations and unknown characteristics, emerging pollutants cannot be efficiently removed by conventional water treatment processes, making technically, economically, and environmentally...

Hydraulic modelling of liquid-solid fluidisation in drinking water treatment processes

In drinking water treatment plants, multiphase flows are a frequent phenomenon. Examples of such flows are pellet-softening and filter backwashing where liquid-solid fluidisation is applied. A better grasp of these fluidisation processes is needed to be able to determine optimal hydraulic states. In this research, models were developed, and...

Fluoride removal from water by Ca-Al-CO₃ layered double hydroxides and simultaneous acidification

Millions of people worldwide are exposed to excessive concentrations of fluoride (F⁻) from groundwater sources. Ca-Al-CO₃ layered double hydroxides (LDHs) have shown promising defluoridation efficiency; however, defluoridation by Ca-Al-CO₃ LDHs is highly pH sensitive. This study showed that simultaneous...

Experimental and numerical insights into heterogeneous liquid-solid behaviour in drinking water softening reactors

Liquid-solid fluidisation is frequently encountered in drinking water treatment processes, for instance in seeded crystallisation softening processes. For modest superficial fluid velocities, liquid–solid fluidisation systems are generally considered to be homogeneous, as reported in literature. However, during fluidisation experiments with...

A novel sensor measuring local voidage profile inside a fluidised bed reactor

Liquid-solid fluidisation is frequently encountered in drinking water treatment processes, often to obtain a large liquid-solid interfacial surface area. A large surface area is crucial for optimal seeded crystallisation in full-scale softening reactors. Due to crystallisation, particles grow and migrate to a lower zone in the reactor which...

Quantification and modelling of organic micropollutant removal by reverse osmosis (RO) drinking water treatment

Reverse osmosis (RO) is the most promising membrane technology in organic micropollutants (MPs) removal of drinking water treatment. For 78 MPs, passage and removal were evaluated with an ESPA3 RO membrane and the robustness of RO against MPs was studied. The MPs were classified according to their charge and hydrophobicity. The results showed...

Fluidisation characteristics of granular activated carbon in drinking water treatment applications

Granular activated carbon (GAC) filtration is an important unit operation in drinking water treatment. GAC filtration is widely used for its filtration and adsorption capabilities as a barrier for undesired organic macro- and micro-pollutants. GAC filtration consists of two successive phases: adsorption and filtration, capturing the impurities...

Arsenic removal from iron-containing groundwater by delayed aeration in dual-media sand filters

Generally, abstracted groundwater is aerated, leading to iron (Fe²⁺) oxidation to Fe³⁺ and precipitation as Fe³⁺-(hydr)oxide (HFO) flocs. This practice of passive groundwater treatment, however, is not considered a barrier for arsenic (As), as removal efficiencies vary widely (15–95%), depending on Fe/As ratio...

Monitoring the characteristics and removal of natural organic matter fractions in selected south african water treatment plants

This study used spectroscopic methods to investigate the fate and dynamics of natural organic matter (NOM) as it traverses the treatment train at three water treatment plants (WTPs) in South Africa. The character, quantity, and removability of NOM at specific treatment stages was investigated by measuring changes in dissolved organic carbon ...

Accurate voidage prediction in fluidisation systems for full-scale drinking water pellet softening reactors using data driven models

In full-scale drinking water production plants in the Netherlands, central softening is widely used for reasons related to public health, client comfort, and economic and environmental benefits. Almost 500 million cubic meters of water is softened annually through seeded crystallisation in fluidised bed reactors. The societal call for a circular...

The properties and removal efficacies of natural organic matter fractions by South African drinking water treatment plants

This study presents an investigation on the fate of natural organic matter (NOM) and its dynamics throughout the treatment train at various drinking water treatment plants (WTP) in South Africa. The characteristics, concentration and removal efficiencies of NOM at various treatment stages on the basis of dissolved organic carbon, UV...

Bromate reduction by iron(II) during managed aquifer recharge: A laboratory-scale study

The removal of bromate (BrO₃ ^-) as a byproduct of ozonation in subsequent managed aquifer recharge (MAR) systems has so far gained little attention. This preliminary study with anoxic batch experiments was executed to explore the feasibility of chemical BrO₃ ^- reduction in Fe-reducing zones of MAR...

Decision support for water quality management of contaminants of emerging concern

Water authorities and drinking water companies are challenged with the question if, where and how to abate contaminants of emerging concern in the urban water cycle. The most effective strategy under given conditions is often unclear to these stakeholders as it requires insight into several aspects of the contaminants such as sources, properties...

Removal of Natural Organic Matter Fractions by Anion Exchange: Impact on drinking water treatment processes and biological stability

This researched focused on improving drinking water quality, specifically the biological stability of the produced drinking water. Natural organic matter (NOM) can be a source of nutrients for bacteria present in the distribution system, which can cause regrowth. Specifically, small organic acids can cause bacterial activity in the distribution...