4D Neutron Imaging of Solute Transport and Fluid Flow in Sandstone Before and After Mineral Precipitation

In many geological systems, the porosity of rock or soil may evolve during mineral precipitation, a process that controls fluid transport properties. Here, we investigate the use of 4D neutron imaging to image flow and transport in Bentheim sandstone core samples before and after in-situ calcium carbonate precipitation. First, we demonstrate...

Application of a smart dosing pump algorithm in identifying real-time optimum dose of antiscalant in reverse osmosis systems

The potential of membrane scaling control by a real-time optimization algorithm was investigated. The effect of antiscalant dosing was evaluated from the induction time measured in glass batch-reactors, and from the operational performance of a lab-scale reverse osmosis (RO) unit and two pilot-scale RO units. Step changes in the antiscalant...

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...

Role of phosphate and humic substances in controlling calcium carbonate scaling in a groundwater reverse osmosis system

The role of phosphate and humic substances (HS) in preventing calcium carbonate scaling and their impact on antiscalant dose was investigated for a reverse osmosis (RO) system treating anaerobic groundwater (GW) (containing 2.1 mg/L orthophosphate and 6-8 mg/L HS). Experiments were conducted with the RO unit (treating anaerobic GW), and with...

Review and recalculation of growth and nucleation kinetics for calcite, vaterite and amorphous calcium carbonate

The precipitation of calcium carbonate is well studied in many fields of research and industry. Despite the fact that, or perhaps because of the fact that, it is well studied in many fields, different approaches have been used to describe the kinetics of the precipitation process. The aim of this study was to collect and compare the data...

Experiments to investigate the effectiveness of a new geochemical method to mitigate backward erosion piping: (Abstract)

Drinking water pellet softening: prediction the terminal settling velocity of natural particles

Natural particles are frequently applied in drinking water treatment in up-flow fluidisation processes. Additionally, sedimentation processes are applied to clarify water and to concentrate solids. To estimate the terminal settling velocity of single solid particles in a liquid system, a comprehensive collection of equations is available. For...

Prediction of the terminal settling velocity of drinking water pellet softening particles

The literature provides a comprehensive collection of equations to estimate the<br/>terminal settling velocity of single solid particles in a liquid system. The settling velocity for perfectly round spheres can accurately be calculated. In the contrary for natural imperfect particles the experimentally measured settling velocity deviates...

Applying MICP by denitrification in soils: A process analysis

The process of microbially induced carbonate precipitation (MICP) by denitrification was investigated in relation to its potential use as a ground improvement method. Liquid batch experiments indicated that the substrate solution had an optimum carbon–nitrogen ratio of 1·6 and confirmed that combining nitrate reduction and calcium carbonate...

Increased sustainability of softening by producing pure calcite pellets for reuse

About 50% of the drinking water in the Netherlands is centrally softened by the drinking water companies in a process known as pellet softening. In this process a base and seeding material are mixed in an upflow reactor, where subsequently CaCO3 precipitates on a seed core as pellets. The seeding material is usually sand, but recently CaCO3 was...

Experimental study on self-healing capability of FRCC with different fiber types and shapes

Abstract only.

Experimental study on evaluation of self-healing capability of FRCCs comprising different components

Fiber reinforced cementitious composite (FRCC) has a great capability for selfhealing of cracks. Concrete cracks with a sufficiently small crack width (below 0.1 mm) can be closed and self-healed by crystallization of calcium carbonate in the presence of moisture, even in the case of ordinary concrete. Such precipitation is caused by reaction of...

Effect of Ultrasound on Calcium Carbonate Crystallization

Scaling comprises the formation of hard mineral deposits on process or membrane equipment and calcium carbonate is the most common scaling salt. Especially in reverse osmosis (RO) membrane systems, scale formation has always been a serious limitation, causing flux decline, membrane degradation, loss of production and elevated operating costs. In...

Surface crack self healing behaviour of mortars with expansive additives (abstract)

Bacteria-based self-healing concrete

A typical durability-related phenomenon in many concrete constructions is crack formation. While larger cracks hamper structural integrity, also smaller sub-millimeter sized cracks may result in durability problems as particularly connected cracks increase matrix permeability. Ingress water and chemicals can cause premature matrix degradation...

Calcium carbonate precipitation in relation to detergent performance