Related Experiment Video
Updated: Aug 12, 2026

Reservoir Condition Pore-scale Imaging of Multiple Fluid Phases Using X-ray Microtomography
Published on: February 25, 2015
Threshold scaling limits of RO concentrates flowing in a long waste disposal pipeline
R Semiat1, D Hasson, G Zelmanov
1Grand Water Research Institute-Rabin Desalination Laboratory, Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel. cesemiat@tx.technion.ac.il
Abstract:
Disposal of RO concentrates emanating from inland brackish water desalination plants presents a difficult environmental problem. The solution adopted by Mekorot--the National Water Company of Israel--is to construct a 30 km waste disposal pipeline for collecting concentrates emanating from several RO desalination plants and discharging them into the sea. The discharged concentrates are highly supersaturated with respect to CaCO3. Scale precipitation during concentrate flow through the RO module is inhibited by the presence of anti-scalants. The retention time of the concentrate solution in the discharge pipe will exceed 100 hours. This raises the issue of the risk of scale precipitation in the discharge pipe that could impair its proper functioning. The aim of the present study was to provide data for guiding the design and operation of the disposal pipeline. The extent of the induction period prior to the onset of precipitation was measured in a pilot plant simulating flow of concentrate solutions dosed with anti-scalants. The parameters investigated were the scaling potential, the anti-scalant concentration and the presence of a mixture of several anti-scalants. The results of this study provide threshold scaling limits under various conditions.
Related Concept Videos
Design Example: Flow of Oil Through Circular Pipes
Laminar Flow: Problem Solving
Turbulent Flow: Problem Solving
Temperature is a key factor in CO2 solubility. In this case, the CO2 gas and the liquid are cooled to 20°C. Lower temperatures enhance...
Single Pipe Systems
In a Type I problem, fluid properties (density and viscosity), pipe characteristics (including diameter, length, and surface roughness), and the flow rate or average velocity are known. The...
Pipe Flowrate Measurement: Problem Solving
Scale-Up Processes

