ACARP ACARP ACARP ACARP
Open Cut

Development of a Pilot Scale Integrated Forward and Reverse Osmosis System for Mine Water Reuse

Open Cut » Environment

Published: June 16Project Number: C23031

Get ReportAuthor: Ramesh Thiruvenkatachari, Michael Cunnington, Shi Su | CSIRO

The forward osmosis (FO) process, also known as direct osmosis, is an emerging membrane technology for water reuse and desalination. In the FO process, water naturally traverses the semi permeable membrane from a lower solute concentration feed solution on one side of the membrane to a higher solute concentration solution, known as the draw solution, on the other side of the membrane. In this process, the two solutions of different concentration create an osmotic gradient, which is the driving force, which induces water permeation across the membrane. Ideally, as the higher osmotic pressure draw solution extracts the water across the membrane from the feed solution, the semipermeable FO membrane acts as a barrier that rejects salts and other contaminants and prevents its passage through the membrane. During the course of this process, feed water stream becomes more concentrated and the draw solution becomes diluted until an osmotic equilibrium is reached. Clean water is recovered from the diluted draw solution using a post treatment such as reverse osmosis. Over the last ten years, significant progress has been made in developing FO membranes and new draw solutions, resulting in the increase in its application to treat various water sources.

 

Environmental constraints prevent untreated mine water being discharged into water-ways. Due to the constraints in releasing the saline water, coal mines require additional water storage facilities and therefore seek to minimise their inventory of saline water. Adopting efficient treatment technologies on-site would help to significantly minimise their inventory of saline mine impacted water storage and achieve consistent discharge quality water. It would also minimise the risk of wet season run-offs and freshwater contamination and allow segregation into different qualities of water to enable greater water recycling. Treated saline mine water can also offer new sources of supply of reusable quality water to coal mines, especially during periods of drought.

 

ACARP project C21043 previously introduced the osmotically driven forward osmosis (FO) process for coal mine water treatment and through a laboratory scale setup using flat sheet membranes, successfully demonstrated the proof-of-concept of integrating forward osmosis with reverse osmosis (RO) to obtain dischargeable or reusable quality water. The current project (ACARP C23031) further progressed this innovative FO-RO technology through the design and development of a modular pilot treatment unit of 1 m3/d treatment capacity. Two actual mine impacted waters, obtained from two different coal mines in Queensland were used in this study. Performance of the individual FO membranes and the integrated system with RO was evaluated and optimised for treating the mine impacted waters. Additional experiments were undertaken in the laboratory to test the performance of the FO membranes. These laboratory-scale tests used a solution of NaCl, which mimicked the properties of mine-impacted water. This study also investigated the feasibility of using actual RO brines as FO draw solution for providing the osmotic gradient across the membrane.

 

Optimum operating parameters for the overall system were determined through a series of stand-alone experiments using FO and RO processes and then as an integrated FO-RO system. The performances of the two FO membranes were evaluated with varying flowrates and concentrations of the feed and draw solutions. For a given starting concentration of mine water feed solution and with constant concentration of 5.5 wt% NaCl draw solution, the performance of FO-B membrane in terms of water flux was found to be about 1.5 times higher than the FO-A membrane. The experimental results obtained from the pilot FO-RO testing, have demonstrated that the combined FO-RO system was able to eliminate extensive pre-treatment steps that are generally required for conventional RO. Treated mine water was consistently of safe discharge quality that can also be reused for mining operations. This project also showed that the FO2 RO system can use coal mine water desalination brine wastes as the draw solution. This has implication for water treatment. Use of desalination brine wastes from coal mines in applications such as in FO draw solution help to minimise brine waste inventory at mine sites and potentially reduce the overall cost of desalination projects.

 

A preliminary economic evaluation was carried for a 10,000 m3 d-1 FO-RO mine water treatment system and was compared with a RO process using conventional pre-treatment with ultrafiltration (UF). Estimations for capital cost, operating cost and the total water cost (for treating one m3 of water), for the two treatment processes were compared. Compared to the conventional UF-RO process, FO-RO process is expected to provide about 15% reduction in CAPEX and about 10 % reduction in OPEX. Various basic assumptions for this estimation are detailed in this report. For an initial mine water feed concentration of 9.5 g L-1, the integrated FO-RO process would reduce the brine volume by 81 %. At least 8 % more reduction in brine waste volume for disposal is expected, compared to a conventional RO treatment. This would be an important cost consideration for this treatment option.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C27039True Triaxial Strength Of Coal Measure Rocks And Its Impact On Roadway Stability And Coal Burst Assessment

Rocks in the ground are subject to a range of stresses. The stresses...

C3063Underground Vehicle Design Standards And Statutory Implications

The Australian underground diesel vehicle fleet has evolved since di...

C3064Conveyor Belting And Lagging Shear Characteristics - Drive Drum Slip

The primary aim of this project was to investigate the relationsh...

Underground

Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C29021Assessing The Impact Of Consecutive Night Shifts On Night-Time Alertness, Daytime Sleep And Timing Of The Circadian System

In the Australian coal mining industry, most guidelines for managing...

C33037Quantifying Recharge To Groundwater Systems In The NSW Coalfields (Sydney, Gunnedah And Gloucester Basins)

The purpose of this project was to estimate the rate of diffuse rec...

C26029Geological Controls On Fluorine And Phosphorus In Bowen Basin Coals

Increasing global restrictions on fluorine in product coal prompted ...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27064Dry Beneficiation Using FGX And X-Ray Sorters

Conventional dry processing methods engage a single beneficiation de...

C26010Multi-Sloped Screening Efficiency With Changing Strokes, Frequencies, Feed Solids And Feed Rates-Pilot Plant Study

Optimising multi-sloped screens is often described as an art and the...

C28059Impact Of Water Quality In Coal Handling And Preparations Plants

The objective of this project was to deliver a concise reference do...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C23052Novel Stone Dust Looping Process For Ventilation Air Methane Abatement

This multi‐phase project is concerned with the mitigation of m...

C27054Optimisation Of A Thermal Flow Reversal Reactor For Ventilation Air Methane Mitigation

Ventilation air methane (VAM) generally accounts for 50-85% of the t...

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community

NERDDC

National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook

NERDDC