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Investigation into the potential of membrane water treatment processes for effluent treatment and reuse within an integrated steel works. / James Evans

Swansea University Author: James Evans

Abstract

Investigation into the potential of membrane water treatment processes for effluent treatment and reuse within an integrated steel works. This project concerns the investigation of the viability of membrane processes applied to water processing for potential recycling and reuse within an integrated...

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Published: 2006
Institution: Swansea University
Degree level: Master of Philosophy
Degree name: M.Phil
URI: https://cronfa.swan.ac.uk/Record/cronfa42615
Abstract: Investigation into the potential of membrane water treatment processes for effluent treatment and reuse within an integrated steel works. This project concerns the investigation of the viability of membrane processes applied to water processing for potential recycling and reuse within an integrated steel works. Two waste streams were identified for further investigation, namely cold mill rolling emulsion and steel plant gas scrubber effluent (particulate rich), both containing variable concentrations of pollutants. To study these processes, a versatile membrane pilot plant was designed, constructed and commissioned. This consisted of a 150 L feed tank, variable speed pump, pipe work and instrumentation with a process datalogger recording process information. Two different full size commercially available membrane modules could be accommodated, i.e. of tubular and hollow fibre formats. Three membranes were used to investigate the filtration of waste emulsion, two tubular PVDF membranes, neutral and anionic surfaces and a PAN hollow fibre. To treat the scrubber effluent, a PS hollow fibre module was used. Experiments were conducted on two real waste streams from the works. The two real waste streams were found to have a variable composition but the membranes were able to consistently produce a high quality product stream that could have many further uses within a steel works. Water could be separated from the oil-in-water emulsion, containing several hundred PPM of oil, to produce an almost particulate free permeate containing consistently less than 10 PPM of oil, at flux rates similar to those reported in literature of 50 L m2h-1 . Similarly, the filtration of the particulate bearing effluent, 7-122 mg / L of solids, produced water that contained less than 4 PPM of solids in the permeate at a flux rate of up to 160 L m2h-1. Due to the variability in concentration of the oil-in-water emulsion, a defined emulsion was prepared, 1.5 g / L and investigated. This gave consistently better fluxes and the key parameters investigated were variable concentration and conductivity of the solution, flow rate and transmembrane pressure. The use of 0.01 and 0.001 M K Cl having a negative effect on the permeate quality for both anionic and neutral membranes. A cost benefit analysis has shown that a cubic meter of treated oil-in-water emulsion based effluent using PVDF tubular membranes has an operating cost of £1.17 / m3. A cost benefit analysis has shown that a cubic meter of treated steel plant effluent using polysulphone hollow fibre membranes has an operating cost of £0.13 / m3. In the case of both tubular membranes, a decline in pure water flux (PWF) was seen over time, with the PAN experiencing significant permanent fouling and the PS was able to be consistently cleaned to recover PWF. This work has shown that the use of membranes for treating waste streams of variable composition produced consistently high quality permeate and that they could be applied to treating these streams. However, further work is required to prove the full commercial viability and to assess the impact on the water system within a steel works of applying membrane water treatment processes on a large scale.
Keywords: Chemical engineering.;Materials science.
College: Faculty of Science and Engineering

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