Groundwater Remediation of Volatile Organic Compounds Using Nanofiltration and Reverse Osmosis Membranes—A Field Study

Abstract

Groundwater contamination by chlorinated hydrocarbons represents a particularly difficult separation to achieve and very little is published on the subject. In this paper, we explore the potential for the removal of chlorinated volatile and non-volatile organics from a site in Bedfordshire UK. The compounds of interest include trichloroethylene (TCE), tetrachloroethylene (PCE), cis-1,2-dichloroethylene (DCE), 2,2-dichloropropane (DCP) and vinyl chloride (VC). The separations were first tested in the laboratory. Microfiltration membranes were of no use in this separation. Nanofiltration membranes performed well and rejections of 70–93% were observed for synthetic solutions and up to 100% for real groundwater samples. Site trials were limited by space and power availability, which resulted in a maximum operating pressure of only 3 bar. Under these conditions, the nanofiltration membrane removed organic materials, but failed to remove VOCs to any significant extent. Initial results with a reverse osmosis membrane were positive, with 93% removal of the VOCs. However, subsequent samples taken demonstrated little removal. Several hypotheses were presented to explain this behavior and the most likely cause of the issue was fouling leading to adsorption of the VOCs onto the membrane and allowing passage through the membrane matrix.

The Effect of pH on Atenolol/Nanofiltration Membranes Affinity

“…This behavior is due to the fact that with the increase in pressure, the permeate flux also increases [ 23 ] and, according to Equation (9), B is proportional to the permeate flux. Furthermore, it has also been reported in the literature that conditions of high permeate fluxes can result in a higher incidence of concentration polarization [ 17 , 33 , 40 ]; that is, a higher concentration of solute at the boundary layer adjacent to the membrane, resulting in higher membrane/solute interactions.…”

Water Purification of Classical and Emerging Organic Pollutants: An Extensive Review

“…The most common depuration solutions consist of steps of air stripping [29,30], adsorption [16,[31][32][33], and oxidative [34,35], reductive [36,37] and biological processes [21,38,39]. In some cases, a combination of several methods is required [40][41][42][43], especially when pollutants are particularly difficult to remove till the limits imposed by the law. Since each technique has its limits, researchers are investing lots of energy in this field, both to improve consolidated methods and to find new ones.…”

“…Ainscough et al [43] used nanofiltration and reverse osmosis membranes to purify water from both TCE and PCE. Thanks to the first kind of process, they removed 70-93% of the pollutants during laboratory tests, and 100% in case of real groundwater samples.…”

Removal of Sulphate Ions from Borehole Water Using Nanofiltration and Reverse Osmosis

“…Thus, membrane technologies such as reverse osmosis and nanofiltration could present an alternative for the treatment of high sulphate concentrations in water [14,[17][18][19]. The literature highlights the performance of reverse osmosis and nanofiltration for the removal of pollutants, but very few associate compliances with WHO potability standards [20][21][22][23]. However, it is assumed that NF offers several advantages in comparison to RO such as low operation pressure, high flux, relatively low investment and low operation/maintenance costs [24].…”