Bisphenol A retention in the direct ultrafiltration of greywater

Abstract

Decentralised treatment is an increasing trend in the attempts to manage water more wisely in light of water restrictions, overconsumption and drought. Greywater is a fraction of household wastewater that offers the potential to be treated locally to be reused for garden irrigation, car washing and toilet flushing. In this paper the performance of submerged and direct ultrafiltration (UF) of synthetic greywater is investigated with regards to organic trace contaminant, namely Bisphenol A (BPA), and fouling. The synthetic greywater solution consisted of inorganic particulates (kaolin), organic fibres (cellulose), protein (casein), surfactant (sodium dodecyl sulphate, SDS), humic acid (HA), calcium, sodium chloride electrolyte and sodium bicarbonate buffer.Results indicate that UF can remove 30-45% of BPA. This removal is attributed to partitioning of the compound to the membrane material, suspended and dissolved solids as well as the fouling layer. Humic acid and calcium were the main contributors to fouling, which also affected BPA retention. Fouling increased with an increase in HA concentration, which calcium contributed most to fouling at a concentration of about 0.5 mM. At higher concentration of calcium aggregation appeared to reduce fouling significantly.The implications of this study are that trace contaminant-solute interactions play an important role for retention potential and this relationship offers room for optimization by selecting particulate additives with a high affinity for target compounds. This is of particular importance if such contaminants are a concern (which is dependent on the product water application) and in the absence of biological treatment which is in this case not desired. The separation of greywater into fractions of low and high strength is of advantage if this can eliminate the presence of humic substances.

Synthesis, properties, water and solute permeability of MWNT buckypapers

“…The presence of these TrOCs in the environment is of significant concern owing to their ability to disrupt normal functioning of the endocrine system [14,15]. As a consequence there have been a number of studies that have investigated the use of different membrane systems to remove TrOCs from water supplies [16][17][18][19][20]. There has also been interest in using carbon nanotubes in electrochemical sensors for detecting BPA [21,22] or in devices used for its quantitative analysis [23].…”

Xenobiotics Removal by Membrane Technology: An Overview

“…Lyko et al [76] measured a UF retention of 36% for BPA at pH 5 and none at higher pH. Schäfer et al [118] obtained similar UF retentions (30%) for this compound in pure water from pH 4 to 9, when BPA is neutral. These high retentions are associated with adsorption on the membrane.…”

“…This case was illustrated by Schäfer et al [118] in a submerged UF process where higher retentions of BPA at pH<9 are obtained in the presence of natural organic matter (NOM) compared to retentions of BPA without NOM. BPA partitions into the NOM and is better retained.…”

Urban water reuse: A triple bottom line assessment framework and review

“…As well, plant-bed could benefit from the remaining nutrients found in the greywater, such as nitrogen, phosphorous and potassium (Khan et al 2013). To recycle water for application in human hygiene such as showering or flushing toilets, a combination of aerobic digestion and membrane filtration (Schäfer et al 2006) (e.g. ultra-filtration, microfiltration) could be used for the removal of organic containments and bacteria.…”