Groundwater pollution potential of additives used in borehole heat exchanger fluids

摘要: Ground-based heat exchanger systems need to be evaluated in terms of potential effects on groundwater quality due the risk leakage borehole fluids. They contain glycols or inorganic brines as major components, but typically also various additives. As identity these additives is proprietary information, objective this study was obtain an overview identities and properties individual additive compounds used Leading companies production distribution fluids were invited participate a confidential data survey. A wide variety assembled, which can grouped into ten chemical classes: triazoles, carboxylic acids/carbonates, phosphonates, alcohols, aldehydes, ethers borates, silicates, nitrates hydroxides. Among substances some are other applications, e.g. aircraft de-icing engine antifreeze formulations, concern for quality. Based their abundance investigated exchangers concerning environmental behaviour subsurface, benzotriazoles, tolyltriazoles carbonates selected further biodegradation experiments.