Improving the use of granular activated carbon to control algal byproducts during drinking water treatment

饮用水处理厂可能会使用颗粒活性炭（GAC）来吸附和去除污染物，但GAC在耗尽之前使用寿命有限，需要更换。最近业界的一个趋势是在生物模式下使用GAC：允许细菌在其表面生长，并通过生物降解去除污染物。这使得GAC可以继续服役，避免了昂贵的更换费用。然而，这种“生物过滤”仍然缺乏了解和不可预测。拟议的研究旨在利用支持者最近的发现，使我们对生物过滤的理解取得实质性进展。特别是，在安大略省的饮用水处理厂已经确定，在表面上看起来相对相似的条件下，有大量证据表明存在有效的生物过滤，也有大量证据表明没有生物过滤。通过研究这些植物的GAC，可以确定导致有效生物过滤的因素。这项工作将得到一项研究生物降解技术的新应用的帮助，称为化合物特定同位素分析（CSIA），该技术传统上用于研究高浓度污染物的命运。通过开发一种将CSIA应用于低水平（µg/L或ng/L）污染物的方法，可以在评估环境中痕量污染物的命运方面开辟新的研究领域。本研究的总体目标是确定稳健、有效和可靠的策略，通过GAC增强目标污染物的生物降解。这将降低GAC处理的成本，从而使GAC能够被更多的公用事业公司使用。GAC对一系列污染物提供了良好的广谱保护，因此更广泛地应用它的能力将带来相应的公共卫生效益。此外，GAC是一种绿色处理方法，不需要化学品和很少的能源，因此将其用作其他形式的处理方法的替代品来破坏微污染物将是朝着更可持续的饮用水处理迈出的一步。

Drinking water treatment plants may use granular activated carbon (GAC) to adsorb and remove contaminants, but the GAC has a finite service life before it is exhausted and needs to be replaced. A recent trend in the industry is to use GAC in a biological mode: allowing bacteria to grow on its surface and remove contaminants through biodegradation. This allows the GAC to remain in service, avoiding costly replacement. Such "biofiltration", however, remains poorly understood and unpredictable. The proposed research aims to take advantage of recent discoveries by the proponent to make substantial gains in our understanding of biofiltration. In particular, drinking water treatment plants have been identified in Ontario that show considerable evidence of both the presence of effective biofiltration, as well as its absence, under conditions that appear on a superficial level to be relatively similar. By studying the GAC from these plants, the factors that lead to effective biofiltration can be identified. This work will be aided by a new application of a technique to study biodegradation, called compound specific isotope analysis (CSIA), which has traditionally been used to study the fate of contaminants at large concentrations. By developing a method to apply CSIA for contaminants at low levels (µg/L or ng/L), new research areas could be opened up in terms of evaluating the fate of trace contaminants in the environment. The overall goal of this research is to identify robust, effective, and reliable strategies to enhance the biodegradation of target contaminants through GAC. This will reduce the cost of GAC treatment, which in turn would allow GAC to be used by a greater number of utilities. GAC offers good broad-spectrum protection against a range of contaminants, so the ability to apply it more widely would bring corresponding public health benefits. Furthermore, GAC is a green treatment, requiring no chemicals and little energy, so its use as an alternative to other forms of treatment to destroy microcontaminants would be a move towards more sustainable drinking water treatment.