Author(s): Dejun Zhu, Lei Jiang, Yongcan Chen, Tao Wu
Linked Author(s): Dejun Zhu
Keywords: Faecal coliforms, attachment, settleable suspended sediments, particle size, surface water
Abstract: Faecal bacteria exist in surface waters as either free cells or cells attached to suspended sediment particles, and the attachment has a great impact on the fate and transport of faecal bacteria. In modeling efforts, the attachment is commonly mathematically described by a linear partition model, i. e. , the concentration of attached bacteria per unit mass of suspended sediments linearly increased with the free floating bacteria concentration. However, the attachment in fact has not yet been well understood. The impact of many factors like the particle size among others is still not clear. In this study, controlled laboratory attachment experiments were conducted to investigate the impact of particle size on the attachment of Faecal coliforms (FC) to suspended sediments in surface waters. In the experiments, the suspended sediment samples (particle diameter ranging from 5 ?m to 62 ?m) were separated into four subsamples with different ranges of particle size, and the experimental results of the four subsamples were compared. It was found that the attachment can be well described by the linear model and the partition coefficients ranging from 0. 1376 g/L to 0. 9387 g/L had a greater value with finer particles. With some assumptions, the attached FC concentration per unit surface area of the suspended particles was calculated. And it was found that the attached FC concentration per unit surface area also linearly increased with the free floating FC concentration whilst did not vary with the particle size. This finding can help to refine water quality models to more accurately simulate and predict the fate and transport of faecal bacteria in surface waters
Year: 2017