Fate and transport of biocolloids and nanoparticles in groundwater and effects of polluted water on public health
Project Coordinator: Prof C.V. Chrysikopoulos
The concentration of pathogenic biocolloids (e.g. bacteria and viruses), manufactured nanomaterials, organic wastes, inorganic chemical substances, pesticides, radioactive materials and pharmaceuticals in the subsurface environment is always increasing throughout the world affecting the potable water and the food chain. Potable water polluted from bacteria may cause typhoid fever, cholera, bacterial dysentery or enteritis to human, whereas when the water is polluted from viruses may cause infectious hepatitis and poliomyelitis. Various parameters such as temperature, water quality, formation type, water content, and presence of suspended in the aqueous phase matter (colloids), affect the transport and fate of biocolloids in the subsurface.
Clay minerals are the finest inorganic components in soils and sediments, which possess very high surface area to volume ratio and great affinity for biocolloids. Biocolloid transport in porous media is affected by physical factors (e.g. velocity and cell concentration), physiological characteristics (e.g. cell size and motility) and cell surface properties (e.g. lipopolysaccharides and hydrophobicity). The attachment of biocolloids onto the solid matrix of a formation is affected by the nature of biocolloid and mineral surfaces as well as by the chemistry of the fluid phase. Biocolloids can often be attached onto sand, clays, and natural suspended colloids. Worthy to note is that viruses attached onto clays may for longer time periods. Although a large number of studies focusing on various factors that affect microbial transport have been published over the past two decades, it is not fully understood yet how these factors concurrently affect biocolloid transport in porous media. In the recent years, nanotechnology has found widespread applications in various environmental, agricultural and industrial sectors. Although the various health and environmental effects of common metals have been thoroughly examined, when the metals take the form of nanomaterials there are numerous unanswered questions. Furthermore, the transport of nanomaterials in the subsurface, their toxicity and impact on human health if introduced in potable waters or in the food chain are yet to be explored.
The proposed research consists of a series of experimental and theoretical studies. Batch attachment and transport experiments are conducted. The batch experiments examine various biocolloid-clay interactions, biocolloid interaction with porous grains, and biocolloid/degradation-product toxicity. The flow-through transport experiments are designed at the bench- as well as pilot-scale, and examine biocolloid transport, and co-transport of biocolloids in the presence of clays. The theoretical developments focus on mathematical modelling of the processes taking place in the proposed experimental studies, and the development of appropriate model simulators. Also, a mathematical model is developed to estimate the risk to public health due to the presence of biocolloids in various waters.
The research project is coordinated by the Environmental Engineering Laboratory (UPeeL) in the Civil Engineering Department of University of Patras in conjunction with the Environmental Engineering Laboratory (TUCeeL) in the School of Environmental Engineering of Technical University of Crete. The work packages of the project are performed by UPeeL and TUCeeL in cooperation with the Environmental Microbiology Unit (EMU) of the Laboratory of Hygiene which belongs to the Department of Public Health (Faculty of Medicine, University of Patras).
The work packages (WP) and their assignment are as following:
- WP1: Dissemination of results (UPeeL, TUCeeL and EMU).
- WP2: Interactions between viruses, nanoparticles and clays (UPeeL, TUCeeL and EMU).
- WP3: Co-transport of bacteria, nanoparticles and clays in porous media (UPeeL and TUCeeL).
- WP4: Co-transport of viruses, nanoparticles and clays in porous media (UPeeL, TUCeeL and EMU
- WP5: Co-transport experiments of bacteria and nanoparticles in 3-D bench scale model aquifers (UPeeL and TUCeeL).