What defines 'void clogging' in a high-rate filter system?

Void clogging in a high-rate filter system refers to the phenomenon where the spaces or "voids" within the filter media are obstructed by the accumulation of solids. When particles accumulate in these voids, it decreases the available pathways for water to flow through the filter, leading to a reduction in flow rate and overall efficiency of the filtration process. This obstruction can significantly impact the system's performance, resulting in increased pressure drops and potential failure to meet water quality standards.

The other concepts mentioned in the remaining options do not align with the definition of void clogging. For instance, biological growth enhancing filtration describes a beneficial process where microorganisms help improve filtration, rather than obstruct it. Excessive chemical injection reactions may lead to issues such as chemical imbalance or treatment inefficiency but are not specifically related to the clogging of voids within the filter media. Lastly, improper media sizing can lead to operational issues but pertains to physical dimensions of the media rather than the accumulation of particles that characterize void clogging.