A method of removing charged contaminants from a fluid is provided. The method may include providing a filtration membrane in a fluid passageway, flowing a fluid through the fluid passageway and through the filtration membrane, and generating an electromagnetic field within the passageway at a location upstream from the filtration membrane to pretreat the fluid prior to the filtration membrane to enable the charged contaminants to precipitate out of solution. The method may further include generating an electric field across the filtration membrane at an amount effective to separate and degrade the charged contaminants on a first side of the filtration membrane. Methods of removing charged nutrients from a fluid are also provided.

The invention relates to a filtration system for use in a method of determining the presence and/or amount of cells, for example, viable cells, in a liquid sample, and to methods of using and manufacturing such a filtration system. The filtration system includes a cup with an upper portion and a ring portion, where the ring portion is separably coupled to the upper portion.