Abstract: A method for determining air borne bacteria which includes successive steps of passing a volume of air by a timed suction pump through a membrane filter at a membrane passing velocity of not more than 15 cm/sec and under a constant transmembrane pressure of not more than 100 mmHg to collect the air borne bacteria on the surface of the membrane filter. The membrane filter has a multiplicity of minute holes and is provided on a medium-absorbing pad housed in a holder. A medium is injected into the medium-absorbing pad housed in said holder. The bacteria thus collected are incubated and the number of the colonies developed on the surface of said membrane filter is measured.

Abstract: A brine recycling method where the used brine containing metal ions is added with a reaction agent to provide a agent-added brine. The reaction agent is of a kind which, when it is reacted with the metal ions, produces an insoluble substance, excluding an oxidant which, when reacted with oxygen, produces metal oxide. The agent-added brine is subsequently filtrated with the use of a microporous filtration membrane having an average pore size within the range of 0.005 to 1 .mu.m. A brine recycling apparatus is also disclosed which includes a filter module containing a microporous filtration membrane having an average pore size within the range of 0.005 to 1 .mu.m. The used brine is, after having been added with the reaction agent, supplied through a supply passage into the filter module. The filtrate is then removed from the filter module through a recovery passage.

Abstract: A method for treating blood uses a tubular body fluid passageway member at least part of which is made of a flexible material, an outer tubular member which is made of a nonflexible material and contains said tubular body fluid passageway member hermetically enclosed therein, a pressure detecting member for monitoring the pressure of the flowing body fluid by means of a fluid filled in the hermetically closed space between the outside surface of said tubular body fluid passageway member and said outer tubular member without substantial contact of the body fluid with air, and a body fluid filtering member comprising a filter. The method is especially useful for non-anticoagulant hemodialysis.