Membrane cleaning protocol

Most chemical cleaning protocols consist of an alkali detergent step followed by an acid step, with appropriate rinses in between. However, for polymeric membranes, it is also common to follow the acid cleaning step with a second alkali cleaning step supplemented with chlorine as this further improves flux [176,179]. In some cases, acid cleaning has been recommended as the first step, especially for whey applications, where mineral fouling maybe more important than protein fouhng [176]. 

There are a wide variety of cleaning mixtures and protocols recommended by either membrane scientists or membrane manufacturers in the open literature, but none of them are versatile for the range of industrial applications. The membrane-cleaning... 

Approximately one liter of rainfall-runoff solution was collected from each of three experimental racks following rainfall events. Limestone and marble reference rocks were in two of the racks a third rack without a rock was used as a control (hereinafter referred to as a blank sample). Runoff volume, specific conductance, and pH measurements were determined at the exposure site as soon as possible after collection, typically within a few hours. Samples then were filtered through a 0.45-micrometer pore size membrane filter, placed in a clean polyethlyene bottle, and sent to the U.S. Geological Survey laboratory in Denver, Colorado, for chemical analysis. Sample preparation, analytical procedures, and laboratory quality-control protocols are described by Skougstad et al. (6). 

DNA contamination is diCBcult to remove from S. aureus RNA preparations. The protocol below uses a single on column DNase digestion followed by two consecutive RNA clean-up assays. The RNeasy silica-membrane removes DNA therefore, additional clean-up steps are used to aid in removal of contaminating S. aureus DNA. 

---