A process for the production of surfactant compounds from a feed obtained from renewable sources, comprising hydrotreatment of feed in a fixed bed reactor having a plurality of catalytic zones disposed in series containing a hydrotreatment catalyst. The glass beads are placed in an inlet means and directed along a path around a drive means, which drive means imparts a velocity to the glass beads for subsequent delivery onto the surface through an outlet means. The welding of the first and second parts is provided at the flange. The tube further includes a sealing structure capable of forming a seal at the distal end of the tube during the surgery. Such a well treatment fluid, comprising a base fluid; a first fiber component that it substantially more dense than the base fluid; and a second fiber component that has a density close to that of the base fluid and is relatively flexible. After a user samples an environmental surface for an analyte of interest with the elution solvent wetted wick, the sampling member is returned to the base where the wick contacts the lateral flow strip contained in the base.