A riser for use with an access opening in a waste water treatment tank is mounted in a top opening in the waste water treatment tank. The riser includes a top portion and an integral bottom portion wherein the top portion is provided with a downwardly extending side wall and the bottom portion is provided with a downwardly extending skirt. The bottom portion is provided with an inner diameter greater than the outer diameter of the top portion and a ring connects the bottom portion to the top portion. The bottom portion is also provided with an inwardly extending flange having an inner terminating end engagable with the outer surface of the top portion. The top portion is provided with lugs at circumferentially spaced positions for engaging relation with slots in the flange portion for connecting adjacent risers in tandem. A plurality of risers may be connected to each other and in turn, the bottommost riser is connectable to the access opening and the uppermost riser is connectable to a cover usually at ground surface.
Regeneration of water treatment media is disclosed which includes a water treatment unit having one or more media therein, and which upon initiation of flow of the water, imparts turbulence and abrasion to the treatment medium to automatically cleanse the medium of light solid contaminants, as well as contaminant coatings on the media. This greatly improves the operation of the media and extends its life. In addition, the water treatment unit disclosed may simply be rotated through any one of a number of positions between service, backwash, flush, off, and/or bypass operational modes for further regeneration of the treatment media.
Water-treatment compositions are provided which contain a water-soluble, water-treatment polymer and, optionally, additional water-treatment chemicals. The polymers are prepared from water-treatment monomers and a photo-inert, latently-detectable moiety which is covalently bonded to the polymer backbone. When the residue of the photo-inert moiety is contacted with an amount of a photoactivator which is effective to cause the residue of the photo-inert moiety to absorb within a wavelength ranging from 300 to 800 nanometers, the residue of the photo-inert moiety is detectable at concentrations of less than 100 parts per million. Methods are also provided which allow for the determination of the concentration of low levels, i.e., less than 100 ppm, of the water-treatment polymer present in an aqueous system.