Water treatment tank

A water filtering and softening method comprising the steps of:

• (a) providing a water treatment tank operative in a treatment mode to receive untreated water through an inlet port means and to pass treated water through an outlet port means, and operative in a backwash mode to receive wash water through said outlet port means and to pass waste water through said inlet port means, said treatment tank comprising:
• a vessel having upstanding side walls extending between a top end wall and a bottom end wall to define an interior cavity, said top end wall having a pair of openings therethrough in fluid communication with said interior cavity to define an inlet port means and an outlet port means;
• a first distributor filter mounted within said interior cavity to extend between said side walls and spaced-apart from said top end wall to define a top headspace portion therebetween;
• a second distributor filter mounted within said interior cavity to extend between said side walls intermediate said first distributor filter and said bottom end wall, said second distributor filter spaced-apart from said bottom end wall to define a bottom headspace portion therebetween and from said first distributor filter to define a treatment bed space portion therebetween;
• a standpipe extending between and in fluid communication with said outlet port means and said bottom headspace portion, said stand pipe defining means for conveying treated water from said bottom headspace portion to said outlet port means when said treatment tank is operated in said treatment mode, and for conveying wash water from said outlet port means to said bottom head space portion when said treatment tank is operated in said backwash mode;
• a particulate ion-exchange resin filling said treatment bed space portion between said first and said second distributor filter;
• and
• a particulate filter medium supported by said first distributor filter and filling a portion of said top headspace portion, the unfilled portion of said top headspace portion defining a freeboard space, said free board space providing means for accommodating the expansion of said filter medium when said treatment tank is operated in said backwash mode;
• (b) operating said treatment tank in said treatment mode to pass untreated water through said filter medium and said ion-exchange resin and out through said standpipe until said resin is in need of regeneration;
• and
• (c) operating said treatment tank in said backwash mode to wash said filter medium.