Originally, it was hoped that through the use of solenoid

valves and a timing system it would be possible to pump effluent

from the sand filter to either the top of the sand filter, back to

the septic tank, or out to the drainfield or dosing chamber.

Unfortunately, we could find no reliable solenoid valves and thus

we could not pump the effluent to one place at a time.

     Gate valves located along the three destination lines allow us

to change the flow rate for the three destinations. By pumping to

all three locations at once and varying the flow rate to each

location, we have been able to accomplish our original goal of

pumping various amounts to each destination. This concept proved

to be much simpler and cheaper than the original plan and still

allows us the opportunity to change the amounts pumped to each

location at one time.

      The Denitrification System at Site 1 was retrofitted onto a

conventional septic system in July 16, 1992. Septic tank effluent

flows from the septic tank by gravity to the bottom of the sand

filter.   Once there, with the help of floats and timers, it is

pumped to the top of the sand filter, the septic tank, and the

drainfield at different rates.

      The Denitrification System at Site 2 was retrofitted onto the

 existing pressurized mound system in August 13, 1992.        A few

 differences between this system and the other system can be noted.
 Due to the depth of the existing system, effluent from the septic

 tank flows by gravity to a sewage ejector pit which was placed in

 the dosing chamber.  Through the use of floats, the effluent from