4.1  Site 1

     At Site 1, the Recirculating Sand Filter was installed in July

of  1992.    Unfortunately, the    electrician  who  designed   and

constructed our timing system encountered many problems debugging

the controls. Thus, we could not begin pumping the effluent from

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

and to the drainfield until early October.

     Once, the pump was started, it took approximately one month

before the nitrifying bacteria became adequately established to

begin nitrifying the effluent.     As can be seen in Figure 4.2,

nitrate levels in the pump chamber of the sand filter did not reach

detectable levels until mid November.       As the nitrate levels

increased, ammonia levels showed a corresponding decrease which

indicates that the nitrifying bacteria were indeed converting the

ammonia to nitrate.

      As of December, no detectable amounts of nitrate have been

 found in the septic tank.       This indicates that denitrifying

 bacteria are present in the septic tank and are able to convert any

 nitrate-N entering the septic tank to nitrogen gas.

      Furthermore, as can be seen in Figure 4.1, as of early

 November, TKN concentrations, which is a measure of both ammonia-N

 and organic-N, have begun to drop significantly in the septic tank.

 Since no appreciable amounts of nitrates have been found in the
 septic tank, the TKN concentration is a very accurate measure of

 the Total Nitrogen concentration of the septic tank.     As of late