December, TKN concentrations in the septic tank are lower than any

concentrations from the past which indicates that the recirculating

sand filter is indeed lowering the concentration of nitrogen in the

septic tank.

     As is shown in figure 4.2, Total Nitrogen concentrations, a

measure of nitrate-N, ammonia-N, and organic-N,     within the pump

chamber   of  the   recirculating   sand  filter  have   also  been

decreasingly steadily since mid-November. By comparing figures 4.1

and 4.2, it becomes apparent that the Total amount of Nitrogen

present in both the septic tank and recirculating sand filter at

Site 1 has decreased significantly since the pump has been started.

Total Nitrogen concentrations of approximately 20 - 25 mg/l N are

being pumped to the drainfield       for disposal as compared to

concentrations of approximately 70 mg/l N before the system was
installed.

      However, as can be seen in Figure 4.3, the temperatures of the

 effluent in both the septic tank and the pump chamber of the sand

 filter have steadily declined since the pump was originally

 started. As of mid-January 1993, teiwperatures of the effluent in

 both the sand filter and the septic tank are approximately 50C,

 which   is  near  the   reported  minimum   temperature   for  both

 nitrification and denitrification processes.

      As can be seen in Figure 4.2, the level of nitrates present in
 the pump chamber of the recirculating sand filter have begun to

 decline since mid-November.   However, this may not be a result of

 the temperature limiting the nitrification process as much as it


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