Canter, L. W. and Knox, R. C. (1986).    Septic Tank System Effects
on Ground Water Ouality, Lewis Publishers, Inc., Chelsea,

Crites, R. W., Meyer, E. L., and Smith, R. G.    (1981).  Process
Design Manual for Land Treatment of Municipal Wastewater. EPA

Gaudy, A. F. and Gaudy, E. T.    (1980). Microbiolocry for
Environmental Scientists and Enaineers. McGraw-Hill Book Co.,
New York, N.Y.

Grady, C. P. L., and Lim, H. C.    (1980). Biological Wastewater
Treatment.   Marcel Dekker, Inc., New York, N.Y.
Kaplan, B.O0.    (1987) . Septic Systems Handbook.  Lewis
Publishers Inc., Chelsea, Michigan.

Kristiansen, R.    (1981a).  "Sand-filter trenches for purification
of septic tank effluent:    I.  The clogging mechanism and soil
physical environment". J. Environ. Qual. 10:353-357.

Kristiansen, R.    (1981b).  "Sand-filter trenches for purification
of septic taml effluent:    II.  The fate of nitrogen".   J.
Environ. Qual. 10:358-360.

Laak, R.    (1981).  "A passive denitrification system for on-site
systems".   Proceedings of Third National Symposium on Individual
and Samll Community Sewage Treatment. ASAE Pub. 1-82. pp. 108-
Laak, R., Parese, M. A., and Costello, R.     (1981).
",Denitrification of Blackwater with Greywater". J. Environ. Eng.
Div. , ASCE. 107: 581-590.
Lamb, B. E., Gold, A. J., Loomis, G. W., and McKiel, C. G.
  (1990).  "Nitrogen Removal for On-Site Sewage Disposal:   A
  Recirculating Sand Filter/Rock Tank Design".   Transactions of the
  ASAE, 33(2), pp. 525-531.

  Lance, J. C.  (1972).  "Nitrogen Removal by Soil Mechanisms". J.
  Water Poll. Control Fed.,   44:1352-1351.
  Lawrence, C. H. , (1973) . "Septic tank Performance".  Journal of
  Environmental Health, Vol. 36, No. 3, pp. 226-228.
  Rittman, B. F. and Langeland, W. E.   (1985).  "Simultaneous
  denitrification with nitrification in single-channel oxidation
  ditches". J. Water Poll. Control Fed. 57:300-308.