<PAGE>   1
                                                                   EXHIBIT 10.01
               
               FURTHER AMENDED AGREEMENT AS OF DECEMBER 20, 1996

               FURTHER AMENDMENT dated December 20, 1996 to that certain License
Agreement  made and entered into as of the 27th day of May, 1986, as amended by
that certain Further Amended Agreement dated October 4, 1994 (together
hereinafter referred to as the "License Agreement") by and between Long
Enterprises, Inc., a corporation organized and existing under the laws of the
State of Alabama, hereinafter referred to as "Long," and Synox Corporation, a
Delaware corporation, having its principal place of business at 3918 Montclair
Road, Suite 206, Birmingham, Alabama 35213, hereinafter referred to as "Synox."

                                   WITNESSETH

     WHEREAS Synox and Long have entered into the aforesaid License Agreement;
and
     WHEREAS the parties desire to extend and restate the option terms in this
Amendment, superseding all conflicting provisions of the License Agreement; and

     WHEREAS Long has acquired or developed improved know-how, trade secrets
and has acquired United States Patent Number 4,487,699, Sewage Sludge Treatment
with Gas Injection, expiring September 28, 2010, which along with the know-how,
trade secrets, and the patents and patent application listed in the License
Agreement is collectively referred to herein as the "Improvements," and desires
to conform the licensing of same to Synox pursuant to the License Agreement as
hereby amended and to confirm that the aforesaid option terms also relate to
the Improvements; and

     WHEREAS the parties mutually desire to amend certain other information and
grant certain waivers on account of changed circumstances.

     NOW, THEREFORE, in consideration of the premises and the mutual covenants
and undertakings set forth herein and for other good and valuable
consideration, the receipt and sufficiency whereof is acknowledged, the parties
hereto agree as follows:

1.   Subparagraph I of Section I of the License Agreement is hereby amended to
     read as follows:

      I.   "LONG LICENSE EXPIRATION" shall mean September 28, 2010 or
           the later date of termination of the last to expire of any patent
           issued pursuant to the patent applications and continuations-in-part
           in existence on May 16, 1991 and thereafter prosecuted by Long or
           its assignor, Charles A. Long, Jr.

2.   Long confirms that its grant to Synox of license and rights set forth in
     Section II of the License Agreement shall extend to the Improvements
     defined above and the Patent Rights, as used in the License Agreement,
     shall be deemed to include the Improvements.

3.   The provisions of Section XIV of the License Agreement are retained,
     except that the addresses for Long and for Synox, respectively, are
     amended as follows:



<PAGE>   2

     For Long:
            Charles A. Long, Jr.
            P.O. Box 130062
            Birmingham, Alabama  35213

     For Synox:
            Synox Corporation
            Attn:  William J. Long
            3918 Montclair Road, Suite 203
            Birmingham, Alabama   35213

4.   With respect to Schedule D to the License Agreement, all provisions are
     retained except that the section titled Minimum Royalty is amended as
     follows:

<TABLE>
<CAPTION>
                                                             PER
                                               TERRITORY    CAPITA    ANNUAL
                 PERIOD                        POPULATION    RATE     ROYALTY
                 -------                       ----------    ----     -------
 <S>                                           <C>          <C>     <C>
   January 1, 1997 - December 1, 1997          90,335,511    .001   $      0.00
   January 1, 1998 - December 1, 1998          90,335,511    .001   $ 90,335.51
   January 1, 1999 - December 1, 1999          90,335,511    .002   $180,671.02
   January 1, 2000 - December 1, 2000          90,335,511    .002   $180,671.02
 January 1, 1997 - Long License Expiration     90,335,511   .0025   $225,838.77
</TABLE>

IN WITNESS WHEREOF, the parties hereto have executed and sealed this Agreement
as of December 20, 1996.



ATTEST:                                  LONG ENTERPRISES, INC.
 
/s/ William J. Long                      By: /s/ Charles A. Long Jr.
--------------------------------            --------------------------------
                                         Its President


ATTEST:                                  SYNOX CORPORATION

/s/ Faye B. Johnston                     By: /s/ William J. Long
--------------------------------            --------------------------------
                                         Its President