<PAGE>   1
                                                                    EXHIBIT 2.2


                          SALE AND PURCHASE AGREEMENT


         This Agreement made and entered into by and between OrganiGro, Inc.,
an Arkansas corporation and a wholly owned subsidiary of Synagro Technologies,
Inc. (the parent), a Delaware corporation, hereinafter called "Sellers" and
Hodges Heavy Duty Truck Repair, Inc., an Arkansas corporation, Tony D.
Childers, an individual, and Jack Hodges, an individual, hereinafter called
"Buyers."

         WITNESSETH:

1)   AGREEMENT OF SALE AND PURCHASE:  This is a sale of assets on location at
     3821 S. Arkansas Ave., Russellville, Arkansas 72801, and other assets
     detailed on Schedule A and as well, the assumption of stated debt and
     trade payables effective March 26, 1997.  The total purchase price shall
     be Nine Hundred Ten Thousand Dollars ($910,000).

2)   The Buyers shall pay the Sellers the sum of Nine Hundred Ten Thousand
     Dollars ($910,000) through and including the following:

     A)     Buyers shall assume debt, effective March 26, 1997, from the
            Sellers of $600,704 as detailed and stated herein.  All guarantees
            by parent, OrganiGro or management personnel will be released with
            the new financing of this debt.

<TABLE>
<CAPTION>
                                                                             Balance
Payee                     Note #           Note Date        Face Amt.        3/26/97
-----                     ------------     ---------        -------------    -------------
<S>                       <C>              <C>              <C>              <C>
Arkansas Valley Bank      44666            12-Feb-93        $   43,894.48    $   21,063.78
Bank of Dardannelle       0095296245       18-Aug-94        $    6,440.29    $    1,179.75
Bank of Dardannelle       0095296886       10-March-94      $    6,500.00    $       17.84
Boatmen's Bank            7135750-9001     Jul-94           $  465,000.00    $  415,926.26
Boatmen's Bank            7363257-0001     Jun-95           $  279,000.00    $  163,609.57
</TABLE>

    B)   Additionally, the Buyers will sign a promissory note with interest at
         6% per annum and a guarantee agreement in the amount of $308,203 and
         the Sellers will receive a second lien on all assets detailed in
         Schedule A.

3)   SERVICE AGREEMENT:  Sellers hereby agree to use Buyers' services at a rate
     of $2,500 per month for a period of sixty (60) months, with said services
     defined in Schedule B.  These monthly service fees shall be applied to the
     note agreement.  Should any of these services not be performed in a manner
     satisfactory to Sellers, in their sole discretion, then this article 4 
     will be null and void upon written documentation via certified mail to 
     Buyers as of the date of that certified letter and all future applications





<PAGE>   2
     of these service payments to the note agreement will cease with no other
     obligations by Sellers.

4)   ADDITIONAL SERVICE OPTION:  Additionally, Sellers agree to provide Buyers
     an additional Service Option ("Option") for all repair work on owned
     vehicles of parent and its subsidiaries within the State of Arkansas.
     This option to Buyers will only be valid and enforceable if Buyers'
     quotation for the repair services are priced at or below a competitive
     quotation and the quality of work performed is satisfactory to Sellers.
     It is further agreed to by the Sellers and Buyers that any and all
     decisions made for repairs under this Option will be at the sole
     discretion of Sellers.  It is understood by Buyers that this article in
     its entirety can be canceled if the pricing and quality of work is not
     satisfactory to Sellers.  It is further understood that this particular
     article 5 will be null and void without creating any other changes to this
     sale and purchase agreement.

5)   COVENANT NOT TO COMPETE:  Sellers covenants and agrees that they will not
     compete directly or indirectly, will not open, own, assist, advise or
     operate a heavy duty truck repair shop, except that should Sellers decide
     to open its own repair shop for services on its owned assets, this would
     not be considered a violation of the Agreement.

6)   EFFECTIVE DATE:  The effective date of this agreement shall be upon
     signing with a thirty (30) day period for Buyers to refinance the assumed
     debt per article 2A.

7)   This sale includes the assignment of any rights and interests Sellers have
     in their present contracts, purchase orders, and oral and written
     agreements concerning the truck repair business by outside, independent
     customers.

8)   Sellers warranties that all assets, equipment and inventory is free and
     clear of any encumbrances except those stipulated in item 2A above.

9)   If any payment shall remain unpaid under the Promissory Note Agreement for
     thirty (30) days, upon written notice to Buyers by Sellers, by registered
     mail, of the delinquency, the Buyers shall have fifteen (15) days to cure
     the delinquency.  If the Buyers fails to cure the delinquency, the Buyers
     shall be in default, and the entire balance shall be accelerated, due and
     payable.  The acceleration shall occur without any further notice from
     Sellers.  Additionally, should Buyers default on any other debt obligation
     assumed in 2A above, and not cured within the stated cure period, then the
     promissory note will be due and payable immediately.

10)  Sellers shall be liable for all acts of the employees, etc. up to the date
     of this agreement and Buyers shall be liable for all acts of his employees
     after said date.





                                       2
<PAGE>   3
11)  It is agreed that certain employment agreements dated October 1, 1994 by
     and between OrganiGro, Inc. and/or Synagro Technologies, Inc. (formerly
     N-Viro Recovery, Inc.) collectively Sellers and Mr. Jack Hodges and Mr.
     Tony D.  Childers are hereby canceled.

12)  Reference is made to a certain asset exchange agreement by and among
     OrganiGro, Inc. and N-Viro Recovery, Inc.  (currently Synagro
     Technologies, Inc.) and Hodges Heavy Duty Truck Parts and Services, Inc.
     dated as of October 1, 1994.  This reference is made to specifically
     unwind this Purchase Agreement and consider all warranties,
     representations and other data contained therein to be rescinded and the
     parties in this agreement agree to assume all existing, prior and future
     liabilities that may become known now or in the future.

13)  MISCELLANEOUS PROVISIONS:  Sellers and Buyers further agree as follows:

     A)   Buyers will have inspected all the assets to be sold under this
          Agreement and accept such assets in an "as is" condition without
          express or implied warranties of any kind as to fitness or
          mercantability.

     B)   Each corporate entity, Sellers and Buyers, shall enact all corporate
          resolutions and acts necessary to authorize the corporation and/or
          individuals to perform all the terms and conditions of this Sale and
          Purchase Agreement.

     C)   Any notice, consent, request, claim or other communication hereunder
          shall be in writing and shall be deemed to have been duly given if
          delivered or mailed by registered and/or certified mail, return
          receipt requested, to the address shown for the respective parties at
          the conclusion of this Agreement.  Such addresses may be changed by
          any party by notice given in the manner provided above.

     D)   In the event either party to this Agreement shall employ legal
          counsel to protect its rights under this Agreement or to enforce any
          term or provision of this Agreement, then the party prevailing in any
          such legal action shall have the right to recover from the other
          party all of its reasonable attorneys' fees, costs and expenses
          incurred in relation to such claim.

     E)   This Agreement, together with all exhibits and the documents referred
          to herein, contain all the terms and conditions agreed upon by the
          parties hereto with respect to the transactions contemplated hereby,
          and shall not be amended or modified except by written instrument
          signed by all the parties.

     F)   This Agreement shall be binding upon and inure to the benefits of the
          representatives, heirs, estates, successors and assigns to the
          parties hereto.





                                       3
<PAGE>   4
     G)   Nothing expressed or implied in this Agreement is indented or shall
          be construed, to confer upon or give any person, firm or corporation,
          other than the parties hereto, their successors, assigns, any
          benefits, rights or remedies under or by reason of this Agreement.

     H)   This Agreement may be executed simultaneously in two (2) or more
          counterparts, each of which shall be deemed an original, but all of
          which shall constitute one and the same instrument.

     I)   Whenever in this Agreement it is provided that any party shall or
          will make any payment or perform or refrain from performing any act
          or obligation, each such provision shall be construed, even though
          not so expressed, as an express agreement to make such payment or to
          perform, as the case may be, such act or obligation.

     J)   Sellers warrants ownership of all assets being sold and warrants they
          are free and clear of any debt, except as scheduled in article 2A.

     K)   This Agreement shall be governed by and construed under the laws of
          the State of Arkansas.

     L)   Upon closing, Buyers and Sellers agree to sign any documents
          necessary to complete this sale as per its terms and conditions.
          This includes titles, deeds, bills of sale, franchise agreements,
          fund remittance, or any other documents necessary to carry out this
          contract.

14)  Buyers shall maintain adequate insurance coverage satisfactory to Sellers
     in an amount sufficient to cover the balance owed to Sellers.  Proof of
     said coverage shall be provided to Sellers by Buyers.  Sellers shall be
     shown as a loss payee as per their interest on said insurance coverage.

15)  OrganiGro agrees to pay all Hodges employees' payroll through March 30,
     1997.

16)  It is agreed that all amounts owed by Sellers and/or its subsidiary, CDR
     Environmental, Inc., are paid in full as of the date of this agreement.

17)  It is agreed to by Buyers that any debts, obligations, taxes or other
     liabilities discovered at any time in the future are to be assumed by
     Buyers.





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<PAGE>   5
         In witness of the parties have hereunto set their hands this 1st day
of April, 1997.



SELLERS
ORGANIGRO, INC.                                SYNAGRO TECHNOLOGIES, INC.


/s/  Donald L. Thone                           /s/  Donald L. Thone        
--------------------------------------         ---------------------------------
Chairman                                       President


                     ATTEST:

                     /s/  Daniel L. Shook                      
                     ----------------------------------     

BUYERS

/s/  Jack Hodges                            /s/  Tony D. Childers              
----------------------------                ------------------------------------
HODGES HEAVY DUTY TRUCK                     TONY D. CHILDERS, an individual    
REPAIR, INC.


Its                  President                 
    -------------------------------------------



/s/  Jack Hodges                  
--------------------------------------
JACK HODGES, an individual

                     ATTEST:

                     /s/  Tony D. Childers             
                     -------------------------------------------





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<PAGE>   6

                          SALE AND PURCHASE AGREEMENT

                      HODGES HEAVY DUTY TRUCK REPAIR, INC.



                                   SCHEDULE A



<TABLE>
<CAPTION>
See detailed fixed asset listing attached hereto.        Stated Value
                                                         ------------
<S>                                                      <C>
Accounts Receivable (see Schedule A-1)                    $109,643.86

Inventory (see Schedule A-2)                              $270,972.50

Fixed Assets (see Schedule A-3)                           $620,069.10

Accounts Payable (see Schedule A-4)                       $ 28,210.98
</TABLE>





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<PAGE>   7
                          SALE AND PURCHASE AGREEMENT

                      HODGES HEAVY DUTY TRUCK REPAIR, INC.


                                   SCHEDULE B


                            RENTAL/SERVICE AGREEMENT

         This Agreement is entered into by and between Hodges Heavy Duty Truck
Repair and CDR-Russellville, a subsidiary of Synagro Technologies, Inc.  This
Agreement shall be effective April 1, 1997 pending the sale agreement by and
between Synagro Technologies and Hodges Heavy Duty Truck Repair.

                                AGREEMENT TERMS

         CDR-Russellville will owe Hodges Heavy Duty Truck Repair $2,500.00 the
         first of every month in arrears, for a period of five years for the 
         following services.
        
         $1,000.00 per month will be for rental of one service bay in the Hodges
         Heavy Duty Truck Parts Shop in Russellville, Arkansas.  $1,500.00 will
         be for the use of the tire bay and wash bay facilities. Hodges Heavy
         Duty Truck Repair will provide a tire man, service truck and tools for
         tire work and tire repairs for CDR-Russellville trucks and equipment
         for six days per week, being Monday through Saturday (Sundays
         excluded).

         It is agreed that the payment of this rent and services will be
         credited by Synagro Technologies, Inc. to the note held by Synagro
         Technologies, Inc. and/or OrganiGro, Inc. against Hodges Heavy Duty
         Truck Parts and Service on the first of each month, in arrears.





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