<PAGE>   1
                                                                   EXHIBIT 10.14




              AGREEMENT AND SEVENTH AMENDMENT TO CREDIT AGREEMENT
                                (August 1, 1996)


         THIS AGREEMENT AND SEVENTH AMENDMENT TO CREDIT AGREEMENT (this
"Amendment") is made and entered into as of August 1, 1996 by and among
ALLWASTE, INC. (the "Company"), a Delaware corporation, EACH OF THE FINANCIAL
INSTITUTIONS SIGNATORY HERETO (individually, a "Bank" and collectively, the
"Banks"), TEXAS COMMERCE BANK NATIONAL ASSOCIATION ("TCB"), a national banking
association acting as agent for the Banks (in such capacity, together with its
successors in such capacity, the "Agent"), and NATIONSBANK OF TEXAS, N.A., a
national banking association, as co-agent under the Credit Agreement (as
defined hereinafter) (in such capacity, the "Co-Agent").

RECITALS:

         A.      The Company, the Agent and the Banks have entered into a
Credit Agreement dated as of November 30, 1993 (which such Credit Agreement, as
the same may have heretofore been amended, modified, supplemented and restated
from time to time, is hereinafter called the "Credit Agreement").

         B.      The Company, the Agent, the Co-Agent and the Banks now desire
to amend the Credit Agreement in certain respects as provided hereinbelow.

AGREEMENTS:

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements, representations and warranties herein set forth, and for other good
and valuable consideration, the receipt and sufficiency of which are
acknowledged, the parties hereto do hereby agree as follows:

         1.      Net Worth Covenant Amended. Section 5.3(b) of the Credit
Agreement is hereby amended in its entirety to be and read as follows:

         "(b) have at all times a NET WORTH equal to (1) $113,291,000 plus (2)
         the Net Worth Floor Adjustment;"

         2.      Rate Hedging Agreement Approved. The Agent and the Banks
hereby ratify and confirm that each of them in advance approved, and each of
them does now acknowledge and approve, the Rate Hedging Agreement into which
the Company has entered with TCB and NationsBank ___________ in the form of a 
"Cap" on $30,000,000 for three (3) years at 7% on a 3-month LIBOR basis, all as
is required pursuant to Section 6.1(n) of the Credit Agreement.

         3.      Limitation on Investments Amended. Section 6.7(j) of the
Credit Agreement is hereby amended by deleting the amount "$10,000,000" where
it appears therein and substituting therefor the amount "$15,000,000."

         4.      Release of Guaranty of Hydrowash Recycling Systems, Inc. The
Agent and the Banks hereby acknowledge and consent to the sale by the Company
of the Stock of Hydrowash Recycling Systems, Inc. ("Hydrowash"), a Texas
corporation, on January 17, 1996 for the consideration of $350,000 to
<PAGE>   2
the original owners of Hydrowash Recycling Systems, Inc. and, further, the
Agent and the Banks do hereby agree that Hydrowash is released from its
liabilities under the Guaranties effective as of the date of such sale.

         5.      Delivery of Certificates of Existence, Good Standing, Etc.
With respect to each Guarantor, the Company hereby agrees to deliver to the
Agent, within thirty (30) days after the date hereof, certificates from the
appropriate public officials of each of the states where such Guarantor is
incorporated and conducts its business as to the continued existence, good
standing and authority to do business in those states.

         6.      Conditions. No part of this Amendment shall become effective
until the Company shall have delivered (or shall have caused to be delivered)
to the Agent each of the following, in Proper Form:

         (a)     a certificate from the Secretary of State or other appropriate
                 public official of the State of Delaware as to the continued
                 existence and good standing of the Company in the State of
                 Delaware;

         (b)     a certificate from the Secretary of State or other appropriate
                 public official of the State of Texas as to the qualification
                 of the Company to do business in the State of Texas;

         (c)     a certificate from the Office of the Comptroller of the State
                 of Texas as to the good standing of the Company in the State
                 of Texas;

         (d)     a legal opinion from the general counsel for the Company and
                 the Current Guarantors acceptable to the Agent in its sole and
                 absolute discretion;

         (e)     certificates dated as of the date hereof of the Secretary or
                 any Assistant Secretary of the Company and each of the
                 Guarantors as of the date hereof, and such other documents and
                 information as the Banks may request;

         (f)     a Consent, in Proper Form, executed by of all of the
                 Guarantors to the execution and delivery of this Amendment and
                 such other related matters as the Banks may reasonably
                 require;

         (g)     a Notice of Entire Agreement and Release of Claims executed by
                 the Company and each of the Guarantors as of the date hereof,
                 and

         (h)     the amendment fee payable to each Bank as provided in Section
                 2.16 of the Credit Agreement.

         7.      Representations True; No Default. The Company represents and
warrants that the representations and warranties contained in Section 4 of the
Credit Agreement and in the other Loan Documents are true and correct in all
material respects on and as of the date hereof as though made on and as of such
date. The Company hereby certifies that no Default or Event of Default under
the Credit Agreement or any of the other Loan Documents has occurred and is
continuing as of the date hereof.
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         8.      Ratification. Except as expressly amended hereby, the Credit
Agreement and the other Loan Documents shall remain in full force and effect.
In the event of any conflict between this Amendment and the Credit Agreement or
any of the other Loan Documents (or any earlier modification of any of them),
this Amendment shall control. The Credit Agreement, as hereby amended, and all
rights and powers created thereby or thereunder and under the other Loan
Documents are in all respects ratified and confirmed and remain in full force
and effect.

         9.      Definitions and References. Terms used herein which are
defined in the Credit Agreement or in the other Loan Documents shall have the
meanings therein ascribed to them. The term "Credit Agreement" as used in the
Credit Agreement, the other Loan Documents or any other instrument, document or
writing furnished to the Agent, the Co-Agent or any of the Banks by the Company
shall mean the Credit Agreement as hereby amended.

         10.     Miscellaneous. This Amendment (a) shall be binding upon and
inure to the benefit of the Company, the Banks, the Agent, the Co-Agent and
their respective successors, assigns, receivers and trustees (provided,
however, that the Company shall not assign its rights hereunder without the
prior written consent of the Agent); (b) may be modified or amended only by a
writing signed by each party; (c) SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS AND THE UNITED STATES OF
AMERICA; (d) may be executed in several counterparts, and by the parties hereto
on separate counterparts, and each counterpart, when so executed and delivered,
shall constitute an original agreement, and all such separate counterparts
shall constitute but one and the same agreement; and (e) together with the
other Loan Documents, embodies the entire agreement and understanding between
the parties with respect to the subject matter hereof and supersedes all prior
agreements, consents and understandings relating to such subject matter. The
headings herein shall be accorded no significance in interpreting this
Amendment.

         IN WITNESS WHEREOF, the Company, the Banks, the Agent and the Co-Agent
have caused this Amendment to be signed by their respective duly authorized
officers, effective as of the date which first appears hereinabove.

                                          ALLWASTE, INC.,
                                          a Delaware corporation


                                          By: /s/ T. Wayne Wren, Jr.            
                                             -----------------------------------
                                          T. Wayne Wren, Senior Vice President


ATTEST:


 /s/ William L. Fiedler                                     
-----------------------------
William L. Fiedler, Secretary


Attachments:
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Schedule I - Non-guaranteeing Subsidiaries
             and Dormant Subsidiaries
<PAGE>   5


                                   TEXAS COMMERCE BANK, 
                                   NATIONAL ASSOCIATION, 
                                   a national banking association, 
                                   as a Bank and as Agent



                                   By: /s/ C. D. Karges                      
                                      -----------------------------
                                       C. D. Karges,
                                       Senior Vice President
<PAGE>   6





                                        NATIONSBANK OF TEXAS, N.A., a national
                                                  banking association, as a
                                                  Bank and as Co-Agent


                                        By: /s/ Forest Scott Sinehuff 
                                           -----------------------------
                                        Name: Forest Scott Sinehuff
                                              --------------------------
                                        Title: Senior Vice President
                                               -------------------------
<PAGE>   7





                                        BANK OF AMERICA TEXAS, N.A., 
                                         a national banking association



                                        By: /s/ Victor N. Tekell 
                                           ---------------------------------
                                            Victor N. Tekell, Vice President
<PAGE>   8





                                        FIRST INTERSTATE BANK OF TEXAS, N.A, 
                                        a national banking association


                                        By: /s/ Christopher King 
                                           --------------------------------
                                        Name: Christopher King 
                                              -----------------------------
                                        Title: Assistant Vice President
                                               ----------------------------



<PAGE>   9





                                        THE BANK OF NOVA SCOTIA


                                        By: /s/ F. C. H. Ashby 
                                           ----------------------------------
                                        Name:  F.C.H. Ashby 
                                             --------------------------------
                                        Title: Senior Manager Loan Operations
                                              -------------------------------


<PAGE>   10





                                        COMERICA BANK-TEXAS,
                                        a Texas banking association


                                        By: /s/ Eric Lundquist 
                                           ----------------------------
                                        Name: Eric Lundquist 
                                             --------------------------
                                        Title: Assistant Vice President
                                              -------------------------
<PAGE>   11





                                        LTCB TRUST COMPANY, 
                                        a New York Trust Company


                                        By: /s/ John J. Sullivan 
                                           --------------------------------
                                        Name: John J. Sullivan 
                                             ------------------------------
                                        Title: Executive Vice President
                                              -----------------------------
<PAGE>   12





                                        ABN AMRO BANK N.V., HOUSTON AGENCY

                                        By: ABN AMRO North America, Inc. 
                                            As Agent


                                        By: /s/ Laurie C. Tuzo 
                                           -------------------------------
                                        Name: Laurie C. Tuzo 
                                             -----------------------------  
                                        Title: Vice President and Director
                                             -----------------------------


                                        By: /s/ Lila Jordan 
                                           -------------------------------
                                        Name: Lila Jordan
                                             -----------------------------
                                        Title: Vice President and Director
                                              ----------------------------
<PAGE>   13



                                   SCHEDULE I


NON-GUARANTORS:

Allwaste Asbestos Abatement of New England, Inc.
Allwaste Environmental Services/North Central, Inc. (ILLINOIS CORP-FOR UNION
PURPOSES ONLY)
Allwaste of Canada Ltd.
Allwaste Servicios Industriales de Control Ecologico S.A. de C.V.
Allwaste Tank Services S.A. de C.V.
Caligo de Mexico, S.A. de C.V.
Caligo Reinigungsges m.b.H.