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                                                                    EXHIBIT 4(d)

                       THIRD AMENDMENT TO CREDIT AGREEMENT


         THIS THIRD AMENDMENT TO CREDIT AGREEMENT (the "Amendment"), dated as of
May 11, 2001 (the "Effective Date"), is entered into by and among MPW Industrial
Services Group, Inc. ("MPW Group"), Aquatech Environmental, Inc., each of the
other Subsidiaries of MPW Group listed on the Schedule of Subsidiary Borrowers
attached hereto, the Lenders listed on the signature pages of this Amendment,
Bank One, NA (Main Office Columbus), as Administrative Agent and LC Issuer, and
National City Bank, as Documentation Agent.

                             Background Information
                             ----------------------

         A. Borrowers, Lenders, Administrative Agent, LC Issuer and
Documentation Agent entered into a certain Credit Agreement, dated as of October
20, 1999, as amended by a (i) First Amendment to Credit Agreement and Other Loan
Documents, dated as of July 17, 2000, and (ii) Second Amendment to Credit
Agreement, dated as of November 10, 2000 (such credit agreement, as so amended,
the "Agreement").

         B. Lenders have extended a revolving line of credit loan (the
"Revolving Loan") to Borrowers in the maximum principal amount of $70,000,000
pursuant to the Agreement.

         C. Borrowers have requested certain amendments to the Agreement and to
the terms of the Revolving Loan, and Lenders are willing to consent to such
request, upon and subject to the terms and conditions set forth herein.

         D. MPW Group has advised Administrative Agent of its desire to enter
into a Stock Purchase Agreement (the "Filtration Agreement") with CLARCOR, Inc.
and CLARCOR Filtration Products, Inc. whereby MPW Group and its subsidiaries
will sell all of the issued and outstanding equity interests or shares of
capital stock (the "Sale Event") of MPW Filtration Management Services Corp., an
Ohio corporation ("MPW Filtration"), ESI International, Inc., an Ohio
corporation, ESI-North Limited, an Ohio limited liability company, Gauthier
Enterprises, Inc., a Michigan corporation, and MPW Industrial, Sociedad de
Responsibilidad Limitada de Capital Variable, a Mexican limited liability
company (collectively, the "Filtration Entities"), each a Borrower or Guarantor.
Prior to the consummation of the Sale Event, Borrowers and Guarantors desire to
effect an internal reorganization (the "Filtration Reorganization") of the
Filtration Entities such that each of the Filtration Entities, other than MPW
Filtration, will become a direct or indirect subsidiary of MPW Filtration.

         E. MPW Group has requested the consent of Lenders to the Sale Event and
the Filtration Reorganization.

         F. Lenders are willing to consent to the Sale Event and the Filtration
Reorganization, which requires that, simultaneously with the consummation of the
Sale Event, (i) the Filtration Entities be released from their respective
obligations under the Agreement, the Security Agreement and the other Loan
Documents, and (ii) all security interests, liens and pledges granted by the

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Filtration Entities with respect to their respective property to Administrative
Agent for the benefit of Lenders pursuant to the Security Agreement be
terminated and released.

                                   Provisions
                                   ----------

         NOW, THEREFORE, in consideration of their mutual agreements hereunder
and under the Agreement, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, Borrowers,
Administrative Agent, Lenders, Documentation Agent and LC Issuer, hereby agree
as follows:

         1.       CAPITALIZED  TERMS.  Except as otherwise  defined herein,
the capitalized terms used herein shall have the same meanings as set forth in
the Agreement.

         2.       AMENDMENT OF THE AGREEMENT; OTHER MATTERS.

                  2.1.     DEFINITIONS.

                           (a)      The following definition set forth in
                  Article I of the Agreement shall be amended in its entirety to
                  provide as follows:

                                    ""Consolidated Net Income" means, with
                           reference to any period, the net income (or loss)
                           from continuing operations of the Borrowers and their
                           Subsidiaries calculated on a consolidated basis for
                           such period. For purposes of this definition,
                           "continuing operations" shall be the continuing
                           operations of the Borrowers as set forth in MPW
                           Group's Form 10-Q filing made with the Securities and
                           Exchange Commission for the fiscal quarter ended
                           March 31, 2001. "

                           (b)      The following new definition shall be added
                  in alphabetical order to Article I of the Agreement:

                                    ""Filtration Division" means MPW Filtration
                           Management Services Corp., ESI International, Inc.,
                           ESI-North Limited, Gauthier Enterprises, Inc. and MPW
                           Industrial, Sociedad de Responsibilidad Limitada de
                           Capital Variable."

                  2.2.     REDUCTION OF AGGREGATE COMMITMENT AND EACH LENDER'S
         COMMITMENT.

                           (i) Borrowers have requested that the Aggregate
         Commitment be reduced from $70,000,000 to $47,500,000 upon the earlier
         to occur of (x) the date the Sale Event is consummated, and (y) August
         10, 2001, and upon such earlier occurrence, the Aggregate Commitment
         shall be reduced to $47,500,000, and the Commitment of each Lender
         shall be reduced on a pro rata basis, and the Commitment of each Lender
         then shall be as follows:

                           Lender                                Commitment
                           ------                                ----------
                           Bank One, NA                          $19,000,000



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                           National City Bank                     16,625,000
                           LaSalle Bank National Association       5,937,500
                           Suntrust Bank                           5,937,500

                           (ii) On the effective date of the reduction of the
         Aggregate Commitment pursuant to subsection (i) above, Borrowers shall
         prepay Advances to the extent, if any, the then Aggregate Outstanding
         Credit Exposure exceeds the Aggregate Commitment as so reduced.

                           (iii) If the Sale Event is consummated, the Borrowers
         shall furnish to Administrative Agent a summary report regarding the
         calculation of the net proceeds realized from the Sale Event as soon as
         possible, but in any event within 120 days after the closing date of
         the Sale Event. In addition to the reduction of the Aggregate
         Commitment in accordance with subsection (i) above, if the net proceeds
         of the Sale Event as so reported exceed $22,500,000, the Aggregate
         Commitment shall be further reduced to the extent the net proceeds of
         the Sale Event exceed $22,500,000, with such reduction being rounded to
         the nearest multiple of $100,000, provided that the Aggregate
         Commitment shall not be reduced to less than $45,000,000. Any such
         additional reduction in the Aggregate Commitment shall be effective
         five (5) Business Days after the receipt by Administrative Agent of
         such summary report and the Commitment of each Lender shall be reduced
         on a pro rata basis on such date.

                           (iv) On the effective date of any reduction of the
         Aggregate Commitment pursuant to subsection (iii) above, Borrowers
         shall prepay Advances to the extent, if any, the then Aggregate
         Outstanding Credit Exposure exceeds the Aggregate Commitment as so
         reduced.

                           (v) Borrowers acknowledge and agree that because of
         this request and their previous request dated August 30, 2000 to reduce
         the Aggregate Commitment, Borrowers' option to propose an increase in
         the Aggregate Commitment pursuant to Section 2.22 of the Agreement has
         been terminated.

                  2.3.     REFERENCE TO SECTION. The reference to "Section 2.19"
in the definition of "Response Date" set forth in Article I of the Agreement is
hereby amended to be a reference to "Section 2.20(i)".

                  2.4.     EXTENSION OF FACILITY TERMINATION DATE.

                           (i) The period during which Borrowers have the option
         to request an extension of the Facility Termination Date as set forth
         in Section 2.20(i) of the Agreement shall be reduced from one-year to
         six months prior to the Facility Termination Date and the first
         sentence of Section 2.20(i) of the Agreement shall be amended in its
         entirety to provide as follows:

                           "The Borrowers may request a one-year extension of
                  the Facility Termination Date by submitting a request for an
                  extension to the Administrative Agent (an

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                  "Extension Request") no more than 60 days prior to the date
                  which is six months prior to the Facility Termination Date."


                           (ii) The option of Borrowers to request an additional
         one-year extension of the Facility Termination Date as set forth in
         Section 2.20(ii) of the Agreement is terminated, and (x) Section
         2.20(ii) of the Agreement shall be deleted in its entirety and replaced
         with "[Intentionally omitted].", and (y) the definitions of "Second
         Extension Request" and "Second Response Date" set forth in Article I of
         the Agreement shall be deleted in their entireties.

                  2.5.     RELEASE OF COLLATERAL. The agreement of Lenders to
release the Property from the Lien granted by the Collateral Documents upon the
occurrence of certain events as set forth in Section 2.23 of the Agreement is
terminated, the last two sentences of Section 2.23 of the Agreement shall be
deleted in their entireties, and the following new sentence shall be added to
the end of Section 2.23 of the Agreement:

                           "The Administrative Agent shall be authorized and
                  permitted to execute and deliver to the Borrowers on the
                  Lenders' behalf any agreements, documents or instruments as
                  shall be necessary or appropriate to effect releases of
                  collateral with respect to leases, sales or other dispositions
                  of the Borrowers' Property which are permitted by Section
                  6.13."

                  2.6.     ACCOUNTS RECEIVABLE AGING SUMMARIES AND REPORTS.
After the Effective Date, Borrowers shall furnish to Administrative Agent
monthly accounts receivable aging reports and Section 6.1(viii) of the Agreement
shall be renumbered to be Section 6.1(ix) and the following new Section
6.1(viii) shall be added to the Agreement:

                           "(viii)  Within 20 days after the end of each
                                    calendar month, an accounts receivable aging
                                    summary as of the end of such month for
                                    Borrowers and their Subsidiaries, on a
                                    consolidated basis, which summary shall be
                                    in form and substance satisfactory to
                                    Administrative Agent; and thereafter, upon
                                    request of Administrative Agent, a detailed
                                    accounts receivable aging report as of the
                                    end of any such month for Borrowers and
                                    their Subsidiaries, on a consolidated basis,
                                    which report shall be in form and substance
                                    satisfactory to Administrative Agent."

                  2.7.     INDEBTEDNESS. As of the Effective Date, (x)
permitted Subordinated Indebtedness shall be reduced from $10,000,000 to
$5,000,000, and (y) permitted Indebtedness secured by purchase money Liens shall
be reduced from $2,500,000 to $1,000,000, and Sections 6.11(iii) and (iv) of the
Agreement shall be amended in their entireties to provide as follows:

                           "(iii)   Subordinated Indebtedness in an aggregate
                                    amount not exceeding $5,000,000 at any time.

                           (iv)     Indebtedness in an aggregate amount not
                                    exceeding $1,000,000 at any time which is
                                    secured by purchase money Liens."


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                  2.8.     SALE OF ASSETS. As of the Effective Date, leases,
sales and other dispositions of Property permitted by Section 6.13(ii) of the
Agreement shall be reduced from $5,000,000 to $500,000, and Section 6.13(ii) of
the Agreement shall be amended in its entirety to provide as follows:

                           "(ii)    Leases, sales or other dispositions of its
                                    Property, the proceeds of which that,
                                    together with all other Property of the
                                    Borrowers and their Subsidiaries previously
                                    leased, sold or disposed of (other than
                                    inventory in the ordinary course of
                                    business) as permitted by this Section
                                    during any fiscal year of the Borrowers,
                                    does not exceed $500,000; provided, however,
                                    such leases, sales and disposition may
                                    exceed $500,000 if the Borrowers make a
                                    mandatory prepayment of Advances in an
                                    amount equal to 100% of the net proceeds in
                                    excess of $500,000 realized from such
                                    leases, sales and dispositions.

                  2.9.     INVESTMENTS AND ACQUISITIONS. As of the Effective
Date, Acquisitions in amounts not exceeding annual and per Acquisition baskets
as set forth in Section 6.14(iii) of the Agreement shall no longer be permitted
and any Acquisitions (other than Acquisitions permitted by Sections 6.14(i) and
(ii)) shall require the approval of all Lenders, and

                           (i)      Section 6.14(iii) of the Agreement shall be
                  deleted in its entirety and replaced with "[Intentionally
                  omitted]", and

                           (ii)     Section 6.14(iv) of the Agreement shall be
                  amended in its entirety to provide as follows:

                                    "(iv)   Acquisitions approved by all
                           Lenders."

                  2.10.    CAPITAL EXPENDITURES. As of the Effective Date, the
limitation on Capital Expenditures by Borrowers and their Subsidiaries set forth
in Section 6.16 of the Agreement shall be modified, and Section 6.16 of the
Agreement shall be amended in its entirety to provide as follows:

                           "6.16.   CAPITAL EXPENDITURES.

                           (i)      Excluding Capital Expenditures for the
                                    Filtration Division, each Borrower will not,
                                    nor will it permit any Subsidiary to,
                                    expend, or be committed to expend, in excess
                                    of $6,000,000 for Capital Expenditures
                                    during any one fiscal year in the aggregate
                                    for Borrowers and their Subsidiaries,
                                    provided, however:

                                            (x)  if such Capital Expenditures
                                                 are less than $6,000,000 during
                                                 fiscal year 2001, the unused
                                                 available amount, up to
                                                 $1,000,000, may be carried over
                                                 to the first fiscal quarter of
                                                 fiscal 2002;


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                                            (y)  if Consolidated EBITDA (on a
                                                 cumulative basis commencing on
                                                 April 1, 2001) for the
                                                 Borrowers and their
                                                 Subsidiaries for the (1) three
                                                 consecutive fiscal quarters
                                                 ending December 31, 2001,
                                                 and/or (2) four consecutive
                                                 fiscal quarters ending March
                                                 31, 2002, exceeds the minimum
                                                 amounts required to be
                                                 maintained in accordance with
                                                 Sections 6.25.4(iii) and (iv),
                                                 respectively, additional
                                                 Capital Expenditures may be
                                                 made by the Borrowers and their
                                                 Subsidiaries in an amount up to
                                                 such excess during fiscal year
                                                 2002; and

                                            (z)  such Capital Expenditures shall
                                                 not exceed $2,500,000 during
                                                 any fiscal quarter of fiscal
                                                 year 2002, provided that the
                                                 unused available amount may be
                                                 carried over from one fiscal
                                                 quarter to the next fiscal
                                                 quarter of fiscal year 2002.

                           (ii)     With respect to the Filtration Division,
                                    each Borrower will not, nor will it permit
                                    any Subsidiary to, expend, or be committed
                                    to expend, in excess of the following
                                    amounts for Capital Expenditures during any
                                    one fiscal year in the aggregate for
                                    Borrowers and their Subsidiaries: (x)
                                    $2,000,000 during fiscal year 2001; and (y)
                                    $250,000 during fiscal year 2002.

                           (iii)    Notwithstanding any other provision of this
                                    Section 6.16, Capital Expenditures during
                                    any fiscal year for the Borrowers and their
                                    Subsidiaries shall not exceed the sum of (x)
                                    $8,000,000, plus (y) the unused available
                                    amount, up to $1,000,000, permitted to be
                                    carried over from fiscal year 2001 to the
                                    first fiscal quarter of fiscal 2002 as
                                    provided in subsection (i)(x) of this
                                    Section 6.16."

                  2.11.    INTEREST COVERAGE RATIO.

                           (a) Pursuant to Section 6.25.1 of the Agreement,
                  Borrowers covenant that Borrowers and their Subsidiaries will
                  maintain the ratio of Consolidated EBIT to Consolidated
                  Interest Expense, determined as of the end of each fiscal
                  quarter, at a certain minimum ratio, which covenant has been
                  violated with respect to the fiscal quarter ended March 31,
                  2001. Therefore, compliance with such Section 6.25.1 of the
                  Agreement is waived by Lenders for the fiscal quarter ending
                  March 31, 2001.

                           (b) The ratio of Consolidated EBIT to Consolidated
                  Interest Expense required to be maintained by Borrowers and
                  their Subsidiaries as set forth in Section 6.25.1 of the
                  Agreement shall not be tested for the fiscal quarter ending
                  June 30, 2001. As of the Effective Date, such ratio of
                  Consolidated EBIT to Consolidated


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                  Interest Expense shall be modified, and Section 6.25.1 of the
                  Agreement shall be amended in its entirety to provide as
                  follows:

                                    "6.25.1. INTEREST COVERAGE RATIO. The
                           Borrowers will not permit the ratio, (x) determined
                           as of the end of each of their fiscal quarters on a
                           cumulative basis beginning with the fiscal quarter
                           ending September 30, 2001, of (i) Consolidated EBIT
                           to (ii) Consolidated Interest Expense to be less than
                           (A) 1.2 to 1.0 for the fiscal quarter ending
                           September 30, 2001, (B) 1.4 to 1.0 for the two
                           consecutive fiscal quarters ending December 31, 2001,
                           (C) 1.6 to 1.0 for the three consecutive fiscal
                           quarters ending March 31, 2002, and (D) 1.8 to 1.0
                           for the four consecutive fiscal quarters ending June
                           30, 2002, and (y) determined as of the end of each of
                           their fiscal quarters beginning with the fiscal
                           quarter ending September 30, 2002 for the then
                           most-recently ended four fiscal quarters, of (i)
                           Consolidated EBIT to (ii) Consolidated Interest
                           Expense to be less than 2.0 to 1.0.

                  2.12.    LEVERAGE RATIO.

                           (a) Pursuant to Section 6.25.2 of the Agreement,
                  Borrowers covenant that Borrowers and their Subsidiaries will
                  maintain the ratio of (i) Consolidated Funded Indebtedness to
                  (ii) Consolidated EBITDA, determined as of the end of each
                  fiscal quarter, at a certain maximum ratio, which covenant has
                  been violated with respect to the fiscal quarter ended March
                  31, 2001. Therefore, compliance with such Section 6.25.2 of
                  the Agreement is waived by Lenders for the fiscal quarter
                  ending March 31, 2001.

                           (b) The ratio of (i) Consolidated Funded Indebtedness
                  to (ii) Consolidated EBITDA required to be maintained by
                  Borrowers and their Subsidiaries as set forth in Section
                  6.25.2 of the Agreement shall not be tested for the fiscal
                  quarters ending June 30, 2001, September 30, 2001 and December
                  31, 2001, and testing of such ratio of (i) Consolidated Funded
                  Indebtedness to (ii) Consolidated EBITDA shall resume
                  beginning with the fiscal quarter ending March 31, 2002.

                  2.13.    MINIMUM NET WORTH.

                           (a) Pursuant to Section 6.25.3 of the Agreement,
                  Borrowers covenant that Borrowers and their Subsidiaries will
                  maintain a certain minimum Consolidated Net Worth, which
                  covenant has been violated with respect to the fiscal quarter
                  ended March 31, 2001. Therefore, compliance with such Section
                  6.25.3 of the Agreement is waived by Lenders for the period
                  commencing March 31, 2001 and ending on the day prior to the
                  Effective Date.

                           (b) As of the Effective Date, the minimum
                  Consolidated Net Worth required to maintained by Borrowers and
                  their Subsidiaries as set forth in Section 6.25.3 of the
                  Agreement shall be modified, and Section 6.25.3 of the
                  Agreement shall be amended in its entirety to provide as
                  follows:


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                                    "6.25.3. MINIMUM NET WORTH. The Borrowers
                           will at all times maintain Consolidated Net Worth of
                           not less than the sum of (i) 90% of Consolidated Net
                           Worth as at March 31, 2001, but in no event less than
                           $34,250,000, plus (ii) (x) 75% of Consolidated Net
                           Income earned in each fiscal quarter beginning with
                           the quarter ending June 30, 2001 (without deduction
                           for losses), and (y) 100% of the net proceeds from
                           the issuance and sale of equity securities of any
                           Borrower or any Subsidiary."

                  2.14.    MINIMUM CONSOLIDATED EBITDA. The following new
Section 6.25.4 shall be added to the Agreement, which new section is with
respect to Borrowers and their Subsidiaries maintaining minimum Consolidated
EBITDA:

                           "6.25.4. MINIMUM CONSOLIDATED EBITDA . The Borrowers
                  will not permit Consolidated EBITDA determined as of the end
                  of each of their fiscal quarters to be less than (i)
                  $2,700,000 for the fiscal quarter ending June 30, 2001, (ii)
                  $5,450,000 for the two consecutive fiscal quarters ending
                  September 30, 2001, (iii) $8,750,000 for the three consecutive
                  fiscal quarters ending December 31, 2001, and (iv) $12,000,000
                  for the four consecutive fiscal quarters ending March 31,
                  2002."

                  2.15.    EVENTS OF DEFAULTS.

                           (i)      The reference to "$1,000,000" in Section 7.5
                  of the Agreement shall be amended in its entirety to be a
                  reference to "$500,000".

                           (ii)     The reference to "$3,000,000" in Section 7.9
                  of the Agreement shall be amended in its entirety to be a
                  reference to "$1,500,000".

                           (iii)    The reference to "$3,000,000" in Section
                  7.10 of the Agreement shall be amended in its entirety to be a
                  reference to "$1,500,000".

                  2.16.    PRICING SCHEDULE. On the Effective Date, the Pricing
Schedule to the Agreement is hereby deleted in its entirety and replaced with
the Pricing Schedule attached hereto as Exhibit A and all references in the
Agreement to the Pricing Schedule are hereby amended to refer to the Pricing
Schedule attached hereto as Exhibit A.

         3.       APPLICABLE MARGIN. From the Effective Date until the date the
Applicable Margin may be adjusted pursuant to the Agreement with respect to
financial information for the fiscal quarter of Borrowers ending March 31, 2002,
the Applicable Margin and the Applicable Fee Rate shall not be less than the
Applicable Margin and the Applicable Fee Rate applicable to Level V Status as
set forth in the Pricing Schedule (which is the amended Pricing Schedule as
provided in Section 2.16 hereof).

         4.       PAYMENT OF NET PROCEEDS FROM SALE EVENT; RELEASE OF LIENS;
ADDENDUM TO AMENDMENT.


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                  (a)     Notwithstanding Section 6.13 or any other provision
         of the Agreement, all net proceeds, which shall not be less than
         $22,500,000, realized by Borrowers from the consummation of the Sale
         Event shall be paid to Administrative Agent as a mandatory prepayment
         of Advances on the date the Sale Event is consummated. If such net
         proceeds are less than $22,500,000, a Default shall be deemed to have
         occurred.

                  (b)      If such net proceeds paid to Administrative Agent
                  pursuant to subsection (a) above are at least $22,500,000:

                           (i) simultaneously with the consummation of the Sale
                  Event, all security interests, liens and pledges granted by
                  the Filtration Entities with respect to their respective
                  Property to Administrative Agent for the benefit of Lenders
                  pursuant to the Security Agreement shall automatically be
                  terminated and released,

                           (ii) simultaneously with the consummation of the Sale
                  Event, Administrative Agent shall deliver all stock
                  certificates or other certificates evidencing the issued and
                  outstanding shares or equity interest of each Filtration
                  Entity, together with all stock powers, to MPW Group or its
                  designee,

                           (iii) promptly after the consummation of the Sale
                  Event, (x) at Borrowers' cost, Administrative Agent shall
                  prepare and file all necessary terminations and releases of
                  such security interests, liens and pledges, including UCC
                  termination statements, and (y) Administrative Agent shall
                  prepare and execute on behalf of Lenders and enter into with
                  Borrowers an addendum to this Amendment to update and
                  otherwise make necessary changes to all exhibits and schedules
                  to the Loan Documents so that the information concerning the
                  Borrowers contained in such exhibits and schedules is accurate
                  after giving effect to the Sale Event, and

                           (iv) effective as of the consummation of the Sale
                  Event, (x) each of the Filtration Entities shall automatically
                  cease to be a party to the Agreement, the Notes, the Security
                  Agreement and all other Loan Documents, and (y) each of the
                  Filtration Entities shall automatically be released from all
                  obligations, including payment obligations, imposed upon it as
                  a "Borrower" or "Guarantor" under the Agreement, the Notes,
                  the Security Agreement and all other Loan Documents.

                  (c) If the net proceeds exceed $22,500,000 as set forth in the
         summary report to be furnished to Administrative Agent pursuant to
         Section 2.2(iii) hereof, notwithstanding Section 6.13 or any other
         provision of the Agreement, such excess net proceeds shall be paid to
         Administrative Agent as a mandatory prepayment of Advances not later
         than five (5) Business Days after the receipt by Administrative Agent
         of such summary report.

         5. REQUIRED RATE MANAGEMENT TRANSACTIONS. Notwithstanding Section 6.21
or any provision of the Agreement, Borrowers, not later than May 31, 2001, will
enter into one or more Rate Management Transactions with one or more Lenders
providing for a fixed rate of interest on a notional amount of at least
$20,000,000 and an average weighted maturity of at least 2 years.


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         6.       TITLES TO MOTOR VEHICLES.

                  (a)      Borrowers shall promptly deliver to Administrative
         Agent, but in any event not later than June 15, 2001, the original of
         all vehicle title certificates for each vehicle owned by the Borrowers
         having a net book value of at least $15,000 and, upon request of
         Administrative Agent, vehicle title certificates for up to 100 vehicles
         owned by the Borrowers each having a net book value of less than
         $15,000.

                  (b)      All such vehicle title certificates shall be held by
         Administrative Agent, and if:

                           (i)      the Sale Event does not occur by August 31,
                  2001, or the Sale Event is abandoned or terminated at any time
                  prior to August 31, 2001, Administrative Agent shall be
                  entitled to have the Lien of Administrative Agent noted on
                  each such vehicle title certificate and each Borrower agrees
                  to do all things necessary to have the Lien of Administrative
                  Agent noted on any such certificate; or

                           (ii)     the Sale Event occurs by August 31, 2001,
                  Administrative Agent shall return all such vehicle title
                  certificates to Borrowers within 30 days of the date the Sale
                  Event is consummated.

         7.       REAL ESTATE MORTGAGES/DEEDS OF TRUST. In accordance with
Section 2.23 of the Agreement, each Borrower has agreed to grant a Lien in favor
of Administrative Agent on each parcel of Real Property owned or leased by it.
Each Borrower shall promptly deliver to Administrative Agent, but in any event
not later than June 15, 2001, all information and documentation which
Administrative Agent may request in connection therewith with granting of Liens
as to each such parcel. Upon the receipt of such information and documentation,
Administrative Agent shall cause appropriate mortgages, deeds of trust or other
necessary documentation to be prepared to grant such Liens and each Borrower
agrees to execute and deliver to Administrative Agent all such mortgages, deeds
of trust or other necessary documentation.

         8.       RELEASE OF EXISTING LIENS IN CONNECTION WITH SALE TRANSACTION.
The Lenders consent to the sale of equipment and other goods having an aggregate
value of approximately $125,000 by MPW Industrial Services, Inc. to Straightline
Optical Services, Inc., and Administrative Agent shall, and hereby is authorized
and permitted by Lenders to, execute and deliver to the Borrowers on the
Lenders' behalf any agreements, documents or instruments as shall be necessary
or appropriate to effect releases of Liens on such equipment and other goods.

         9.       REVISED UCC ARTICLE 9. Each Borrower hereby agrees, in
anticipation of the possible application, in one or more jurisdictions, to the
transactions contemplated by the Agreement and the Security Agreement, of the
Revised Article 9 of the Uniform Commercial Code in the form or substantially in
the form approved by the American Law Institute and the National Conference of
Commissioners on Uniform State Laws and contained in the 2000 official text of
Revised Article 9 ("Revised Article 9"), as follows:


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                  (a)      In applying the law of any jurisdiction in which
         Revised Article 9 is in effect, the Collateral (as defined in the
         Security Agreement) shall consist of all assets of Borrowers whether or
         not within the scope of Revised Article 9. If any Borrower shall at any
         time, whether or not Revised Article 9 is in effect in any particular
         jurisdiction, acquire a commercial tort claim, as defined in Revised
         Article 9, such Borrower shall immediately notify Administrative Agent
         in a writing signed by such Borrower of the brief details thereof and
         grant to Administrative Agent in such writing a security interest
         therein and in the proceeds thereof, with such writing to be in form
         and substance reasonably satisfactory to Administrative Agent.

                  (b)      Administrative Agent may at any time and from time to
         time, pursuant to the provisions of the Security Agreement, file
         financing statements, continuation statements and amendments thereto
         that describe the Collateral as all assets of the applicable Borrower
         or words of similar effect and which contain any other information
         required by Part 5 of Revised Article 9 for the sufficiency or filing
         office acceptance of any financing statements, continuation statements
         or amendments. Each Borrower agrees to furnish any such information to
         Administrative Agent promptly upon request. Any such financing
         statements, continuation statements or amendments may be signed by
         Administrative Agent on behalf of applicable Borrower and may be filed
         at any time in any jurisdiction whether or not Revised Article 9 is
         then in effect in that jurisdiction.

                  (c)      Borrowers shall at any time and from time to time,
         whether or not Revised Article 9 is in effect in any particular
         jurisdiction, take such steps as Administrative Agent may reasonably
         request as are necessary for Administrative Agent to insure the
         continued perfection of Administrative Agent's security interest in any
         of the Collateral with the same priority required by the Agreement and
         the Security Agreement and the preservation of its rights therein,
         whether in anticipation of or following the effectiveness of Revised
         Article 9 in any jurisdiction.

                  (d)      Nothing contained herein shall be construed to narrow
         the scope of Administrative Agent's security interest in any of the
         Collateral or the perfection or priority thereof or to impair or
         otherwise limit any of the rights, powers, privileges or remedies of
         Agent or any Lender except (and then only to the extent) mandated by
         Revised Article 9 to the extent then applicable.

         10.      CONDITIONS TO LENDER'S OBLIGATIONS. The agreement of Lenders
to enter into this Amendment, and for Lenders to be bound by the terms hereof,
are subject to the satisfaction of the following conditions precedent:

                  (a)      DELIVERY OF DOCUMENTS. On or prior to the Effective
         Date, Administrative Agent shall have received the following:

                           (i) a copy of the resolutions (in form and substance
                  satisfactory to Lender) of the board of directors of each
                  Borrower authorizing (A) the execution, delivery and
                  performance of this Amendment and all other documents in
                  connection herewith or therewith, as applicable, and (B) the
                  consummation of the transactions


                                       11
<PAGE>   12

                  contemplated hereby and thereby, certified by the secretary or
                  an assistant secretary (or other appropriate representative)
                  of each Borrower. Each such certificate shall state that the
                  resolutions set forth therein have not been amended, modified,
                  revoked or rescinded as of the date hereof; and

                           (ii) such other certificates, documents and other
                  items as Administrative Agent, in its reasonable discretion,
                  deems necessary or desirable.

                  (b)      AMENDMENT FEE. Borrowers shall pay to Administrative
         Agent, for the ratable benefit of Lenders, an amendment fee in the
         amount set forth in the fee letter of even date herewith.

                  (c)      REPRESENTATIONS AND WARRANTIES. The representations
         and warranties made by Borrowers in this Amendment shall be true and
         correct in all material respects as of the date of this Amendment.

         11.      EXHIBITS AND SCHEDULES. Each Borrower confirms and warrants
that the information set forth in all schedules and exhibits to the Agreement is
true, accurate and complete as of the date hereof.

         12.      REPRESENTATIONS AND WARRANTIES; NO DEFAULTS. Each Borrower
hereby represents and warrants to Lenders and Administrative Agent that the
following are true and correct as of the date of this Amendment:

                  (a)      the representations and warranties of each Borrower
         contained in the Agreement are true and correct on and as of the date
         of this Amendment as if made on and as of such date, unless stated to
         relate to a specific earlier date, in which case they were true,
         correct and complete in all material respects on and as of such earlier
         date;

                  (b)      all financial statements and information of Borrowers
         provided to Administrative Agent and Lenders are true, accurate and
         complete in all material respects as of the date of, and for the
         periods covered by, such financial statements and information;

                  (c)      neither this Amendment nor any other document,
         certificate or written statement furnished to Administrative Agent
         and/or Lenders or to special counsel to Administrative Agent by or on
         behalf of any Borrower in connection with the transactions contemplated
         hereby contains any untrue statement of a material fact or omits to
         state a material fact necessary in order to make the statements
         contained herein and therein not misleading;

                  (d)      each Borrower has full power and authority (i) to
         execute, deliver and perform this Amendment, and (ii) to incur the
         obligations provided for herein and therein, all of which have been
         duly authorized by all necessary and proper action by each Borrower;


                                       12
<PAGE>   13

                  (e)      no consent, waiver or authorization of, or filing
         with, any person, entity or governmental authority is required to be
         made or obtained by any Borrower in connection with the execution,
         delivery, performance, validity or enforceability of this Amendment;

                  (f)      this Amendment constitutes the legal, valid and
         binding obligation of Borrowers, enforceable against Borrowers in
         accordance with its terms;

                  (g)      giving effect to the changes to the Agreement
         contemplated by this Amendment, no Unmatured Default nor Default has
         occurred and is continuing;

                  (h)      no event has occurred which would have a Material
         Adverse Effect; and

                  (i)      the execution and delivery by Borrowers of this
         Amendment and the performance by Borrowers of this Amendment and the
         transactions contemplated hereby: (i) do not and will not violate any
         law or regulation; (ii) do not and will not violate any order, decree
         or judgment by which any Borrower is bound; (iii) do not and will not
         violate or conflict with, result in a breach of or constitute (with
         notice, lapse of time, or otherwise) a default under any material
         agreement, mortgage, indenture or other contractual obligation to which
         any Borrower is a party, or by which any Borrower's properties are
         bound; or (iv) do not and will not result in the creation or imposition
         of any lien upon any property or assets of any Borrower.

13.      REAFFIRMATION OF LIABILITY. Subject to the terms and conditions
contained herein, each Borrower hereby reaffirms its liability to Lender under
the Agreement, the Security Agreement, the Notes, the other Loan Documents and
all other agreements and instruments executed by Borrowers for the benefit of
Administrative Agent, Lenders, LC Issuer or Documentation Agent in connection
with the Agreement and the Revolving Loan (collectively, the "Bank Documents").
Without limiting the generality of the foregoing, each Borrower reaffirms all
of its payment obligations, including with respect to the Revolving Loan under
the Agreement and the Notes and with respect to the Facility LCs. In addition,
each Borrower agrees that Administrative Agent, each Lender, LC Issuer and
Documentation Agent have performed all of their obligations under the Bank
Documents and that none of Administrative Agent, any Lender, LC Issuer or
Documentation Agent is in default under any obligation any of them has or ever
did have to any Borrower under the Bank Documents or any other agreement. As a
specific inducement and consideration to Lenders, Administrative Agent, LC
Issuer and Documentation Agent to enter into this Amendment and agree to the
transactions contemplated hereby, each Borrower hereby waives and releases each
Lender, Administrative Agent, LC Issuer and Documentation Agent, their
respective officers, directors, employees and representatives, from any and all
claims or causes of actions, if any, accruing on or before the date hereof and
arising out of the past and/or present business relationship among each
Borrower and each Lender, Administrative Agent, LC Issuer or Documentation
Agent which any Borrower now has or may have or in the future may have against
any Lender, Administrative Agent, LC Issuer or Documentation Agent or any of
their respective officers, directors, employees or representatives.


                                       13
<PAGE>   14

         14.      EFFECTIVENESS OF AMENDMENT. All of the terms, covenants and
conditions of, and the obligations of Borrowers under, the Bank Documents shall
remain in full force and effect as amended hereby.

         15.      PRESERVATION OF EXISTING SECURITY INTERESTS. Each mortgage,
security interest, pledge, assignment, lien or other conveyance or encumbrance
of any right, title, or interest in any property of any kind delivered to
Administrative Agent for the benefit of Lenders at any time by any Borrower or
any other Person in connection with the Bank Documents or to secure the
performance of the obligations of Borrowers under the Bank Documents, including
pursuant to the Security Agreement, shall remain in full force and effect
following the execution of this Amendment.

         16.      EXPENSES. Borrowers shall reimburse Administrative Agent and
Arranger for any costs, internal charges and out-of-pocket expenses (including
reasonable attorneys' fees and time charges of attorneys for Administrative
Agent and Arranger, which attorneys may be employees of Administrative Agent)
paid or incurred by Administrative Agent and Arranger in connection with the
preparation, negotiation, execution, delivery, performance, review, amendment,
modification, and administration of this Amendment, the Agreement and the other
Bank Documents. Borrowers also agree to reimburse Administrative Agent for any
costs, internal charges and out-of-pocket expenses (including reasonable
attorneys' fees and time charges of attorneys for Administrative Agent and
Lenders, which attorneys may be employees of Administrative Agent) paid or
incurred by Administrative Agent and Lenders in connection with the collection
and enforcement of the Agreement and the other Bank Documents.

         17.      APPLICABLE  LAW. This Amendment shall be deemed to be a
contract made under the laws of the State of Ohio and for all purposes shall be
construed in accordance with the laws of such state.

         18.      SEVERABILITY. Any provision of this Amendment that is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective only to the extent of such prohibition or unenforceability,
without invalidating the remaining provisions hereof or affecting the validity
or enforceability of such provision in any other jurisdiction.

         19.      COUNTERPARTS. This Amendment may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         20.      AMENDMENTS AND SUPPLEMENTS. This Amendment may not be amended
or supplemented except by an instrument in writing executed by Borrowers and
Agent.

         21.      COVENANTS TO SURVIVE, BINDING AGREEMENT. This Amendment shall
be binding upon and inure to the benefit of Borrowers, Lenders, Administrative
Agent, LC Issuer and Documentation Agent and their respective successors or
assigns; provided, however, that Borrowers may not assign or otherwise dispose
of any of their rights or obligations hereunder.

         22.      ENTIRE AGREEMENT. This Amendment embodies the entire agreement
and understanding among Borrowers, Administrative Agent, Lenders, Documentation
Agent and LC


                                       14
<PAGE>   15

Issuer relating to, and supersedes all prior agreements and understandings among
Borrowers, Administrative Agent, Lenders, Documentation Agent and LC Issuer
relating to, the subject matter hereof.

         23.      HEADINGS. The headings of the sections of this Amendment are
for convenience only and shall not affect the meaning or interpretation of this
Amendment.

         24.      INTERPRETATION. This Amendment is to be deemed to have been
prepared jointly by the parties hereto, and any uncertainty or ambiguity
existing herein shall not be interpreted against any party but shall be
interpreted according to the rules for the interpretation of arm's length
agreements.

         25.       WAIVER OF JURY TRIAL. EACH BORROWER, ADMINISTRATIVE AGENT,
DOCUMENTATION AGENT, LC ISSUER AND EACH LENDER HEREBY WAIVE TRIAL BY JURY IN ANY
JUDICIAL PROCEEDING INVOLVING, DIRECTLY OR INDIRECTLY, ANY MATTER (WHETHER
SOUNDING IN TORT, CONTRACT OR OTHERWISE) IN ANY WAY ARISING OUT OF, RELATED TO,
OR CONNECTED WITH ANY LOAN DOCUMENT OR THE RELATIONSHIP ESTABLISHED THEREUNDER.

                   [Balance of Page Intentionally Left Blank]




                                       15
<PAGE>   16


         IN WITNESS WHEREOF, the parties hereto entered into this Amendment to
be effective as of the Effective Date.

                                BORROWERS:

                                MPW Industrial Services Group, Inc.


                                By: /s/ Ira O. Kane
                                    -------------------------------------
                                      Ira O. Kane, President and Chief
                                         Operating Officer


                                Aquatech Environmental, Inc.


                                By:   /s/ Peter G. Schumacher
                                    -------------------------------------
                                     Peter G. Schumacher, Vice President
                                         and Treasurer


                                Each of the Other Borrowers Listed
                                on the Schedule of Subsidiary Borrowers


                                By:  /s/ Ira O. Kane
                                    -------------------------------------
                                      Ira O. Kane, President and Chief
                                         Operating Officer










[Signatures of Lenders, Administrative Agent, LC Issuer and Documentation Agent
                         Continued on Following Pages]




                                       16
<PAGE>   17


                                   BANK ONE, NA (Main Office Columbus),
                                   as a Lender and as Administrative Agent and
                                   LC Issuer


                                   By:   /s/ Steven P. Shepard
                                         --------------------------------------

                                   Name:     Steven P. Shepard
                                         --------------------------------------

                                   Title: First Vice President
                                         --------------------------------------





                                       17
<PAGE>   18


                                   NATIONAL CITY BANK,
                                   as a Lender and as Documentation Agent

                                   By:   /s/ Brian T. Strayton
                                         --------------------------------------

                                   Name: Brian T. Strayton
                                         --------------------------------------

                                   Title: Vice President
                                         ---------------------------------------






                                       18
<PAGE>   19


                                   LASALLE BANK NATIONAL ASSOCIATION


                                   By:    /s/ Bijon Jalaie
                                         --------------------------------------

                                   Name:  Bijon Jalaie
                                         --------------------------------------

                                   Title: Assistant Vice President
                                         --------------------------------------




                                       19
<PAGE>   20


                                   SUNTRUST BANK


                                   By:   /s/ Shelley M. Browne
                                         --------------------------------------

                                   Name: Shelley M. Browne
                                         --------------------------------------

                                   Title: Managing Director
                                         --------------------------------------




                                       20
<PAGE>   21


                        SCHEDULE OF SUBSIDIARY BORROWERS

MPW Industrial Services, Inc.
MPW Management Services Corp.
MPW Filtration Management Services Corp.
MPW Industrial Water Services, Inc.
MPW Container Management Corp.
MPW Container Management Corp. of Michigan
ESI International, Inc.
ESI-North Limited
Gauthier Enterprises, Inc.
MPW Industrial Services of Indiana, LLC
MPW Industrial Cleaning Corp.




                                       21
<PAGE>   22


                       CONSENT AND AGREEMENT OF GUARANTORS

         Each of the undersigned, MPW Industrial Services, Ltd. and MPW
Industrial, Sociedad de Responsibilidad Limitada de Capital Variable (the
"Guarantors"), being a guarantor pursuant to the Subsidiary Guaranty dated as of
October 20, 1999 in favor of Lenders (the "Guaranty") whereby each of Guarantors
has guaranteed the payment and performance of Borrowers' obligations and
indebtedness owed to Lenders, joins in the execution of this Amendment and
hereby consents and agrees to the terms, conditions, execution and performance
of the this Amendment. Each of Guarantors has read and understands all terms and
provisions of the Guaranty, the Bank Documents and this Amendment, and agrees
that all of the terms, covenants and conditions of, and the obligations of each
of Guarantors under, the Guaranty shall continue in full force and effect and be
binding upon Guarantors.

         Each of Guarantors represents and warrants that all representations and
warranties contained in the Guaranty are true, correct and complete in all
material respects on and as of the date hereof to the same extent as though made
on and as of this date, except to the extent such representations and warranties
specifically relate to an earlier date, in which case they were true, correct
and complete in all material respects on and as of such earlier date.

         Each of Guarantors hereby reaffirms its liability to Lenders under the
Guaranty and all other agreements and instruments executed by each of Guarantors
for the benefit of Lenders in connection therewith. Each of Guarantors agrees
that Administrative Agent, each Lender, LC Issuer and Documentation Agent have
performed all of their obligations under the Bank Documents and that none of
Administrative Agent, any Lender, LC Issuer or Documentation Agent is in default
under any obligation any of them has or ever did have to either of Guarantors
under the Guaranty or the other Bank Documents or any other agreement.

         Each of Guarantors acknowledges and agrees that (i) notwithstanding the
conditions to effectiveness set forth in this Amendment, each of Guarantors is
not required by the terms of the Guaranty or any other Bank Document to consent
to the terms of this Amendment, and (ii) nothing in the Guaranty, this Amendment
or any other Bank Document shall require, or be deemed to require, the consent
of either of Guarantors to any future amendments to any Bank Document.

GUARANTOR:                                GUARANTOR:

MPW Industrial Services, Ltd.             MPW Industrial, Sociedad de
                                          Responsibilidad Limitada de
                                          Capital Variable

By:   /s/ Ira O. Kane                     By:    /s/ Ira O. Kane
   --------------------------------           ---------------------------
   Ira O. Kane, President and Chief           Ira O. Kane, President and Chief
      Operating Officer                          Operating Officer




                                       22
<PAGE>   23


                                    EXHIBIT A

                                Pricing Schedule
                                ----------------
                           (on the following 2 pages)






















                                       23
<PAGE>   24


                                PRICING SCHEDULE
      (Applicable Margin and Applicable Fee Rate in basis points per annum)

<TABLE>
<CAPTION>
============================================================================================================
APPLICABLE MARGIN      LEVEL    I    LEVEL    II         LEVEL   III    LEVEL    IV       LEVEL   V
                       STATUS        STATUS              STATUS         STATUS            STATUS
------------------------------------------------------------------------------------------------------------
<S>                    <C>             <C>                <C>              <C>             <C>
Eurodollar Rate        200             225                250              275             300
------------------------------------------------------------------------------------------------------------
Floating Rate          37.5            62.5               87.5             112.5           137.5
============================================================================================================

<CAPTION>

============================================================================================================
APPLICABLE FEE RATE    LEVEL    I    LEVEL    II         LEVEL   III    LEVEL    IV       LEVEL   V
                       STATUS        STATUS              STATUS         STATUS            STATUS
============================================================================================================
<S>                    <C>             <C>                <C>              <C>             <C>
Commitment Fee         30              35                 40               45              50

============================================================================================================
</TABLE>

         For the purposes of this Schedule, the following terms have the
following meanings, subject to the final paragraph of this Schedule:

         "Financials" means the annual or quarterly financial statements of the
Borrowers delivered pursuant to Section 6.1(i) or (ii).

         "Level I Status" exists at any date if, as of the last day of the
fiscal quarter of the Borrowers referred to in the most recent Financials, the
Leverage Ratio is less than 1.5 to 1.0.

         "Level II Status" exists at any date if, as of the last day of the
fiscal quarter of the Borrowers referred to in the most recent Financials, (i)
the Borrowers have not qualified for Level I Status and (ii) the Leverage Ratio
is less than 2.0 to 1.0.

         "Level III Status" exists at any date if, as of the last day of the
fiscal quarter of the Borrowers referred to in the most recent Financials, (i)
the Borrowers have not qualified for Level I Status or Level II Status and (ii)
the Leverage Ratio is less than 2.5 to 1.0.

         "Level IV Status" exists at any date if, as of the last day of the
fiscal quarter of the Borrowers referred to in the most recent financials, (i)
the Borrowers have not qualified for Level I Status, Level II Status or Level
III Status, and (ii) the Leverage Ratio is less than 3.0 to 1.0.

         "Level V Status" exists at any date if the Borrowers have not qualified
for Level I Status, Level II Status, Level III Status or Level IV Status.

         "Status" means either Level I Status, Level II Status, Level III
Status, Level IV Status or Level V Status.

         The Applicable Margin and Applicable Fee Rate shall be determined in
accordance with the foregoing table based on the Borrower's Status as reflected
in the then most recent Financials. Adjustments, if any, to the Applicable
Margin or Applicable Fee Rate shall be effective five


                                       24
<PAGE>   25

Business Days after the Administrative Agent has received the applicable
Financials. If the Borrowers fail to deliver the Financials to the
Administrative Agent at the time required pursuant to Section 6.1, then the
Applicable Margin and Applicable Fee Rate shall be the highest Applicable Margin
and Applicable Fee Rate set forth in the foregoing table until five days after
such Financials are so delivered.









                                       25