Exhibit 10.23

Amendment No. 4 to

Loan and Security Agreement

This AMENDMENT NO. 4 TO LOAN AND SECURITY AGREEMENT (this “Amendment”) is entered into on the above date, by and between the borrower named above (“Borrower”) and ORIX Ventures, LLC, a Delaware limited liability company (“ORIX”).

RECITALS:

WHEREAS, Borrower and ORIX are parties to that certain Loan and Security Agreement dated as of October 7, 2011 (as from time to time amended, restated, supplemented or otherwise modified, the “Loan Agreement”), pursuant to which ORIX has agreed to make loans and other extensions of credit to Borrower in accordance with the terms thereof;

WHEREAS, Borrower and ORIX wish to amend the Loan Agreement, subject to the terms and conditions of this Amendment; and

WHEREAS, this Amendment shall constitute a Loan Document and capitalized terms used but not otherwise defined in this Amendment shall have the meanings ascribed to them in the Loan Agreement.

NOW, THEREFORE, in consideration of the foregoing and the agreements, promises and covenants set forth below, and for other good and valuable consideration the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows:

Section 1                                              Amendment to Loan Agreement.  Clause (c) of Section 5 of the Schedule is hereby amended by inserting the following proviso immediately after the word “Borrower” set forth therein:

“; provided, however, that, so long as Borrower is a consolidated subsidiary of Aquaventure Holdings LLC or any other entity (including any successor to Aquaventure Holdings LLC or such other entity thereto, “Parent”), such financial statements may be the audited consolidated financial statements of Parent if

Parent’s audited consolidated financial statements include the segment reporting in accordance with GAAP or International Financial Reporting Standards (“IFRS”)”.

Section 2                                              Representations and Warranties.  To induce ORIX to enter into this Amendment, Borrower represents and warrants that:

(a)                                 No Default.  After giving effect to this Amendment, no Default or Event of Default shall have occurred and be continuing as of the date hereof;

(b)                                 Representations and Warranties.  No event has occurred and is continuing or would result from the execution, delivery or performance of this Amendment which constitutes an Event of Default and, after giving effect to this Amendment and the transactions contemplated hereby, the representations and warranties of Borrower contained in the Loan Documents are true, accurate and complete in all material respects on and as of the date hereof to the same extent as though made on and as of such date except to the extent such representations and warranties specifically relate to an earlier date, in which case such representation or warranty shall be true, accurate and complete in all material respects as of such earlier date; and

(c)                                  Corporate Authority.  (i) The execution, delivery and performance by Borrower of this Amendment is within its corporate powers and has been duly authorized by all necessary corporate action on the part of Borrower, (ii) this Amendment is the legal, valid and binding obligation of Borrower enforceable against Borrower in accordance with its terms, and (iii) neither the execution, delivery or performance by Borrower of this Amendment (1) violates any law or regulation, or any other or decree of any governmental authority, (2) conflicts with or result in the breach or termination of, constitute a default under or accelerate any performance required by, any indenture, mortgage, deed of trust, lease, agreement or other instrument to which Borrower is a party or by which Borrower or any of its property is bound, (3) results in the creation or imposition of any lien upon any of the Collateral, (4) violates or conflicts with the certificate of incorporation or bylaws of Borrower, or (5) requires the consent, approval or authorization of, or declaration or filing by Borrower with, any other Person, except for those already duly obtained.

Section 3                                              Miscellaneous.

(a)                                 Binding Obligation.  This Amendment has been duly executed and delivered by Borrower and is the binding obligation of Borrower, enforceable against Borrower in accordance with its terms, except as such enforceability may be limited by bankruptcy, insolvency, reorganization, liquidation, moratorium or other similar laws of general application and equitable principles relating to or affecting creditors’ rights.

(b)                                 Ratification.  Notwithstanding anything contained herein, the terms of this Amendment are not intended to and do not effect a novation of the Loan Agreement or any other Loan Document.  Borrower hereby ratifies and reaffirms each of the terms and conditions of the Loan Documents to which it is a party and all of its obligations thereunder.

(c)                                  Limitation; Reservation of Rights.  The amendments set forth in this Amendment shall be limited precisely as written and shall not be deemed (a) to be a waiver or

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modification of any Event of Default or any other term or condition of any Loan Document or of any other instrument or agreement referred to therein or to prejudice any right or remedy which ORIX may now have or may have in the future under or in connection with the Loan Documents or any instrument or agreement referred to therein; or (b) to be a consent to any future amendment or modification or waiver to any instrument or agreement the execution and delivery of which is consented to hereby, or to any waiver of any of the provisions thereof.  Except for the amendments set forth herein, ORIX hereby expressly reserves all of its rights and remedies under the Loan Documents and at law and equity.  Except as expressly amended hereby, the Loan Documents shall continue in full force and effect.

(d)                                 Releases.  In further consideration of ORIX’s execution of this Agreement, Borrower for itself and on behalf of its respective successors (including, without limitation, any trustees acting on behalf of Borrower and any debtor-in-possession with respect to Borrower), assigns, subsidiaries and affiliates, hereby forever releases ORIX and its respective successors, assigns, parents, subsidiaries, affiliates, officers, employees directors, agents and attorneys (collectively, the “Releasees”) from any and all debts, claims, demands, liabilities, responsibilities, disputes, causes, damages, actions and causes of action (whether at law or in equity) and obligations of every nature whatsoever, whether liquidated or unliquidated, known or unknown, matured or unmatured, fixed or contingent, that Borrower may have against the Releasees which arise from or relate to any actions which the Releasees may have taken or omitted to take prior to the date this Amendment was executed with respect to the Obligations, any Collateral, the Loan Agreement, any other Loan Document and any third parties liable in whole or in part for the Obligations, other than arising out of the gross negligence or willful misconduct of such Releasee or its respective officers, employees directors, agents or attorneys as determined by a non-appealable decision of a court of competent jurisdiction.  This provision shall survive and continue in full force and effect whether or not Borrower shall satisfy all other provisions of this Amendment, the Loan Documents or the Loan Agreement including payment in full of all Obligations.

(e)                                  Successors and Assigns.  This Amendment shall be binding on and shall inure to the benefit of Borrower and ORIX and their respective successors and assigns.

(f)                                   ENTIRE AGREEMENT.  THIS AMENDMENT AND THE OTHER LOAN DOCUMENTS CONSTITUTE AND CONTAIN THE ENTIRE, FINAL AGREEMENT AND UNDERSTANDING CONCERNING THE SUBJECT MATTER HEREOF BETWEEN THE PARTIES HERETO, AND SUPERSEDES ALL OTHER PRIOR AGREEMENTS, UNDERSTANDINGS, NEGOTIATIONS AND DISCUSSIONS, REPRESENTATIONS, WARRANTIES, COMMITMENTS, PROPOSALS, OFFERS AND CONTRACTS CONCERNING THE SUBJECT MATTER HEREOF, WHETHER ORAL OR WRITTEN.  THIS AMENDMENT, ANY SUPPLEMENTS HERETO, AND ANY INSTRUMENTS OR DOCUMENTS DELIVERED OR TO BE DELIVERED IN CONNECTION HEREWITH MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES HERETO.  THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES HERETO.

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(g)                                  Headings.  Section headings in this Amendment are included herein for convenience of reference only and shall not constitute a part of this Amendment for any other purpose.

(h)                                 Severability.  Wherever possible, each provision of this Amendment shall be interpreted in such a manner as to be effective and valid under applicable law, but if any provision of this Amendment shall be prohibited by or invalid under applicable law, such provision shall be ineffective to the extent of such prohibition or invalidity, without invalidating the remainder of such provision or the remaining provisions of this Amendment.

(i)                                     Counterparts.  This Amendment may be executed in any number of separate original counterparts (or telecopied counterparts with original execution copy to follow) and by the different parties on separate counterparts, each of which shall be deemed to be an original, but all of such counterparts shall together constitute one agreement.  Delivery of an executed counterpart of a signature page to this Amendment by telecopy shall be effective as delivery of a manually executed counterpart of this Amendment.

(j)                                    Incorporation of Loan Agreement Provisions.  This Amendment is executed pursuant to the Loan Agreement and shall be construed, administered and applied in accordance with the terms and provisions of the Loan Agreement.  The provisions contained in Section 8.11 (Governing Law) and Section 8.13 (Jury Trial) of the Loan Agreement are incorporated herein by reference to the same extent as if reproduced herein in their entirety.

[Signature Page to Follow]

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IN WITNESS WHEREOF, this Amendment has been duly executed on the date first written above.

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