Covanta Holding (CVA) 10-Q 2005 Q3 Quarterly report

Exhibit 32.1

Certification Of Periodic Financial Report Pursuant to

Section 906 of the Sarbanes-Oxley Act of 2002

      In connection with the Quarterly Report on Form 10-Q for the third quarter ended September 30, 2005 of Covanta Holding Corporation as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Anthony J. Orlando, as Chief Executive Officer of Covanta Holding Corporation, hereby certifies, pursuant to 18 U.S.C. 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to his knowledge:

      (1) the Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934;

      (2) the information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of Covanta Holding Corporation; and

      This certification accompanies the Report pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by the Sarbanes-Oxley Act of 2002, be deemed filed by Covanta Holding Corporation for purposes of Section 18 of the Securities Exchange Act of 1934, as amended.

      A signed original of this written statement has been provided to Covanta Holding Corporation and will be retained by Covanta Holding Corporation and furnished to the Securities and Exchange Commission or its staff upon request.

/s/ Anthony J. Orlando

Anthony J. Orlando,

Chief Executive Officer

Date: November 9, 2005