U.S. energy company Covanta Holding Corp. plans to issue $400 million of senior unsecured notes. We are assigning a 'B' rating and '6' recovery rating to the new notes. The stable outlook reflects our expectation for the predictable cash flow from waste contracts and energy markets under the S&P energy price deck. NEW YORK (Standard&Poor's) Nov. 10, 2010--Standard&Poor's Ratings Services assigned its 'B' rating and '6' recovery rating to Covanta Holding's $400 million senior unsecured notes due 2020, indicating the expectation for negligible recovery (0-10%) of principal if a payment default occurs. At the same time, we affirmed the 'BB-' corporate credit rating and 'B' ratings on the $325 ($374 million outstanding as of Sept. 30,