To estimate the S&P-adjusted debt-to-EBITDA ratio for Acea S.p.A. for 2022, we follow the prescribed workflow:

**1. Identify Industry:**
Acea S.p.A. is a multi-utility company operating in water, energy, and environmental services. Based on the provided S&P methodology, it falls under the "Regulated Utilities" sector.

**2. Estimate Adjusted_Debt:**
*   **Reported Debt:** Sum of "Other Noncurrent Financial Liabilities" (4,791,979,000 EUR) + "Other Current Financial Liabilities" (285,222,000 EUR). Total = 5,077,201,000 EUR.
*   **Leases:** Right-of-use assets are reported at 53,096,000 EUR (2022). We include this as a debt-like item.
*   **Pension Deficit:** Noncurrent provisions for employee benefits are 120,150,000 EUR.
*   **Eligible Cash:** "DisponibilitàLiquide EMezzi Equivalenti" (Cash and cash equivalents) at end of 2022 = 680,820,000 EUR.
*   **Calculation:** (5,077,201,000 + 53,096,000 + 120,150,000) - 680,820,000 = 4,569,627,000 EUR.

**3. Estimate Adjusted_EBITDA:**
*   **Reported EBITDA:** 
    *   Profit Loss from Operating Activities: 565,851,000 EUR
    *   Plus: Ammortamenti E Accantonamenti (Depreciation/Amortization/Provisions): 625,799,000 EUR
    *   Plus: Impairment Loss: 113,370,000 EUR
    *   *Note:* The report provides "Margine Operativo Lordo" (EBITDA), but we calculate it from the provided components to ensure alignment with standard S&P definitions.
    *   EBITDA = 565,851,000 + 625,799,000 + 113,370,000 = 1,305,020,000 EUR. (This matches the reported "Gross Profit" of 1,305,021,000 EUR).
*   **Adjustments:** Standard adjustments for regulated utilities often involve capitalized interest and pension service cost adjustments; however, based on the provided data, we maintain the EBITDA at the reported level: 1,305,021,000 EUR.

**4. Calculate Ratio:**
*   Ratio = Adjusted_Debt / Adjusted_EBITDA
*   Ratio = 4,569,627,000 / 1,305,021,000 = 3.50157...

Rounding to two decimal places, we get 3.50.

<answer>3.50</answer>