**4. Results**

Determination of the energetic potential based on the ERWP model was performed for the municipality of Koszalin with statistical data pertaining to the volume of municipal waste amassed in 2018 using the results of research describing waste composition and selected physicochemical parameters. The volume of household and commercial waste that was generated at that time was 30,760 t. The mechanical part of the plant to which the waste is directed comprises recovery of the fraction (Fr. > 200 mm) set for manual separation. The fraction below 200 mm makes up 89.2% and is directed in full to a rotary drum sifter with 90 mm mesh [44]. The average share of the oversized (Fr. > 90 mm) and subscreen (Fr. < 90 mm) fractions was 46.1% and 53.9%, respectively. The percentage shares of separated waste elements in both fractions are shown in Figure 2. Classifying all separated waste elements into four groups, shares in both fractions (Figure 3) were fixed and on this basis average shares of Groups No I–IV in mixed waste were calculated; they were: 44.2, 14.0, 20.7 and 21.1%, respectively.

**Figure 2.** Percentage of waste components in two particle size fractions.

**Figure 3.** Percentage of four groups (I–IV) in two particle size fractions.

The mass balance was set assuming 280 working days per year, which allowed for fixing the daily volume of mixed waste (Md) directed to MTP as approx. 110 t. Using Equations (3) and (5), the mass of the waste attributed to Group No II—*mi*2—directed to CSP and mass of the waste attributed to Group No III—*mf*3—directed to DFI were calculated. These masses amounted to 13.7 and 20.3 t/d, respectively. The results of physicochemical tests of samples of both waste groups and sewage sludge before and after mechanical dehydrations are shown in Table 6. The content of organic matter found in sewage sludge was in the range of 65–75% *dm*, defined as characteristic [78].


