Item 5: Resolution Adopting Amended SDC Methodologies and Rates

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. The definition and capacity assessment development for these three subcomponents are · presented in the following paragraphs.. General The general subcomponent consists of biosolids thickening and anaerobic digestion at the WPCF;' the biosoli~ .P~p station/ force main system that conveys digested biosolids from the WPCF to the BMF; and'facultative sludge storage lagoons and drying beds at the remote BMF. The majority of the infrastructure associated with this'iGeneral" component was constructed in the 19805 and early,1990s. The cunent loading or current required capacity is presented .as' annual average dry tons of digested biosplids. Current biosolids loading:;: 4,962 x 1.183 = 5,869 tons per year Where: '4,962.dry tons per year (actual 2002 value) 1.183 factor to convert actual value to a value that can be directly compared to . the projected 2025 capacity value when a greater biosolids load will be generated by changes in the treatment process, and is calculated as follows: = {{60 x 1.23) + (40 x 1.11)} 1100= 1.183 Where: 60is the weighting given to BOD for biosolids production 1.23 is the BOD ppcd ratio (selectedl actual) calculated as follows: = 0.185/0.15 = 1.23 Where: 0.185 is the selected annual average BOD ppcd'for proJected influent BOD values 0.15 is the actual BOD ppcd (annual average over 12-year period) 40 is the weighting given to TSS for biosolids production 1.11 is the TSS ppcd ratio (selected/actual) calculated as follows: = 0.233/0.21 = 1.11 Where: 0.233 is the select~d annual average TSS ppcd for projected influent TSS values (average of dry (0.205) and wet (0.26) seasonal values) 0.21 is the actual TSS ppcd (annual average over 12-year period) A-32