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<br />14 | Final Report Bay Area Clean Water Agencies | City of San Leandro <br />Table 4-4 presents a list of the ancillary benefits and impacts associated with the optimization <br />strategies at SLWPCP. <br />Table 4-4. Ancillary Benefits and Impacts for the Optimization Strategies <br />Benefits Adverse Impacts <br />Add CEPT <br />· Ability to reduce total phosphorus discharge loads <br />· Increased capacity in the FFRs and activated <br />sludge process <br />· Increased solids/organics diverted to the digesters, <br />which translates to increased biogas production <br /> <br />· Additional chemicals to handle <br />· Carbon management issues for meeting low level <br />total nitrogen discharge limits (if required in the <br />future) <br />Operate Aeration Basins in Series <br />· Ability to reduce ammonia/total nitrogen loads <br /> <br />· Changed mode of operation <br />· Most likely requires alkalinity <br />· Additional loading on the secondary clarifiers <br />· Additional energy demand associated with extra <br />blower <br />Operate Aeration Basins in Step Feed Mode <br />· Ability to further reduce total nitrogen loads <br />(predicated on implementation of operating aeration <br />basins in series) <br />· Alkalinity recovery <br />· Reduce solids loading on the secondaries <br />compared to operating in non-step feed mode <br /> <br />· Changed mode of operation that requires operator <br />input on step feed distribution <br />· Occasionally bleed ammonia if step feed is not <br />appropriately distributed between the in series <br />trains <br />5 Sidestream Treatment <br />As previously described, the SLWPCP was identified as a potential candidate for sidestream <br />treatment. The plant currently uses belt filter presses followed by drying beds. <br />A questionnaire was included with the July 2015 sidestream sampling to better understand the <br />biosolids operations (e.g., days of week that dewatering is operated). Based on the questionnaire <br />and sampling results, a deammonification sidestream treatment technology is recommended for <br />ammonia and total nitrogen load reduction and metal salts/solids separation facilities for total <br />phosphorus load reduction. <br />Deammonification is an innovative technology that is well suited for treating wastewater with a <br />typical sidestream composition of high ammonia, alkalinity to allow 50 percent nitrification, and warm <br />temperature. It also offers several benefits over conventional nitrogen removal (i.e., nitrification/ <br />denitrification) including requiring 60 percent less oxygen than conventional nitrification, elimination <br />of organic carbon demand for nitrogen removal, and requires 50 percent less alkalinity than <br />conventional nitrification. Based on these benefits, deammonification is recommended for the <br />SLWPCP. <br />The removal of total phosphorus from the sidestream relies upon metal salt and subsequent solids <br />separation. The most common metal salts are alum and ferric chloride. Ferric chloride offers the <br />advantage over alum in that it also assists with odor control and dewaterability. Given that most <br />sidestreams are returned to the potentially odorous headworks the use of ferric chloride is <br />recommended. The solids separation can occur in a stand-alone sidestream tank, simultaneous with <br />dewatering solids separation, or in a main stream sedimentation tank (e.g., primary clarifier if