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(1) Alternative 1 —Construction of new square/rectangular clarifier units. <br /> (2) Alternative 2—Rehabilitation of existing solids contact clarifier equipment within <br /> the existing basins with alternative solids contact clarifier equipment. <br /> (a) Circular basin <br /> (b) Square basins with existing corner fillets <br /> (c) Square basins with improved corner fillets <br /> ii) Develop two (2) conceptual designs. This includes preliminary mechanical layout, <br /> site plan, process flow diagram, and cost estimate (AACE Level 5) for Alternatives 1 <br /> and 2. <br /> e) Primary Treatment Expansion Workshop <br /> i) To be combined with the filter workshop (see Task 4) <br /> ii) Organize and facilitate one (1)virtual workshop (up to 2 hours) with the City to <br /> present the findings of the analysis and the alternatives. <br /> iii) The purpose of this workshop is to discuss the alternatives and for the City to select a <br /> preferred path forward for the preliminary design. <br /> iv) A summary of the workshop, which may be in the form of meeting minutes and/or <br /> presentation slides, will be provided to document the decisions made by the City. <br /> 5) FILTER EXPANSION <br /> a) Become generally familiar with historical filter design, media configuration, backwash <br /> procedures, and historical performance data, including filter run times, backwash <br /> frequency and duration, and finished water turbidity,as provided by the City. <br /> i) Review historical data from the past two years,which will be provided by City staff. <br /> ii) Develop a design capacity rating for existing filters to identify current hydraulic <br /> loading limitations and operational constraints. <br /> iii) Identify filters with poor historical performance or abnormal trends compared to <br /> generally accepted water industry standards, such as Ten State Standards. <br /> b) Field Testing: <br /> i) Prepare and submit a field testing plan to the City for approval. The plan will outline <br /> proposed on-site testing procedures, operational adjustments, and monitoring <br /> parameters to evaluate the filters'performance under specific conditions at <br /> incremental loading rates. Upon City review and approval of the field testing plan,the <br /> City will conduct full-scale WTP filter loading testing, anticipated to be conducted at <br /> up to two different rates (to be conducted concurrently). BMcD will provide two (2) <br /> staff for a total of up to two (2) days of testing. <br /> ii) Filter Loading and Solids Retention Cores <br /> (1) Conduct filter loading testing on up to two filters to estimate the maximum <br /> sustainable filtration rate while meeting performance goals for turbidity and <br /> particle removal. The duration of testing at each different loading rate is proposed <br /> to last until equilibrium is reached. This is anticipated to take a minimum of 1 <br /> week but may last up to 4 weeks. Testing should not be conducted during the <br /> same timeframe as primary treatment testing described in Task 4. Loading rate <br /> testing will be conducted by the City. <br /> (2) Collect four core samples per filter, one filter at normal loading rate and one from <br /> each filter at higher loading rate (total of three filters to be cored) before and after <br /> a standard backwash for solids retention profile analysis per AWWA Filter <br /> 4 <br />