Laserfiche WebLink
File Number: 21-069 <br />was discarded. <br />Reusing the dirt on site after treating with biochar is estimated to cost $7.5M. This estimate is <br />based on an assumed volume of biochar, if the actual quantity needed is different the cost will be <br />higher or lower; the maximum likely value of the work is $8M and this amount will be known when <br />the design is complete. This option uses innovative materials to remediate the soil and extensive <br />testing will be performed after treatment to ensure performance. If the post-treatment test results <br />are unsatisfactory, the design consultant is required to pay for additional treatment until such time <br />as all samples pass testing. This option requires a minimal amount of truck trips as the material is <br />re-used on site. <br />Off hauling the dirt after cement treatment is the only other viable option. Similar to the biochar <br />option, the design and construction cost is estimated at $7.5M. This estimate includes the price <br />to bring in an equivalent volume of soil for placement in the former polishing pond. There is risk of <br />higher costs with this option as the cost is primarily to transport the material, which will be hauled <br />to a permitted waste disposal site. The estimate is based on a local disposal site, but it is <br />possible that the material will need to be moved out of state at an increased cost. Although this <br />process can stabilize only the metals within the soil and will not address the pesticides, the <br />material should be acceptable for placement in a class II regulated dump facility. This process <br />requires approximately 2,600 more truck trips than the biochar option and the design time is <br />slightly longer which results in approximately $240,000 of additional costs to haul sludge due to <br />one season of lost use of the drying beds upon which the dirt is stored. <br />Staff recommends the third option: hiring Leland and mitigating all the contaminants in the dirt. <br />Use of biochar is innovative and that carries some risk of higher than estimated costs, but there <br />are cost savings due to quicker implementation as well as less impact on the neighborhood from <br />trucking activity. Reducing the number of truck trips as well as the attendant emissions associated <br />with this activity supports the goals of the City’s Climate Action Plan. Leland has quoted a <br />significant fee for the design work; Leland guarantees that its design will work and agrees to pay <br />for rework of the soil if certain testing goals are not met. Rework of the soil could potentially cost <br />millions of dollars; thus, Leland’s fee reflects not just the effort required to do the work but also the <br />cost of carrying the risk that Leland may need to rework the soil. <br />Leland must complete its design work before the exact quantity of biochar is known. In order to <br />respond to changes in the amount of biochar needed in a timely fashion and avoid delaying work, <br />staff requests authorization to issue individual contract amendments to the consultant up to 10% <br />or $267,000. If the design indicates the need for a quantity of biochar that exceeds the current <br />change order authorization, staff will bring a report to the City Council before proceeding. <br />Staff recommends appropriation of an additional $500,000 of WPCP enterprise funds for the <br />project, which is sufficient to cover the work by Leland and the design phase of the project. <br />Additional funding will be requested when a construction contract is awarded to mix and move the <br />dirt. <br />Current Agency Policies <br />·Maintain and enhance San Leandro’s infrastructure. <br />Page 3 City of San Leandro Printed on 2/24/2021