SU0008455 SSNL - Laserfiche WebLink

Home Browse Search

B. MOUND SYSTEM SITE PREPARATION The following calculations illustrate the design parameters for the future mound system to serve the Sikh Temple facility. The pumping system for the effluent disposal will consist of a custom quad(four)pump arrangement,with the pumps operating sequentially with each pump serving one cell of four cells. General Construction Notes for a mound system installation can be found in the California State Water Resources Control Board- Guidelines for the Design, Installation and Operations of Mound Sewage Disposal Systems, and the EPA Design Manual:On Site Wastewater Treatment and Disposal Systems. The location of the mound system will be directly north of the proposed Darbar and Langar Halls. The mound footprint will be ultimately determined by the Project Manager, Mr. Singh,and the author of this report as the engineer-of-record. The mound must be constructed east-to-west,which is perpendicular to the general contour of the land and groundwater flow direction. The 100%replacement area is designated to be directly north of the constructed mound system,where ample area exists. Prior to the commencement of any and all construction activities,the proposed mound disposal area shall be cordoned off to prevent soil compaction from equipment driving over the disposal area. At the start of mound construction, the native soil/sand media interface must be properly prepared. The native soil basal area must stripped of all native vegetation and then ripped to a depth of 8-10 inches with a plow or soil chisels. Soil moisture content at the time of ripping is critical,with the soil not too wet or too dry. Ripping must be perpendicular to the land contour,which again is east-to-west. After plowing and before emplacement of the sand media, it is imperative that no equipment be driven over this area. C. CALCULATION OF MOUND DIMENSIONS BASAL LOADING RATE Due to the long-term acceptance rate anticipated,a conservative basal rate will be employed for design purposes. Consequently,a basal loading rate figure of 0.2 gallons/ft'/day will be used. HYDRAULIC LINEAR LOADING RATE From the percolation tests and direct observation of the soil,it was evident that there was both vertical and lateral flow of water. Consequently,a linear loading rate of 3 gallons/lineal foot/day is sufficient. SAND MEDIA/GRAVEL BED SPECIFICATIONS AND LOADING RATE The filter media is typically a sand soil material that underlies the gravel bed. The sand media should be tested by an engineering laboratory,or be certified by the sand supplier before emplacement. A sieve analysis(ASTM C-33 Specifications)should demonstrate the sand media material must not have more than 20%(by wt.)of material greater than 2 mm dia.and no more than 2%(by wt.)passing the No.200 sieve. Effective Diameter(d1o)should be 0.20 to 0.30 mm with a Unifomrity Coefficient(Dw/13,0)of s4. The sand media loading rate complying with the specifications above will be 0.6 gpd/ft2. The aggregate bed on top of the sand media shall also be tested for conformance with the following size distribution and must be washed and exceptionally clean: 1.0 inch to 2.5 inch washed drain rock. A geotextile filter fabric must be placed over the top of the aggregate bed and extend outward separating the loam soil cap and the sand media(See Plans). 12