Laserfiche WebLink
® The GSE Drainage Design Manual Chapter 4-Design Methods And Concepts <br /> where 8,,, = required hydraulic transmissivity for geonet or geocomposites (M3/sec per in <br /> width); Xtga, = dynamic viscosity of landfill gas (kPa); X,, = dynamic viscosity of water <br /> (kPa); yware,=unit weight of water(kg/m);and yg,,,=unit weight of gas(kg/m). . <br /> Table 4.3 provides density and viscosity values for various fluids for use in Equation 4.12. <br /> Again we note that a very significant side benefit of providing a gas collection layer under the <br /> final cover is that it will also serve to collect sideslope seeps.The seeps would be collected at the <br /> toe of the geocomposite gas collection layer,as illustrated in Figure 4.5. <br /> Table 4.3 Density and viscosity of various fluids[Thiel, 1998]. <br /> DENSITY UNIT WEIGHT DYNAMIC VISCOSITY KINEMATIC VISCOSITY <br /> v=u/ <br /> slugfft kg/m Wit N/m poise lb-s/R N-s/m ft/s m/s <br /> 9/(crn-s) or or <br /> lsluW(S-ft) kqfs-m) <br /> Water 1.94E+ 9.99E+02 6.24E+01 9.80E+03 1.01E-02 Z12E-05 1.01E-03 1.09E-05 1.01 E <br /> Air 2.34E-03 1.20E 7.53E-02 1.18E+01 1.80E-04 3.78E-07 1.79E-05 1.62E-04 1.48E-05 <br /> CO2 3.55E-03 1.83E 1.14E-01 1.79E+01 1.50E-04 3.15E-07 1.50E-05 8.88E-05 8.21 E-06 <br /> Methane 1.29E-03 6.66E-6 4.16E-02 6.54E+00 1.10E-04 2.31E-07 1.10C-O5 1.79E-o4 1.65E-05 <br /> LFG 55% 2.53E-03 1.31E+00 8.15E-02 1.28E+41 1.32E-04 2.77E-07 1.32E-05 1.09E-04 1.01E-05 <br /> CO2,45% <br /> CH4 <br /> Notes:(1)Values for LFG(landfill gas)were assumed to be prorated as 55%properties of carbon dioxide,and <br /> 45%properties of methane. This ratio was used to match the LFG characteristics for the Coffin Butte case <br /> history,which may be different than other landfills. <br /> (2)Values are at standard temperature and pressure. <br /> 18"Vegetative Cover <br /> Geocomposite Drain <br /> i :; - >•``:':yj*"`"'"� Geomembrane <br /> 18 Soil Barrier Layer <br /> (k<10-5 cm/s) <br /> ''•-:K;" / / // �/„ `-1.Geocomposite for <br /> '� •'- Gas Venting and <br /> Seep Collection <br /> o , <br /> Waste and Interim Cover Soil <br /> Perforated PE Underdrain Pipe to Perforated Lateral PE Pipe at <br /> Collect Seepage Underlain by 150 O.C.to Vent Gas and Drain Seeps <br /> Geomembrane Rub Sheet <br /> Figure 4.5 Seep collection at toe of gas collection layer under final cover system. <br /> 4.2.3 Landfill Leachate Collection and Removal System <br /> Leachate impingement into the leachate collection layer is buffered due to relatively large <br /> ® thickness of overlying waste and soil material making the effect of precipitation much more <br /> Page 4-7 <br />