A method comprising: introducing a slurry to a shaker having a first screen proximate an inlet located in a back wall of the shaker and a second screen proximate an outlet end of the shaker, a first sump being located below the first screen and a second sump being located below the second screen to receive material passed through the screens, wherein the first and second sumps (50A, 50B) are not in fluid communication, wherein the first sump is fluidly connected via a first flowline to a first degassing chamber which is fluidly connected via a second flowline to a first valve and a first pressure differential device, and wherein the second sump is fluidly connected via a third flowline to a second degassing chamber which is fluidly connected via a fourth flowline to a second valve and a second pressure differential device; flowing the slurry over the first and second screens; selectively using the first pressure differential device to generate an intermittent first pressure differential across the first screen, creating a first pressure zone and causing both liquids and vapors to be pulled through an outlet of the first sump into the first degassing chamber via the first flowline and selectively using the second pressure differential device to generate an intermittent second pressure differential across the second screen, creating a second pressure zone and causing both liquids and vapor to be pulled through an outlet of the second sump into the second degassing chamber via the third flowline, wherein the first pressure differential is the same or different from the second pressure differential; recovering vapors collected in the first and second degassing chambers via the second and fourth flowlines while generating the intermittent first and second pressure differentials and venting the recovered vapors via fifth and sixth flowlines connected to the first and second pressure differential devices respectively; degassing or partially degassing fluids collected in the first and second degassing chambers by a vacuum or partial vacuum generated by the respective first and second pressure differential devices connected thereto; and recovering liquids collected in the first and second degassing chambers via seventh and eight flowlines. introducing a slurry to a shaker having a first screen proximate an inlet located in a back wall of the shaker and a second screen proximate an outlet end of the shaker, a first sump being located below the first screen and a second sump being located below the second screen to receive material passed through the screens, wherein the first and second sumps (50A, 50B) are not in fluid communication, wherein the first sump is fluidly connected via a first flowline to a first degassing chamber which is fluidly connected via a second flowline to a first valve and a first pressure differential device, and wherein the second sump is fluidly connected via a third flowline to a second degassing chamber which is fluidly connected via a fourth flowline to a second valve and a second pressure differential device; flowing the slurry over the first and second screens; selectively using the first pressure differential device to generate an intermittent first pressure differential across the first screen, creating a first pressure zone and causing both liquids and vapors to be pulled through an outlet of the first sump into the first degassing chamber via the first flowline and selectively using the second pressure differential device to generate an intermittent second pressure differential across the second screen, creating a second pressure zone and causing both liquids and vapor to be pulled through an outlet of the second sump into the second degassing chamber via the third flowline, wherein the first pressure differential is the same or different from the second pressure differential; recovering vapors collected in the first and second degassing chambers via the second and fourth flowlines while generating the intermittent first and second pressure differentials and venting the recovered vapors via fifth and sixth flowlines connected to the first and second pressure differential devices respectively; degassing or partially degassing fluids collected in the first and second degassing chambers by a vacuum or partial vacuum generated by the respective first and second pressure differential devices connected thereto; and recovering liquids collected in the first and second degassing chambers via seventh and eight flowlines.