Patent ID: 8877488

Claim:
A photobioreactor system comprising: at least one longitudinally extending photobioreactor unit comprising at least one photobioreactor section, the photobioreactor unit being constructed and arranged to carry a flow of a liquid medium comprising phototrophic organisms therein, the photobioreactor unit comprising: at least one cover constructed and arranged to cover at least a substantial portion of the liquid medium within the photobioreactor unit and constructed and arranged to provide a gas headspace under the cover and above the liquid medium, the cover being capable of providing the gas headspace even when a gas pressure within the gas headspace of the photobioreactor unit is less than the atmospheric pressure surrounding the photobioreactor unit; a first liquid inlet constructed and arranged to provide the liquid medium to the photobioreactor unit; a first liquid outlet from which the liquid medium is removable from the photobioreactor unit; a second liquid outlet positioned between the first liquid inlet and the first liquid outlet, from which the liquid medium is removable from the photobioreactor unit; and a channel fluidically interconnecting the second liquid outlet to the photobioreactor unit at a position which is upstream of the second liquid outlet to enable return and recycle of the liquid medium within the photobioreactor unit.