Biological and algae harvesting and cultivation systems and methods

An algae harvesting system comprising:

• at least one treatment tank structured and arranged to hold an algae slurry;
• at least one membrane filtration module positioned inside the at least one treatment tank, the at least one membrane filtration module including a plurality of hollow fiber membranes defining lumens;
• a backwash tank positioned such that a level of backwash fluid contained in the backwash tank is above a level of the algae slurry contained in the at least one treatment tank;
• at least one backwash conduit coupled fluidly to the backwash tank and to the plurality of hollow fiber membranes;
• and
• wherein the system is configured to:
• (a) perform dead-end filtration of the algae slurry contained in the at least one treatment tank by pulling a substantially algae-free permeate through pores of the plurality of hollow fiber membranes so that the permeate flows inside the lumens of the plurality of hollow fiber membranes and a retentate of the algae slurry is produced outside the lumens of the plurality of hollow fiber membranes;
• and
• (b) perform a backwash sequence in which the backwash liquid (i) gravity flows from the backwash tank, through the at least one backwash conduit, to inside the lumens of the plurality of hollow fiber membranes, and (ii) is pushed through the pores of the plurality of hollow fiber membranes to remove any foulants that have accumulated on the plurality of hollow fiber membranes.

An algae harvesting system comprising:

• at least one treatment tank;
• a cassette positioned inside the at least one treatment tank, the cassette including a plurality of membrane filtration modules coupled fluidly in parallel via a cassette header, each of the plurality of membrane filtration modules having hollow fiber membranes defining lumens, and wherein the total outside surface area of all of the hollow fiber membranes of the cassette is about 500 m2 to 2200 m2;
• a single permeate valve coupled fluidly to the header;
• a single backwash valve coupled fluidly to the header;
• and
• wherein the system is configured to:
• (a) perform dead-end filtration of an algae slurry contained in the at least one treatment tank by pulling permeate through pores of the hollow fiber membranes so that the permeate flows inside the lumens of the hollow fiber membranes and retentate is produced outside the lumens of the hollow fiber membranes, and
• (b) perform a backwash sequence in which a backwash fluid flows inside the lumens of the hollow fiber membranes and is pushed through the pores of the hollow fiber membranes so as to remove any foulants that have accumulated on the hollow fiber membranes, wherein an actuation time for the single backwash valve and the single permeate valve is about three seconds or less, the actuation time including the time to (i) open the single backwash valve and the single permeate valve or (ii) close the single backwash valve and the single permeate valve.

An algae harvesting system comprising:

• at least one treatment tank;
• a bank positioned inside the at least one treatment tank, the bank including a first cassette and a second cassette, the first cassette and the second cassette coupled fluidly in parallel via a bank header, the first cassette including a first plurality of membrane filtration modules coupled fluidly in parallel via a first cassette header, the second cassette including a second plurality of membrane filtration modules coupled fluidly in parallel via a second cassette header, each of the first and second plurality of membrane filtration modules having hollow fiber membranes defining lumens, wherein the total outside surface area of all of the hollow fiber membranes of the bank is about 500 m2 to 10,000 m2;
• a single permeate valve coupled fluidly to the bank header;
• a single backwash valve coupled fluidly to the bank header;
• and
• wherein the system is configured to:
• (a) perform dead-end filtration of an algae slurry contained in the at least one treatment tank by pulling permeate through pores of the hollow fiber membranes so that the permeate flows inside the lumens of the hollow fiber membranes and a retentate is produced outside the lumens of the hollow fiber membranes, and
• (b) perform a backwash sequence in which a backwash fluid flows inside the lumens of the hollow fiber membranes and is pushed through the pores of the hollow fiber membranes so as to remove any foulants that have accumulated on the hollow fiber membranes, wherein an actuation time for the single backwash valve and the single permeate valve is about three seconds or less, the actuation time including the time to (i) open the single backwash valve and the single permeate valve or (ii) close the single backwash valve and the single permeate valve.

An algae harvesting system comprising:

• a first lined earthen treatment tank defining a first filtration stage;
• a second treatment tank defining a second filtration stage;
• wherein the first filtration stage includes
• a first at least one membrane filtration module positioned inside the first lined earthen treatment tank, said first at least one membrane filtration module including a first plurality of hollow fiber membranes having a first total outside filtration area and defining lumens,
• a retentate outlet, and
• a permeate outlet, and
• wherein the second filtration stage includes
• a second at least one membrane filtration module positioned inside the second treatment tank, said second at least one membrane filtration module including a second plurality of hollow fiber membranes having a second total outside filtration area and defining lumens,
• an inlet coupled fluidly with the retentate outlet of the first filtration stage,
• a retentate outlet, and
• a permeate outlet;
• and
• wherein the system is configured to perform dead-end filtration of an algae slurry contained in the first lined earthen treatment tank and the second treatment tank by pulling permeate through pores of the first and second plurality of hollow fiber membranes so that retentate is produced outside the lumens of the first and second plurality of hollow fiber membranes.

An algae harvesting and cultivation system comprising:

• a first algae cultivator defining a first cultivation stage, the first cultivation stage including a first at least one cultivation device having a first algae cultivation media for cultivating algae;
• a first dead-end filtration system in fluid communication with the first cultivation stage such that the first dead-end filtration system receives at least a portion of the algae cultivated from the first cultivation stage, the first dead-end filtration system having a first plurality of hollow fiber membranes and configured to dead-end filter the algae received from the first cultivation stage through the first plurality of hollow fiber membranes so as to produce a first retentate and a first permeate;
• wherein the system is constructed and arranged such that the first permeate flows back to the first cultivation stage;
• a second algae cultivator defining a second cultivation stage, the second cultivation stage in fluid communication with the first dead-end filtration system such that the second cultivation stage receives the first retentate, the second cultivation stage including a second at least one cultivation device having a second media for cultivating additional algae using the first retentate;
• a second dead-end filtration system in fluid communication with the second cultivation stage such that the second dead-end filtration system receives at least a portion of said additional algae cultivated in the second cultivation stage, the second dead-end filtration system having a second plurality of hollow fiber membranes and configured to dead-end filter the additional algae received from the second cultivation stage so as to produce a second permeate and a second retentate;
• wherein the system is further constructed and arranged such that the second permeate flows back to the second cultivation stage.

An algae harvesting and cultivation system comprising:

• an algae cultivator including at least one cultivation device having a cultivation media for growing algae to produce an algae slurry;
• at least one treatment tank defining a plurality of filtration stages including at least a first filtration stage and a second filtration stage, the first filtration stage in fluid communication with the algae cultivator such that the first filtration stage receives the algae slurry;
• wherein the first filtration stage includes:
• a first at least one membrane filtration module positioned inside the at least one first treatment tank, said first at least one membrane filtration module including a first plurality of hollow fiber membranes having a first total outside filtration area and defining lumens,
• a retentate outlet, and
• a permeate outlet;
• wherein the second filtration stage includes:
• a second at least one membrane filtration module positioned inside the at least one treatment tank, said second at least one membrane filtration module including a second plurality of hollow fiber membranes having a second total outside filtration area and defining lumens,
• an inlet coupled fluidly to the retentate outlet of the first filtration stage,
• a retentate outlet, and
• a permeate outlet;
• and
• wherein the system is configured to cultivate algae and perform dead-end filtration of the algae slurry by:
• (i) allowing the algae slurry to flow from the algae cultivator to the first filtration stage,
• (ii) pulling permeate through pores of the first plurality of hollow fiber membranes at a first flux so that a first retentate is produced outside the lumens of the first plurality of hollow fiber membranes,
• (iii) allowing at least a portion of the first retentate to flow from the first filtration stage retentate outlet to the second filtration stage retentate inlet,
• (iv) pulling permeate through pores of the second plurality of hollow fiber membranes at a second flux so that a second retentate is produced outside the lumens of the second plurality of hollow fiber membranes, and
• (v) allowing the permeate from the first and second filtration stages to flow back to the algae cultivator for use in the cultivation media for growing algae.

An algae harvesting system comprising:

• at least one treatment tank including
• a rinse fluid inlet, and
• a retentate outlet;
• at least one membrane filtration module positioned inside the at least one treatment tank, the at least one membrane filtration module including a plurality of hollow fiber membranes defining lumens;
• a source of algae slurry in a media, the source of algae slurry coupled fluidly to the at least one treatment tank such that the at least one treatment tank can receive the algae slurry;
• a source of rinse fluid, the source of rinse fluid coupled fluidly to the rinse fluid inlet of the at least one treatment tank such that the at least one treatment tank can receive the rinse fluid;
• a media sensor configured to sense the concentration of media in the algae slurry;
• and
• wherein the system is configured to:
• (a) perform dead-end filtration of the algae slurry received in the at least one treatment tank by pulling a substantially algae-free permeate through pores of the plurality of hollow fiber membranes so that the permeate flows inside the lumens of the plurality of hollow fiber membranes and a retentate of the algae slurry is produced outside the lumens of the plurality of hollow fiber membranes,
• (b) perform a backwash sequence in which a backwash liquid flows inside the lumens of the plurality of hollow fiber membranes and is pushed through the pores of the plurality of hollow fiber membranes to remove any foulants that have accumulated on the plurality of hollow fiber membranes, and
• (c) perform a rinse sequence in which (i) the at least one treatment tank stops receiving the algae slurry from the source of algae slurry, and (ii) the at least one treatment tank receives the rinse fluid from the source of rinse fluid through the rinse fluid inlet until the at least one media sensor senses that at least ninety percent of the media has been replaced with the rinse fluid.

An algae harvesting system comprising:

• at least one treatment tank defining a plurality of filtration stages including at least a first filtration stage and a second filtration stage;
• wherein the first filtration stage includes:
• a first at least one membrane filtration module positioned inside the at least one treatment tank, said first at least one membrane filtration module including a first plurality of hollow fiber membranes having a first total outside filtration area and defining lumens,
• a retentate outlet, and
• a permeate outlet;
• and
• wherein the second filtration stage includes:
• a second at least one membrane filtration module positioned inside the at least one treatment tank, said second at least one membrane filtration module including a second plurality of hollow fiber membranes having a second total outside filtration area and defining lumens,
• a retentate inlet coupled fluidly to the retentate outlet of the first filtration stage,
• a rinse fluid inlet,
• a retentate outlet, and
• a permeate outlet;
• a media sensor configured to sense a concentration of media in an algae slurry in the at least one treatment tank;
• and
• wherein the system is configured to:
• (a) perform dead-end filtration of the algae slurry contained in the at least one treatment tank by (i) pulling permeate through pores of the first plurality of hollow fiber membranes at a first flux so that the permeate flows inside the lumens of the first plurality of hollow fiber membranes and a first retentate is produced outside the lumens of the first plurality of hollow fiber membranes, (ii) allowing at least a portion of the first retentate to flow through the retentate outlet of the first filtration stage to the inlet of the second filtration stage, and (iii) pulling permeate through pores of the second plurality of hollow fiber membranes at a second flux so that the permeate flows inside the lumens of the second plurality of hollow fiber membranes and a second retentate is produced outside the lumens of the second plurality of hollow fiber membranes,
• (b) perform a backwash sequence in which a backwash liquid flows (i) inside the lumens of the first plurality of hollow fiber membranes and is pushed through the pores of the first plurality of hollow fiber membranes to remove any foulants that have accumulated on the first plurality of hollow fiber membranes, and (ii) inside the lumens of the second plurality of hollow fiber membranes and is pushed through the pores of the second plurality of hollow fiber membranes to remove any foulants that have accumulated on the second plurality of hollow fiber membranes,
• (c) perform a rinse sequence in which (i) the first retentate stops flowing from the first filtration stage to the second filtration stage, and (ii) the rinse fluid flows to the second filtration stage through the rinse fluid inlet until the media sensor senses that that at least ninety percent of the media has been replaced with the rinse fluid.

An algae harvesting and cultivation system comprising:

• an algae cultivator including at least one cultivation device having a cultivation media for growing algae to produce an algae slurry;
• at least one treatment tank defining a plurality of filtration stages including at least a first filtration stage and a second filtration stage, the first filtration stage in fluid communication with the algae cultivator such that the first filtration stage receives the algae slurry;
• wherein the first filtration stage includes:
• a first at least one membrane filtration module positioned inside the at least one first treatment tank, said first at least one membrane filtration module including a first plurality of hollow fiber membranes having a first total outside filtration area and defining lumens,
• a retentate outlet, and
• a permeate outlet;
• wherein the second filtration stage includes:
• a second at least one membrane filtration module positioned inside the at least one treatment tank, said second at least one membrane filtration module including a second plurality of hollow fiber membranes having a second total outside filtration area and defining lumens,
• an inlet coupled fluidly to the retentate outlet of the first filtration stage,
• a retentate outlet, and
• a permeate outlet;
• a live algae container coupled fluidly to the second filtration stage to receive the second retentate;
• and
• wherein the system is configured to cultivate algae and perform dead-end filtration of the algae slurry by:
• (i) allowing the algae slurry to flow from the algae cultivator to the first filtration stage,
• (ii) pulling permeate through pores of the first plurality of hollow fiber membranes at a first flux so that a first retentate is produced outside the lumens of the first plurality of hollow fiber membranes,
• (iii) allowing at least a portion of the first retentate to flow from the first filtration stage retentate outlet to the second filtration stage retentate inlet,
• (iv) pulling permeate through pores of the second plurality of hollow fiber membranes at a second flux so that a second retentate is produced outside the lumens of the second plurality of hollow fiber membranes,
• (v) allowing the permeate from the first and second filtration stages to flow back to the algae cultivator for use in the cultivation media for growing algae, and
• (vii) flowing live algae in the second retentate from the second filtration stage to the live algae container.