Evaluating the integrity of a forward osmosis membrane using transmembrane pressure

A control arrangement for evaluating the integrity of a forward osmosis (FO-) membrane of a FO-device in a dialysis solution generation apparatus, the FO-membrane separating a feed side and a draw side of the FO-device, the FO-device comprising a feed inlet port and a feed outlet port in fluid communication with the feed side, and a draw inlet port and a draw outlet port in fluid communication with the draw side, the control arrangement comprising:

• a feed pump configured to provide a flow of feed solution at the feed side via the feed inlet port;
• a draw pump configured to provide a flow of draw solution at the draw side via the draw inlet port, at an osmotic pressure at the draw side that is higher than an osmotic pressure at the feed side, thereby allowing extraction of water from the feed side to the draw side to dilute the draw solution;
• one or more pressure sensors configured to measure one or more pressures indicative of a TMP between the draw side and the feed side;
• and
• a valve arrangement configured to control one or more flows via at least one of the draw inlet port, feed inlet port or feed outlet port,
• wherein the control arrangement is configured to:
• stop the flow via the draw inlet port, flow via the feed inlet port and flow via the feed outlet port, using the feed pump, the draw pump, and the valve arrangement, thereby allowing water to continue to be extracted from the feed side to the draw side until a transmembrane pressure (TMP) between the draw side and the feed side has reached a maximum value,
• monitor one or more pressures indicative of the TMP using the one or more pressure sensors, and
• evaluate integrity of the FO-membrane based on a monitored one or more parameters including the one or more pressures indicative of the TMP.

A solution generation apparatus for generating dialysis solution, the apparatus comprising a forward osmosis (FO-) device comprising a FO-membrane that separates a feed side and a draw side of the FO device, the apparatus further comprising a control arrangement, the control arrangement comprising:

• a feed pump configured to provide a flow of feed solution at the feed side via a feed inlet port;
• a draw pump configured to provide a flow of draw solution at the draw side via a draw inlet port, at an osmotic pressure at the draw side that is higher than an osmotic pressure at the feed side, thereby allowing extraction of water from the feed side to the draw side to dilute the draw solution;
• one or more pressure sensors configured to measure one or more pressures indicative of a TMP between the draw side and the feed side;
• and
• a valve arrangement configured to control one or more flows via at least one of the draw inlet port, feed inlet port or feed outlet port,
• wherein the control arrangement is configured to:
• stop the flow via the draw inlet port, flow via the feed inlet port and flow via the feed outlet port, using the feed pump, the draw pump, and the valve arrangement, thereby allowing water to continue to be extracted from the feed side to the draw side until a transmembrane pressure (TMP) between the draw side and the feed side has reached a maximum value, monitor one or more pressures indicative of the TMP using the one or more pressure sensors, and
• evaluate integrity of the FO-membrane based on a monitored one or more parameters including the one or more pressures indicative of the TMP.