NL2026106B1

NL2026106B1 - System for removing pharmaceuticals from water, such as waste water and method therefore

Info

Publication number: NL2026106B1
Application number: NL2026106A
Authority: NL
Inventors: Veenendaal Gerrit
Original assignee: Nieuwater B V
Priority date: 2020-07-21
Filing date: 2020-07-21
Publication date: 2022-03-21

Abstract

The invention relates to a system for removing pharmaceuticals from water, preferably waste water, the system comprising: — a water channel that is configured for transporting a ﬂow of water, Wherein the water channel extends from a water inlet to a water outlet; — a biological oxygen dosed activated carbon (BODAC) filter unit that is positioned in the water channel and that is configured to operate substantially continuous; and — an oxygen supply that is operatively connected to the water channel and that is configured to supply substantially pure oxygen. The invention further relates to a method for removing pharmaceuticals from water.

Description

SYSTEM FOR REMOVING PHARMACEUTICALS FROM WATER, SUCH AS WASTE

WATER AND METHOD THEREFORE In the past years, an increasing amount of pharmaceuticals and/or pharmaceutically active compounds (PhACs) has been observed in water such as surface water and groundwater bodies, and especially municipal waste water and waste water from hospitals. This is mainly due to the fact that the world-wide use of pharmaceuticals has significantly grown over the past decades, and that part of the used pharmaceuticals are excreted by consumers and patients. As a result, the used pharmaceuticals end up in waste water, and, when not removed, ultimately in other water bodies, such as streams, rivers and underground reservoirs from which drinking water is (or may be) produced.

The increasing use of pharmaceuticals also has increased the production of pharmaceuticals by the industry, leading to increased flows of waste water containing pharmaceuticals and/or pharmaceutically active compounds (PhACs) from these industries.

Conventional (waste) water treatment systems have proven inadequate to remove such pharmaceuticals or pharmaceutical compounds from water, especially waste water, in sufficient amounts. Especially in waste water, it is observed that, due to the limited amount of removal, a significant amount of pharmaceuticals remains in the treated waste water that is discharged into surface water, such as streams and rivers.

In order to solve these problems, an improved water treatment system for waste water was developed. The system comprises a sequential bioreactor (i.e. a batch reactor) in which an amount of activated carbon was added to improve the amount of pharmaceuticals removed from the waste water.

Although improved results with regard to the removal of pharmaceuticals are achieved, these systems also have various drawbacks. A first disadvantage is that these systems are based on a batch reactor, which makes them unsuitable for treating larger (continuous) flows of waste water.

A second disadvantage is that system requires relatively high amounts of activated carbon. This is mainly due to the fact that the efficiency of the activated carbon with regard to removal of pharmaceuticals is reduced after saturation of the activated carbon is achieved.

Therefore, a system is required which allows continuous treatment of waste water while simultaneously achieving a high amount of efficiency in removing pharmaceuticals over a longer period of time.

This object is achieved by the system for removing pharmaceuticals from water, especially waste water, the system comprising: — a water channel that is configured for transporting a flow of water, wherein the water channel extends from a water inlet to a water outlet;

— abiological oxygen dosed activated carbon (BODAC) filter unit that is positioned in the water channel, and =— an oxygen supply that is operatively connected to the water channel and that is configured to supply substantially pure oxygen.

An advantage of the system according to the invention is that, due to the fact that substantially pure oxygen is added to the water stream that is provided to the BODAC filter unit, the activated carbon has a significantly increased lifetime. It has been found that activated carbon in the BODAC filter unit remains efficient in respect to pharmaceuticals removal even (long) after the activated carbon has been saturated with Dissolved Organic Carbon (DOC). It has also been 19 found that the operational period of the activated carbon in the BODAC filter unit may surpass several years and may provide efficient removal up to ten years, and possibly even longer.

Another advantage of the system according to the invention is that the BODAC filter unit can be operated in continuous processing rather than in batch processing. As a result, the system is useable for treating larger flows of (waste) water, leading to a more efficient (waste) water treatment process. This also results in lower costs and a lower carbon footprint.

It is noted that the oxygen supply can be provided in the form of an oxygen supply unit that is configured to manufacture oxygen on-site or as part of the system, or can be provided as an oxygen supply in the form of oxygen cylinders or containers or can be provided as an oxygen pipeline that is configured for supplying oxygen to the system. In other words, the oxygen may be provided with any suitable means, as long as the oxygen comprises substantially pure oxygen.

It is further noted that an advantage of the system is that, in addition to removing pharmaceuticals and/or pharmaceutically active compounds (PhACs), it also removes other organic micropollutants from the water stream.

In an embodiment of the system according to the invention, the system may comprise a mixing unit that is positioned upstream of the BODAC filter unit, wherein the oxygen supply is connected to the mixing unit, and wherein the mixing unit is configured to mix the water flow and the substantially pure oxygen.

An advantage of providing a mixing unit to mix the oxygen and the water flow is that the contact between the oxygen and the water is increased and substantially a homogeneous mixture is achieved. By feeding the homogeneous mixture into the BODAC filter unit, the efficiency of the activated carbon with respect to the removal of pharmaceuticals is increased even further.

It is noted that the system according to the invention is suitable to treat substantially any water flow or stream containing pharmaceuticals, and it has been found that it is highly effective in waste water treatment. The terms water and waste water are therefore used interchangeably in this application.

In an embodiment of the system according to the invention, a flow rate of a flow of substantially pure oxygen that is supplied via the oxygen supply is in the range of 1 — 15 gram/m’, and is preferably in the range of 3 — 10 gram/m”, and most preferably is in the range of 6 — 7 gram/m’.

It has been found that, when providing an oxygen flow in the abovementioned range, it is substantially prevented that the conditions in the BODAC filter unit become anaerobic. At the same time, the amount of oxygen in the BODAC filter unit is, when using this range, low enough to prevent oversaturation of oxygen in the water flow in the water channel.

In an embodiment of the system according to the invention, the system may comprise a control unit that is configured to control the oxygen supply to the water channel or to the mixing unit.

An advantage of regulating or controlling the oxygen supply with a control unit is that a reactive or even pro-active control can be exercised over the oxygen supply, such that the oxygen supply is adapted to the water flow in the water channel and/or the characteristics of the water flow in the water channel. Preferably, the control unit is configured to operate based on system parameters that are provided to the control unit by the system. Moreover, it is preferred that the control unit is also configured to regulate and/or control other system parameters.

In an embodiment of the system according to the invention, the system may comprise an ammonium sensor that is positioned upstream of the BODAC filter unit and that is configured to measure an ammonium concentration in the water flow.

An advantage of providing an ammonium sensor in or near the water inlet is that the concentration of ammonium can be measured and that anaerobic conditions in the BODAC filter unit can therewith be prevented. This is achieved by controlling the oxygen flow from the oxygen supply in dependence of the ammonium concentration. This is advantageous as the ammonium in the water flow reacts with oxygen, which reduces the oxygen level in the water flow. By controlling the oxygen flow from the oxygen supply in dependence on the measured ammonium concentration, oxygen depletion and (thus) anaerobic conditions in the BODAC filter unit can be prevented. For completeness sake, it is noted that an increase in ammonium would necessitate an increase in oxygen flow to the water flow.

In an embodiment of the system according to the invention, the control unit may be configured to compare a measured ammonium concentration from the ammonium sensor with a threshold value and increase a flow of substantially pure oxygen from the oxygen supply if the measured ammonium concentration exceeds the threshold value.

It is known that a high concentration of ammonium in the water flow has a negative impact onthe efficiency and operation of the BODAC-filter unit. It is therefore an advantage if the measured ammonium concentration is compared with a threshold, because it allows the control unit to reduce the amount of ammonium in the water flow by increasing the oxygen flow from the oxygen supply before the water flow enters the BODAC filter unit. As a result, damage to the BODAC filter unit is prevented.

In an embodiment of the system according to the invention, the system may comprise an oxygen sensor that is positioned downstream from the BODAC filter unit and is associated therewith and that is configured to measure an oxygen concentration in a filtrate flow from the BODAC filter unit.

An advantage of providing an oxygen sensor is that the oxygen concentration in the filtrate from the BODAC filter unit can be measured. It is noted that the biological process in the BODAC filter unit is an process which requires oxygen (i.e. an oxygen-based or aerobic process). By measuring the oxygen concentration in the filtrate of the BODAC filter unit, it can be established whether sufficient oxygen was provided in the water flow that was provided (at the inlet of) the BODAC filter unit. If the concentration would be zero or close thereto, the oxygen concentration in the water flow provided to the BODAC filter unit was too low.

In an embodiment of the system according to the invention, the control unit may be configured to regulate a quantity of oxygen supplied to a water flow in the water channel based on the measurement data received from the at least one oxygen sensor.

An advantage of this embodiment is that it provides data on the correctness of the input variables in the oxygen supply. In other words, the input value of oxygen, which is preferably based on the volume of the water flow, can be evaluated based on the oxygen concentration of the filtrate flow from the BODAC filter unit. This allows the input values to be corrected based on the oxygen concentration in the filtrate flow to further increase the efficiency of the system.

It should be noted that the correction based on the oxygen concentration is preferably corrected with a time delay factor which is based on the retention or processing time of the BODAC filter unit. Thus, a measured oxygen concentration in the filtrate at a predetermined time is the result of the input value and input water flow provided at the predetermined time minus the retention time, Preferably, the control unit is configured to take into account the mentioned time delay upon regulation the quantity of oxygen from the oxygen supply to the water flow.

In an embodiment of the system according to the invention, the control unit may be configured to compare the measured oxygen concentration provided by the at least one oxygen sensor with a predetermined oxygen ratio set point (OR-SP) to obtain a dosage ratio (DR), and multiply the dosage ratio (DR) with a measured feed flow volume (FFV) upstream of the oxygen supply to obtain a dosage flow set point (DF-SP), and compare the dosage flow set point (DF-SP) with a current flow dosage (CFD) of the oxygen supply, and adjust the current flow dosage (CFD) to the dosage flow set point (DF-SP).

In this embodiment, the oxygen supply to the water flow is controlled based on the measured oxygen concentration and the actual flow volume of the water flow in the water channel (which is defined as the measured feed flow volume or FFV) which are combined in a dosage flow set point (DF-SP). The flow dosage set point is used as reference for the actual flow dosage (CFD) 5 of the oxygen from the oxygen supply. In other words, the quantity of oxygen supplied from the oxygen supply (defined as the actual flow dosage of CFD) is corrected based on the dosage flow set point (DF-SP). An advantage thereof is that the measured oxygen concentration in the filtrate is corrected for the actual flow volume of the water flow in the water channel, thus obtaining a more accurate control.

In an embodiment of the system according to the invention, the dosage ratio may have an upper dosage limit (UDL) and a lower dosage limit (LDL), and wherein, when the dosage ratio (DR) would exceed the upper dosage limit (UDL), the control unit is configured to use the upper dosage limit (UDL), and wherein, when the dosage ratio (DR) would be lower than the lower dosage limit (LDL), the control unit is configured to use the lower dosage limit (LDL).

To limit the impact of the control actions by the control unit, an upper (UDL) and lower (LDL) dosage limit may be used to reduce the off-set in the oxygen quantity supplied by the oxygen supply to the water flow in the water channel. An advantage of limiting the impact is that the oxygen supply is not increased (or decreased) too much in response to a large deviation from the desired oxygen concentration set point in the filtrate from the BODAC filter unit.

In an embodiment of the system according the invention, the system may comprise a second BODAC filter unit that is positioned downstream of and in series with the BODAC filter unit.

An advantage of providing two BODAC filter units placed in series is that the removal of pharmaceuticals from the water flow is enhanced even further.

In an embodiment of the system according the invention, the system may additionally comprise one or more of a second mixing unit that is positioned between the BODAC filter unit and the second BODAC filter unit, a second oxygen supply that is operatively connected to the water channel between the BODAC filter unit and the second BODAC filter unit, wherein the second oxygen supply is configured to supply substantially pure oxygen, and an oxygen sensor that is positioned downstream of the second BODAC filter and is associated therewith and is configured to measure an oxygen concentration in a filtrate flow from the second BODAC filter unit.

An advantage of this embodiment is that the both BODAC filter units can be regulated independently from each other, which allows a more precise control over the system. In addition, this configuration allows each BODAC filter unit to be used independently, for example allowing maintenance of one of both BODAC filter units, while still operating the other.

Another advantage of this embodiment, is that it allows a more redundant control over the system and the associated removal of pharmaceuticals, because the second BODAC filter unit may increase removal and, if necessary, also correct mistakes from the BODAC filter anit.

It is preferred that, when a second oxygen supply and a second mixing unit are present, the second oxygen supply is connected to the second mixing unit to provide a better mixing of the oxygen and the water flow.

In an embodiment of the system according the invention, the system comprises a second control unit, wherein the second control unit is configured to regulate a quantity of oxygen supplied through the second oxygen supply to a water flow in the water channel based on the measurement data received from the second oxygen sensor.

An advantage of providing a second control unit is that a more redundant system is achieved. Not only can both BODAC filter units be operated completely independent from each other, one control unit can also be used to provide a back-up in case of failure or maintenance of the other control unit.

Another advantage of providing a second control unit is that a more precise control can be exercised over the system.

In an embodiment of the system according the invention, the second control unit may further be configured to compare the measured oxygen concentration provided by the second oxygen sensor with a second predetermined oxygen ratio set point (OR2-SP) to obtain a second dosage ratio {DR2), multiply the second dosage ratio (DR2) with a measured feed flow volume (FFV2) between the oxygen sensor and the second oxygen supply to obtain a second dosage flow set point (DF2-SP), compare the second dosage flow set point (DF2-SP) with a current second flow dosage (CFD2) of the second oxygen supply and adjust the current second flow dosage (CFD2) to the second dosage flow set point (DF2-SP).

In this embodiment, the oxygen supply to the water flow before the second BODAC filter unit is controlled based on the measured oxygen concentration by the second oxygen sensor and the actual flow volume of the water flow in the water channel between the oxygen sensor and the second oxygen supply (which is defined as the measured feed flow volume or FFV2) which are combined in a dosage flow set point (DF2-SP). The flow dosage set point is used as reference for the actual flow dosage (CFD2) of the oxygen from the oxygen supply. In other words, the quantity of oxygen supplied from the oxygen supply (defined as the actual flow dosage of CFD2) is corrected based on the dosage flow set pomt (DF2-SP). An advantage thereof is that the measured oxygen concentration in the filtrate is corrected for the actual flow volume of the water flow in the water channel, thus obtaining a more accurate control.

In an embodiment of the system according the invention, the second dosage ratio (DR2) may have an upper dosage limit (UDL2) and a lower dosage limit (LDL 2), and wherein, when the second dosage ratio (DR2) would exceed the upper dosage limit (UDL2), the second control unit is configured to use the upper dosage limit (UDL2), and wherein, when the second dosage ratio (DR2) would be lower than the lower dosage limit (LDL2), the second control unit is configured to use the lower dosage limit (LDL2).

To limit the impact of the control actions by the second control unit, an upper (UDL2) and lower (LDL2) dosage limit may be used to reduce the off-set in the oxygen quantity supplied by the oxygen supply to the water flow in the water channel. An advantage of limiting the impact is that the oxygen supply is not increased (or decreased) too much in response to a large deviation from the desired oxygen concentration set point in the filtrate from the second BODAC filter unit.

In an embodiment of the system according the invention, a retention time of the water flow in the second BODAC filter unit is in the range of 6 — 48 minutes, and preferably is in the range of — 36 minutes, and more preferably is around 32 minutes.

It has been found that a retention time in the abovementioned range provides excellent results with regard to removal of pharmaceuticals. It is preferred that the retention time is achieved {5 by the dimensions of the BODAC filter unit and/or by adapting the flow rate of the water flow in the water channel that is provided to the BODAC filter unit.

In an embodiment of the system according the invention, the flow of substantially pure oxygen comprises more than 90% oxygen, preferably comprises more than 95% oxygen and more preferably comprises more than 99% oxygen.

20 An advantage of substantially pure oxygen, that is in the abovementioned range, is that a high amount of removal of pharmaceuticals is achieved. In addition, it has been found that the addition of substantially pure oxygen also increases the lifetime and operational effect of the activated carbon even after saturation of the activated carbon has been reached. The operational life-time of the activated carbon may even be increased to ten years or more by providing substantially pure oxygen to the water flow.

In an embodiment of the system according the invention, a retention time of the water flow in the BODAC filter unit is in the range of 2 — 36 minutes, and preferably is in the range of 10 — 25 minutes, and more preferably is 14 — 18 minutes.

It has been found that a retention time in the abovementioned range provides excellent results with regard to removal of pharmaceuticals. It is preferred that the retention time is achieved by the dimensions of the BODAC filter unit and/or by adapting the flow rate of the water flow in the water channel that is provided to the BODAC filter unit.

In an embodiment of the system according to the invention, the system may comprise at least one reverse osmosis (RO) unit that is positioned downstream of the BODAC filter unit.

An advantage of providing at least one RO-unit is that the purity of the water flow is increased even further, even up to providing ultrapure water (UPW).

In an embodiment of the system according to the invention, the system may comprise one or more filtration units that are positioned upstream of the BODAC filter.

An advantage of providing filtration units is that solids are filtered from the water stream that is provided in the water inlet from the water channel, which (further) reduces the risk of clogging of the BODAC filter unit.

In an embodiment of the system according to the invention, the one ore more filtration units may comprise one or more ultrafiltration (UF) units.

An advantage of providing ultrafiltration (UF) units is that such units are capable of removing both relatively large and relatively small particles, which reduces the amount of particles inthe water flow to the BODAC filter unit.

In an embodiment according to the invention, the system comprises a backflush-outlet that is positioned upstream of the BODAC filter unit, preferably directly upstream of the BODAC filter unit, and wherein the control unit is additionally configured to periodically backflush the BODAC filter unit, wherein the backflushing comprises providing a flow of filtrate in an upstream direction through the BODAC filter, and discharging the filtrate from the backflush-outlet.

In an embodiment of the method according to the invention, the system comprises additional BODAC filter units and additional oxygen supplies, wherein each BODAC filter unit is associated with an oxygen supply that is positioned upstream of the BODAC filter unit with which said oxygen supply is associated, and the system optionally comprises oxygen sensors and/or mixing units, wherein each additional mixing unit is associated with one of the additional BODAC filter units and is positioned upstream thereof, and wherein each additional oxygen sensor is associated with one of the additional BODAC filter units and is positioned downstream thereof for measuring an oxygen concentration in the filtrate flow from the additional BODAC filter unit with which it is associated.

The system according to the invention can advantageously be modularly expanded to include additional BODAC filter units. Each of these additional BODAC filter units is preferably associated with an oxygen supply and optionally a mixing unit and an oxygen sensor. This allows the system to be applied to any water flow, even when such flows have a (very) high concentration of pharmaceuticals contained therein.

The invention also relates to a method for removing pharmaceuticals from water, the method comprising: — providing a system according to any one of the preceding clauses; — providing a flow of water to the water channel through the water inlet; and — adding substantially pure oxygen to the water flow upstream of the BODAC-filter; — filtering the water flow in the BODAC filter unit to remove pharmaceuticals; and — discharging the filtered water flow through the water outlet.

The method according to the invention has similar effects and advantages as the system according to the invention. In addition, it is noted that the embodiments as described for the system may also be applied to the method with corresponding or similar effects and/or advantages for the method according to the invention.

An advantage of the method according to the invention is that, by adding substantially pure oxygen to the water flow upstream of the BODAC filter unit, the activated carbon in the BODAC filter unit has an increased operational lifespan which extends even after saturation of the activated carbon has set in.

Another advantage is that providing substantially pure oxygen to the water flow in combination with a BODAC filter unit allows substantially continuous processing of the water flow, therewith increasing the operational volume and throughput of water.

In an embodiment of the method according to the invention, the method additionally may comprise the steps of filtering the water flow in the filtration unit, providing a flow of substantially pure oxygen to the filtered water flow downstream of the filtration unit and upstream of the BODAC filter unit, and supplying the water flow to the BODAC filter.

An advantage of filtering the water flow from the water inlet is that the water flow in the water channel is substantially devoid of solids, which reduces the risk of clogging and/or fouling of the BODAC filter unit.

In an embodiment of the method according to the invention, the method additionally may comprise the steps of filtering the water flow from the BODAC filter unit in a reverse osmosis (RO) filter unit and discharging the water from the RO filter unit through the water outlet.

An advantage of the step of filtering the water flow from the BODAC filter unit is that the water flow that is discharged from the water outlet is substantially pure water which can be used for a great variety of applications.

In an embodiment of the method according to the invention, the system may comprise a control unit and an ammonium sensor that is positioned upstream of the BODAC filter unit, and wherein the method comprises the steps of measuring, by the ammonium sensor, an ammonium concentration in the water flow, comparing, by the control anit, the measured ammonium concentration with a threshold concentration value, and increasing, by the control unit, a flow of substantially pure oxygen from the oxygen supply if the measured ammonium concentration exceeds the threshold value.

The advantage of the abovementioned embodiment, is that additional oxygen is provided to the water flow only if the ammonium concentration becomes too high (i.e. exceeds a predetermined threshold value). Herewith it is realized that the control of the oxygen flow from the oxygen supply is controlled to prevent excess oxygen and, simultaneously also prevent oxygen depletion and/or anaerobic conditions in the BODAC filter unit.

In an embodiment of the method according to the invention, the system may comprise a control unit and an oxygen sensor that is positioned downstream from the BODAC filter unit, and wherein the method additionally comprises the steps of measuring, by the oxygen sensor, an oxygen concentration in the filtrate flow from the BODAC filter unit, comparing, by the control unit, the measured oxygen concentration with a predetermined oxygen ratio set point, and adjusting, by the control unit, the flow of substantially pure oxygen from the oxygen supply.

An advantage of measuring the oxygen concentration after the BODAC filter unit is that the oxygen flow that is provided to the water flow in the water channel is based on the result (i.e. measured in oxygen concentration) of the BODAC filter unit.

Thus, if the BODAC filter unit uses alarge amount of oxygen, this is visible as a lower oxygen concentration in the outflow of the BODAC filter unit.

By measuring the oxygen concentration in the outflow, the oxygen concentration can be adapted to the functionality of the BODAC filter unit {in terms of oxygen use). Therewith, it can be prevented that anaerobic conditions will occur in the BODAC filter unit.

In an embodiment of the method according to the invention, wherein the steps of comparing and adjusting comprise comparing, by the control unit, the measured oxygen concentration with the predetermined oxygen ratio set point (OR-SP) and obtaining a dosage ratio (DR), multiplying the dosage ratio (DR) with a measured feed flow volume (FFV) that is measured upstream of the oxygen supply to obtain a dosage flow set point (DF-SP), and comparing the dosage flow set point (DF-SP) with a current flow dosage (CFD) of the oxygen supply, and adjusting the current flow dosage (CFD) to the dosage flow set point (DE-SP). The abovementioned method steps provide a more integral and extensive control over the process, which in turn results in a more accurate dosage of the oxygen to the BODAC filter unit.

As a result, the performance of the BODAC filter unit is (further) increased and the removal of pharmaceuticals is optimized.

In an embodiment of the method according to the invention, the system, when viewed in a downstream direction from the oxygen sensor, may additionally comprise a second oxygen supply, a second BODAC filter unit and a second oxygen sensor, and wherein the method additionally may comprise the steps of comparing, by the control unit, the measured oxygen concentration with the predetermined oxygen ratio set point (OR2-SP) and obtaining a dosage ratio (DR2), multiplying the dosage ratio (DR2) with a measured feed flow volume (FFV) that is measured upstream of the oxygen supply to obtain a dosage flow set point (DF2-SP), comparing the dosage flow set point (DF2-SP) with a current flow dosage (CFD2) of the oxygen supply, adjusting the current flow dosage (CFD?2) to the dosage flow set point (DF2-SP) and filtering water flow F in the second BODAC filter unit to remove pharmaceuticals.

In an embodiment of the method according to the invention, the system comprises a backflush-outlet that is positioned upstream of the BODAC filter unit, preferably directly upstream of the BODAC filter unit and the method comprises the step of backflushing the BODAC filter unit, wherein backflushing comprises providing a flow of filtrate in an upstream direction through the BODAC filter, and discharging the filtrate from the backflush-outlet. It is preferred that the method comprises filtering the flow in two separate BODAC filter units that are placed in series to obtain an even higher removal of pharmaceuticals from the water flow.

Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which: Figure 1 is a schematic overview of an example of the system according to the invention; Figure 2 is an example of a control schematic for the oxygen supply for the system according to the invention; Figure 3 is a second example of a control schematic for regulating oxygen supply, which includes ammonium correction; and Figure 4 is a schematic overview of an example of the method according to the invention.

In an example of system 2 according to the invention (see figure 1), system 2 comprises water channel 4 that extends from water inlet 6 to water outlet 8. In order to filter pharmaceuticals from water stream W, system 2 is provided with BODAC filter unit 10. It is noted that BODAC filter unit 10 works best under aerobic circumstances (i.e. in an oxygen-containing environment).

In order to ascertain that sufficient oxygen is available for BODAC filter unit 10, system 2 is further provided with oxygen supply 12 which provides substantially pure oxygen stream O.. In this example, oxygen supply 12 is oxygen generator 12, although oxygen supply 12 may also be provided by means of an oxygen pipeline or containers. In this example, oxygen supply 12 is not directly connected to water channel 4, yet is connected to mixing unit 14. Mixing unit 14 is positioned in water channel 4 upstream of BODAC filter unit 10 and is configured to mix oxygen stream O, from oxygen supply 12 with water stream F in water channel 4 to obtain a well-mixed stream W. System 2 is further provided with oxygen sensor 16, which in this example is positioned directly downstream of BODAC filter unit 10 to measure oxygen concentration in water stream F downstream of BODAC filter unit 10. The oxygen concentration data measured by oxygen sensor 16 is subsequently provided to control unit 18, which is configured for controlling at least part of system 2 including BODAC filter unit 10. Apart from being connected to oxygen sensor 16, control unit 18 is further operatively connected to oxygen supply 12 and mixing unit 14. Control unit 18 is configured to regulate oxygen stream O. based on the data received from oxygen sensor 16 to ascertain that the oxygen concentration is kept within acceptable ranges. This control by control unit 18 can be provided by regulating the amount of O; (and thus concentration) from oxygen supply 12 and/or by controlling mixing unit 14 to provide increased mixing in water channel 4. This example further includes flow meter 20 that is operatively connected to control unit

18. The information from flow meter 20 may be used by control unit 18 to control mixing unit 14 and/or oxygen supply 12 to increase or decrease the oxygen stream O; in order to maintain a substantially constant oxygen concentration in water stream F that is fed to BODAC filter unit 10. In this example, system 2 is further provided with a pre-treatment comprising filtration unit 22 which is positioned directly downstream of water inlet 6. It is noted that filtration unit 22 may, in some cases, be ultrafiltration unit 22. Filtration unit 22 is configured to remove solids and/or particles from water stream Wy, from water inlet 6 to prevent clogging of the subsequent system elements 10, 14 of system 2.

System 2 in this example also comprises ammonium sensor 24, which is positioned downstream of filtration unit 22, and which is configured to provide measurement data on the ammonium concentration in water stream F in water channel 4 to control unit 18. Based on the ammonium measurement data, control unit 18 can control oxygen supply 12 to correct for high concentrations of ammonium by increasing the flow rate of oxygen stream O..

In order to provide an even higher rate of removal of pharmaceuticals from water stream W, system 2 in this example comprises second BODAC filter unit 26, which is positioned downstream of BODAC filter unit 10 and in series therewith. System 2 is further provided with oxygen supply unit 28, which emanates in mixing unit 30, and with oxygen sensor 32, all of which are configured to support operation of second BODAC filter unit 26. To that end, system 2 also comprises second control unit 34, which is operatively connected to oxygen supply unit 28 and mixing unit 30, which are positioned upstream of second BODAC filter unit 26, and to oxygen sensor 32, which is positioned downstream of second BODAC filter unit 26. In an alternative example (not shown), system 2 may have a single control unit that is configured to perform the control fanctions of both control unit 18 and second control unit 34.

System 2 in this example further comprises reverse osmosis (RO) filter unit 36, which is positioned directly upstream of water outlet 8, and which is configured to filter water stream or flow F before discharging it via water outlet 8.

In use of system 2, water containing pharmaceuticals is taken in via water inlet 6 to enter water channel 4. In the example (see figure 1), solids and/or particles are removed from the water stream or flow F using filtration unit 22. Although this is not essential for the invention, it contributes to a longer operation time of BODAC filter units 10, 26. Ammonium sensor 24 is used to register the ammonium concentration in the filtrate from filtration unit 22, which measurement is passed on to control unit 18. In addition, the flow quantity of water flow F is measured by means of flow meter 20, which also provides its measurement data to control unit 18.

The information from flow meter 20 and ammonium sensor 24 is used by control unit 18 to at least in part control the amount of oxygen in oxygen flow Oa that is provided to water flow F in water channel 4. This is performed to off-set a high amount of ammonium in water flow F.

Water flow F in water channel 4 continues to flow towards and through mixing unit 14, in which oxygen from oxygen supply 12 is mixed with water flow F. The mixed flow F is subsequently provided to BODAC filter unit 10 in which the pharmaceuticals are at least partially removed from water flow F. The added (pure) oxygen is partially used to regenerate the activated carbon in the BODAC filter unit to allow a continued operation even after saturation levels are achieved. Oxygen sensor 12, which is positioned downstream of BODAC filter unit 10, measures the oxygen concentration in the filtrate of BODAC filter unit 10. The measurements are provided to control unit 18, which controls oxygen supply 12 based (in part) on the measurements from oxygen sensor 12 to ascertain that the oxygen concentration in water flow F before BODAC filter unit 10 is sufficiently high and at least above 0.

In order to provide an even more enhanced removal of pharmaceuticals, system 2 is provided with second BODAC filter unit 26. Thus, the filtrate flow from BODAC filter unit 10 flows downstream towards mixing unit 30, in which oxygen from oxygen supply 28 is mixed into flow F in water channel 4, after which the oxygen-enriched flow F is provided to BODAC filter unit 26 to remove additional amounts of pharmaceuticals. Downstream of BODAC filter unit 26, oxygen sensor 32 is positioned, which measures oxygen concentration in the filtrate of BODAC filter unit 26 and provides measurement data to control unit 34. Control unit 34 processes measurement data from oxygen sensor 32 to control the oxygen flow Os supplied by oxygen supply 28 to mixing unit 30.

The filtrate flow F from BODAC filter unit 26 is, in this particular example, filtered using reverse osmosis (or RO) filter unit 36 before being discharged from system 2 via water outlet 8 of water channel 4.

In an example control unit 118 for the oxygen supply 12 for the system 2 comprises a number of control functions (see figure 2). In this example of control unit 118, control unit 118 is configured to control oxygen flow O, based on information from oxygen sensor 16 and flow meter

20. The control comprises providing a set point OR-SP for the oxygen concentration in water flow F. From set point OR-SP the measured actual oxygen concentration (MO) at oxygen sensor 16 is subtracted and fed into a PID controller. The PID controller provides as input a dosage rate DR for oxygen in gram O>/m’. In this control schematic, dosage rate DR is limited by an upper dosage limit and a lower dosage limit LDL. This means that the output value DR is, regardless of the input values OR-SP and MO, always between UDL and LDL.

Dosage rate DR is subsequently multiplied with the actual feed flow volume FFV in m’/hour that is measured by flow meter 20 in order to obtain a dosage flow set point DF-SP.

Dosage flow set point DF-SP is the desired value for the oxygen flow in gram O»/hour provided by oxygen supply 12 to mixing unit 14. It may, in another embodiment, dosage flow set point DF-SP may also be used to directly supply oxygen from oxygen supply 12 to water flow F in water channel 4. Control unit 118 is configured to compare, by means of a PID, dosage flow set point DF-SP with current flow dosage CFD of oxygen supply 12 to establish whether current flow dosage CFD needs to be adapted to arrive at dosage flow set point DF-SP. The outcome of the PID is the actual control value that is sent to oxygen supply 12 by control unit 118 to control current flow dosage CFD to dosage flow set point DE-SP. It is noted however, that flow dosage of oxygen supply 12 is limited between a maximum dosage (Max Dose) and a minimum dosage (Min Dose) regardless of whether the actual outcome is higher (max dose) or lower (min dose).

In a second example, control unit 218 comprises a number of control functions to control or regulate oxygen supply 12. In this example, control unit 218 also includes an ammonium concentration correction ACC. Oxygen sensor 16 measures oxygen concentration MO in the filtrate of BODAC filter unit 10, which concentration measurement is provided to control unit 218, Measured oxygen concentration MO is subtracted from oxygen rate set point OR-SP and subsequently fed as control signal to a PID. The output of the PID is dosage rate DR in gram O,/m’, which in this control schematic is limited by an upper dosage limit and a lower dosage limit LDL. This means that the output value DR is, regardless of the input values OR-SP and MO, always between UDL and LDL. It is noted that, for the purpose of controlling oxygen flow based on the oxygen sensor measurements, the control unit as depicted in the first example may also be used as part of this control unit 218.

Control unit 218 further comprises ammonium reduction start-up control ARS and ammonium reduction operation control ARO, which are both used to reduce ammonium concentration in the water flow F in water channel 4.

The ammonium reduction start-up control ARS is used only during start-up of system 2 to provide additional oxygen to water flow F in water channel 4 in absence of measurement values of ammonium sensor 24. This means that during start-up of system 2, the flow of oxygen from oxygen supply 12 is provided based on start-up control value SCV and a (preferably standard) ammonium correction value ACV. In this example, start-up control value SCV also includes a predetermined oxygen dosage rate value for the start-up phase during which no oxygen sensor measurements are available.

During operation of system 2, the flow of oxygen from oxygen supply 12 is provided based on ammonium correction value ACV, which is based on the measured ammonium value, and operation control value OCV. The resulting output value OV (in gram O,/m’) is added to dosage rate DR to provide

The switch between modes ARS and ARO is provided by start-up selection control SUS. The value from either ARS or ARO is (via start-up selection control SUS) multiplied with feed flow volume FFV. The outcome thereof is the actual control value that is sent to oxygen supply 12 by control unit 218 to control the flow dosage of oxygen. It is noted however, that flow dosage of oxygen supply 12 is limited between a maximum dosage (Max Dose) and a minimum dosage (Min Dose) regardless of whether the actual outcome is higher (Max dose) or lower (Min dose).

In an example of method 1000 according to the invention, method 1000 comprises a number of steps. Some of these steps are regarded optional, since they provide an additional beneficial effect, yet are not required for the method according to the invention as such.

Method 1000 according to the invention comprises the steps of providing 1002 a system 2 for removing pharmaceuticals from water (according to the invention) and subsequently providing 1004 a flow of water to the water channel 4 through the water inlet 6. Furthermore, method 1000 comprises adding 1006 substantially pure oxygen to the water flow F upstream of BODAC-filter 10 and filtering 1008 water flow F in BODAC filter unit 10 to remove pharmaceuticals. Subsequently, it comprises discharging 1010 the filtered water flow F through water outlet 8.

Optionally, method 1000 may comprise the steps of filtering 1012 the water flow in unit

22. The step of providing 1004 a flow of substantially pure oxygen to the filtered water flow occurs downstream of unit 22 and upstream of BODAC filter unit 10, and also includes the step of supplying 1014 the water flow to the BODAC filter (previous to step 1008).

Optionally, method 1000 comprises the step of filtering 1016 water flow F from the BODAC filter unit in a reverse osmosis (RO) filter unit 36 before the step of discharging 1010 the water from water outlet 10.

Further, in this example system 2 comprises a control unit 18 and an ammonium sensor 24 that is positioned upstream of the BODAC filter unit 10, and method 1000 comprises the optional steps of measuring 1018 by the ammonium sensor an ammonium concentration in the water flow, and comparing 1020 the measured ammonium concentration with a threshold concentration value by the control unit, and subsequently increasing 1022, by control unit 18, a flow of substantially pure oxygen from the oxygen supply if the measured ammonium concentration exceeds the threshold value.

In this example, system 2 further comprises control unit 18 and oxygen sensor 16 that is positioned downstream from BODAC filter unit 10, and method 1000 additionally (and optionally) comprises the steps of measuring 1024 by the oxygen sensor, an oxygen concentration in the filtrate flow from the BODAC filter unit, comparing 1026 by the control unit the measured oxygen concentration with a predetermined oxygen ratio set point, and adjusting 1028 by the control unit, the flow of substantially pure oxygen from the oxygen supply.

In a more elaborate embodiment of control unit 18, the steps of comparing 1026 and adjusting 1028 comprise the steps of comparing 1030 by the control unit, the measured oxygen concentration with the predetermined oxygen ratio set point (OR-SP) and obtaining a dosage ratio (DR) and subsequently multiplying 1032 the dosage ratio (DR) with a measured feed flow volume (FFV) that is measured upstream of the oxygen supply to obtain a dosage flow set point (DF-SP). It further comprises comparing 1034 the dosage flow set point (DF-SP) with a current flow dosage (CFD) of the oxygen supply and adjusting 1036 the current flow dosage (CFD) to the dosage flow set point (DF-SP).

Moreover, in this example of method 1000, an optional embodiment is shown in which system 2, when viewed in a downstream direction from oxygen sensor 16, additionally comprises second oxygen supply 28, second BODAC filter unit 26 and second oxygen sensor 32, and method 1000 additionally comprises the steps of comparing 1038, by the control unit, the measured oxygen concentration with the predetermined oxygen ratio set point (OR2-SP) and obtaining a dosage ratio (DR2) and subsequently multiplying 1040 the dosage ratio (DR2) with a measured feed flow volume (FFV) that is measured upstream of the oxygen supply to obtain a dosage flow set point (DF2-SP) as well as comparing 1042 the dosage flow set point (DF2-SP) with a current flow dosage (CFD2) of the oxygen supply, and adjusting 1044 the current flow dosage (CFD2) to the dosage flow set point (DF2-SP). It also comprises the step of filtering 1046 water flow F in second BODAC filter unit 26 to remove pharmaceuticals.

It is clear that method 1000 may comprise one or more, or even all, optional steps as described above.

It is noted that in the application the terms water stream F, water flow F and/or water quantity F used in the application are interchangeable with each other and all refer to the same subject.

The present invention is by no means limited to the above described preferred embodiments thereof. The rights sought are described in the following clauses, wherein the scope of which many modifications can be envisaged.

CLAUSES l. System for removing pharmaceuticals from water, such as waste water, the system comprising: — a water channel that is configured for transporting a flow of water, wherein the water channel extends from a water inlet to a water outlet; — a biological oxygen dosed activated carbon (BODAC) filter unit that is positioned in the water channel and that is configured to operate substantially continuous; and — an oxygen supply that is operatively connected to the water channel and that is configured to supply substantially pure oxygen.

2. System according to clause 1, comprising a mixing unit that is positioned upstream of the BODAC filter anit, wherein the oxygen supply is connected to the mixing unit, and wherein the mixing unit is configured to mix the water flow and the substantially pure oxygen.

3. System according to clause 1 or 2, wherein a flow rate of a flow of substantially pure oxygen that is supplied via the oxygen supply is in the range of 1 — 15 gram/m’, and is preferably in the range of 3 — 10 gram/m’, and most preferably is in the range of 6 — 7 gram/m’.

4. System according to any one of the preceding clauses, comprising a control unit that is configured to control the oxygen supply to the water channel or, when dependent on clause 2, to the mixing anit.

5. System according to any one of the preceding clauses, comprising an ammonium sensor that is positioned upstream of the BODAC filter unit and that is configured to measure an ammonium concentration in the water flow.

6. System according to clause 5, when dependent on clause 4, wherein the control unit is configured to: — compare a measured ammonium concentration from the ammonium sensor with a threshold value, and — increase a flow of substantially pure oxygen from the oxygen supply if the measured ammonium concentration exceeds the threshold value.

7. System according to any one of the preceding clauses, comprising at least one oxygen sensor that is positioned downstream from the BODAC filter unit and is associated therewith and that is configured to measure an oxygen concentration in a filtrate flow from the BODAC filter unit.

8. System according to clause 7, when dependent on clause 4, wherein the control unit is configured to regulate a quantity of oxygen supplied to a water flow in the water channel based on the measurement data received from the at least one oxygen sensor.

9. System according to clause 8, wherein the control unit is configured to: — compare the measured oxygen concentration (MO) provided by the at least one oxygen sensor with a predetermined oxygen ratio set point (OR-SP) to obtain a dosage ratio (DR); — multiply the dosage ratio (DR) with a measured feed flow volume (FFV) upstream of the oxygen supply to obtain a dosage flow set point (DF-SP); and — compare the dosage flow set point { DF-SP) with a current flow dosage (CFD) of the oxygen supply: and — adjust the current flow dosage (CFD) to the dosage flow set point (DE-SP).

10. System according to any one of preceding clauses, comprising a second BODAC filter unit that is positioned downstream of and in series with the BODAC filter unit.

ll. System according to clause 10, additionally comprising one or more of: — asecond mixing unit that is positioned between the BODAC filter unit and the second BODAC filter unit; — asecond oxygen supply that is operatively connected to the water channel between the BODAC filter unit and the second BODAC filter unit, wherein the second oxygen supply is configured to supply substantially pure oxygen; and — an oxygen sensor that is positioned downstream of the second BODAC filter and is associated therewith and is configured to measure an oxygen concentration in a filtrate flow from the second BODAC filter unit.

12. System according to clause 11, wherein the system comprises a second control unit, and wherein the second control unit is configured to regulate a quantity of oxygen supplied through the second oxygen supply to a water flow in the water channel based on the measurement data received from the second oxygen sensor.

13. System according to clause 12, wherein the second control unit is further configured to:

— compare the measured oxygen concentration provided by the second oxygen sensor with a second predetermined oxygen ratio set point (OR2-SP) to obtain a second dosage ratio (DR2); — multiply the second dosage ratio (DR2) with a measured feed flow volume (FFV2) between the oxygen sensor and the second oxygen supply to obtain a second dosage flow set point (DF2-SP); and — compare the second dosage flow set point (DF2-SP) with a current second flow dosage (CFD2) of the second oxygen supply; and — adjust the current second flow dosage (CED2) to the second dosage flow set point (DF2-SP).

14. System according to any one of clauses 10 — 13, wherein a retention time of the water flow in the second BODAC filter unit is in the range of 6 — 48 minutes, and preferably is in the range of 20 - 36 minutes, and more preferably is around 32 minutes.

15. System according to any one of the preceding clauses, wherein the flow of substantially pure oxygen comprises more than 90% oxygen, preferably comprises more than 95% oxygen and more preferably comprises more than 99% oxygen. 16, System according to any one of the preceding clauses, wherein a retention time of the water flow in the BODAC filter unit is in the range of 2 — 36 minutes, and preferably is in the range of 10 — 25 minutes, and more preferably is 14 — 18 minutes.

17. System according to any one of the preceding clauses, comprising at least one reverse osmosis (RO) unit that is positioned downstream of the BODAC filter unit.

18. System according to any one of the preceding claims, comprising one or more filtration units that are positioned upstream of the BODAC filter.

19. Method for removing pharmaceuticals from water, such as waste water, the method comprising: ~ providing a system according to any one of the preceding clauses; — providing a flow of water to the water channel through the water inlet; and — adding substantially pure oxygen to the water flow upstream of the BODAC-filter; — filtering the water flow in the BODAC filter unit to remove pharmaceuticals; and — discharging the filtered water flow through the water outlet.

20. Method according to clause 19, wherein the method additionally comprises the steps of:

— filtering the water flow in the filtration anit; — providing a flow of substantially pure oxygen to the filtered water flow downstream of the filtration unit and upstream of the BODAC filter unit; and — supplying the water flow to the BODAC filter.

21. Method according to clause 19 or 20, wherein the method additionally comprises the steps of: — filtering the water flow from the BODAC filter unit in a reverse osmosis (RO) filter unit; and — discharging the water from the RO filter unit through the water outlet.

22. Method according to any one of the clauses 19 — 21, wherein the system comprises a control unit and an ammonium sensor that is positioned upstream of the BODAC filter unit, and wherein the method comprises the steps of: — measuring, by the ammonium sensor, an ammonium concentration in the water flow; — comparing, by the control unit, the measured ammonium concentration with a threshold concentration value; and — increasing, by the control unit, a flow of substantially pure oxygen from the oxygen supply if the measured ammonium concentration exceeds the threshold value.

23. Method according to any one of the clauses 19 — 22, wherein the system comprises a control unit and an oxygen sensor that is positioned downstream from the BODAC filter unit, and wherein the method additionally comprises the steps of: — measuring, by the oxygen sensor, an oxygen concentration in the filtrate flow from the BODAC filter unit; — comparing, by the control unit, the measured oxygen concentration with a predetermined oxygen ratio set point; and — adjusting, by the control unit, the flow of substantially pure oxygen from the oxygen supply.

24. Method according to clause 23, wherein the steps of comparing and adjusting comprise: — comparing, by the control unit, the measured oxygen concentration with the predetermined oxygen ratio set point {OR-SP) and obtaining a dosage ratio (DR); — multiplying the dosage ratio (DR) with a measured feed flow volume (FFV) that is measured upstream of the oxygen supply to obtain a dosage flow set point (DF-SP); and — comparing the dosage flow set point (DF-SP) with a current flow dosage (CFD) of the oxygen supply; and

— adjusting the current flow dosage (CFD) to the dosage flow set point (DE-SP).

25. Method according to any one of the clauses 19 — 24, wherein the system, when viewed in a downstream direction from the oxygen sensor, additionally comprises a second oxygen supply, a second BODAC filter unit and a second oxygen sensor, and wherein the method additionally comprises the steps of: — comparing, by the control unit, the measured oxygen concentration by the second oxygen sensor with the predetermined oxygen ratio set point (OR2-SP) and obtaining a dosage ratio (DR2); — multiplying the dosage ratio (DR2) with a measured feed flow volume (FFV2) that is measured upstream of the second oxygen supply and downstream of the oxygen sensor to obtain a dosage flow set point (DF2-SP); and — comparing the dosage flow set point (DF2-SP) with a current flow dosage (CFD2) of the second oxygen supply; = adjusting the current flow dosage (CFD2) to the dosage flow set point (DF2-SP): and — filtering water flow F in the second BODAC filter unit to remove pharmaceuticals.

Claims

CONCLUSIONS

A system for removing drugs from water, such as waste water, the system comprising: - a water channel adapted to transport a stream of water, the water channel extending from a water inlet to a water outlet; - a biologically activated carbon (BODAC) filter unit which is positioned in the water channel and which is adapted to operate substantially continuously; and - an oxygen supply operatively connected to the water channel and adapted to supply substantially pure oxygen.

A system according to claim 1, comprising a mixing unit positioned upstream of the BODAC filter unit, wherein the oxygen supply is connected to the mixing unit, and wherein the mixing unit is adapted to mix the water stream and the substantially pure oxygen.

3. System according to claim | or 2, wherein a flow rate of a stream of substantially pure oxygen supplied via the oxygen supply is substantially in the range of 1 - 15 grams/m', preferably in the range of 3 - 10 grams/m', and more preferably in the range of 6 - 7 grams/m 2 .

A system according to any one of the preceding claims, comprising a control unit adapted to regulate the oxygen supply to the water channel or, when dependent on claim 2, to the mixing unit.

A system according to any one of the preceding claims, comprising an ammonium sensor positioned upstream of the BODAC filter unit and adapted to measure an ammonia concentration in the water stream.

System according to claim 5, when dependent on claim 4, wherein the control unit is arranged for: - comparing a measured ammonia concentration of the ammonia sensor with a threshold value; and - increasing the flow of substantially pure oxygen from the oxygen supply if the measured ammonia concentration exceeds the threshold value.

A system according to any one of the preceding claims, comprising an oxygen sensor positioned downstream of the BODAC filter unit and associated with the BODAC filter unit and adapted to measure an oxygen concentration in a filtrate stream of the BODAC filter unit.

A system according to claim 7, when dependent on claim 4, wherein the control unit is adapted to control an amount of oxygen to be supplied to the water flow on the basis of the measurement data received from the at least one oxygen sensor.

The system of claim 8, wherein the control unit is arranged to: compare a measured oxygen concentration (MO) provided by the at least one oxygen sensor with a predetermined oxygen ratio set point (OR-SP) to obtain a dose ratio (DR). ); — multiplying the dose rate (DR) by a feed flow volume (FFV) measured upstream of the oxygen supply to obtain a dose flow set point (DF-SP); and — comparing the dose flow set point (DF-SP) with a current flow dose (CFD) of the oxygen supply; and — adjusting the current flow rate (CFD) to the flow rate setpoint (DF-SP).

A system according to any one of the preceding claims, comprising a second BODAC filter unit positioned downstream and in series with the BODAC filter unit.

The system of claim 10, further comprising one or more of: - a second mixing unit positioned between the BODAC filter unit and the second BODAC filter unit; - a second oxygen supply operatively connected to the water channel between the BODAC filter unit and the second BODAC filter unit, the second oxygen supply being adapted to supply substantially pure oxygen; and - an oxygen sensor positioned downstream of the second BODAC filter unit and associated with the second BODAC filter unit and arranged to measure an oxygen concentration in a filtrate stream from the second BODAC filter unit.

12. A system according to claim 11, wherein the system comprises a second control unit, and wherein the second control unit is designed for controlling an amount of oxygen supplied to the water channel by the second oxygen supply on the basis of the measurement data received from the second oxygen sensor.

The system of claim 12, wherein the second control unit is further configured to: compare a measured oxygen concentration provided by the second oxygen sensor with a predetermined second oxygen ratio set point (OR2-SP) to obtain a second dose ratio (DR) : — multiplying the second dose rate (DR) by a feed flow volume (FFV2) measured between the oxygen sensor and the second oxygen supply to obtain a second dose flow set point (DF2-SP); and - comparing the second dose flow setpoint (DF2-SP) with a current second flow dose (CFD2) of the second oxygen supply; and — adjusting the current second flow dose (CFD2) to the second flow dose setpoint (DF2-SP).

A system according to any one of claims 10 to 13, wherein a residence time of the water stream in the second BODAC filter unit is in the range of 6 to 48 minutes, preferably in the range of 20 to 36 minutes, and more preferably is around 32 minutes.

The system of any preceding claim, wherein the substantially pure oxygen stream comprises greater than 90% oxygen, preferably greater than 95% oxygen, and more preferably greater than 99% oxygen.

A system according to any one of the preceding claims, wherein a residence time of the water stream in the BODAC filter unit is in the range of 2 - 36 minutes, preferably in the range of 10 - 25 minutes, and more preferably in the range from 14 to 18 minutes.

A system according to any one of the preceding claims, comprising at least one reverse osmosis (RO) unit positioned downstream of the BODAC filter unit.

A system according to any one of the preceding claims, comprising one or more Tiltration units positioned upstream of the BODAC filter unit. A method for removing drugs from water, such as waste water, the method comprising: - providing a system according to any one of the preceding claims;

- providing a flow of water to the water channel through the water inlet; and - adding substantially pure oxygen to the water stream upstream of the BODAC filter unit; — purifying the water stream in the BODAC drug removal filter unit; and — discharging the purified water through the water outlet.

The method of claim 19, wherein the method further comprises the steps of: - purifying the water stream in the filtration unit; — adding a stream of pure oxygen to the purified water stream downstream of the filtration unit and upstream of the BODAC filter unit; and - supplying the water flow to the BODAC filter unit.

A method according to claim 19 or 20, wherein the method further comprises the steps of: - purifying the water stream from the BODAC filter unit in a reverse osmosis (RO) filter unit; and — discharging the water from the RO filter unit through the water outlet.

A method according to any one of claims 19 - 21, wherein the system comprises a control unit and an ammonia sensor positioned upstream of the BODAC filter unit, and wherein the method comprises the steps of: - measuring the ammonia concentration in the water stream by the ammonia sensor ; — comparing the measured ammonia concentration with a concentration threshold value by the control unit; and — increasing a flow of substantially pure oxygen from the oxygen supply by the control unit when the measured ammonia concentration exceeds the concentration threshold value,

A method according to any one of claims 19 to 22, wherein the system comprises a control unit and an oxygen sensor positioned downstream of the BODAC filter unit, and wherein the method further comprises the steps of: - measuring an oxygen concentration in the oxygen sensor by the oxygen sensor filtrate stream from the BODAC filter unit; - comparing the measured oxygen concentration with a predetermined oxygen ratio set point by the control unit; and

- adjusting the flow of substantially pure oxygen from the oxygen supply by the control unit.

A method according to claim 23, wherein the comparing and adjusting steps comprise: - comparing the measured oxygen concentration by the control unit with a predetermined oxygen ratio set point (OR-SP) and obtaining a dose ratio (DR): - multiplying the dose rate (DR) by a feed flow volume (FEV) measured upstream of the oxygen supply to obtain a dose flow set point (DF-SP); and - comparing the dose flow set point (DF-SP) to a current flow dose (CFD) of the oxygen supply; and - adjusting the current flow rate (CFD) to the flow rate setpoint (DF-SP).

The method of any one of claims 19 to 24, wherein the system, when viewed in a downstream direction from the oxygen sensor, further comprises a second oxygen supply, a second BODAC filter unit and a second oxygen sensor, the method further comprising the steps of of: - comparing an oxygen concentration measured by the second oxygen sensor with a predetermined oxygen ratio set point (OR2-SP) by the control unit to obtain a dose ratio (DR2); - multiplying the dosing ratio (DR2) by a supply flow volume (EEV2) measured upstream of the second oxygen supply and downstream of the oxygen sensor to obtain a dosing flow set point (DF2-SP); and - comparing the dose flow set point (DF2-SP) with a current dose flow (CFD2) of the second oxygen supply; — adjusting the current flow rate (CFD2) to the flow rate setpoint (DF2-SP); and - purifying the water stream (F) in the second BODAC drug removal filter unit.