WO2019151963A1

WO2019151963A1 - Membrane bioreactor for nitrate removal from ground water

Info

Publication number: WO2019151963A1
Application number: PCT/TR2018/050764
Authority: WO
Inventors: Serdar GONCU; Eda TUNA OZTURK
Original assignee: Anadolu Universitesi
Priority date: 2017-12-05
Filing date: 2018-12-05
Publication date: 2019-08-08
Also published as: EP3720822A1; EP3720822A4

Abstract

The invention relates to a membrane bioreactor which ensures that nitrate pollution in groundwater is removed by using algae biomass and by which the treatment of groundwater is implemented without being stained by the algae culture and nitrate pollution is removed from groundwater. The invention particularly relates to a membrane bioreactor for nitrate removal from groundwater, which prevents the microalgae culture to be directly mixed in groundwater by positioning the media in which groundwater and microalgae culture are present such that they are physically separated from each other and which ensures that groundwater biologically rehabilitated after treatment can be directly send back to underground.

Description

MEMBRANE BIOREACTOR FOR NITRATE REMOVAL FROM GROUND WATER

Related Technical Field of the Invention

The invention relates to a membrane bioreactor which ensures that nitrate pollution in groundwater is removed by using algae biomass and by which the treatment of groundwater is implemented without being stained by the algae culture and nitrate pollution is removed from groundwater.

The invention particularly relates to a membrane bioreactor which prevents the microalgae culture to be directly mixed in groundwater by positioning the media in which groundwater and microalgae culture are present such that they are physically separated from each other and which ensures that groundwater biologically rehabilitated after treatment can be directly send back to underground, and by which the nitrate removal from groundwater is realized.

State of the Art:

Currently, water is the leading one among the sources we need most. Specifically drinking water springs can be rapidly polluted and thus they may become non-potable. Therefore, purification of the water is of great importance in terms of human health. Although groundwater used for drinking water spring is more reliable and cleaner compared to other water sources, its purification is quite difficult when polluted.

Two main sources causing groundwater pollution are called as natural and artificial sources. Pollutant sources such as agricultural irrigation, fertilizers, animal wastes, domestic and industrial waste water, and nitrate pollution reaching to groundwater are important pollution parameters. Since nitrate is not degraded but is stabile in aerobic conditions, groundwater polluted by nitrate is particularly difficult to purify. Also in anaerobic groundwater conditions, while there is not enough denitrification bacteria performing the removal of nitrate in the aquifers having groundwater, nitrate removal from groundwater cannot be performed by natural ways. For the sustainability of groundwater that is reliable and important water spring, making groundwater to be potable again by using natural purification and treatment technologies com into prominence in the recent studies. Although methods such as denitrification, ion exchange and reverse osmosis are used for removal of nitrate pollution, biological treatment methods are effectively continued to be used. Because the methods of denitrification, reverse osmosis and ion exchange used for the removal of nitrate pollution are expensive and have operation problems, nitrate removal method by use of algae culture which is one of the biological treatment methods comes into prominence. Even though the microalgae are used as an alternative method among the biological methods for the removal of nitrate from groundwater, there are some drawbacks and deficiencies regarding the subject.

After preliminary research about the state of the art, the patent document numbered "US2005117977" has been examined. In the subject matter invention, chemical and biological treatment are hold together. In the subject matter method, a pre-treatment is conducted and subsequently precipitation is realized via sedimentation tank by refining via membrane bioreactor and the final treatment is performed by a secondary membrane filtration. Chemicals called as flocculent are added in pre-treatment and sedimentation step of the reactor.

After preliminary research about the state of the art, the patent document numbered "US2008290025" has been examined. The subject matter invention is based on the fact of ensuring degradation of solid organic substances located inside the filter bed. In biolytic filtration system, it is mentioned that while purifying waste water also removal of solid organic substances in the filter bed is performed. It is indicated that including the membrane to treatment process increased the water quality and pathogen removal. The membrane system is used for biological removal, wherein it is not mentioned that any kind of algae is used for removal of pollution in the system.

After preliminary research about the state of the art, the patent document numbered "2017/04060" has been examined. In the abstract of the invention, a sustainable method and system for low-intensity recreational use, and for low cost, purification and protection of water masses are disclosed. A system of the invention typically comprise at least one conservation medium, at least one coordination medium, at least one chemical application medium, at least one convenient mobile absorption medium and at least one filtration medium. Coordination medium may obtain the information about checked water quality parameters and may activate the required process in time for adjusting the water quality parameters within its respective borders. Disclosed methods and systems filtrate only a small part of the total water volume, less than the flow filtered by conventional swimming pool systems up to 200 times a day. Disclosed methods and system also use less chemicals up to 100 times when compared to conventional swimming pool water treatment systems. It is disclosed that, "Methods and system of the present invention can be used to provide sustainable methods for being able to swim with whole body contact, as indicated by official regulatory agents such as Environment Protection Agent, for production of water in conformity with bacteriologic and physicochemical requirements for the recreational water and to purify the water masses". A low-cost treatment method for the treatment of water intended for recreational use (water for swimming) is mentioned in said method. It is mentioned in said system that there is an electronic control module for controlling the process. Also it is mentioned that it has equipment for chemical use and about a filtration equipment.

Drinking water treatment methods used in the state of the art also bring along some problems. In chemical treatment methods, uncontrolled use of chemical substance may cause health problems depending on amount and type of chemicals.

In biological treatment methods used in the state of the art, generally there is no food substance additive in MBR (membrane bioreactor) to meet food requirement of algae biomass. Also there is not a system that provides external food entrance and collection of extra algae cells from the device.

As a result, due to the above-mentioned problems and because of the inadequacy of the existing solutions, it has become necessary to make an improvement in the technical field.

Aim of the Invention :

The most important aim of the invention is positioning the media in which groundwater and microalgae culture are present such that they are separated from each other. Thereby, the microalgae culture is prevented to be directly mixed in groundwater and groundwater biologically rehabilitated after treatment can be directly send back to underground.

Another aim of the invention is that the microalgae culture growing after the treatment can be used as raw material depending on its properties.

Another aim of the invention is that the bioreactor is used flexibly in scale-up due to its modular structure. Thereby, the reactor can be manufactured in desired sizes. A further aim of the invention is that the system flexibility can be achieved by increasing desired treatment efficiency by using series or parallel modules.

Another aim of the invention is that the biomass amount in unit volume can be kept high as the microalgae culture is in a separated medium.

Structural and characteristic specifications and all advantages of the invention will be understood more clearly by means of following figures and detailed descriptions written by referencing to those figures. Therefore assessment should be done by taking these figures and detailed description into consideration .

Description of the Figures :

FIGURE -1; The illustration showing the exploded perspective view of subject matter membrane bioreactor for removal of nitrate from groundwater.

FIGURE -2; The illustration showing the flow diagram of operating system view of subject matter membrane bioreactor for removal of nitrate from groundwater.

Reference Numbers:

100. Membrane Bioreactor

110. Groundwater Cell

111. Water Inlet Line

112. Cell Cover

113. Water Outlet Line

114. Sealing Gasket 120. Algae Culture Cell

121. Food Inlet Line

122. Algae Collection Line

123. Air Diffusor and Mixer

124. Window

130. Semipermeable Membrane 140. Food Substance 150. Groundwater Storage 160. Produced Algae Biomass 200. Borehole 300. Injection Hole Description of the Invention:

Subject matter membrane bioreactor (100) mainly consists of two parts as groundwater cell (110) and algae culture cell (120) . Furthermore, there is semipermeable membrane (130) between the groundwater cell (110) and the algae culture cell (120) .

Groundwater cell (110) mainly consists of the elements of water inlet line (111), cell cover (112), water outlet line (113) and sealing gasket (114) . Water inlet line (111) ensures the entrance of water to be treated into the groundwater cell (110) . Cell cover (112) is used for cleaning and checking of the groundwater cell (110) . Thereby user can open the cell cover (112) and clean and check the groundwater cell (110) . Water outlet line (113) ensures the transportation of groundwater treated in membrane bioreactor (100) into the injection hole (300) . The sealing gasket (114) prevents leakages while connecting the groundwater cell (110) and algae culture cell (120) to each other. Thereby, liquid exchange between the groundwater cell (110) and the algae culture cell (120) is only performed by the semipermeable membrane ( 130 ) .

Algae culture cell (120) mainly consists of the elements of food inlet line (121), algae collection line (122), air diffusor and mixer (123) and window (124) . Food inlet line (121) ensures that the algae culture takes additional food that it may need in treatment process. Algae collection line (122) ensures that the surplus of algae grown in treatment process is removed from the system. Air diffusor and mixer (123) ensures a complete mixing in the groundwater cell (110) and algae culture cell (120) and prevents formation of biofilm on the semipermeable membrane (130) and prevents the short circuits. Window (124) ensures that the light needed by algae cells is transmitted to the membrane reactor (100) via the light source from outside. Optionally, the window (124) can be placed also to outside of the groundwater cell (110) thus ensuring double-sided light support. The window (124) can be manufactured from translucent plexiglass or glass material. The food inlet line (121) and the algae collection line (122) are positioned transversely to each other thus avoiding the short circuits.

Semipermeable membrane (130) is located between the groundwater cell (110) and the algae culture cell (120) and prevents the algae culture to be mixed into the groundwater. Thereby, it only permits water and food substances to be transferred among the cells .

In order to perform the treatment of groundwater polluted by nitrate, water drawn from underground borehole (200) or from groundwater storage (150) is transferred to the groundwater cell (110) . This water is not mixed with the algae culture cell by means of the semipermeable membrane (130) located between the groundwater cell (110) and the algae culture cell (120) having the algae culture. Groundwater cleaned in terms of nitrate by the help of algae is discharged through the water outlet line (115) and transferred into the injection hole (300) . At this moment, the food substance (140) needed by the algae is transmitted to the culture cell (120) through the food inlet line (121) . The produced algae biomass (160) during treatment is collected by 122 and these collected algae are used as raw material depending on their properties. By this means, both the groundwater is cleaned in terms of nitrate and also raw material is produced having different areas of usage.

Example embodiment - 1

In an exemplary embodiment of the subject matter membrane bioreactor (100), it has been observed that nitrate removal of synthetic groundwater in 36,13 starting mg N03-N / L concentration each division of which is 4 L, was performed at the rate of 97,6% at the end of second day by using Scenedesmus obliquus culture, and at the rate of 82,8% at the end of fifth day by using Chlorella vulgaris culture. When the resulting removal efficiencies are analyzed, it can be seen that the nitrate pollution is highly removed and algae culture is produced as production.

Claims

1. This invention is a membrane bioreactor (100) which ensures that nitrate pollution in groundwater is removed by using algae biomass and by which the nitrate pollution is removed from groundwater, characterized in that it comprises;

• A groundwater cell (110) accommodating a water inlet line (111) ensuring entrance of water to be treated into the groundwater cell (110), a cell cover (112) used for cleaning and checking of the groundwater cell (110) and a water outlet line (113) ensuring the transportation of groundwater treated in the membrane bioreactor (100) into injection hole (300),

• An algae culture cell (120) having algae cells therein and accommodating a food inlet line (121) ensuring that algae culture takes additional food that it may need in treatment process, an algae collection line (122) ensuring that surplus of algae grown in treatment process is removed from the system, an air diffusor and mixer (123) ensuring a complete mixing in the groundwater cell (110) and algae culture cell (120) and preventing formation of biofilm on semipermeable membrane (130), a window (124) ensuring that the light needed by algae cells is transmitted to the membrane reactor (100) via the light source from outside,

• And a semipermeable membrane (130) located between the groundwater cell (110) and the algae culture cell (120) and preventing the algae culture to be mixed into the groundwater, allowing the transfer of only water and food substances between the groundwater cell (110) and the algae culture cell (120) .

2. The membrane bioreactor (100) according to Claim 1, characterized by comprising a sealing gasket (100) preventing leakages while connecting the groundwater cell (110) and algae culture cell (120) to each other.

3. The membrane bioreactor (100) according to Claim 1, characterized in that preferably it comprises a window (124) placed also to outside of the groundwater cell (110) thus ensuring double-sided light support.

4. The membrane bioreactor (100) according to Claim 1, characterized in that it comprises a food inlet line (121) and an algae collection line (122) positioned transversely to each other thus avoiding the short circuits.

5. The membrane bioreactor (100) according to Claim 1 or Claim 3, characterized in that the window is made of plexiglass material.

6. The membrane bioreactor (100) according to Claim -1 or Claim 3, characterized in that the window is made of glass material .