Abstract:
The present invention relates to a floating filter module installed in a water treatment apparatus, such as in a public water treatment plant, a village water supply facility, a public sewage treatment plant, a wastewater treatment plant, or a village sewage treatment plant, in order to remove contamination particles. The floating filter module according to the present invention comprises: a hollow-type sintered filter having a plurality of fine pores which is arranged in wastewater within a water treatment tank in order to separate and filter the contamination particles from the wastewater introduced into the water treatment tank; a floating body connected to the sintered filter, and which floats to the surface of the wastewater within the water treatment tank so as to position the sintered filter at the upper portion of the wastewater in the water treatment tank; a main pipe communicating with an inner space of the sintered filter; a suction device coupled to the main pipe in order to provide a suction force to the sintered filter through the main pipe, thereby suctioning the wastewater in the water treatment tank through the plurality of fine pores and into the sintered filter; and a compressed-air supply apparatus having a compressed-air supply tube communicating with the inner space of the sintered filter through the main tube and an air compressor coupled to the compressed-air supply tube in order to supply compressed air into the inner space of the sintered filter, thereby releasing from the sintered filter the contamination particles that clog the fine pores of the sintered filter.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a floating filter module to remove micro-pollution particles, which is installed in a water treatment apparatus, such as in a public water treatment plant, a village water supply facility, a public sewage treatment plant, a wastewater treatment plant, or a village sewage treatment plant. More particularly, the present invention relates to a floating filter module for separating and filtering the upper water which is placed in the upper side of a wastewater tank and have relatively low concentration of suspension solids, and a water treatment apparatus and a method using the floating filter module. 
         [0003]    2. Description of the Related Art 
         [0004]    Environmental pollution like soil and air contaminations and global warming is becoming increasingly serious, and the amount of sewage, wastewater or dirty water (hereinafter referred to as the “wastewater”) has been greatly increased. As a result, treatment facilities have been developed highly and the cost for processing wastewater is on the increase. Moreover, various water pollutants are not processed perfectly and can be introduced into rivers or rakes which may be used as source water. Therefore, it is difficult to manage the quality of water effectively. 
         [0005]    The water treatment techniques for treating and purifying wastewater are divided into physicochemical treatment and biological treatment. Examples of physicochemical treatment are such methods as filtering, chemical coagulation, precipitation and oxidation treatment. In the biological treatment, various pollutants are removed by maximizing metabolic process of microorganism in bioreactor retaining activated sludge. Biological treatment is mostly used for wastewater treatment. 
         [0006]    In physicochemical water treatment, the method for separating and filtering micro-pollution particles is added in the existing treatment facility without big change, and is effective for removing total phosphorus (T-P) as well as micro-pollution particles. Examples of the method and apparatus for separating and filtering micro-pollution particles are as follows. 
         [0007]    Registered Korean Patent No. 0558510, there is disclosed a high class wastewater treatment apparatus using an immersion type membrane separator. The patent discloses that, in the wastewater treatment apparatus using microbial response, suspended solids (SS) and colon bacillus of wastewater are removed by using a membrane bio-reactor (MBR) instead of a precipitation tank. 
         [0008]    Registered Korean Patent No. 0843656, there is disclosed a water treatment apparatus in which an immersion type membrane bio-reactor is installed in two stages. The patent discloses a first membrane filtration tank which includes an immersion type membrane separator; a suction pump by which the membrane separator communicates with a storage tank and the source water of the membrane filtration tank is forcibly sucked to transfer to the storage tank; and an aeration tube for removing adhesion floating matters from the membrane separator by supplying air, and a second membrane filtration tank which includes an immersion type membrane separator; a suction pump by which the membrane separator communicates with a storage tank and the source water of the membrane filter tank is forcibly sucked to transfer to the storage tank; and an aeration tube for removing adhesion floating matters from the membrane separator. 
         [0009]    Registered Korean Patent No. 0875733, there is disclosed a technique using an immersion type membrane separator. According to the above technique, return sludge is supplied to the a reactor in accordance with the load change of the inflowing water to remove nutrient salts such as nitrogen and phosphorus included in the inflowing water, and the quantity of sludge is controlled in accordance with phosphorus concentration to improve the quality of treatment water. 
         [0010]    Registered Korean Patent No. 0718791, there is disclosed an immersion type filtering apparatus for processing water. According to the above apparatus, when plenty of foreign materials are deposited on the surface of a immersion type filter for filtering foreign materials included in water, strong compressed air is injected momentarily into the filter to remove the foreign materials deposited on the surface of the filter. 
         [0011]    Registered Korean Patent No. 1000742, there is disclosed a water treatment method for effectively removing phosphorus content that is a main cause substance of eutrophication. The patent discloses a micro-particles separating means which separates easily micro-pollution particles from wastewater. 
         [0012]    Registered Korean Patent No. 0489328, there is disclosed a high class treatment apparatus for processing organic material, nitrogen and phosphorus included in wastewater. The patent discloses an immersion type membrane bio-reactor which decomposes organic material by using aerobic microbes, accumulates phosphorus, oxidizes ammoniacal nitrogen and separates sludge and wastewater through a membrane separating module. 
         [0013]    According to these conventional techniques, however, an immersion type membrane separator is placed in the middle or lower portion of a treatment tank in which the concentration of suspended solids or mixed liquor suspended solids (SS or MLSS) is relatively high. Thus, there is a problem that the micro pores of the immersion type membrane separator are clogged for a short time, thereby drastically decreasing the separating and filtering efficiency of micro-pollution particles. 
         [0014]    In addition, with the conventional techniques, the immersion type membrane separator having the clogged micro pores cannot be cleaned efficiently. For example, according to registered Korean Patent No. 0718791, there is disclosed that the immersion type membrane separator is cleaned by using compressed air. However, there is a problem that, after cleaning, the inside of the immersion type membrane separator is filled with air so that a suction pump become hollow in re-suction process of the immersion type membrane separator. In addition, according to the registered Korean Patent No. 1000742 or 0489328, there is disclosed that the immersion type membrane separator having the clogged micro pores is cleaned by returning wastewater. However, this method has a problem that the cleaning time is increased. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention has been proposed to solve the problem aforementioned, and it is an object of the present invention to provide a floating filter module and a water treatment apparatus and method using it, which are capable of improving filtration rate and filtration duration time by separating and filtering only upper water having relatively low concentration of suspended solids in a wastewater tank. 
         [0016]    It is also another object of the present invention to provide a floating filter module and a water treatment apparatus and method using it, which are capable of reducing of the adhesion amount of micro-pollution particles in a separating and filtering process and removing the adhered micro-pollution particles effectively and quickly when filtration rate is decreased due to adhering of micro-pollution particles. 
         [0017]    In order to accomplish the objects, a floating filter module according to the present invention comprises a hollow-type sintered filter arranged in wastewater of the water treatment tank and having a plurality of micro-pores, for separating and filtering the micro-pollution particles from the wastewater introduced into the water treatment tank; a floating body coupled with the sintered filter and floated to the surface of the wastewater in the water treatment tank, for placing the sintered filter at the upper side of the wastewater in the water treatment tank; a main pipe for connecting to an inside space of the sintered filter; a suction device coupled to the main pipe and providing suction force to the sintered filter through the main pipe, for sucking the wastewater of the water treatment tank into the inside space of the sintered filter through the plurality of micro-pores; and a compressed-air supply device having a compressed-air supply pipe connecting with the inside space of the sintered filter through the main pipe and an air compressor coupled with the compressed-air supply pipe, for supplying compressed air into the inside space of the sintered filter to remove the micro-pollution particles that clog the micro-pores of the sintered filter. 
         [0018]    The floating filter module according to the present invention may further comprise a vibration generating device for vibrating the sintered filter to remove the micro-pollution particles that clogs the micro-pores of the sintered filter. 
         [0019]    The floating filter module according to the present invention may further comprise a makeup water supply device for supplying makeup water in the inside space of the sintered filter filled with air by the compressed-air supply device. The makeup water supply device is connected to the main pipe. 
         [0020]    It is desirable that the sintered filter is made of stainless metal or synthetic resin. 
         [0021]    The suction device may comprise a suction pump and a differential pressure detector. The suction pump is connected with the main pump to generate suction force, and the differential pressure detector detects the difference between the forward and backward pressures of the suction pump to detect the blockage degree of the sintered filter. 
         [0022]    The compressed-air supply device may further comprise an actuator arranged between the sintered filter and the air compressor, for converting the compressed air to pulse form, the compressed air being continuously supplied from the air compressor to the sintered filter. 
         [0023]    In order to accomplish the objects, a water treatment apparatus according to the present invention comprises a water treatment tank into which wastewater is introduced; a floating filter module arranged in the water treatment tank, for separating and filtering the micro-pollution particles from the wastewater introduced into the water treatment tank; a control device for controlling operations of the floating filter module. The floating filter module comprises a hollow-type sintered filter arranged in the wastewater of the water treatment tank and having a plurality of micro-pores; a floating body coupled with the sintered filter and floated to the surface of the wastewater in the water treatment tank, for placing the sintered filter at the upper position of the wastewater in the water treatment tank; a main pipe for connecting with an inside space of the sintered filter; a suction device coupled to the main pipe and providing suction force to the sintered filter through the main pipe, for sucking the wastewater of the water treatment tank into the inside space of the sintered filter through the plurality of micro-pores; and a compressed-air supply device having a compressed-air supply pipe connecting with the inside space of the sintered filter through the main pipe and an air compressor coupled with the compressed-air supply pipe, the compressed-air supply device supplying compressed air into the inside space of the sintered filter to remove the micro-pollution particles that clog the micro-pores of the sintered filter. 
         [0024]    In order to accomplish the objects, the water treatment method according to the present invention comprises the steps of: (a) arranging a hollow-type sintered filter having a plurality of micro-pores in the upper side of wastewater in the water treatment tank, by using of a floating body capable of floating on the surface of water; (b) separating and filtering the micro-pollution particles from the wastewater, by providing suction force for the sintered filter and by sucking the wastewater of the water treatment tank into the inside space of the sintered filter through the plurality of micro-pores; (c) detecting the blockage degree of the sintered filter; (d) cleaning the sintered filter with returning of filtration water and spraying of compressed air to the inside space of the sintered filter, by stopping a suction device for providing the sintered filter with suction force and by supplying compressed air into the inside space of the sintered filter for a period of time, when the blockage degree of the sintered filter reaches a preset value, and (e) stopping a compressed air supply device for supplying compressed air to the sintered filter and restarting the suction device, after the cleaning of the sintered filter. 
         [0025]    The floating filter module according to the present invention uses a semi-permanent sintered filter in which micro pores are hardly deformed. This reduces the risk of damage and increase lifespan. 
         [0026]    In addition, the floating filter module according to the present invention is a moveable floating type and placed in the upper side of the water treatment tank, and separates and filters the upper water having relatively low concentration of suspended solids. Therefore, filtration rate and filtration duration time is excellent compared with the conventional apparatus. 
         [0027]    In addition, the floating filter module according to the present invention, when the clogging of the sintered filter is occurred, can remove micro-pollution particles adhered to the sintered filter quickly and efficiently, with returning filtration water and spraying the compressed air. 
         [0028]    In addition, the floating filter module according to the present invention, when the clogging of the sintered filter is occurred, can clean the sintered filter efficiently without using chemicals as before. Therefore, the activity degradation of microorganism due to chemicals is not occurred. 
         [0029]    In addition, the floating filter module according to the present invention vibrates the sintered filter by using a vibration generating device so that micro-pollution particles are hardly adhered to the sintered filter. Therefore, it is possible to reduce the frequency of the cleaning process, and operate efficiently. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]      FIG. 1  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a first embodiment of the present invention. 
           [0031]      FIG. 2  is a block diagram showing some configuration of a water treatment apparatus according to a first embodiment of the present invention. 
           [0032]      FIG. 3  is a side view schematically showing a filtration tank of a water treatment apparatus according to a first embodiment of the present invention. 
           [0033]      FIG. 4  is a side view showing a floating filter module according to an embodiment of the present invention. 
           [0034]      FIG. 5  is a top view taken along the line I-I of  FIG. 4 . 
           [0035]      FIG. 6  is a side cross sectional view showing a sintered filter of a floating filter module according to an embodiment of the present invention. 
           [0036]      FIG. 7  is a view showing a manufacturing process of a sintered filter provided in a floating filter module according to an embodiment of the present invention. 
           [0037]      FIG. 8  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a second embodiment of the present invention. 
           [0038]      FIG. 9  is a top view schematically showing a water treatment apparatus according to a second embodiment of the present invention. 
           [0039]      FIG. 10  is a side view schematically showing an aeration tank of a water treatment apparatus according to a second embodiment of the present invention. 
           [0040]      FIG. 11  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a third embodiment of the present invention. 
           [0041]      FIG. 12  is a top view schematically showing a water treatment apparatus according to a third embodiment of the present invention. 
           [0042]      FIG. 13  is a side view schematically showing a sequencing batch reactor of a water treatment apparatus according to a third embodiment of the present invention. 
           [0043]      FIG. 14  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a forth embodiment of the present invention. 
           [0044]      FIG. 15  is a top view schematically showing a water treatment apparatus according to a forth embodiment of the present invention. 
           [0045]      FIG. 16  is a view respectively showing (a) an installation initial state, (b) a state after sucking and filtering and (c) a state after cleaning with compressed air, of a sintered filter installed in a sequencing batch reactor. 
           [0046]      FIG. 17  is a graph showing filtering characteristics according to the operation of a floating filter module installed in a sequencing batch reactor. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    Hereinafter, the present invention will be described by way of examples illustrating best mode embodiments. Examples described below are only for illustrative purposes. Therefore, the scope of the present invention is limited only by the scope of the claims, but not to the examples. 
         [0048]      FIG. 1  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a first embodiment of the present invention,  FIG. 2  is a block diagram showing some configuration of a water treatment apparatus according to a first embodiment of the present invention, and  FIG. 3  is a side view schematically showing a filtration tank of the water treatment apparatus shown  FIG. 3 . 
         [0049]    As shown in  FIGS. 1 to 3 , a first embodiment of the present invention is an A 2 /O (Anaerobic/Anoxic/Oxic) type of water treatment apparatus which includes three stages of bio-reactors comprising anaerobic tank  115 , anoxic tank  120  and aerobic tank  125 , and a plurality of treatment tanks arranged in the upper and downstream of the bio-reactors. Additional treatment tanks except for the three stages of bio-reactors are a flow rate control tank  110  arranged in the upper stream of the anaerobic tank  115 , a filtration tank  130  arranged in the lower stream of the anoxic tank  120 , a processing water tank  170  and a sludge thickener  175 . A floating filter module  140  for separating and filtering wastewater is arranged in the filtration tank  130 . 
         [0050]    In addition, the water treatment apparatus according to the first embodiment of the present invention further includes a water level detection device  131  for detecting the water level of the filtration tank  130 , a agitation device  132  for agitating the wastewater of the filtration tank  130 , a bubble generating device  133  for supplying bubbles to the floating filter module  140 , a monitoring device  180  for providing the water treatment processing state for a user, a control device  185  for controlling various devices, a remote management device  190  for providing a manager with information about the water treatment processing state and allowing the manager to control remotely the water treatment processes, and a communication device  195  for communication between the control device  185  and the remote management device  190 . 
         [0051]    A bubble generating device  133  includes a plurality of aeration tubes  134  arranged in the lower position of the floating filter module  140 , an air supply device  136  for introducing air into the aeration tubes  134  through an air supply tube  135 , and an air control valve  137 , arranged in the air supply tube  135 , for opening and closing air path in the air supply tube  135 . The air supply device  136  and the air control valve  137  are controlled by the control device  185 . The bubble generating device  33  generates bubbles through the plurality of aeration tubes  134  and provides the sintered filter  141  of the floating filter module  140 . This removes micro-pollution particles adhered to the sintered filter  141  and prevent micro-pollution particles from being adhered to the sintered filter  141 . The plurality of aeration tubes  134  are coupled to the floating filter module  140  through a separate coupling device, thereby not interfering with the floating filter module  140  for elevating according to the water level of wastewater. Thus, the aeration tubes  134  can be elevated with the floating filter module  140  and installed in the bottom of the filtration tank. 
         [0052]    The communication device  195  connects the control device  185  with the remote management device  190  so that a manager who is far away checks the progress of the water treatment processes or the state of the water treatment apparatus through the remote management device  190  in real time and controls the water treatment processes remotely. 
         [0053]    This A 2 /O type of water treatment apparatus is most basic and high class of biological treatment apparatus for effectively removing total nitrogen (T-N) and total phosphorus (T-P) nutrient salts in addition to biochemical oxygen demand (BOD) and suspension floating material in wastewater. An ordinary activated sludge type of conventional biological reactor is comprised of only the activated sludge of aerobic tank so that the wastewater processed in the aerobic tank is precipitated in a precipitation tank and then discharged. This degrades the efficiency of removing nitrogen and phosphorus and causes eutrophication when discharging in the river. However, the A 2 /O type of water treatment apparatus, in which bio-reactor comprises an anaerobic tank  115 , an anoxic tank  120  and an aerobic tank  125 , can solve the conventional problems. 
         [0054]    According to the water treatment processes executed by the water treatment apparatus of the first embodiment of the present invention, an anaerobic tank  115  and an anoxic tank  120  are installed in the upper stream of an aerobic tank  125 , the wastewater processed in the aerobic tank  125  is returned to the anoxic tank  120  to remove nitrate nitrogen NO 3 —N, and a portion of activated sludge precipitated in the filtration tank  130  is returned from the upper stream of the sludge thickener  175  to the anaerobic tank  115 . Thus, microbial concentration of all reactors remains constant. Further, by releasing phosphorus in anaerobic state and taking in superfluous phosphorus, the phosphorus is pulled out sludge state and then removed. 
         [0055]    The water treatment process of the water treatment apparatus according to the first embodiment of the present invention includes an internal recycle for removing nitrate nitrogen and an external recycle of sludge from the filtration tank for removing phosphorus. With this, phosphorus can be released from anaerobic tank  115  and microorganism can ingest phosphorus superfluously in the aerobic tank  125  so that the total phosphorus content ratio of the activated sludge is increased and the total phosphorus removal ratio of wastewater is increased. Therefore, nitride nitrogen in internal recycle water from the aerobic tank  125  is denitrified in the anoxic tank  120  and reduced to nitrogen gas so that nitrogen is removed from wastewater. 
         [0056]    The processing efficiency in the A 2 O type of water treatment process is generally known as follows: the removal rate of biological oxygen demand (BOD) is more than 90%, the removal rate of suspended floating matter is more than 90%, the removal rate of total nitrogen is 40˜70%, and the removal rate of total phosphorus is about 60%. Further, the hydraulic retention time (HRT) is 5˜8 hours (the anaerobic tank: 0.5˜1.0 hours, the anoxic tank: 0.5˜1.0 hours, and the aerobic tank: 3.5˜6.0 hours), the solids retention time (SRT) is 4˜27 days, the external rate of the returned activated sludge (RAS) is 25˜50%, and the internal rate of the inlet water quantity (Q) is about 100˜200%. 
         [0057]    The water treatment apparatus according to the first embodiment of the present invention has an additional function of separating and filtering micro-pollution particles with using a filtration tank  130  installed a floating filter module  140  so that the treatment efficiency of suspended floating matter is higher than that of conventional A 2 /O type of wastewater treatment process. By using a floating filter module  140 , a forced pressure type of separating and filtering process is adopted instead of gravitational settling type, thereby being capable of processing the suspended floating matter stably and efficiently. 
         [0058]    In case of a water treatment apparatus having a conventional immersion type membrane separator, the immersion type membrane separator is arranged in the lower stream of a bio-reactor and waste water is discharged by using immersion type membrane which is installed in the separator. The conventional immersion type membrane, which is made of 0.01˜1.0 μm grade of a hollow fiber membrane or a plate type membrane, is fixed in the lower part of the membrane separator, thereby being exposed to suspended solids having relatively high concentration. Therefore, their initial filtration efficiency is satisfactory, but as operating time goes by, it causes clogging of micro-pores, that is, blockage of micro-pores due to deposition of micro-pollution particles or microorganism, in a short period of time, thereby decreasing the filtration efficiency sharply. 
         [0059]    In case that of the conventional water treatment apparatus, when the clogging of micro-pores is occurred in the immersion type membrane, generally the membrane is cleaned by inputting cleaning chemicals and flowing high pressure treatment water backward, namely back-washing. But this method for cleaning the immersion type membrane has several problems that the activity of microorganism is degraded by inputting chemicals, total filtration throughput is decreased by flowing treatment water backward, and the initial cost, electricity cost and maintenance cost is increased by installing equipment for inputting chemicals and a pump for back-washing. 
         [0060]    In addition to the clogging of fine holes, self-defects may occurs in the hollow fiber membrane used in the immersion type membrane of the conventional water treatment apparatus, thereby easily degrading the efficiency of the filtration. Generally, one element of the hollow fiber membrane comprises about 160 strands of hollow filers with 2 mm of external diameter, 0.8 mm of internal diameter, 1.5 m of length and 0.1 μm of pore size. However, in this hollow fiber membrane, the hollow fibers may be easily snapped or destroyed while using it. Thus, it is difficult to keep the treatment efficiency stably. Further, the hollow fiber membrane used in the convention immersion type membrane cannot be cleaned by using compressed air because of the thickness and material of membrane, thereby restricting the cleaning method. 
         [0061]    In the present invention, because a floating filter module  140  including a sintered filter  141  is used, the problems of the prior art can be solved. As shown  FIGS. 2 to 4 , the floating filter module  140  according to an embodiment of the present invention is arranged to float on the upper side of water in the filtration tank  130  so that only upper water, whose suspended solids concentration is relatively low, is separated and filtered. Therefore, in addition to excellent initial filtration efficiency, the floating filter module  140  has a stable efficiency, even though over time. Even if micro-pores are clogged by adhering of micro-pollution particles or microorganism, they are rapidly cleaned by spraying of air and returning of treatment water. 
         [0062]    As shown  FIGS. 3 to 5 , the floating filter module  140  installed in the filtration tank  130  has a plurality of sintered filters  141  immerged within wastewater of the filtration tanks  130 , a main pipe  142  connected to the sintered filters  141 , a plurality of floating bodies  143  for placing the sintered filters at the upper position in the wastewater by floating to the water surface with buoyancy, a suction device  147  connected to the sintered filters  141 , for providing suction force to the sintered filters  141 , a compressed-air supply device  152  for providing the compressed-air to the sintered filters  141  so as to remove micro-pollution particles deposited on the sintered filters  141 , a makeup water supply device  160  for providing makeup water to the inside space of the sintered filters  141  filled with air after cleaning the sintered filters, a vibration generating device  166  for vibrating the sintered filters  141  so as to remove micro-pollution particles deposited on the sintered filters  141 . In the floating filter module  140  of  FIG. 3 , the compressed-air supply device  152  and the makeup water supply device  160  are omitted for clarity. 
         [0063]    In the floating filter module  140  according to the present invention, the sintered filters  141  for separating and filtering are arranged in upper side of wastewater in the filtration tanks  130  by buoyancy of the floating bodies  143 , and elevated up and down by changing of water level, thereby separating and filtering only upper water having relatively low concentration of suspension solids. Therefore, the filtration speed, the filtration rate of filtrate flux and filtrate duration time are far superior to the conventional immersion type membrane arranged in the lower or middle side of wastewater. 
         [0064]    The sintered filter  141  is connected to the main pipe  142  through filter coupling member  144  having internal path, and the main pipe  142  is connected to the floating body  143  through a flexible connection member  145 . When the floating body  143  and the sintered filters  143  are elevated up and down by changing of water level in the filtration tank  130 , a shock can occur between the floating body  143  and the sintered filters  143 . The flexible connection member  145  can absorb the shock. The compressed air supply device  152  and the makeup water supply device  160  are connected to the sintered filters  141  through the main pipe  142 , just like the suction device  147 . 
         [0065]    The sintered filter  141  is made of stainless metal powder or synthetic resin fine powder and by a sintering method. The sintered filter  141  is a hollow type filter having a cavity in the center and 0.01˜10 μm of micro-pores. The sintered filter  141  made by the sintering method has uniform pore size and high porosity, and be durable not to be deform the size or shape of micro-pores easily under the high compressed air or back washing water. 
         [0066]    As shown  FIG. 6 , it is advantageous that the sintered filter  141  is formed in the hollow type having a cavity in the center so as to increase the efficiency of filtration or cleaning. 
         [0067]      FIG. 7  is a manufacturing process of a sintered filter  141  which is core parts of a floating filter module  140  according to an embodiment of the present invention. Referring to  FIG. 7 , the manufacturing process comprises the steps of supplying feedstock powder, mixing, compression molding and sintering. The sintering is a molding method in which uniform particle size distribution of powder, that is high purity and high compression, is mixed completely with a precision instrument, and compression formed in a designed shape with a high precision tool having about 3˜7 ton/cm 2  of pressure. And then, the compression formed body is heated until it reaches the melting point so as to adhere and cement each other. 
         [0068]    The sintered filter  141  according to the present invention can be made to put fine powder in a mold, press with high pressure, mold a designed shape, and heat at a temperature near the melting point, in which the fine powder is stainless steel or synthetic resin having a particle size of micrometer order. By heating the molded body of fine powder at the temperature near the melting point, a diffusion bonding or a partial deposition is achieved in contact portion between the body of fine powder so that the fine powder is connected to each other to form a strong porous sintered filter. If adjusting the particle size of fine powder used as a raw material for the sintered filter  141 , it is possible to make the sintered filter  141  having various size of micro-pores. 
         [0069]    If stainless steel powder is used as a raw material for the sintered filter  141 , it is possible to produce a metal porous sintered filter  141  having good heat proof, corrosion proof and durability characteristics. If synthetic resin powder is used as a raw material for the sintered filter  141 , it is possible to produce a resin porous sintered filter  141  having good chemical resistant characteristics and low costs. 
         [0070]    The sintered filter  141  made by above sintering method has various merits, compared to the conventional immersion type membrane. That is, with adjusting particle size of powder used as a raw material when making, the size of micro-pores can be easily defined as 0.01˜100 μm. Further, the filter used uniform particle size of powder has better porosity than the conventional filter, and can be made in various shapes. Further, the filter is durable not to be deform the size and shape of the micro-pores under long use, and can be cleaned rapidly and effectively by spraying high compressed air, for example 0.2˜0.7 MPa. Because the sintered filter  141  that forms the floating filter module  140  according to the present invention has better porosity than the conventional hollow fiber membrane, the amount of filtration per hour, that is, the filtration rate is also excellent. 
         [0071]    The floating body  143  can be made in various materials capable of floating to the water surface. The buoyancy index of the floating body  143  is variously defined according to the total weight of the floating filter module  140  such that the floating body  143  is always positioned at the surface of wastewater. In case that the sintered filter  141  is made of metal material or other frame is added such that the total weight has increased, the floating body can be filled with air or helium (He). 
         [0072]    Referring to  FIG. 4  again, the suction device  147  includes a suction pump  148  installed in the main pipe  142  and being capable of generating suction force, a treatment water control valve  149  arranged in the upper stream of the main pipe  142  and being capable of controlling the flowing of the treatment water through the main pipe  142 , and a differential pressure detector. The suction pump  148  provides the suction force to the sintered filters  141  such that wastewater is flowed into the inside of the sintered filters  141 , and pumps the in-flowed filtration water to a treatment water tank  170 . As the suction pump  148  for providing filtration power to the sintered filter  141 , it is desirable to use a self priming pump or a vacuum self priming pump in which cavitations do not occur even if air is inflowed in some degree. 
         [0073]    The differential pressure detector  150  detects pressure loss in forward and backward of the suction pump  148  and provides to a control device  185 . The control device  150  receives the detection signal from the differential pressure detector  150  and determines the clogging degree of the sintered filter  141 . If the clogging degree of the sintered filter  141  reaches to a predetermined value, the control device  150  stops the separating and filtering process and starts the cleaning process of the sintered filter  141 . The value of the pressure loss that is a criterion of the clogging degree of the sintered filter  141  is preset according to the type of the sintered filter  141  or the suction pump  148 . 
         [0074]    A compressed-air supply device  152  has a compressed-air supply pipe  153 , and an air compressor  154 , a pressure adjuster  155 , a compressed-air control valve  156  and an actuator  157  installed the compressed-air supply pipe  153 . The compressed-air supply pipe  153  is connected to the main pipe  142 , for supplying air to the sintered filters  141  through the main pipe  142 . A dust filter  158  is installed in a suction part of the air compressor  154 . The air compressor  154 , a pressure adjuster  155 , a compressed-air control valve  156  and an actuator  157  are controlled by a control device  185 . 
         [0075]    In the cleaning process, the control device  185  opens the compressed-air control valve  156 , operates the air compressor  154  and the pressure adjuster  155 , and sprays the compressed air the sintered filters  141  through the main pipe  142 . The cleaning process of the sintered filter  141  with spraying the compressed air is automatically executed by the control device  185  for a preset time, and supplies in a pulse form compressed-air through the actuator  157  to clean effectively. 
         [0076]    After the cleaning process of the sintered filter  141  with spraying compressed-air, the inside of the sintered filter  141  is filled with compressed air. In this state, the suction device is restarted and the air remaining the sintered filter  141  and the main pipe  142  is flowed into the suction pump  148 , resulting in the cavitations of the suction pump  148 . For preventing the cavitations of the suction pump  148 , before restarting the suction device  147 , a makeup water supply device  160  supplies makeup water to the sintered filter  141  and the main pipe  142 . 
         [0077]    The makeup water supply device  160  includes a makeup water supply pipe  161  connected to the main pipe  142 , a makeup water tank  142  for storing the makeup water, and a makeup water control valve  163  installed in the makeup water supply pipe  161 . The makeup water tank  162  may be omitted. In this case, the makeup water supply pipe  161  connects directly to the water main to use water from the water main as the makeup water, or the filtration water filtered through the sintered filter  141  is used as the makeup water. A pump for pumping the makeup water may be installed in the makeup water supply pipe  161 . The makeup water supply pipe  161  has a discharge valve  161  for discharging air filled in the sintered filter  141  and the main pipe  142  such that the makeup water is effectively filled in the sintered filter  141  and the main pipe  142 . 
         [0078]    As shown  FIGS. 4 and 5 , a vibration generating device  166  vibrates the sintered filters through the main pipe  142 . It is used various vibration generating devices for generating vibration of a predetermined frequency, for example 1˜200 Hz. The vibration generating device  166  vibrates the sintered filters  141  during the cleaning process or the separating and filtration process so that micro-pollution materials deposited on the sintered filters  141  is removed or reduced. 
         [0079]    Hereinafter, the operation of the water treatment apparatus according to the first embodiment of the present invention will now be described in detail with reference to  FIGS. 1 to 4 . 
         [0080]    First, the wastewater is flowed into a flow adjusting tank  110 , and flowed into anaerobic tank  114 , anoxic tank  120 , aerobic tank  125  and filtration tank  130  by turns. A part of wastewater in aerobic tank  125  is returned to the anoxic tank  120 , in which nitride nitrogen of wastewater is denitrified to reduce to nitrogen gas so that nitrogen is removed from wastewater. The filtered water in which micro-pollution materials is removed by the floating filter module  140  in the filtration tank  130 , is discharged by the way of the treatment water tank  170 . The sludge is collected in a sludge pit  138  arranged in the lower side of the filtration tank  130  and pulled out to a sludge thickener  175 . A part of sludge pulled out from the filtration tank  130  is returned to the anaerobic tank  115 . This maintains steady microbial concentration of the whole reactor, releases phosphorus in anaerobic state and allows microorganism to eat excessive phosphorus in the aerobic tank  125 , thereby increasing total phosphorus content within sludge and the total phosphorus removal rate. 
         [0081]    The water treatment process is described in more detail below. The wastewater is sucked into the inside of the sintered filters  141 , and after the micro-pollution particles included in the wastewater are separated and filtered, the wastewater is flowed into the treatment water tank  170  through the main pipe. During the separating and filtering process with the sintered filter  141 , the agitation device  132  agitates wastewater to prevent sludge of wastewater from depositing and being anaerobic. The bubble generating device  133  supplies bubbles to the sintered filter  141  so that the adhering amount of micro-pollution particles or microorganism on the sintered filter  141  is decreased. Further, the vibration generating device  166  vibrates the sintered filter  141  during the separating and filtering process so that micro-pollution particles or microorganism is hardly adhered on the sintered filter  141 . 
         [0082]    The separating and filtering process with the floating filter module  140  is executed when the wastewater level in the filtration tank  130  is within a predetermined range. That is, according to the wastewater level from the water level detection device  131 , the control device  185  operates the suction device  147 , the agitation device  132  and the bubble generating device  133 . If the wastewater level is lower than the predetermined low level, the separating and filtering process is not progressed. If the floating filter module  140  operates when the wastewater level is lower than the predetermined low level, the wastewater having high concentration of suspended solids is passed through the sintered filter  141 . This clogs rapidly the sintered filter  141  so that it is impossible to operate effectively. 
         [0083]    On the other hand, the control device  185  checks the clogging degree of the sintered filter  141  by the differential pressure detector  150 . When the clogging degree of the sintered filter  141  reaches to the predetermined value, the control device  185  stops the separating and filtering process and proceeds to the cleaning process for the sintered filter  141 . The detailed cleaning process is as follows. 
         [0084]    When the clogging degree of the sintered filter  141  reaches to the predetermined value, the control device  185  closes the treatment water control valve  149  and stops the suction pump  148 . And then, the control device  185  opens the compressed-air control valve  156  and operates the air compressor  154 , the pressure adjuster  155  and actuator  157  so as to supply the compressed-air having a predetermined pressure, for example 0.2˜0.7 MPa, to the sintered filter  141 . When the compressed-air is supplied to the sintered filter  141 , the filtrate filled in the sintered filter  141  is strongly pushed out by the compressed-air and rapidly gets out of the outside of the sintered filter  141  through the micro-pores of the sintered filter  141 . 
         [0085]    The filtrate getting out instantaneously functions a back washing water to remove micro-pollution particles adhered on the sintered filter  141 . Next, the compressed-air supplying to the inside of the sintered filter  141  passes through micro-pores of the sintered filter  141  and discharges to the outside of the sintered filter  141 , and the micro-pollution particles adhered on the sintered filter  141  are removed. The compressed-air is provided in a pulse form by the actuator  157  or provided successively without the operation of the actuator  157 . 
         [0086]    The cleaning process with returning of filtration water and spraying of the compressed-air is preceded by the control device  185  for a predetermined time. After the cleaning process, the control device  185  closes the compressed-air control valve  156 , stops the compressed-air supply device  152 , and operates the makeup water supply device  160 . When the makeup water control valve  163  and a discharge valve  164  are opened and the makeup water stored in the makeup water tank  162  is filled in the main pipe  142  and the sintered filters  141  through the makeup water supply pipe  161 . This prevents the suction pump from cavitating in the separating and filtering process. 
         [0087]    A monitoring device  180 , a remote management device  190  and a communication device  195  are provided the information for the separating and filtering process, the cleaning process and defects of devices, to a manager. The manager remotely controls the separating and filtering process through the remote management control device  190  in home or office. 
         [0088]    On the other hand,  FIG. 8  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a second embodiment of the present invention and  FIG. 9  is a top view schematically showing the water treatment apparatus of  FIG. 8 . 
         [0089]    The wastewater treatment apparatus according to the second embodiment of the present invention is medium and small sized wastewater treatment apparatus and includes a water flow adjusting tank  110 ; a denitrification and dephosphorization tank  210  for executing both functions of the anaerobic tank and anoxic tank according to the first embodiment of the present invention, and maintaining the concentration of dissolved oxygen below a predetermined level, for example 0.2 mg/L; an aerobic tank  215  in which the floating filter module  140  is installed; a dissolved oxygen reduction tank  225  for reducing the dissolved oxygen of the treatment solution returned to the denitrification and dephosphorization tank  210  to improve the denitrification and dephosphorization efficiency; a treatment water tank  170  in which the treatment water through the aerobic tank  214  is flowed in; and a sludge thickener  175  in which the sludge discharged from the aerobic tank  214  is flowed in. 
         [0090]    The denitrification and dephosphorization tank  210  is divided into an anaerobic region  212  and an anoxic region  213  by a partition wall, and the anaerobic region  212  and the anoxic region  213  are connected through a pathway  214 . The water treatment apparatus according to the second embodiment of the present invention is designed to process wastewater under 10,000 ton/day. 
         [0091]    Referring to  FIG. 10 , the water treatment apparatus according to the second embodiment of the present invention further includes a water level detection device  216  for detecting the level of the wastewater in the aerobic tank  215 , a agitation device  217  for wastewater of the aerobic tank  215 , and a aerobic device  218  for supplying air to the wastewater of the aerobic tank  215 . The aerobic device  218  includes a plurality of aeration tube  134  arranged within the wastewater of the aerobic tank  215 , an air supply device  221  for supplying air to the aeration tube  219  through a air supply tube  220  connected to the aeration tube  219 , and an air control valve  222  installed in the air supply tube  220 . The floating filter module  140  for separating and filtering micro-pollution particles of wastewater is installed in the aerobic tank  215 , and a sludge pit  223  for collecting sludge is provided in the lower side of the aerobic tank  215 . In  FIG. 10 , the compressed-air supply device  152  and the makeup water supply device  160  are omitted for clarity, and the floating filter module  140  is the same as that of the first embodiment of the present invention. 
         [0092]    The water treatment apparatus according to the second embodiment of the present invention, but not shown in the drawings, further includes a monitoring device for providing the water treatment processing state to a user, a control device for controlling various devices, a remote management device and a communication device, in the same as the first embodiment. 
         [0093]    Hereinafter, the water treatment process with water treatment apparatus according to the second embodiment of the present invention will now be described. First, the wastewater is flowed into the anaerobic region  212  of the denitrification and dephosphorization tank  210  by way of the flow adjusting tank  110 . In addition to the wastewater, a portion of sludge discharged from the aerobic tank  215  to the sludge thickener  175  is flowed into the anaerobic region  212 . Accordingly, a P-release mechanism is occurred in the anaerobic region  212 , and in the aerobic tank  215 , microorganism eats excessive phosphorus to increase total phosphorus content within sludge, thereby improving the total phosphorus removal rate. The nitride solution nitrified in the aerobic tank  215  is returned to the anoxic region  213  of the denitrification and dephosphorization tank  210 , and denitrified and reduced to remove the nitrogen component of water. The treatment solution returned from the aerobic tank  215  to the denitrification and dephosphorization tank  210  is passed through the dissolved oxygen reduction tank  225  to reduce the dissolved oxygen, thereby improving the denitrification and dephosphorization efficiency in the denitrification and dephosphorization tank  210 . 
         [0094]    As shown  FIG. 10 , the wastewater passed through the denitrification and dephosphorization tank  210  is flowed into the aerobic tank  215 . In the aerobic tank  215 , microorganism mechanism such as organic matter decomposition, nitrification reaction and excess phosphorus ingestion is occurred and, at the same time, micro-pollution particles is separated and filtered by the floating filter module  140 . The separating and filtering process with the floating filter module  140  is the same as above described. As shown in drawings, by arranging the floating filter module  140  in the upper side of the aerobic device  218  and using bubbles supplied from the aerobic device  218  into water, it is possible to decrease micro-pollution particles or microorganism adhered on the sintered filter  141  of the floating filter module  140 . 
         [0095]    In the operation of the floating filter module  140  of the water treatment apparatus according to the second embodiment of the present invention, if the separating and filtering process is executed during aeration rest period, the upper water having relatively low concentration of suspension solids is filtered by the sintered filter  141 , thereby being capable of separating and filtering effectively. In the floating filter module  140  of the water treatment apparatus according to the second embodiment of the present invention, it is desirable that the operation range between high and low water levels is narrow. This minimizes the concentration change of suspended solids in the wastewater to be separated and filtered by the sintered filter  141 . 
         [0096]    On the other hand,  FIG. 11  is a flowsheet showing the wastewater treatment process of a water treatment apparatus according to a third embodiment of the present invention,  FIG. 12  is a top view schematically showing a water treatment apparatus according to a third embodiment of the present invention, and  FIG. 13  is a side view schematically showing a sequencing batch reactor of a water treatment apparatus according to a third embodiment of the present invention. 
         [0097]    The water treatment apparatus according to the third embodiment of the present invention is a sequencing wastewater treatment apparatus using a sequencing batch reactor (SBR)  310  for executing a series of processes that is inflowing—microorganism reacting—depositing—discharging, and includes a flow adjusting tank  110 , a denitrification and dephosphorization tank  210 , a sequencing batch reactor  310 , a sludge transferring tank  325 , a treatment water tank  170  and a sludge thickener  175 . The denitrification and dephosphorization tank  210  is divided into an anaerobic region  212  and an anoxic region  213  by a partition wall so that the phosphorus removal reaction and the nitrogen removal reaction are not interfered each other. The anaerobic region  212  and the anoxic region  213  are connected through the pathway  214 . 
         [0098]    According to a conventional sequencing wastewater treatment method using a sequencing batch reactor  310  in major reaction process, the inflowing of wastewater—microorganism reacting—depositing—discharging are done in the sequencing batch reactor  310 , and the mechanism for removing nitrogen, phosphorus and nutrient salts is done only in the sequencing batch reactor  310 . Thus, the removal efficiency of nitrogen, phosphorus and nutrient salts may be relatively low. According to the present invention, however, because the denitrification and dephosphorization tank  210  having the anaerobic region  212  and the anoxic region  213  is arranged in the upper stream of the sequencing batch reactor  310 , the removal efficiency of nitrogen, phosphorus and nutrient salts is more excellent than the conventional sequencing wastewater treatment method. 
         [0099]    Referring to  FIG. 13 , the water treatment apparatus according to the third embodiment of the present invention includes a water level detection device  311  for detecting the level of the wastewater in the sequencing batch reactor  310 , a agitation device  312  for wastewater of the sequencing batch reactor  310 , and a aerobic device  313  for supplying air to the wastewater of the sequencing batch reactor  310 . The aerobic device  313  includes a plurality of aeration tube  314  arranged within the wastewater of the sequencing batch reactor  310 , an air supply device  316  for supplying air to the aeration tube  314  through a air supply tube  315  connected to the aeration tube  314 , and an air control valve  317  installed in the air supply tube  315 . 
         [0100]    The floating filter module  140  for separating and filtering micro-pollution particles of wastewater is installed in the sequencing batch reactor  310 , and a sludge pit  318  for collecting sludge is provided in the lower side of the sequencing batch reactor  310 . In  FIG. 13 , the compressed-air supply device  152  and the makeup water supply device  160  are omitted for clarity, and the floating filter module  140  is the same as that of the first embodiment of the present invention. 
         [0101]    The water treatment apparatus according to the third embodiment of the present invention, but not shown in the drawings, further includes a monitoring device for providing the water treatment processing state to a user, a control device for controlling various devices, a remote management device and a communication device, in the same as the first embodiment. 
         [0102]    Hereinafter, the water treatment process with water treatment apparatus according to the third embodiment of the present invention will now be described. First, wastewater is temporarily stored in the flow adjusting tank  110 , and flowed into the anaerobic region  212  of the denitrification and dephosphorization tank  210  intermittently or sequentially. In the anaerobic region  212 , the phosphorus (PO 4 —P) releasing speed by microorganism is increased. The wastewater in which phosphorus is released is flowed into the anoxic region  213 . In the anoxic region  213 , by the mechanism of facultative anaerobe denitrification microorganism, the nitrate nitrogen (NO 3 —N) and nitrite nitrogen (NO 2 —N) are reduced into nitrogen gas so that the removal efficiency of the nitrogen and phosphorus is improved. The wastewater of the anoxic region  213  is transferred to the sequencing batch reactor  310 . 
         [0103]    As shown  FIGS. 12 and 13 , the wastewater passed through the denitrification and dephosphorization tank  210  is dispersed and flowed into the lower side of the sequencing batch reactor  310  through a guide tube  319  and a spray tube  320  connected thereto. In the sequencing batch reactor  310 , the wastewater is agitated by the agitation device  312 , and an aerobic process is executed during a predetermined time by bubbles provided from the aerobic device  313 . The sludge included in the wastewater is collected in the sludge pit  318  and transferred to the sludge thickener  175 . The upper water is separated and filtered by the floating filter module  140  to discharge to the treatment water tank  170 . The sludge flowed into the sludge thickener  175  is dehydrated after a predetermined sludge retention time (SRT), and the treatment water transferred to the treatment tank  170  is transiently retained and discharged to outside. 
         [0104]    A portion (approximately under 30%) of sludge pulled out from the sequencing batch reactor  310  is returned to the anaerobic region  212  of the denitrification and dephosphorization tank  210 . This promotes the phosphorus removal reaction, and maintains the concentration of suspended solids within the denitrification and dephosphorization tank  210  at a certain level, for example 3,000˜20,000 mg/L, even in case of emergency. 
         [0105]    The sequencing batch reactor  310  is connected to the sludge transferring tank  325  through a pathway  321  having a whirlpool prevention device  322 . Through the pathway  321 , the activated sludge and nitrate nitrogen (NO 3 —N) are flowed from sequencing batch reactor  310  into the sludge transferring tank  325 , and returned to the anoxic region  213  of the denitrification and dephosphorization tank  210 . This maintains the concentration of suspended solids within the anoxic region  213  at a certain level, for example 3,000˜20,000 mg/L, the returned nitrate nitrogen (NO 3 —N) is reduced to nitrogen gas (N2). In the sludge transferring tank  325 , the dissolved oxygen of the activated sludge and nitride solution transferred from the sequencing batch reactor  310  is decreased to return the anoxic region  213  in absorbable form. Accordingly, the nitrogen removal reaction by facultative anaerobe microorganism is more promoted. 
         [0106]    The floating filter module  140  installed in the sequencing batch reactor  310  separates and filters micro-pollution particles of the upper water and transfers it to the treatment water tank  170 . The detailed structure and operation of the floating filter module  140  is the same as above described, and the operation of the floating filter module  140  is done when the level of the wastewater is within a predetermined range between high and low water levels. 
         [0107]    In the water treatment apparatus according to the third embodiment of the present invention, the floating filter module  140  and the denitrification and dephosphorization tank  210  are used in the sequencing batch wastewater treatment process, thereby being capable of simplifying the process, upgrading facilities and improving the water treatment efficiency. 
         [0108]    On the other hand,  FIG. 14  is a flowsheet showing the wastewater treatment processes of a water treatment apparatus according to a forth embodiment of the present invention, and  FIG. 15  is a top view schematically showing a water treatment apparatus according to a forth embodiment of the present invention. 
         [0109]    The water treatment apparatus according to the forth embodiment of the present invention is a semi-batch type or a semi-continuous type of wastewater treatment apparatus in which a main reaction process uses an alternating batch reactor  410  having two batch reactors  411  and  412 . The water treatment apparatus according to the forth embodiment of the present invention includes a flow adjusting tank  110 , a denitrification and dephosphorization tank  210 , an alternating batch reactor  410 , two sludge transferring tank  415  and  416 , a treatment water tank  170  and a sludge thickener  175 . 
         [0110]    The water treatment apparatus according to the forth embodiment of the present invention is the same constitutions as the apparatus according to the third embodiment except that two of the batch reactors  412  and  413  and two of the sludge transferring tanks  415  and  416  are provided. The first batch reactor  411  is connected to the first sludge transferring tank  415  through a pathway  418 , and the second batch reactor  412  is connected to the second sludge transferring tank  416  through a pathway  419 . 
         [0111]    The first batch reactor  411  and the second batch reactor  412  have the floating filter module  140  for filtering the upper water of wastewater, respectively. The detailed structure and operation of the floating filter module  140  is the same as above described. Two floating filter modules  140  installed in the first batch reactor  411  and the second batch reactor  412  can be operated alternatively and, as the case may be, used to share the suction device  147 , the compressed air supply device  152  and the makeup water supply device  160 . 
         [0112]    The drawings show two of the batch reactors  412  and  413  and two of the sludge transferring tanks  415  and  416 , but the number of the batch reactors and the sludge transferring tanks are changed variously. And according to the number of the batch reactors, the number of the floating filter module  140  is changed. 
         [0113]    On the other hand,  FIG. 16  is a view respectively showing (a) an installation initial state, (b) a state after sucking and filtering, and (c) a state after cleaning with compressed air, of the sintered filter provided to the floating filter module in the sequencing batch reactor, and  FIG. 17  is a graph showing filtering characteristics according to the operation of the floating filter module installed in a sequencing batch reactor. 
         [0114]    In this case, the sintered filter is made of synthetic resins, the concentration of suspended solids is 60 mg/L in the sequencing batch reactor, and the cleaning process is executed by the returning of treatment water and the spraying of the compressed air during 5 minutes. 
         [0115]    Referring to  FIG. 16 , it is can be confirmed that the surface of the sintered filter after the sucking and filtering (b) is totally contaminated by adhering micro-pollution particles and microorganism, compared with the initial state (a). Further, the state after cleaning (c) shows that almost micro-pollution particles and microorganism is removed from the surface of the sintered filer. 
         [0116]    Referring to  FIG. 17 , from the filtration characteristics after cleaning and operating the sintered filter by one hour period, it is can be confirmed that the filtration rate of the sintered filter is excellent at first, and gradually decreased over time by adhering micro-pollution particles and microorganism. However, the filtration rate of the sintered filter after 5 minutes of cleaning is returned to that of the initial state. On operating the sintered filter for 4 weeks, the average filtration rate is 248.2 m 3 /m 2 ·day, this is excellent more than that of the conventional immersion type membrane (MBR)? in which the average filtration of the hollow fiber is 20˜50 m 3 /m 2 ·day. The reason why the porosity of the sintered filter is high, microspores are solidity, and the cleaning with returning of the treatment water and spraying of compressed air is possible. 
         [0117]    As described above, the floating filter module  140  according to the present invention has various advantages, compared with the conventional immersion type membrane. First, a semi-permanent sintered filter  141  is used, in which the micro pores are not deformed. Second, the whole filter module  140  is the floating and flow type and arranged in the upper side of the water treatment tank, and the upper water that has relatively low concentration of suspended solids is separated and filtered. Third, a bubbles or vibration generating means is used for reducing the clogging of the sintered filter  141 . Forth, when the sintered filter is clogged, the micro-pollution particles and microorganism adhered on the sintered filter  141  are rapidly removed by returning of the filtration water and spraying of the compressed air. The characteristics distinguished from the conventional immersion type membrane are described below in table 1. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 CONVENTIONAL 
                   
               
               
                   
                 IMMERSION TYPE 
               
               
                   
                 MEMBRANE 
                 FLOATING 
               
               
                 ITEM 
                 SEPARATOR 
                 FILTER MODULE 
               
               
                   
               
             
             
               
                 Separation/filtration 
                 Hollow fiber membrane or 
                 Sintered filter 
               
               
                 means 
                 flatsheet membrane 
               
               
                 Filter module 
                 Fixed immersion type 
                 Movable floating type 
               
               
                 installation type 
               
               
                 Region for 
                 High concentration of 
                 Low concentration of 
               
               
                 separating/filtering 
                 suspended solids region 
                 upper water 
               
               
                 Material of 
                 Synthetic resin 
                 Stainless steel or 
               
               
                 filtration means 
                   
                 synthetic resin 
               
               
                 Size of micro 
                 0.01~1.0 
                 0.01~10 
               
               
                 pore (μm) 
               
               
                 Porosity 
                 Medium 
                 High 
               
               
                 Means for reducing 
                 Coarse bubble 
                 Coarse bubble and 
               
               
                 the clogging 
                   
                 vibration 
               
               
                 Cleaning method of 
                 Returning of treatment 
                 Returning of filtration 
               
               
                 filtration means 
                 water 
                 water and spraying of 
               
               
                   
                   
                 compressed air 
               
               
                 Chemicals for 
                 Used 
                 Unused 
               
               
                 cleaning 
               
               
                 Durability of 
                 Possibility of breakage 
                 Semi-permanent 
               
               
                 filtration means 
                 or damage is high. 
               
               
                 Filtration rate 
                 Medium 
                 High 
               
               
                   
               
             
          
         
       
     
         [0118]    The floating filter module  140  according to the present invention, as described above, is installed in various water treatment tank such as a filtration tank  130 , an aerobic tank  215 , a sequencing batch reactor  310 , and an alternating batch reactor  410 . Thus, various water treatment apparatuses are upgraded to high facilities effectively, and complex water treatment apparatus is simplified 
         [0119]    While the invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.