Patent Publication Number: US-2021178331-A1

Title: Ultrafiltration system for advanced treatment of coal mine water

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of Chinese Patent Application No. 201911268745.5, filed on Dec. 11, 2019, entitled “ULTRAFILTRATION SYSTEM FOR ADVANCED TREATMENT OF COAL MINE WATER”, the contents of which is expressly incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present technology belongs to the field of water treatment and relates to treatment of coal mine water, and specifically to an ultrafiltration system for advanced treatment of coal mine water. 
     BACKGROUND 
     Plenty of mine water are produced during exploitation and excavation of coal. Under the impact of underground mining and human activities, the mine water contains a lot of impurities such as rock powder and mineral powder, and also contains a small quantity of organisms and microorganisms. If the mine water is directly discharged without treatment, on one hand, water source in a mine area is polluted, and on the other hand, the ecological environment in the mine area is destroyed. 
     Currently, Coagulation-sedimentation and filtration processes are mainly adopted to treat mine water. After such processes, the effluent quality can reach the originally formulated effluent standard of “Code for design of the fire protecting, sprinkling system in underground coalmine” (GB 50383-2016). However, with increasingly severe environment protection situation, a higher discharge standard for mine wastewater treatment is proposed. In order to ensure that discharged mine water steadily reaches the standard of class III of surface water, it is necessary to perform advanced treatment on water treated by an original treatment system, to further reduce content of pollutants in the water and finally reach the new discharge standard. 
     The inorganic ceramic membrane is a type of inorganic material with a special selective separation function that can separate a fluid into two disconnected parts. One or several types of materials can permeate the inorganic ceramic membrane, so as to separate other materials. With characteristics such as high-efficiency, energy conservation, environment friendliness, and molecule-scale filtration, the separation technology of the inorganic ceramic membrane has been wildly applied to the fields such as medicine, water treatment, chemical industry, electronics, and food processing, and is acknowledged as one of most important industry technologies in the 21st century. However, there is no report on the inorganic ceramic membrane being applied to coal mine water treatment. Besides, during coal mine water treatment, as time going by, fine coal powder not coagulated and sedimented in the mine water flows into hole paths of the ceramic membrane, to cause blockage of the ceramic membrane in different degrees, thereby affecting the water production efficiency. Therefore, the existing inorganic ceramic membrane technology cannot be applied to the mine water treatment. 
     SUMMARY 
     The objective of the present technology is to resolve the problem of the quality of discharged effluent water in the existing coal mine water treatment process, and provide an ultrafiltration system for advanced treatment of coal mine water. 
     The present technology is realized by the following technical solution: 
     An ultrafiltration system for advanced treatment of coal mine water is provided, including an intermediate water pool, an ultrafiltration membrane pool, an adjustment pool, a water production pool, and a water removal pool; 
     wherein the ultrafiltration membrane pool is connected to the intermediate water pool through a water inlet valve and a water inlet pump, connected to the water production pool through a backwashing valve and a backwashing pump, and connected to the water removal pool through a water production valve and water production pump, and the adjustment pool is connected to the ultrafiltration membrane pool through a drain valve disposed at a bottom of a side surface of the ultrafiltration membrane pool; and 
     an ultrafiltration membrane assembly and a cleaning device are disposed in the ultrafiltration membrane pool, an aeration tube is disposed in the ultrafiltration membrane pool below the ultrafiltration membrane assembly, the aeration tube is connected to a blower through an intake valve, and a water production channel in a ceramic membrane assembly is connected to the water production pool through a pipe. 
     Further, an overflow pipe is disposed on a side wall above the ultrafiltration membrane pool, and the overflow pipe is connected to the adjustment pool. 
     The cleaning device is an ultrasonic generator, and is used in cooperation with a backwashing device; a working current of the cleaning device can be adjusted. 
     The cleaning device is mounted on the side wall of the ultrafiltration membrane pool, and removes or loosens pulverized coal particles blocking hole paths of the ultrafiltration membrane with ultrasonication. 
     The ultrafiltration membrane assembly is a flat-sheet ceramic membrane with an aperture of 100 nm to 200 nm. 
     A quantity of the flat-sheet ceramic membrane is one or more group. The quantity of the ultrafiltration membrane assembly may be adjusted according to a size of the ultrafiltration membrane pool and the water production speed. 
     A liquid level indicator is disposed on a side wall at an upper part of the ultrafiltration membrane pool. 
     During operation, the water inlet valve and the water inlet pump are turned on at first. Water being treated by front-end coagulation-sedimentation flows into the ultrafiltration membrane pool. When a water level in the ultrafiltration membrane pool reaches a designated water level and when the water overflows an ultrafiltration membrane, the water production valve and the water production pump are turned on sequentially. Under the negative pressure of the water production pump, the upstream water flows into a water production device through the ultrafiltration membrane and starts to produce water. Until the membrane flux of the ultrafiltration system is less than a specific value, it is considered that the membrane starts to be blocked. In this case, the ultrafiltration membrane starts to be cleaned. The water production pump, the water production valve, the water inlet pump, and the water inlet valve are turned off sequentially. The ultrasonic cleaning device is turned on and the working current is adjusted. After a period of ultrasonication, the ultrasonic cleaning device is turned off. The intake valve and the blower are turned on sequentially to start aeration, and the drain valve is turned on at the same time to discharge the sewage in the ultrafiltration system which free flows, under gravity, into the front-end adjustment pool. After all the sewage is discharged, the drain valve is turned off. The backwashing valve and the backwashing pump are turned on sequentially. Backwashing water reverses through the ceramic membrane from the water production device to perform backwashing. After the backwashing, the backwashing pump, the backwashing valve, the blower, and the intake valve are turned off sequentially. Then the water inlet valve and the water inlet pump are turned on to start a second-round water production. 
     In order to verify effects of the present technology, the impact of ultrasonication time on the membrane flux is measured, and the result is shown in  FIG. 2 ; the impact of the current of the ultrasonic cleaning device on the membrane flux is measured, and the result is shown in  FIG. 3 . An optimal ultrasonication time and current can be obtained from the results shown in  FIG. 2  and  FIG. 3 . 
     The present technology is of a simple structure and is convenient to operate; no chemical reagent is needed during operation to implement quick cleaning and regeneration of the ceramic membrane, greatly improving the water production efficiency of the system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram of the present technology; 
         FIG. 2  shows an impact of an ultrasonication time on a membrane flux; and 
         FIG. 3  shows an impact of a current of an ultrasonic cleaning device on a membrane flux. 
     
    
    
     In the drawings:  1 —ultrafiltration membrane assembly,  2 —ultrafiltration membrane pool,  3 —water inlet valve,  4 —water inlet pump,  5 —water production valve,  6 —water production pump,  7 —cleaning device,  8 —intake valve,  9 —blower,  10 —drain valve,  11 —backwashing valve,  12 —backwashing pump,  13 —overflow pipe,  14 —liquid level indicator,  15 —intermediate water pool,  16 —water production pool,  17 —water removal pool,  18 —adjustment pool. 
     DETAILED DESCRIPTION 
     The present technology is further described below with reference to embodiments and the accompanying drawings. 
     Embodiment 1 
     An ultrafiltration system for advanced treatment of coal mine water as shown in  FIG. 1  includes an intermediate water pool, an ultrafiltration membrane pool  2 , an adjustment pool, a water production pool, and a water removal pool. The ultrafiltration membrane pool  2  is connected to the intermediate water pool  15  through a water inlet valve  3  and a water inlet pump  4 , connected to the water production pool  16  through a backwashing valve  11  and a backwashing pump  12 , and connected to the water removal pool  17  through a water production valve  5  and a water production pump  6 . The adjustment pool  18  is connected to the ultrafiltration membrane pool  2  through a drain valve  10  disposed at a bottom of a side surface of the ultrafiltration membrane pool. An ultrafiltration membrane assembly  1  (which is an assembly formed by the ceramic membrane) is disposed in the ultrafiltration membrane pool  2 . A cleaning device  7 —ultrasonic generator is mounted on a side wall of the ultrafiltration membrane pool  2 . An aeration tube is disposed in the ultrafiltration membrane pool below the ultrafiltration membrane assembly. The aeration tube is connected to a blower  9  through an intake valve  8 . A water production channel in the ceramic membrane assembly  1  is connected to the water production pool  16  through a pipe. 
     During operation, the chemical oxygen demand (CODCr) of the quality of mine water in mine #1 after coagulation-sedimentation is 30.5 mg/L, the content of ammonia-nitrogen is 1.12 mg/L, the turbidity is 2.34 NTU, and the content of petroleum-like substance is 0.06 mg/L. The water flows into the ultrafiltration system for filtration. The average aperture of the ceramic membrane is 200 nm. The frequency of the water production pump is 30 Hz. The initial membrane flux is 45.8 m3/h. After the filtration of the ultrafiltration system, most of suspensions and organisms including petroleum-like substances are removed. The CODCr of the effluent quality is reduced to 13.6 mg/L, the turbidity is reduced to 0.26 NTU, and the content of petroleum-like substance is reduced to 0.03 mg/L. After the system operates for 36 hours, the membrane flux is reduced to 35.0 m3/h. At this time, the ceramic membrane starts to be cleaned. 
     During cleaning, at first, the water production pump, the water production valve, the water inlet pump, and the water inlet valve are turned off sequentially. The ultrasonic cleaning device is turned on with a frequency of 40 MHz and a working current of 15 A. The ultrasonic cleaning device is turned off after 10-minute ultrasonication. The intake valve and the blower are turned on sequentially to start aeration, and the drain valve is turned on at the same time to discharge the sewage in the ultrafiltration system into the front-end treatment system. After all the sewage is discharged, the drain valve is turned off. The backwashing valve and the backwashing pump are turned on sequentially to start 4-minute backwashing. After the backwashing, the backwashing pump, the backwashing valve, the blower, and the intake valve are turned off sequentially. Then the water inlet valve and the water inlet pump are turned on. When a water level in the ultrafiltration membrane pool reaches a designated water level and when the water overflows the ultrafiltration membrane, the water production valve and the water production pump are turned on sequentially to start a second-round water production. At this time, the membrane flux restores to 45.6 m3/h. The system has operated for 127 days with such a recycle, and is cleaned once a day. The effluent quality still meets the Class III standard of environmental quality standards for surface water, and the membrane flux maintains within 44.5±1.6 m3/h (a designed flux is 50.0 m3/h). 
     Embodiment 2 
     An ultrafiltration system for advanced treatment of coal mine water as shown in  FIG. 1  includes an intermediate water pool, an ultrafiltration membrane pool  2 , an adjustment pool, a water production pool, and a water removal pool. The ultrafiltration membrane pool  2  is connected to the intermediate water pool  15  through a water inlet valve  3  and a water inlet pump  4 , connected to the water production pool  16  through a backwashing valve  11  and a backwashing pump  12 , and connected to the water removal pool  17  through a water production valve  5  and water production pump  6 . An overflow pipe  13  is disposed on a side wall at an upper part of the ultrafiltration membrane pool  2 . The overflow pipe  13  is connected to the adjustment pool  18 . The adjustment pool  18  is connected to the ultrafiltration membrane pool  2  through a drain valve  10  disposed at a bottom of a side surface of the ultrafiltration membrane pool. An ultrafiltration membrane assembly  1  (which is an assembly formed by the ceramic membrane) is disposed in the ultrafiltration membrane pool  2 . A cleaning device  7 —ultrasonic generator and a liquid level indicator  14  are mounted on a side wall of the ultrafiltration membrane pool  2 . An aeration tube is disposed in the ultrafiltration membrane pool below the ultrafiltration membrane assembly. The aeration tube is connected to a blower  9  through an intake valve  8 . A water production channel in the ceramic membrane assembly  1  is connected to the water production pool  16  through a pipe. 
     During operation, CODCr of the quality of mine water in mine #2 after coagulation-sedimentation is 42.6 mg/L, the content of ammonia-nitrogen is 1.07 mg/L, the turbidity is 5.61 NTU, and the content of petroleum-like substance is 0.07 mg/L. The water flows into the ultrafiltration system for filtration. The average aperture of the ceramic membrane is 150 nm. The frequency of the water production pump is 30 Hz. The initial membrane flux is 43.6 m3/h. After the filtration of the ultrafiltration system, most of suspensions and organisms including petroleum-like substances are removed. The CODCr of the effluent quality is reduced to 11.4 mg/L, the turbidity is reduced to 0.42 NTU, and the content of petroleum-like substance is reduced to 0.04 mg/L. After the system operates for 29 hours, the membrane flux is reduced to 35.0 m3/h. At this time, the ceramic membrane starts to be cleaned. 
     During cleaning, at first, the water production pump, the water production valve, the water inlet pump, and the water inlet valve are turned off sequentially. The ultrasonic cleaning device is turned on with a frequency of 40 MHz and a working current of 12 A. The ultrasonic cleaning device is turned off after 20-minute ultrasonication. The intake valve and the blower are turned on sequentially to start aeration, and the drain valve is turned on at the same time to discharge the sewage in the ultrafiltration system into the front-end treatment system. After all the sewage is discharged, the drain valve is turned off. The backwashing valve and the backwashing pump are turned on sequentially to start 4-minute backwashing. After the backwashing, the backwashing pump, the backwashing valve, the blower, and the intake valve are turned off sequentially. Then the water inlet valve and the water inlet pump are turned on. When a water level in the ultrafiltration membrane pool reaches a designated water level and when the water overflows the ultrafiltration membrane, the water production valve and the water production pump are turned on sequentially to start a second-round water production. At this time, the membrane flux restores to 42.7 m3/h. The system has operated for 114 days with such a recycle, and is cleaned once a day. The effluent quality still meets the Class III standard of environmental quality standards for surface water, and the membrane flux maintains within 43.1±1.4 m3/h (designed flux is 50.0 m3/h). 
     Embodiment 3 
     An ultrafiltration system for advanced treatment of coal mine water as shown in  FIG. 1  includes an intermediate water pool, an ultrafiltration membrane pool  2 , an adjustment pool, a water production pool, and a water removal pool. The ultrafiltration membrane pool  2  is connected to the intermediate water pool  15  through a water inlet valve  3  and a water inlet pump  4 , connected to the water production pool  16  through a backwashing valve  11  and a backwashing pump  12 , and connected to the water removal pool  17  through a water production valve  5  and water production pump  6 . An overflow pipe  13  is disposed on a side wall at an upper part of the ultrafiltration membrane pool  2 . The overflow pipe  13  is connected to the adjustment pool  18 . The adjustment pool  18  is connected to the ultrafiltration membrane pool  2  through a drain valve  10  disposed at a bottom of a side surface of the ultrafiltration membrane pool. An ultrafiltration membrane assembly  1  (which is an assembly formed by the ceramic membrane) is disposed in the ultrafiltration membrane pool  2 . A cleaning device  7 —ultrasonic generator and a liquid level indicator  14  are mounted on a side wall of the ultrafiltration membrane pool  2 . An aeration tube is disposed in the ultrafiltration membrane pool below the ultrafiltration membrane assembly. The aeration tube is connected to a blower  9  through an intake valve  8 . A water production channel in the ceramic membrane assembly  1  is connected to the water production pool  16  through a pipe. 
     CODCr of the quality of mine water in mine #3 after coagulation-sedimentation is 27.9 mg/L, the content of ammonia-nitrogen is 1.03 mg/L, the turbidity is 3.38 NTU, and the content of petroleum-like substance is 0.06 mg/L. The water flows into the ultrafiltration system for filtration. The average aperture of the ceramic membrane is 200 nm. The frequency of the water production pump is 30 Hz. The initial membrane flux is 46.3 m3/h. After the filtration of the ultrafiltration system, most of suspensions and organisms including petroleum-like substances are removed. The CODCr of the effluent quality is reduced to 8.9 mg/L, the turbidity is reduced to 0.21 NTU, and the content of petroleum-like substance is reduced to 0.03 mg/L. After the system operates for 32 hours, the membrane flux is reduced to 35.0 m3/h. At this time, the ceramic membrane starts to be cleaned. 
     During cleaning, at first, the water production pump, the water production valve, the water inlet pump, and the water inlet valve are turned off sequentially. The ultrasonic cleaning device is turned on with a frequency of 40 MHz and a working current of 10 A. The ultrasonic cleaning device is turned off after 25-minute ultrasonication. The intake valve and the blower are turned on sequentially to start aeration, and the drain valve is turned on at the same time to discharge the sewage in the ultrafiltration system into the front-end treatment system. After all the sewage is discharged, the drain valve is turned off. The backwashing valve and the backwashing pump are turned on sequentially to start 4-minute backwashing. After the backwashing, the backwashing pump, the backwashing valve, the blower, and the intake valve are turned off sequentially. Then the water inlet valve and the water inlet pump are turned on. When a water level in the ultrafiltration membrane pool reaches a designated water level and when the water overflows the ultrafiltration membrane, the water production valve and the water production pump are turned on sequentially to start a second-round water production. At this time, the membrane flux restores to 45.9 m3/h. The system has operated for 139 days with such a recycle, and is cleaned once a day. The effluent quality still meets the Class III standard of environmental quality standards for surface water, and the membrane flux maintains within 46.1±1.1 m3/h (designed flux is 50.0 m3/h). 
     Embodiment 4 
     An ultrafiltration system for advanced treatment of coal mine water as shown in  FIG. 1  includes an intermediate water pool, an ultrafiltration membrane pool  2 , an adjustment pool, a water production pool, and a water removal pool. The ultrafiltration membrane pool  2  is connected to the intermediate water pool  15  through a water inlet valve  3  and a water inlet pump  4 , connected to the water production pool  16  through a backwashing valve  11  and a backwashing pump  12 , and connected to the water removal pool  17  through a water production valve  5  and water production pump  6 . An overflow pipe  13  is disposed on a side wall at an upper part of the ultrafiltration membrane pool  2 . The overflow pipe  13  is connected to the adjustment pool  18 . The adjustment pool  18  is connected to the ultrafiltration membrane pool  2  through a drain valve  10  disposed at a bottom of a side surface of the ultrafiltration membrane pool. An ultrafiltration membrane assembly  1  (which is an assembly formed by the ceramic membrane) is disposed in the ultrafiltration membrane pool  2 . A cleaning device  7 —ultrasonic generator and a liquid level indicator  14  are mounted on a side wall of the ultrafiltration membrane pool  2 . An aeration tube is disposed in the ultrafiltration membrane pool below the ultrafiltration membrane assembly. The aeration tube is connected to a blower  9  through an intake valve  8 . A water production channel in the ceramic membrane assembly  1  is connected to the water production pool  16  through a pipe. 
     CODCr of the quality of mine water in mine #4 after coagulation-sedimentation is 15.4 mg/L, the content of ammonia-nitrogen is 0.86 mg/L the turbidity is 1.49 NTU, and the content of petroleum-like substance is 0.05 mg/L. The water flows into the ultrafiltration system for filtration. The average aperture of the ceramic membrane is 100 nm. The frequency of the water production pump is 30 Hz. The initial membrane flux is 47.4 m3/h. After the filtration of the ultrafiltration system, most of suspensions and organisms including petroleum-like substances are removed. The CODCr of the effluent quality is reduced to 4.6 mg/L, the turbidity is reduced to 0.16 NTU, and the content of petroleum-like substance is reduced to 0.02 mg/L. After the system operates for 45 hours, the membrane flux is reduced to 35.0 m3/h. At this time, the ceramic membrane starts to be cleaned. 
     At first, the water production pump, the water production valve, the water inlet pump, and the water inlet valve are turned off sequentially. The ultrasonic cleaning device is turned on with a frequency of 40 MHz and a working current of 8 A. The ultrasonic cleaning device is turned off after 5-minute ultrasonication. The intake valve and the blower are turned on sequentially to start aeration, and the drain valve is turned on at the same time to discharge the sewage in the ultrafiltration system into the front-end treatment system. After all the sewage is discharged, the drain valve is turned off. The backwashing valve and the backwashing pump are turned on sequentially to start 4-minute backwashing. After the backwashing, the backwashing pump, the backwashing valve, the blower, and the intake valve are turned off sequentially. Then the water inlet valve and the water inlet pump are turned on. When a water level in the ultrafiltration membrane pool reaches a designated water level and when the water overflows the ultrafiltration membrane, the water production valve and the water production pump are turned on sequentially to start a second-round water production. At this time, the membrane flux restores to 46.7 m3/h. The system has operated for 198 days with such a recycle, and is cleaned once a day. The effluent quality still meets the Class III standard of environmental quality standards for surface water, and the membrane flux maintains within 47.2±1.3 m3/h (designed flux is 0.0 m3/h). 
     The quality of water of mines #1-4 that flows through the ultrafiltration system is measured. The results are shown in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Detection results of the effluent quality of mine water in each mine (mg/L) 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 Limit value  
                   
                   
                   
                   
               
               
                   
                   
                 of class  
                   
                   
                   
                   
               
               
                   
                   
                 III of 
                   
                   
                   
                   
               
               
                   
                   
                 surface  
                 Mine  
                 Mine  
                 Mine  
                 Mine  
               
               
                 No. 
                 Indicator 
                 water 
                 #1 
                 #2 
                 #3 
                 #4 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                  1 
                 pH 
                 6-9 
                 7.34 
                 7.94 
                 7.75 
                 7.66 
               
               
                   
                 (dimension- 
                   
                   
                   
                   
                   
               
               
                   
                 less) 
                   
                   
                   
                   
                   
               
               
                  2 
                 Dissolved  
                 5 
                 6.5 
                 7.1 
                 6.9 
                 8.2 
               
               
                   
                 oxygen 
                   
                   
                   
                   
                   
               
               
                  3 
                 Permanganate 
                 6 
                 0.85 
                 1.17 
                 1.28 
                 1.23 
               
               
                   
                 index 
                   
                   
                   
                   
                   
               
               
                  4 
                 Chemical  
                 20 
                 3.755 
                 11.36 
                 6.012 
                 3.010 
               
               
                   
                 Oxygen 
                   
                   
                   
                   
                   
               
               
                   
                 Demand  
                   
                   
                   
                   
                   
               
               
                   
                 COD Cr   
                   
                   
                   
                   
                   
               
               
                  5 
                 Biological  
                 4 
                 2.2 
                 3.1 
                 2.6 
                 1.8 
               
               
                   
                 Oxygen 
                   
                   
                   
                   
                   
               
               
                   
                 Demand for  
                   
                   
                   
                   
                   
               
               
                   
                 5 days 
                   
                   
                   
                   
                   
               
               
                   
                 BOD 5   
                   
                   
                   
                   
                   
               
               
                  6 
                 NH 3 -N  
                 1 
                 0.468 
                 0.030 
                 0.014 
                 0.066 
               
               
                   
                 (ammonia 
                   
                   
                   
                   
                   
               
               
                   
                 nitrogen) 
                   
                   
                   
                   
                   
               
               
                  7 
                 Total  
                 0.2 
                 0.011 
                 0.021 
                 0.005 
                 0.114 
               
               
                   
                 phosphorus 
                   
                   
                   
                   
                   
               
               
                  8 
                 Total  
                 1 
                 0.876 
                 0.895 
                 0.765 
                 0.785 
               
               
                   
                 nitrogen 
                   
                   
                   
                   
                   
               
               
                  9 
                 Fluoride 
                 1 
                 0.394 
                 0.437 
                 0.650 
                 0.593 
               
               
                 10 
                 Se 
                 0.01 
                 0.006 
                 0.006 
                 0.008 
                 0.009 
               
               
                 11 
                 As 
                 0.05 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                 12 
                 Hg 
                 0.0001 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                 13 
                 Cr (VI) 
                 0.05 
                 ND 
                 0.012 
                 0.021 
                 0.017 
               
               
                 14 
                 Cu 
                 1 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                 15 
                 Zn 
                 1 
                 0.036 
                 ND 
                 0.014 
                 HD 
               
               
                 16 
                 Pb 
                 0.05 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                 17 
                 Cd 
                 0.005 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                 18 
                 Cyanide 
                 0.02 
                 0.005 
                 0.005 
                 0.011 
                 0.005 
               
               
                 19 
                 Volatile  
                 0.005 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                   
                 phenols 
                   
                   
                   
                   
                   
               
               
                 20 
                 Petroleum- 
                 0.05 
                 0.02 
                 ND 
                 ND 
                 0.02 
               
               
                   
                 like 
                   
                   
                   
                   
                   
               
               
                 21 
                 Anionic  
                 0.2 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                   
                 surfactant 
                   
                   
                   
                   
                   
               
               
                 22 
                 Sulfide 
                 0.2 
                 ND 
                 ND 
                 ND 
                 ND 
               
               
                 22 
                 Fecal  
                 10000 
                 70 
                 31 
                 35 
                 46 
               
               
                   
                 coliforms 
                   
                   
                   
                   
                   
               
               
                   
                 (number/L)