The Basic Research On Using Hat Creek Coal As The Solid-phase Organic Carbon-source To Remove The Nitrate From The Water

With the development of industry and agriculture, nitrate pollution in the groundwater become more and more seriously. At present, the drinking water in many countries has been polluted by nitrate. Comcern for possible health consequences has led to a desire for remedition of the contaminated groundwater. But all the current technologies to remove nitrate from groundwater have disadvantages, especially when be used for the purpose of in situ remediation.In this experiment, coal is used as the carbon-souece and the bio-carrier to remove the nitrate from the groundwater. Different conditions such as the concentration of the carbon-source, the flow rate, the ratio of carbon/hydrogen, and the bio-carrier are used in the experiment, meanwhile, the ceramisite is used as comparision in it. Studied by experiment, we draw conclusions that: (1) When the conditions like flow rate and so on are the same, the removal rate of the nitrate on the condition that the concentration of the carbon-source is 150mg/L is higher than it on the conditon that the concentration of the carbon-source is 100mg/L and 50mg/L. (2)when the flow rate is decreased to 200μl/min, the removal rate of the nitrate is higher than it on the condition that the flow rate is 625μl/min. (3)when the other conditions are the same, the removal rate of the nitrate in the high ratio of carbon/hydrogen condition is correspondingly high. when the concentration of the carbon-source is 50mg/L, the removal rate of the nitrate on the conditon that using filter paper as bio-carrier is about 95%, and is higher than it on the conditon that using coal as bio-carrier. Meanwhile, the removal rate of the nitrate on the condition that using ceramisite as bio-carrier is the lowest and about 50%. (4)With the same other conditions, when the flow rate is 625μl/min, the removal rate of the nitrate on two conditions that using ceramisite and coal as bio-carrier is almost the same. However, when the flow rate are 300μl/min and 200μl/min, the better removal rate of the nitrate is obtained as the coal is used for bio-carrier. (5)When the concentration of the carbon-source is 0mg/L, after the coal is changed through some certain methods, the removal rate of the nitrate on the condition that using the modified coal as bio-carrier is comparatively high and up to 60%.Coal is half-inert solid materials,therefore we can solve the problem of the carbon-source lack during the denitrification process based on the double-roles of the organic carbon-source and the bio-carrier. It is important that the problems of external carbon-source and secondary pollution can be sovled.