Zero-valent iron polyculture denitrification coupling modified charcoal two-stage PRB underground water denitrification method and reactor

Abstract

The invention discloses a zero-valent iron polyculture denitrification coupling modified charcoal two-stage PRB underground water denitrification method and a reactor. The method disclosed by the invention comprises the following steps: firstly, treating groundwater containing NO3 <->-N by a primary PRB reactor filled with Fe<0> (iron shavings) filler wrapped by a polyethylene mesh bag, and carrying out denitrification by virtue of autotrophic and heterotrophic coexisting polyculture denitrifying bacteria so as to reduce most of NO3 <->-N into N2 to be removed; and then adsorbing and removing the residual NO3 <->-N through a second-stage PRB reactor provided with a modified biochar filler. According to the method, the carbon source and Fe < 0 > are added to form a polyculture denitrification nitrogen removal effect, so that the problems that zero-valent iron is easy to passivate and the growth rate of autotrophic denitrifying bacteria is low can be solved, and the method is easy to operate and manage and relatively low in operation cost.

Description

technical field [0001] The invention relates to a zero-valent iron polyculture denitrification coupled modified biochar two-stage PRB groundwater denitrification method and a reactor, belonging to the technical field of groundwater restoration. Background technique [0002] Groundwater is an important part of water resources. Due to its stable water quantity and excellent water quality, it is an important water source for agricultural irrigation, industrial production and urban life. However, industrial wastewater discharge and excessive use of agricultural chemical fertilizers and pesticides have caused widespread nitrate nitrogen pollution in groundwater. Drinking groundwater with excessive nitrate content can lead to diseases such as methemoglobinemia, liver cancer, and gastric cancer, causing great ecological environment and health risks. How to effectively reduce NO in groundwater 3 - -N, become an urgent problem to be solved at present. [0003] press NO 3 - Depe...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is: the use of zero-valent iron in the autotrophic denitrification of groundwater as the electron donor has a tendency of passivation and agglomeration and is easy to harden, hindering the reaction process, resulting in a decrease in denitrification efficiency; The growth rate of denitrifying bacteria is slow, and it is greatly affected by environmental factors such as water temperature and pH, high cost, low efficiency, and incomplete nitrogen removal.

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