Stacked circulatable microbial electrochemical reactor and degradation method of petroleum hydrocarbon contaminated soil

A stacked microbial electrochemical reactor, comprising:

• a reactor body, comprising a reactor housing, and an inner bottom of the reactor housing being in a slope shape;
• a water circulation system, located outside the reactor body;
• an electrode group, being partially inserted into soil and located inside the reactor housing, and the electrode group being laid perpendicularly onto the inner bottom, the electrode group comprising a plurality of electrode couples inserted into the soil which are placed in parallel to each other, wherein a distance between adjacent electrode couples in the plurality of electrode couples is about 15 cm to about 25 cm;
• and
• a DC power supply, connected with the electrode group via a wire;
• wherein the plurality of electrode couples each comprise a working electrode and a counter electrode arranged in parallel to each other;
• the working electrode comprises two sheets of steel mesh arranged in parallel to each other and a mixture of biochar particles and soil particles filled between the two sheets of steel mesh, a distance between the two sheets of steel mesh is about 4 cm to about 6 cm, wherein the soil particles are farmland soil particles;
• the counter electrode is a conductive steel mesh;
• a distance between the counter electrode and a steel mesh in the working electrode which is adjacent to the counter electrode is about 4 cm to about 6 cm in each of the plurality of electrode couples;
• a water outlet is provided at a bottom of the reactor housing at a first side of the reactor housing;
• the water circulation system comprises a water storing and regulating tank located at a top of the reactor housing, at a second side of the reactor housing, the second side of the reactor housing provided with the water storing and regulating tank is opposite to the first side of the reactor housing provided with the water outlet, wherein the water outlet is in communication with the water storing and regulating tank via a water circulating pipe located outside the reactor housing.