What Are the Best Methods for Irrigation Repair?
Contaminated site repair technology can be divided into in situ repair technology and ectopic repair technology according to the repair method. Ex situ repair refers to excavating the contaminated soil from the location where the pollution occurred, and then treating it within the original site or after transportation Technology. [1]
- Ex-situ bioremediation mainly includes on-site treatment, prefabricated bed method, stacking treatment method, bioreactor and anaerobic biological treatment method.
- Prefabricated bed
- The prefabricated bed composting process has proven to be one of the most effective methods for remediation of petroleum-contaminated soil. The principle is that after adding a leavening agent to the polluted soil, it is piled into a bar or a cylinder on a prefabricated bed. It is artificially supplemented with nutrients and air and moderately stirred to ensure its aerobic repair conditions to achieve the degradation of organic pollutants .
- The prefabricated bed method is a form of off-site processing, which requires a lot of engineering and certain containers. The contaminated soil was moved to a special prefabricated bed. The bottom of the prefabricated bed is packed with a material with a relatively high density and low permeability, such as polyethylene or Mongolian soil, and then maintained the best degradation state through fertilization, irrigation, and pH control. Sometimes, some microorganisms need to be added And surface penetrant. The design of the prefabricated bed can minimize the migration of pollutants because it has a filtrate absorption and controlled discharge system. The design of the prefabricated bed should meet the requirements for the treatment of petroleum pollutants and avoid the spillage of pollutants. Generally, the prefabricated bed does not have a leachate collection system and an spill control system. [2]
- Soil physics
- Soil is a dispersed system composed of three phases: solid, liquid and gas. The composition of the three-phase matter interacts with each other to form various physical properties. These differences in physical properties lead to differences in soil environmental functions. [4]
- Soil colloids
- Soil colloid refers to fine solid particles with colloidal properties and a particle size of less than 0.001mm and 0.002mm. It is composed of mineral particles (aluminosilicates), humic aluminum, iron, manganese, and silicon water oxides. . The most important properties of soil colloids are fully charged and have a significant impact on the physical and chemical properties of the soil. [4]
- Soil chemical equilibrium
- Soil is a complex chemical system. The behavior of pollutants entering the soil is directly controlled by the soil chemical balance system. The balance between soil chemical elements or compounds, that is, dissolution and precipitation is a conditional, temporary dynamic balance. One can take advantage of the chemical equilibrium movement characteristics of various compounds in the soil and the changes in the equilibrium conditions, and use the transformation of balance to increase the quantity and effectiveness of soil nutrient release, and strengthen phytoremediation. In addition to the effects of element and compound concentrations, ambient temperature, and pressure, the chemical equilibrium system in the soil is also controlled by the properties of the soil colloid, pH, and Eh. Generally, the chemical equilibrium of ions in the soil solution and the ion adsorption between the solution and the colloid are difficult to be completely separated. [4]
- Soil complex-chelate
- As a complex chemical system, soil contains organic and inorganic ligands and a variety of metal center ions that form a chelate complex. Soil complexation and chelation can increase the activity of metal ions, increase the stability of soil structure, and improve soil physical and chemical properties and biological processes. [4]