Redox technology for soil remediation

Chemical oxidation reduction technology is by adding chemical oxidant (Fenton reagent, sodium persulfate, hydrogen peroxide, Potassium Permanganate, etc.) or reducing agent to the soil for remediation. The commonly used reducing agents are iron containing reducing agents (zero valent iron, nanoscale zero valent iron and ferrous reducing agents), reductive sulfides (H2S, FeSx, thiosulfate, etc.) and some organic compounds with reduced activity. In general, chemical oxidation technology is to add chemical oxidants to contaminated soil treatment, and rely on the oxidation capacity of chemical oxidants to decompose and destroy the structure of pollutants in the polluted environment, so that the pollutants can be degraded or converted into low toxic and low mobility substances.

At present, the use of chemical reduction method to restore the sensitive organic pollutants is the focus of current research. The use of sodium persulfate chemical oxidation technology as oxidation in the soil remediation process, the concentration of pollutants and pollutant distribution, pollution site actual situation determines the amount of sodium persulfate, and effect of reducing bacteria and its environment and soil remediation of sulfate, soil remediation can realize the contaminated site, bring good restoration effect and environmental benefit.

New catalysts and surface activation technologies need to be developed. By using chemical reduction method, chromium contaminated groundwater system in soil remediation process, the solubility and migration of chromium six strong reduction into trivalent chromium hydroxide stable, so as to achieve the purpose of pollution control and remediation of chromium. At the same time, the reductive dechlorination of nanoscale iron powders by reducing agents has been accepted and applied to the remediation of soils and groundwater. However, there are still some problems such as passivation of iron surface activity, adsorption by soil and polymerization failure due to the application of zero valent iron to dechlorination and degradation of chlorinated organic compounds.

评论

发表评论

此博客中的热门博文

Treatment of soft soil foundation by high pressure injection method

图片
The method is to use a drilling machine to inject a nozzle pipe into the soil layer. The slurry or water is ejected from the nozzle at high pressure to form a jet stream to destroy the soil layer. When the energy of high speed jet fluctuation was shaped, the dynamic pressure is greater than the strength of soil structure, soil particles stripping down from soil, part of the particles spread out with slurry or water, other soil particles mixed with slurry under the jet impact force, centrifugal force and gravity force, re arrange regularly according to the size of a certain percentage of soil and quality. After the slurry solidified, forming a solidified body in soil, can improve the bearing capacity of the foundation, reduce the settlement, can also improve the effecf of supporting and anti-seepage. It is suitable for foundations of silt, cohesive soil, loess, sandy soil, artificial fill and crushed stone soil. PARFECT soil stabilization equipment can transfer the soil binder t
阅读全文

What is soil remediation

图片
Contaminated soil remediation refers to physically, chemically and biologically transfer, absorb, degrade and transform pollutants in soil, which concentration can be reduced to acceptable levels, or turn toxic and harmful pollutants into harmless substances. Fundamentally, the technical principles for contaminated soil remediation may include: 1.Change the existing form or the mode of combining with the soil of pollutants in soil, reduce the mobility and bioavailability in the environment. 2.Reduce the concentration of harmful substances in the soil. The United States invested nearly $100 billion in contaminated soil restoration in 1990s. The theory and technology of contaminated soil remediation have become the frontiers of environmental science and technology research. The process of soil restoration is quite long, the need to solve the problem of soil pollution, it needs scientists of different disciplines, such as soil science, agronomy, ecology, biogeochemistry, marine scien
阅读全文

Traditional sludge disposal methods

图片
Most of the mud from the small ponds or river in the countryside is directly backfilled to farmlands nearby, which is the most common sludge disposal method used in rural areas in the past few decades. This sludge disposal method has many disadvantages: Some of the sludge has heavy metal pollution, or contains a lot of household waste and construction waste, and farmers refuse to accept it; After returning to the fields, it takes several years to dry. After airing, it needs second treatments. During this period, the fields can not be planted, and the government should pay farmers 1 ~ 2 years’ compensation fees in the form of rent. Cleaned out sludge of coastal rivers, lakes, ponds, and a considerable part of ithave been dumped at sea. In this way, the freight is expensive and tidal, and mud may be washed back inland. In Ningbo, China, the sludge being cleared will be dumped into sea which cost 176 RMB per cubic meter. The river silt in urban areas are often polluted, will usually
阅读全文