Soil biometric engineering technology.

As far as soil is involved, there are three kinds of biometric engineering techniques in practice: 1, in-place treatment This method is to directly use biometric technology in contaminated areas, there is no need to dig out and transport soil.
are generally treated with indigenous microorganisms, and sometimes domesticated and cultured microorganisms are added to speed up treatment.
Need to be reinforced by a variety of engineering measures, such as drilling in contaminated areas, with wells divided into two groups, one for injecting water wells to inject inoculated microorganisms, water, nutrients and electronic subjects into the soil, and the other for pumping wells, which facilitate the distribution of microorganisms and the transport of nutrients and other substances by pumping groundwater from the ground to facilitate the transport of substances such as microorganisms (figure 11-3).
equipment that is often required are pumps and air compressors.
systems, bioprocessing devices using activated sludge methods are also built on the ground to treat the extracted groundwater and then inject it underground.
The process is a simpler treatment and less costly, although due to the use of less engineering reinforcement measures, treatment time will increase, and in the long-term bio-rehabilitation process, pollutants may spread further into deep soil and groundwater, and therefore suitable for the treatment of long-term pollution, the situation has been basically stable areas or contaminated areas.
bioventing is a way to repair in-place organisms.
in these contaminated areas, organic pollutants in the soil reduce the concentration of oxygen in the soil and increase the concentration of carbon dioxide, thus creating conditions that inhibit further biodegradation of the pollutants.
, in order to improve the degradation of pollutants in the soil, carbon dioxide and oxygen supplements need to be emitted from the soil, and bioventilation systems are designed to change the composition of gases in the soil.
bioventilation methods have now been successfully applied to biometric treatment in a variety of soils, known as "bioventilation reactors", mainly through vacuum or pressurized soil aeration, resulting in changes in the composition of gases in the soil.
bioventilation processes are commonly used for biomediation of mildly contaminated soil caused by leaks from underground storage tanks.
the successful application of bioventilated methods at military bases, the U.S. Air Force has listed bioventilated methods as an essential method for dealing with soil contaminated with jet fuel.
2. Excavation stacking, also known as treatment beds or reserve beds, is the excavation of contaminated soil from contaminated areas to prevent the spread of pollutants to groundwater or the wider area, transporting soil to a site that has been prepared for various projects (including lining, ventilation ducts, etc.) to form rising slopes, where biometric treatment is carried out and the treated soil is returned to its original location (Figure 11-5).
complex systems can be piped and enclosed with greenhouses, and simple systems can be stacked in the open air.
sometimes the contaminated soil is excavated and transported to a site for temporary stacking, and then some engineering preparation is carried out in the contaminated site before the contaminated soil is transported back to the site for disposal.
water seeping out of the system is collected, re-sprayed or treated separately.
Other engineering measures include the replenishment of soil with organic block materials (e.g. bark or wood flakes), such as a treatment bed made of 35m3 cork bark and 70m3 contaminated soil in a soil contaminated with chlorpyrophenol, and the addition of nutrients, which, after three months of treatment, reduced chlorpyrol concentrations from 212 mg/L to 30 mg/L.
addition of these materials, on the one hand, can improve the soil structure, maintain humidity, buffer temperature changes, on the other hand, can also provide some high-efficiency degradation bacteria such as geotrichumcandidum to provide a suitable growth base.
Inoculation of sodium PCP degradation bacteria in bark or wrapped in polypolymer materials enhances the degradation of sodium PCP in microorganisms and increases their resistance to contaminant toxicity.
advantage of this technique is that it can limit the diffusion and migration of pollutants and reduce the range of pollution at the beginning of soil contamination.
But the cost of digging and transporting is significantly higher than in-place treatment methods, and further exposure of pollutants may be caused during transport, as well as damage to the soil ecological structure of the site as a result of excavation.
3, reactor treatment This method is to excavate the contaminated soil, mixed with water, inoculated microorganism reactor treatment, the process is similar to the sewage biological treatment method.
after the soil has been treated and separated from the water, it is dehydrated and returned to its original place (Figures 11-6).
discharge or feed directly into the sewage treatment plant for continued treatment, depending on the water quality.
reactors include not only a variety of small reactors that can be dragged, but also large facilities similar to stable ponds and sewage treatment plants.
in some cases, only aeration machinery and mixing equipment need to be assembled in an existing stable pond for biometric treatment.
high concentration solid mud reactor can be used to directly deal with contaminated soil, the typical way is liquid solid contact type.
The method is run in batches, mixing soil, water, nutrition, bacteria, surfactants and other substances in the first unit, and finally forming a mixed phase containing 20% to 25% of the soil, and then entering the second unit for preliminary treatment, completing most of the biodegradation, and finally in the third unit for deep treatment.
on-site application show that liquid-solid contact reactors can successfully handle soil and sediments with toxic and harmful organic pollutants exceeding 1% of the total organic matter concentration.
the size of the reactor ranged from 100m3/d to 250m3/d, and was related to the concentration of pollutants and organic matter in the soil.
the first two treatment methods, one of the main features of reactor treatment is that the water phase is the treatment medium, while the first two treatment methods are soil as the treatment medium.
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