Soil Treatment Technologies Research Articles

Review on biopolymer-based soil treatment (BPST) technology in geotechnical engineering practices

Abstract Various applications of biopolymer-based soil treatment (BPST) in geotechnical engineering have been implemented in recent years, including dust control, soil strengthening and erosion control. Despite BPST methods can ensure the effectiveness of engineering while meeting environmental protection requirements, BPST technology requires further validation in terms of site applicability, durability, and economic feasibility. This study aims to provide a state-of-the-art review and future prospective of BPST. Current biopolymer types, engineered and assessed in laboratory scales, are described along with site implementation attempts. The effect of biopolymers on soil behavior is reviewed with regard to geotechnical engineering application and practice, including soil consistency limits, strength parameters, hydraulic conductivity, soil-water characteristics, and erosion control. The economic feasibility and sustainability of BPST application in ground improvement and earth stabilization practices is discussed. This review postulates biopolymers to be a promising new, environmentally friendly ground improvement material for geotechnical and construction engineering practice.

Efficiency of the Erosion Protection Methods Involving Biologizing Agriculture in the Steppe and Forest-steppe Areas of Cultivated Land in Siberia

The research has been carried in the steppe zone of the Minusinsk Hollow and forest-steppe of the Altai Ob Region. The paper presents the results of studying the efficiency of erosion protection methods using biologizing agriculture and technologies of soil treatment. The authors have analyzed long-term data provided by numerous research institutions located in different agro-ecological conditions in the forest-steppe and steppe areas of cultivated land. Long-term field experiments carried out to study and make a comparative analysis of soil treatment technologies in green manure fallows have shown different soil conservation efficiencies in various soil climatic conditions of the Middle Siberia. In the steppe area of cultivated land, in the case of erosion-hazard soil, it is worth using stubble mulch tillage treatment, which allows preserving plant residues on the soil surface in order to increase the soil protection efficiency of green manure fallows. After this type of treatment no removal of fine soil by wind was observed on black soil, while in the case of tillage the soil removal amounts to 2,5 - 8,1 tons per hectare per year. In the steppe area on slope lands, winter stubble residues allow one to completely prevent the soil wash out in spring. The number of days with dust storms after the Virgin Lands Campaign in Khakassia in 1961 – 1965 amounted to 5 – 13. At present, with the decreased areas of strongly eroded plough land and increased volume of fallow land, dust storms do not occur. A fallow grown crop (summer planted oats) and, on the slope lands, mulching with rape completely prevented the spring wash out. The grain yield from a hectare of the crop rotation area in the case of sweet clover tillage and stubble mulch plowing was almost the same: 1,64 and 1,76 tons per hectare, respectively. Treatment of the deposit land followed by spraying with Tornado herbicide in August reduces soil erosion 2.2 times compared to its introduction in June.

Research on Deformation Characteristics of New Breakwater Structure

With the increasingly stringent of environmental protection requirements of the China, there is fewer and fewer land reclamation projects, so the related research on dredged soil treatment technology has become a hot spot. A new type of mud-sand interbedded structure is put forward in this paper. The dredged soil is filled in membrane bag and interbedded with sandy membrane bag, which gradually forms a stable new seawall core structure. From the finite element simulation results, it is known that the maximum displacement of mud-sand interbedded structure is 2.73 m. After the calculation, the top surface of the mud-sand interbedded structure is 1.9 m from the back surface, and the compression of the mud-sand interbedded structure is mainly occurs in the middle of the body, the bottom and top are less compressed. The design and construction of the breakwater meets the engineering requirements, and it is a feasible and fast breakwater technology on soft soil foundation.

Nitrogen in Chernozems under Traditional and Direct Seeding Cropping Systems: A Review

The functional role of nitrogen in the formation of crop yield on chernozems under conditions of traditional and direct seeding (DS) cropping systems is considered. In the course of long-term experimental studies of DS cropping system on chernozems, considerable experience has been gained and has found efficient practical application. It is shown that the effect of nitrogen as the most important element in the composition of humic substances influencing the fertility of chernozems depends on the variability of environmental factors, the forms and rates of nitrogen fertilizers, the rotation systems, and the soil treatment technologies. The DS cropping system has been tested for 4–10 years on experimental fields of the Stavropol Agricultural Research Institute and in a number of farms in Stavropol region. The obtained data on the yields of cereal crops and the application of fertilizers attest to the importance of the formation of a mulching layer of plant residues on the surface of ordinary and southern chernozems in the DS systems. This layer contributes to a gradual accumulation of nitrogen, protects the soil from erosion, and increases the number and mass of earthworms. Nitrogen in the DS cropping systems on chernozems in Russia is characterized by the high mobility and the capacity for considerable transformation. In this context, further investigations and special experiments are necessary to gain better knowledge of the behavior of nitrogen in different cropping systems. In particular, the relationships between nitrogen fluxes, agrophysical soil properties (aggregate-size distribution at the macro and micro levels), and specificity of the organic matter in different subtypes of chernozems under different cultivation technologies have to be clarified. In general, the role of DS cropping systems in farming practices has become more significant in the recent years; application of the DS cropping system is considered a positive factor in maintaining and restoring soil fertility.

A review of life cycle greenhouse gas (GHG) emissions of commonly used ex-situ soil treatment technologies

Abstract GHG emissions are important footprints because of increasing concern over climate change. Remediation methods produces GHGs in varying quantities based on which activities are involved through its entire life cycle and which contaminants are present, often because some contaminants are more difficult to remove from soil than others. Accounting for emissions from all phases of the project requires a life cycle assessment (LCA) approach. LCA can help in choosing the best available technology to reduce the environmental burden of the remediation technology or to improve the sustainability of the technology by implementing systematic approaches to ensure that future developments are optimized for environmental performance throughout the life cycle. The primary objective of this paper is to review existing LCA studies that report GHG emissions (CO2-eq) or Global warming potential (GWP) from six ex-situ soil remediation technologies (ESRTs), including excavation and disposal, ex-situ thermal desorption, ex-situ soil vapor extraction, ex-situ bioremediation, excavation and incineration, and soil washing, and present the variability in GHG/GWP results and how this data can help in selecting an ex-situ soil remediation technology with a lower global warming potential. A second objective of this study is to compare the GWP levels of ex-situ remediation to the GWP levels of typical in situ remediation methods. Our results showed a large variation in GHG emissions of treated soil from six ESRTs varying from 3.1 × 10−7 t to 8.2 t CO2-eq/m3. Incineration had the highest mean GHG emissions (0.7 t CO2-eq/m3) and thermal desorption the lowest (0.07 t CO2-eq/m3). It was also found that there was a large variation range of GHG emissions from the ex-situ excavation and disposal method soil treatment technologies, varying from 3.1 × 10−7 t to 8.2 t CO2-eq/m3 of treated soil. This knowledge provides opportunities to increase sustainability of soil remediation throughout the investigation, design, construction, operation, and monitoring phases of site remediation regardless of the selected cleanup remedy. This shows data on LCA GHGs are useful to assess the impact of different scenarios and management practices on ESRTs.

Micelles as Soil and Water Decontamination Agents.

Contaminated soil and water pose a serious threat to human health and ecosystem. For the treatment of industrial effluents or minimizing their detrimental effects, preventive and remedial approaches must be adopted prior to the occurrence of any severe environmental, health, or safety hazard. Conventional treatment methods of wastewater are insufficient, complicated, and expensive. Therefore, a method that could use environmentally friendly surfactants for the simultaneous removal of both organic and inorganic contaminants from wastewater is deemed a smart approach. Surfactants containing potential donor ligands can coordinate with metal ions, and thus such compounds can be used for the removal of toxic metals and organometallic compounds from aqueous systems. Surfactants form host-guest complexes with the hydrophobic contaminants of water and soil by a mechanism involving the encapsulation of hydrophobes into the self-assembled aggregates (micelles) of surfactants. However, because undefined amounts of surfactants may be released into the aqueous systems, attention must be paid to their own environmental risks as well. Moreover, surfactant remediation methods must be carefully analyzed in the laboratory before field implementation. The use of biosurfactants is the best choice for the removal of water toxins as such surfactants are associated with the characteristics of biodegradability, versatility, recovery, and reuse. This Review is focused on the currently employed surfactant-based soil and wastewater treatment technologies owing to their critical role in the implementation of certain solutions for controlling pollution level, which is necessary to protect human health and ensure the quality standard of the aquatic environment.

A CASE STUDY ON SOIL IMPROVEMENT WITH DEEP SOIL MIXING APPLICATION

Soil improvement is defined as the improvement of the some soil parameters by using different methods when the soil properties are insufficient to prevent static and dynamic loads. The Deep Soil Mixing (DSM) is an in situ soil treatment technology whereby the soil is blended with cementitious and/or other materials. The method has gained its popularity after 1990’s in the world and last ten years in Turkey. In this study, a case study on soil improvement with deep soil mixing application in Eskisehir, Turkey is presented. The application procedure was created according to steps of usual geotechnical projects. Firstly, soil investigation was done and soil parameters were defined. And then, bearing capacity of deep soil mixing columns was calculated and modelled by “All Pile” software. After the site application, core samples were taken and the load test was applied to the core samples. Finally, deep soil mixing is becoming a popular as a soil improvement method and gives succeeding results.

Microbiological soil treatment technology using natural biocenosis

The paper discusses the use of different biocenosis to clean soil from oil pollution. Indicated that the use of artificial biocenosis expensive and not always effective. It is shown that the use of natural ecological communities, for example, in the form of activated sludge wastewater treatment plants were selected on the oil refineries are much cheaper and as effective as the action of biological products, which are based on artificial biocenosis.

Potential application of a biosurfactant in phytoremediation technology for treatment of gasoline-contaminated soil

Biosurfactants are amphiphilic compounds excreted extracellularly that contain hydrophobic and hydrophilic moieties, allowing them to accumulate between the fluid phases on an organism and thus reduce the surface and interfacial tension. The objectives of this study were to evaluate the potential application of a biosurfactant to the phytoremediation of gasoline-contaminated soil and compare it to other additives such as hydrocarbon degrading bacteria, sodium dodecyl sulphate (SDS) and bacterial culture supernatant. The results showed that the biosurfactant removed a significant amount (up to 93.5%) of the total petroleum hydrocarbons (TPH) compared with the other additives that removed only 85.4% (bacteria), 70.3% (culture supernatant) and 86.3% (SDS). Kinetic analysis showed that the phytoremediation of gasoline-contaminated soils by the biosurfactant fitted pseudo-second-order kinetics with a coefficient of determination (R2) of 0.9318 and a second-order rate constant (k2) of 0.0032 (g TPH/kg plant d). Thus, biosurfactants have strong potential as supporting biocatalysts to increase the performance of phytoremediation technology for soil treatment.

Brownfield Sites Remediation Technology Overview, Trends, and Opportunities in China

Over decades of economic development, China's industrialization has led to significant environmental issues due to unregulated discharges into air, water, and soil. As cities continue to expand (i.e., urbanization trend) and awareness/concerns about environmental pollution rises, many industrial facilities along the edge of or within the city boundaries have been relocated or closed. This urbanization trend leaves behind idled and abandoned land that is contaminated from the former industrial activities and unregulated discharges. China released its first nationwide soil quality survey in April 2014, and the survey suggests that soil conditions in China represent a significant challenge. China has encouraged local engineering firms to demonstrate soil treatment technologies through pilot‐scale studies, but the outcomes of many demonstrations have not been promising due to the lack of remediation experience and underdeveloped technical guidelines that are needed to guide the remediation processes. During the past decade, some local soil remediation experience has been established, but it is limited for certain technologies that address their primary contaminants of concern: heavy metals and persistent organic pollutants. In 2014, national technical guidelines were published regarding environmental investigation, risk assessment, monitoring, and remediation; however, regulations and funding systems are still underdeveloped. Thus, the remediation processes that should maximize economic and environmental benefits are not streamlined. This article provides an overview of the latest regulatory developments, remediation technologies applied, technology trends, and market opportunities in China. The provided information aims to allow international remediation practitioners to better understand and appreciate this unique and emerging remediation market, which is growing fast, and to highlight the importance of developing a sustainable model that not only provides for cleanup of the environment but also supports economic development. ©2015 Wiley Periodicals, Inc.

Potential of activated carbon to recover randomly-methylated-β-cyclodextrin solution from washing water originating from in situ soil flushing

Despite the overall high efficacy of cyclodextrins to accelerate the treatment of soil aquifer remediation by in-situ soil flushing, the use in practice remains limited because of the high costs of cyclodextrin and high concentrations needed to significantly reduce the treatment time. The current study tested the potential of activated carbon to treat washing water originating from soil flushing in order to selectively separate hydrocarbon contaminants from washing water containing cyclodextrin and subsequently reuse the cyclodextrin solution for reinfiltration. A high recovery of the cyclodextrin from the washing water would reduce the costs and would make the technique economically feasible for soil remediation. This study aimed to investigate whether cyclodextrin can pass through the activated carbon filter without reducing the cyclodextrin concentration when the contaminated washing water is treated and whether the presence of cyclodextrin negatively affects the purification potential of activated carbon to remove the organic pollutants from the pumped soil water. Lab-scale column experiments showed that with the appropriate activated carbon 100% of cyclodextrin (randomly-methylated-β-cyclodextrin) can be recovered from the washing water and that the effect on the efficiency of activated carbon to remove the hydrocarbon contaminants remains limited. These results show that additional field tests are useful to make in-situ soil flushing with cyclodextrin both a technical and an economical interesting technique. These results might stimulate the application of cyclodextrin in soil treatment technology.

Ex situ remediation of polluted soils by absorptive polymers, and a comparison of slurry and two-phase partitioning bioreactors for ultimate contaminant degradation

The present study has provided a comparison between a conventional ex situ method for the treatment of contaminated soil, a soil slurry bioreactor, with a novel technology in which a contaminant is rapidly and effectively removed from the soil by means of absorptive polymer beads, which are then added to a two-phase partitioning bioreactor (TPPB) for biodegradation of the target molecule. 4-nitrophenol (4NP) was selected as a model contaminant, being representative of a large class of xenobiotics, and the DuPont thermoplastic Hytrel™ 8206 was utilized for its extraction from soil over ranges of soil contamination level, soil moisture content, and polymer:soil ratios. Since the polymers were able to rapidly (up to 77% and 85% in 4 and 24h respectively) and selectively remove the contaminant, the soil retained its nutrient and microflora content, which is in contrast to soil washing which can remove these valuable soil resources. After 4h of reaction time, the TPPB system demonstrated removal efficiency four times higher (77% vs 20%) than the slurry system, with expected concomitant savings in time and energy. A volumetric removal rate of 75mg4NPh−1L−1 was obtained in the TPPB, significantly greater than the value of 1.7 obtained in the slurry bioreactor. The polymers were readily regenerated for subsequent reuse, demonstrating the versatility of the polymer-based soil treatment technology.

Review of soft soils stabilization by grouting and injection methods with different chemical binders

Soil stabilization has become one of the useful solutions to treat the soft soils to achieve the required engineering properties and specification so that structures can be placed safely without undergoing large settlements. Soil stabilization by admixture was developed in Japan during 1970s and 1980s. The treated soil has greater strength, reduced compressibility and lower hydraulic conductivity than the original soil. The use of admixture such as lime, cement, oils and bitumen is one of oldest and most widespread method for improving soil. When mixed with soil, it forms a material called soil-cement. The original technique known internationally as the deep mixing method (DMM) was developed simultaneously in Sweden and Japan in the mid-1970s. It is an in-situ soil treatment technology whereby the soil is blended with cementitious and/or other materials. Jet grouting is suitable to be used as the injection method for the DMM. It utilizes a fluid jet (air, water and/or grout) to erode and mix the in-situ soft or loose soils with grout. The grouting method is one of the ground improvement methods suitable for the soft soil. Chemical stabilization is the effective method to improve the soil properties by mixing additives to soils. Usually the additives are cement, lime, fly ash and bituminous material. The chemicals usually used are sodium silicate, acrylamide, N-methylolacrylamide, polyurethane epoxy resins, aminoplasts, phenoplasts, lignosulfonates, among others. The choice of a particular chemical for soil stabilization will depend upon many factors like, purpose, soil strength desired, toxicity, rheology among others. Key words: Injection, jet grouting, chemical grouting, deep mixing method.

Review of Contaminated Sites Remediation Technology

The contaminated site remediation is an important content of site management. Plans for the introduction of measures and requirements to prevent and remediate soil contamination, particularly through the development of inventories of contaminated sites and the definition of targets for prioritization of remediation actions, are expected to have important consequences for site management practice and national site policies. Nowadays contaminated soil and groundwater treatment technologies can be sorted as three categories, that is bioremediation, chemical treatment and physical treatment. Biodegradation generally refers to the breakdown of organic compounds by living organism eventually resulting in the formation of carbon dioxide and water or methane. Chemical remediation is a kind of method that chemical reagent, chemical reaction and chemistry principles are used to reduce the mobility, organisms use ratio of heavy metals and decrease the heavy metals in the soil so as to remediate and repair the soil. Physical treatments in the remediation of contaminated site contains revising methods, capping methods, stabilization methods, electrokinetic methods and so on.

Key Construction Technology for Highway on Soft Foundation

In recent years, a lot of research practices have been done on improving the quality of subgrade construction and solving the differential settlement of subgrade. Therefore, key construction technology for highway on soft foundation is very important. This paper analysis common engineering problems on soft foundation and the development status for soft soil treatment technology, then build up the technology trends on it.

History and Current Situation of Night Soil Treatment Systems and Decentralized Wastewater Treatment Systems in Japan

In Japan, night soil, or black water, was formerly used as fertilizer for agriculture. However, during the rapid economic growth that took place after 1960, chemical fertilizers began to be adopted for agriculture and night soil was almost abandoned. How to treat the excess of night soil then became a big challenge to tackle. From that time a variety of night soil treatment technologies have been developed and the Japanese government has actively promoted the construction of night soil treatment facilities all over the country. As measures for domestic wastewater treatment, sewerage systems were spread in high-density urban areas, while a decentralized system called johkasou was diffused in rural areas with low population density. Johkasou is a unique system that was devised in Japan and mainly treats domestic wastewater on-site. Night soil treatment systems and decentralized wastewater treatment systems used in Japan are introduced in this paper, in the hope that the experience acquired in Japan will contribute to improve the sanitation conditions in other countries.

Natural Remediation of TNT‐Contaminated Water and Soil

AbstractContamination of soil and water with explosives, especially TNT, is a widespread problem on military sites, explosives producing plants and ammunition factories. Because the contaminated areas are often very large, off‐site soil treatment technologies are prohibitively costly. Groundwater decontamination has to deal with large quantities of water, so pump‐and‐treat remediation has to be operated for decades. Since there is a need for cost‐effective new technologies for cleaning up soil and groundwater, biological technologies for the remediation of TNT in both media have been developed and tested. In this article, an overview of the results of container experiments and a pilot scale in‐situ remediation of TNT‐contaminated soil, as well as the results of 1 m3 constructed wetlands for the cleaning of TNT contaminated water is presented. The biological removal of TNT was observed with autochthonous microorganisms; their degradation efficiencies differed depending on the carbon source added. Molasses was found to be a superior carbon source for the TNT cometabolism, compared to wood chips. In constructed wetlands with a hydraulic retention time of 24 h, a reduction in TNT levels of more than 99% was shown.

Pilot remediation of sediment from the petroleum harbour in Amsterdam

The Petroleum harbour project is the third pilot remediation, which was carried out within the framework of POSW (the national development programme for treatment processes of polluted sediments). The main objectives of the pilot remediation are:– to demonstrate the biological treatment of dredged materials on a practical scale;– to gain knowledge and experience for the future remediation of the total Petroleum harbour. A strict tender procedure was carefully executed in order to select the most effective and ‘state of the art’ biodegradation technology. The selected remediation chain was a combination of ‘standard’ soil treatment technology and newly developed biotechnology. The contaminated sediments were separated by hydrocyclones, then the sand fraction was cleaned by froth flotation, and the fines were treated in a continuous flow reactor consisting of a cascade of 4 bioreactor tanks. A belt press was used for dewatering the fines. Dredging, biotechnological treatment and the effects of the remediation on the environment were monitored in detail. The quality of the treated sand fraction complied with the Dutch standards for re- use and was actually applied in a project of Rijkswaterstaat. Biodegradation resulted in a substantial decrease of the oil and PAH's contents, but due to the lack of breakdown of a few high-molecular PAH's, the quality requirements of the contract were not achieved. For less heavily polluted sediments and soils the applied biotechnology may be more effective. The results of the project show that biodegradation in bioreactors on a large scale is feasible. Furthermore useful information was gathered for the future remediation of the Petroleum harbour. It is concluded that the two main objectives of the project have been attained. Finally some recommendations for the future clean-up of the Petroleum harbour are given.

Pilot remediation of sediment from the Petroleum harbour in Amsterdam

The Petroleum harbour project is the third pilot remediation, which was carried out within the framework of POSW (the national development programme for treatment processes of polluted sediments). The main objectives of the pilot remediation are:-to demonstrate the biological treatment of dredged materials on a practical scale;-to gain knowledge and experience for the future remediation of the total Petroleum harbour.A strict tender procedure was carefully executed in order to select the most effective and ‘state of the art’ biodegradation technology. The selected remediation chain was a combination of 'standard' soil treatment technology and newly developed biotechnology. The contaminated sediments were separated by hydrocyclones, then the sand fraction was cleaned by froth flotation, and the fines were treated in a continuous flow reactor consisting of a cascade of 4 bioreactor tanks. A belt press was used for dewatering the fines. Dredging, biotechnological treatment and the effects of the remediation on the environment were monitored in detail. The quality of the treated sand fraction complied with the Dutch standards for re- use and was actually applied in a project of Rijkswaterstaat. Biodegradation resulted in a substantial decrease of the oil and PAH's contents, but due to the lack of breakdown of a few high-molecular PAH's, the quality requirements of the contract were not achieved. For less heavily polluted sediments and soils the applied biotechnology may be more effective. The results of the project show that biodegradation in bioreactors on a large scale is feasible. Furthermore useful information was gathered for the future remediation of the Petroleum harbour. It is concluded that the two main objectives of the project have been attained. Finally some recommendations for the future clean-up of the Petroleum harbour are given.

Best management practices to prevent cross‐media transfers during soil cleanup

AbstractCleanup activities often focus on the initial and final concentration levels of contaminants. What happens in‐between, during implementation of treatment technologies, has raised major concerns by several environmental groups. To address this issue, the U.S. Environmental Protection Agency (EPA) has undertaken the task of developing a guidance that would identify the potential for cross‐media transfer during implementation of various soil treatment technologies and recommend best management practices (BMPs) to prevent or control these cross‐media transfers. The soil treatment technologies have been grouped into seven major categories in this effort. This article provides some details of the seven soil treatment technology groups and the general BMPs recommended in the draft BMP guidance document. One case history of existing control practices is also presented in this article and compared with the recommended BMPs.