Soil Washing
Soil washing is generally considered a media transfer technology.
Typical environmental problems involve contaminated soil, sludge, surface water, and groundwater, usually containing widely distributed contaminants such as heavy metals, organics and their byproducts/decomposition products, and low-level radioactive materials. To develop an effective treatment for a contact-contaminated soil or other waste, it is necessary to understand its physical and chemical characteristics, including the distribution of the contaminants. Soil washing process can be defined as a water-based process for scrubbing soils ex situ to remove contaminants. The process removes contaminants from soils in one of two ways:
The concept involves literally washing the contaminates from the soil using specially designed equipment.
1. By dissolving or suspending them in the wash solution (which can be sustained by chemical manipulation of pH for a period of time).
2. By concentrating them into a smaller volume of soil through particle size separation, gravity separation, and attrition scrubbing (similar to those techniques used in sand and gravel operations).
A novel soil washing process that is called Electrod Assisted Soil Washing (EASW) technology has been invented and demonstrated by Harry W. Parker, and the graduate student Ramesh Krishnan. These persons are working in the continued development of this process. EASW process technology is assigned to Toxic Environment Control Systems, Lubbock, Texas. This firm supplied the funding for the invention and development of the process over the past five years.
Advantage of the EASW Soil Washing Technology and Theory of Operation
Soil washing is frequently the most cost effective me...
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...ice geometry and to plan for higher capacity soil washing units. In the future, the cost of soil washing by this technology will be much cheaper than today by optimization using computer simulations.
References
(1) Krishnan, R., H.W. Parker and R.W. Tock, "Electrode Assisted Soil Washing," Journal of Hazardous Materials, Vol. 48, pp. 111-119, (1996).
(2) Snyder, B.M., R.M. Dennis, M.J.S. Roth, R. Krishnan, and H.W. Parker, "Evaluation of soilwashing process for 'unwashable' clays and silts from the Palmerton zinc site," Remediation, pp. 69-80, Winter 1995/96, (1995).
(3) Parker, H.W., "Process for washing contaminated soil," U.S. Patent 5,391,018, Feb. 21, (1995).
(4) EPA, "Engineering Bulletin -- Soil Washing Treatment," EPA/540/2-90/017, Sept., (1990).
1. http://erb.nfesc.navy.mil/restoration/technologies/remed/phys_chem/phc-27.asp
Whether soil particles are attached to carpet fibers, wood floors or restroom sinks, they need to be removed. But how is this done? Most of us wipe or scrub a dirty surface with soap and water without a second thought about how they actually work to remove soil. The process of removing dirt begins at the molecular level. In order to understand how soap works, we must first acknowledge what soap actually does.
The word “remediate” means to solve a problem, so the word “bioremediation” refers to the use of biological organisms to solve an environmental problem. Bacteria, fungi, protists and other microorganisms in a non-polluted environment are constantly breaking down organic matter, and when the soil is polluted, some of the organisms may die, but others will still be able to break down the pollutants. Bioremediation provides organisms that can consume the pollutants with fertilizer, oxygen, and other conditions to encourage the rapid growth of these organisms. They then would be able to break down the organic pollutants at a correspondingly faster rate. There are two general ways in which bioremediation functions. One way is where specific survival conditions of a microorganism living in the soil are enhanced to increase the rate of a pollutant’s degradation. The second way is when specialized microbes are added to degrade the contaminant. This way is less common. For many types of polluted soil, bioremediation provides an excellent method of clean-up, but in some cases the pollutant is toxic even for the microbes. These pollutants include metals such as cadmium or lead, and salts such as sodium chloride. Although it may not work in all cases, bioremediation is considerably easier than other methods because it enhances the functions that the microbes already carry out in the soil. Along with being easier, it can be much less expensive because the soil does not have to be pumped out of the ground for treatment (Environmental Inquiry-Bioremediation). Serratia Marcescens is a bacterium that is commonly used for bioremediation.
In conclusion my hypothesis was correct towards this experiment, the concentration with the most Dettol disinfectant had the least bacterial growth and the least Dettol disinfectant had the most bacterial growth occurring in our agar plates, the experiment was successful to show the soil bacterial growth and how well the Dettol disinfectant works to prevent the growth.
No, it seems to me the only real option is the chemical. Melt them down and flush 'em down
Fairly inexpensive compared to other techniques, the financial savings of bioremediation is an attractive alternative when used properly. A study conducted by Alper “states that bioremediation is six times lower in cost than incineration and three times cheaper than entombment.” . After the Exxon Valdez spill, the cost to clean the shoreline was less than cost to provide physical washing of the shore for one day. This saves a great deal of money which would be spent on labor hours, and it also allows for time t...
Chemicals: Ultrapure water with an electrical conductivity of 18.2 MΩ cm-1 produced from nano-filter (EMD Millipore Corporation, UK) was used for cleaning, making solutions, and doing electrochemical measurements. Cleaning solvents such as ethanol was purposed from Decon Laboratories (USA), acetone was purposed from Fisher Chemicals, USA, and isopropanol was purchased from Macron Fine Chemicals, USA. Chloroauric acid, hydrogen chloride, nitric acid, sodium phosphate monobasic, and sodium phosphate bibasic were purchased from Sigma-Aldrich, USA. L-ascorbic acid were purchased from Sigma-Aldrich, USA
There are a number of non-chemical, non-mechanical water treatment technologies. Many of these are known by names such as electronic, magnetic, electrostatic, electromagnetic, and AC induction. The history of these devices goes back to at least 1952. Claims for and against the effectiveness of such systems have a long history. One would think that if these types of systems were truly effective, then the knowledge of their successful deployment would be common place in the industry.
The aim of this test was to find the relationship between moisture content and dry density of an engineering soil. This information could be used to find the optimum moisture content and the maximum dry density. At this value of maximum dry density the void ratio, porosity, degree of saturation and air content could also be calculated.
This model is designed as a guide to farmers, scientists and other workers relevant with the evaluation and control of soil erosion by water.
One sustainable solution that has been proposed by the scientific community is bioremediation. Bioremediation is the application of microorganisms or biological enzymes to treat or remove contaminants. (“In Situ Bioremediation,” para. 1) Bioremediation is a lower cost and more effective option than removing contaminated soil offsite as a preventative measure, before the contaminants reach groundwater. When contaminants reach ground water bioremediation is still an excellent option, but it takes a longer period of time to remove the contaminants. Bioremediation is a sustainable option because it uses naturally occurring microbes that degrade contaminants naturally. This is most evident in the Exxon Valdez spill, where bioremediation was applied and was a major factor in restoring the environment. One of the most beneficial aspects of bioremediation is that this solution is ready for use today. From the time that the microbes are applied to the contaminants it can take anywhere from 65 days to several hundred days. Factors that can influence the time it takes to render the contaminants ineffective are seasonal temperatures, which contaminants where spilled, and the depth and area of contamination. The cost of bioremediation is another appealing aspect to this option because the cost is relatively low. There is no construction cost and the machinery cost is low. The cost of aerobic
This review shows the pros and cons of using the combination of various technologies for industrial wastewater treatment plant. Rapid industrialization, intensive agriculture and other human activities cause soil degradation, pollution and lowers the productivity and sustainability of the crops that further increase the pressure on natural resources and contribute to their degradation. Environmental bioremediation is an effective management tool for managing the polluted environment and in restoring the contaminated soil. The use of microbial sources, coupled with advanced technology is one of the most promising and economic strategies for the removal of environmental pollutants. There is a strong scientific growth with both the in situ
Soil is a complex medium consists of many chemical and minerals, but to ease understanding on this study, soil can be referred as combination of solid mineral and organic particles and pore. Pores allow air and water to move in between soil particles. Compaction and force applied on top of soil cause reduction in pore volume. As an example, frequent road used by tractor have less pore compare to un touch soil.
There are countless sources of water pollutions that exist today due to our industrious and technologically advanced lifestyles. However, the most vexing is caused by the most basic necessity for survival, Agricultural Pollution. Agricultural Pollution is defined as, “ liquid and solid wastes from all types of farming activities, including run-off from pesticide and fertilizer use, and from feedlots; erosion and dust from ploughing; animal manure and carcasses; and crop residues and debris. In essence Agricultural Pollution is a nonpoint source water pollutant since it comes from various locations and cannot be pinpointed” (EPA-web). Although there are many practices already in place that will decrease the pollution, increase productivity, and save farmers money in the long run, the farmers are careful to change practices.
Phytoextraction is the uptake and storage of pollutants in the plants stem or leaves. Some plants, called hyperaccumulators, draw pollutants through the roots. After the pollutants accumulate in the stem and leaves the plants are harvested. Then plants can be either burned or sold. Even if the plants cannot be used, incineration and disposal of the plants is still cheaper than traditional remediation methods. As a comparison, it is estimated a site containing 5000 tons of contaminated soil will produce only 20-30 tons of ash (Black, 1995). This method is particularly useful when remediating metals. Some metals are also being recycled from the ash.
It also decreases the amount of sludge, which needs to be disposed. Electrocoagulation is a technology that removes components from wastewater by applying a strong electric field that produces a series of oxidation and reduction reactions. By decomposing the electrodes, the metallic ions produced are subject to fast hydrolysis and the products of the hydrolysis neutralize the charge of the suspended particles driving them to a fast coagulation and sedimentation. Electrodes consist of iron and aluminium have special coagulation properties and are very efficient in decolouring industrial wastewater. In recent years, the EC has been successfully tested to decolourization of dye-containing solutions. Applied electrodes in EC process are usually iron or aluminium. The dye in coloured wastewater is coagulated by iron and aluminium hydrates or hydroxides produced from the sacrificial anode. EC technology, compared with other techniques, enjoys some advantages like plain equipment, easy functionality, short resistance time, no need of chemicals, low sludge production, sludge stability, suitable sedimentation of sludge, dewatering and environmental compatibility. EC process is being used for the removal of ions, organic matters, colloidal and suspended particles, dyes, oil and heavy metals from aqueous