| Salinization soil is probably also called saline soil, means the salinity ofpotassium, sodium, calcium and magnesium which exist as chloride, sulfate,bicarbonate etc., is higher in the soil, or the soil salinity is little, but it’s exchangesodium percentage get to a certain degree. Land salt-alkalinization is harmful toagriculture and forestry production, ecological environment and sustainabledevelopment, so the improvement and utilization of salinization soil is importantsignificance. As a kind of soil resources, saline soil is widely distributed in all overthe world. It is also very rich in China, improvement and utilization of these resourcesis significant approach to Chinese agricultural sustainable development, it also haveimportant meaning on improving the ecological environment, promoting the regionaleconomic and social and ecological sustainable development. the west part of Jilinprovince is one of the most serious salinization areas in China, salinization land area isnear153.27×104hm2, the development trend was accelerated in recent years, theform that the accelerate development usually assumes, is area expansion, degreeexacerbation, it severely restricts agricultural sustainable development and theimprovement of people’s living standard.Heavy metal pollution means heavy metals or its compounds causingenvironmental pollution.“Heavy Metal Pollution Comprehensive Prevention andControl12th Five-Year Planning” obtained the state council official reply at thebeginning of April2011, the plan seeks to control five heavy metal (lead, mercury,chromium, cadmium, arsenic). The source of heavy metal is very wide, mining,industrial activities, use of pesticides and the continuous frequent pollution events, allof them increase the source of heavy metals in the environment. Heavy metal hasenrichment quality, it is difficult to degrade in the environment. The impact of heavymetal existed in the soil on the environment, is not only on the basis of its content, butalso according to its existence form, for the different form, the migration ortransformation and the toxic action to the plant is different also. Chromium in soil hastwo primary kinds of valence, trivalent and hexavalent, and the trivalent is more stable. Most of metal elements in the soil solution in acid conditions exist as free ionor hydration ion, having greater toxicity, and on the alkaline or neutral conditions,they are likely generated as hard dissolved precipitation of hydroxide, reducingtoxicity.It is one of the hot issues in the present environment field that is how to usesalinization soils to dispose the sewage containing heavy metals, which not onlyachieves saline-alkaline soil amelioration, heavy metal sewage get properly treatment,and heavy metal pollutants get fixed, but also keeps the agricultural environment andgroundwater environment from pollution.This experiment design the organic glass pillar which is used for acid wastewatercontaminated by chromium infiltration through saline soil, and clear water leachingprocess, simulating saline and alkaline land in idle to deal with chromiumcontaminating wastewater and the rain shower function. The following rules wereobtained by my experiments:1. Chromium-contaminating wastewater penetration through different pH valuesalinization soils test:（1）The total water soluble form chromium content in effluent relatives to5mg/L in the inflow are obviously reduced in each soil column series. In the wholeoperation cycle, the total water soluble form chromium content variation curves inalkaline soil column effluent is divided into three stages: short rise stage, gentledecline stage, rapid decline stage and smooth trailing stage. Concentration attenuationratio of chromium in effluent even achieves to100%.（2）Through the clear water elution, the results show that the total water solubleform of chromium brought out is mainly Cr(III), Cr(VI) is very little.（3）The five forms chromium in the soils are extracted with Tessier law, itspercentage composition show that the residue form has the biggest percentage,exchangeable form is less than the residue form, carbonate combination form, Fe-Mncombination form, organic combination form have relatively small proportions.（4）Over the characteristic indexes of effluent, the pH of effluent change isgradually descending; COD undergoes slow down stage of aerobic reaction andquickly drop stage of anaerobic reaction; ORP value in the soils that’s pH value near the neutral wave to220mv, in the soils that have larger pH value wave to150mv;while the general calcium magnesium content in the soil within a certain range,chromium occur exchange adsorption with calcium magnesium and it is limited, thatis to say the processing won’t wastage too much calcium magnesium in the soil.（5）Over the characteristics index of soils, alkaline soils get improved. Soil pHvalue have different reduction, all inclining to neutral; The ESP also tends to beneutral: soil pH value is closed to neutral, ESP is changeless that’s less than10%,while the pH value is higher, ESP is gradually reducing. While it tends to be neutralsoil, it’s benefit for the growth of plant; And the content of organic matter in soil doesnot change, maintaining in the original level.2. Different chrome content in inflow permeating and leaching the same salinizationsoil test:（1）During higher chrome content in the inflow penetration tests, there exists apositive correlation between the total water solubility form chromium content ineffluent and chrome in inflow. And, chromium content in inflow decided the rate ofdescend of chromium content in effluent water, while it’s high content, the rate is slowdown.（2）There is a positive correlation between the cumulative effect of chromiumcontents existing in the soil and chromium content in inflow.（3）When the chrome content in the inflow is above10mg/L, the percentagecompositions of exchangeable form chromium and carbonate combination formchromium in the soil are significantly increased, residue form percentage compositiondeclined, the percentage compositions of Fe-Mn combination form and organiccombination form are increased marginally.（4）through the Index of Geoaccumulation (Igeo) evaluation method, the resultdemonstrates that pollution level of saline alkali soil increases with the extension oftime and chromium content in the inflow. |
PDF Full Text Request