化工厂场地酸化土壤工程化中和修复案例研究

对江苏某化工厂酸化地块进行了氧化钙中和修复工程研究。Ⅰ、Ⅱ、Ⅲ号地块剖面混合土样pH值分别为3.56、4.68和4.74,土壤修复目标定在pH值为6~8基本近中性。通过室内试验确定Ⅰ、Ⅱ、Ⅲ号地块土壤生石灰掺混比例为0.5%、0.3%和0.3%;现场中试后Ⅰ、Ⅱ、Ⅲ号地块石灰掺混比例调整为0.7%、0.35%和0.3%;中试结果用于场地机械搅拌工程修复,修复过程中定期随机采样对中和效果进行连续监测。监测结果基本达标后请第三方对修复效果进行评估,最后土壤回填压实。修复结果表明借助于科学的石灰添加量和工程机械混合措施,能快速有效地修复酸化地块土壤。     

Effects of calcium peroxide on arsenic uptake by celery (Apium graveolens L.) grown in arsenic contaminated soil

The ability of calcium peroxide (CaO₂) to immobilize As of contaminated soil was studied using pot and field experiments. In pot experiment, CaO₂ applied at 2.5 and 5 g kg⁻¹ significantly increased celery shoot weight and decreased shoot As accumulation, which was ascribed to the formation of stable crystalline Fe and Al oxides bound As and the reduction of labile As fractions in the soil. The labile As fractions were pH dependent and it followed a “V” shaped profile with the change of pH. In field experiment, the dose of CaO₂ application at 750 kg ha⁻¹ was optimal and at which the celery was found to produce the highest biomass (63.4 Mg ha⁻¹) and lowest As concentration (0.43 mg kg⁻¹). CaO₂ probably has a promising potential as soil amendment to treat As contaminated soils.     

Chemical Tracking and Marine Environmental Impact of Ocean Disposal of Calcium Carbonate Residue in the North Yellow Sea

The objective of this study is to determine the sedimentation rate and dispersion area of calcium carbonate residue dumped at sea and the impact to marine environment of dumping by a laboratory simulation experiment; chemical tracking in the field with the help of acoustic and optical tracking; and a comparative study of baseline conditions and marine environmental impact after dumping. Turbidity, pH and phosphate are selected as the chemical tracers to be monitored.

Results show that in the dumping area of 15 square miles with water depth of 50 m, if 217 t calcium carbonate residue is dumped (spot dumping) in the presence of a pycnocline with a current velocity of 60 cm/s (close to the maximum) the maximum dispersion distance of the calcium carbonate residue plume front is less than 2100 m; the dispersion area is less than 0.56 km²; and the maximum dispersion time is about 60 min when the turbidity and pH in the whole dispersion area return to background level. Therefore, the ocean disposal of calcium carbonate residue is feasible.     

Mercury in some chemical fertilizers and the effect of calcium superphosphate on mercury uptake by corn seedlings(Zea mays L.)

Mercury (Hg) contents in ten chemical fertilizers were determined, and the effect of calcium superphosphate (CSP) on the uptake and translocation of Hg in corn seedlings was investigated by pot experiments. CSP was applied at the levels of 0, 66.7, and 133.4 mg P2O5/kg to Hg-treated (2 mg/kg) and untreated soils. CSP had the highest Hg content (5.1 mg/kg), followed by the NPK compound fertilizer 15-5-5 (15% N, 5% P2O5, 5% K2O) (1.2 mg/kg), then by nitrogen fertilizers (except for ammonia sulfate) and potassium fertilizers. Application of CSP did not obviously iuence the biomass of corn roots, but it significantly increased the biomass of corn shoots in Hg-treated soil. Application of CSP at the levels of 66.7 and 133.4 mg P2O5/kg did not obviously iuence the uptake of Hg by corn seedlings on soils without Hg treatment, but it decreased the Hg uptake of corn seedlings significantly on Hg-treated soils. The transfer coefficient of Hg in corn seedlings improved slightly on soils without Hg treatment, but decreased slightly on Hg-treated soils with the application of CSP. These results implied that CSP could ameliorate Hg toxicity to corn seedlings by inhibiting the uptake and the translocation of Hg in plants on Hg-polluted soils.     

新型固定化生物小球的研制及其处理模拟苯胺废水的特性

从焦化废水二级处理系统的生物膜中富集、培养、浓缩得到能降解苯胺的混合菌种GAl作为固定化微生物的来源.用3种不同方法制备了新型固定化生物活性炭纤维小球(IBACFBs),并研究了其机械性能;通过降解模拟苯胺废水考察了固定化生物活性炭纤维小球的生化活性和循环使用寿命.同时也比较了小球中活性炭纤维和活性炭对小球生化性能的影响.结果表明,以Ca(N03)2为唯一固化剂,采用冷冻-解冻法制得的IBACFBs具有最好的机械性能和生化活性,对高浓度苯胺溶液有优异的降解效果,最适条件下经过46h反应,苯胺浓度从初始的526mg·L-1降至9.6mg·L-1,降解率达到98.4%.由于具有特殊的孔结构和巨大的比表面积,相比于活性炭,活性炭纤维更能提升固定化小球的生化活性.循环批次降解苯胺实验表明,IBACFBs具有良好的机械强度,生化活性随着循环次数的增加不但没有降低,反而有不同程度的提高;循环批次反应后,在最适条件下IBACFBs仅用30h就可将苯胺溶液浓度从513mg·L-1降至7.6mg·L-1,降解率高达98.5%.     

Chemical Tracking and Marine Environmental Impact of Ocean Disposal of Calcium Carbonate Residue in the North Yellow Sea

The objective of this study is to determine the sedimentation rate and dispersion area of calcium carbonate residue dumped at sea and the impact to marine environment of dumping by a laboratory simulation experiment; chemical tracking in the field with the help of acoustic and optical tracking; and a comparative study of baseline conditions and marine environmental impact after dumping. Turbidity, pH and phosphate are selected as the chemical tracers to be monitored.

Results show that in the dumping area of 15 square miles with water depth of 50 m, if 217 t calcium carbonate residue is dumped (spot dumping) in the presence of a pycnocline with a current velocity of 60 cm/s (close to the maximum) the maximum dispersion distance of the calcium carbonate residue plume front is less than 2100 m; the dispersion area is less than 0.56 km²; and the maximum dispersion time is about 60 min when the turbidity and pH in the whole dispersion area return to background level. Therefore, the ocean disposal of calcium carbonate residue is feasible.     

西湖水体中铁铝钙镁的环境行为探讨

研究西湖水中铁，铝，钙，镁的含量分布，水平方向的动态交换，以及在引物水期与非引水期的变化，探讨这些元素在西湖水体自净中的作用。     

Calcium carbonate waste from an integrated pulp and paper mill as a potential liming agent

Calcium carbonate is used in large amounts in the pulp and paper industry as a paper filler. When it is manufactured, the calcium carbonate waste is purged from the process. Here we demonstrate that, due to the elevated calcium concentration of 168.5 g kg⁻¹ dry weight (dw), alkaline pH of 12.6 and neutralizing (liming) effect value of 42.4% expressed as Ca equivalents, this waste is a potential liming agent and a pH buffer. The heavy metal concentrations in the waste were lower than the new Finnish limit values for fertilizers used in agriculture, as well as for a material, e.g. ash, used as an earth construction agent. These limit values came into force in March 2007 and in June 2006, respectively.     

Mineralogy and chemistry of urinary stones: patients from North Jordan

Urinary stone diseases are increasing in the Middle East. The majority of urinary stone cases are found in the northern part of the country. Stone samples taken from patients living in the Irbid area were collected from Princess Basma Hospital. The present study concentrates on the mineralogical and chemical composition of the urinary stones and on the effective environmental factors that assist in developing the different types of urinary stones. Using X-ray diffraction techniques, the mineralogical composition of the urinary stones was found to be as follows: oxalate, cholesten, and uric acid, with cystine stones occuring more frequently than the others. Cholesten and calcium oxalate stones are the most dominant types of stones. Calcium oxalate is the most common type of oxalate stone. Calcium oxalate is represented in: whewellite, wheddellite, and calcium carbonate oxalate hydrate minerals, in addition to other minerals such as brushite, ammonium phosphate, vaterite, valleriite, and bobierrite from other types of stones. Bobierrite (phosphate group) is a new mineral reported in urinary stones, and this has not been determined in any previous study worldwide. Apatite (calcium phosphate) is deduced using scanning electron microscope (SEM) images. The SEM technique determined crystal forms and systems, shapes, morphological features, and the names of the minerals forming urine stones, while optical properties are studied by polarizing microscope. X-ray fluorescence technique determined the concentrations of major and some trace elements. It revealed that Ca is the main constituent of the urinary stones, especially those composed of calcium oxalate and calcium phosphate. The concentration of trace elements was Ba = 1.57, P = 3.61, Fe = 1.78, S = 2.08, Zr = 4.63, Mo = 3.92, Cu = 1.89, Co = 1.56, and F = 4.2% and was higher in the urinary stones of Jordanian patients than in foreigners in the country. Questionnaires completed by patients suggest that the most significant factors directly effecting the formation of stones are water, climate conditions, food rich in protein and rich in different chemicals. Moreover, some drugs and diseases might also help in developing other stones.