The recycling of sewage sludge on agriculture land represents an alternative, advantageous, disposal of this waste material.
The aim of the present study was to evaluate the feasibility of using industrial sewage sludge, produced in Pakistan, as a
fertiliser. Agricultural soil amended with 25% (w/w) sewage sludge with or without lime treatment was used for growing a variety
of sorghum (PARC-SS-1). The mobility of the heavy metals (HMs) (Cd, Cu, Cr, Ni, Pb and Zn) and metalloid (As) in the untreated
industrial waste water sewage sludge (UIWS) samples were assessed by applying a modified BCR (Community Bureau of Reference)
sequential extraction procedure. The single extraction procedure comprised of the application of mild extractant (CaCl2) and water for the estimation of the proportion of easily soluble metal fractions. The precision and accuracy of BCR was
evaluated by using a certified reference material of soil amended with sewage sludge BCR 483. The plant available metal contents,
as extracted by the deionised water and 0.01 M CaCl2 solution and exchangeable fraction of BCR sequential, decreased with lime application in the range of 10–44% for As, Cr,
Ni, Pb and Zn, except in the cases of Cd and Cu, where their mobility was increased by 10% and 24%, respectively. Sludge amendment
enhanced the dry weight yield of sorghum and the increase was more obvious after liming up to 25%. The uptake of HMs were
lower in test samples (3.2–21.8%), except for Cu and Cd, which was higher (4%), while they were below the permissible limit
of these metals. The present experiment demonstrates that liming was important in factors facilitating the growth of sorghum
in sludge-amended soil. 相似文献
A novel process for carbon dioxide (CO2) separation, which was named a membrane flash process, was developed to realize an energy-saving technology and to substitute it for a conventional regenerator. The electric energy for CO2 recovery in a membrane flash process using aluminum oxide and diethanolamine was lower than the thermal energy of the conventional chemical absorption process. Flashing at elevated temperature by the low temperature energy significantly reduced the electric energy and required much less membrane area. This process has potentiality of low cost capture of CO2 when the low temperature energy, which is not available for other purposes, can be utilized to elevate flashing temperature. 相似文献
13C CP-MAS NMR spectroscopy is a technique that has proved to be useful in studying soil organic matter (SOM). Nevertheless, NMR spectra exhibit a weak signal and have very low resolution due to: the low natural abundance of 13C (1.1 % of C) in SOM, the generally low SOM content of soils, and the presence of paramagnetic impurities. This paper studies the effects of soil chemical pre-treatments on 13CP-MAS NMR spectra quality and spectra representativity i.e. soil C mass balance.
After chemical pre-treatment to increase total organic carbon (TOC) content and C/Fe ratio, eight soils characterized by different levels of organic carbon content and C/Fe ratios were studied using 13CP-MAS NMR. Moreover, where chemical treatments were not applicable due to high carbon losses, the number of 13CP-MAS NMR scans was increased in order to obtain satisfactory spectra.
Results show that chemical pre-treatment of soils with C/Fe > 1 caused high C losses. Bulk soils were therefore studied by increasing the number of 13CP-MAS NMR scans. Acceptable spectra were obtained from 8K scans (1K = 1024 transient). On the other hand, even when a large number of scan (32K) are used, soil with C/Fe < 1 cannot be studied. As these soils are characterized by low C losses after HCl treatments (range of 2.9–25.4%), a pre-treatment of at least 1.39 mol l−1 HCl removes excess Fe and at the same time increases C/Fe ratio resulting in 32K scans providing good spectra. 相似文献
Growth, accumulation and intracellular speciation and distribution of copper (Cu) in Sesbania drummondii was studied using scanning-electron microscopy (SEM), X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). The growth of seedlings was assessed in terms of biomass accumulation. The growth of the seedling was enhanced by 73.5% at a low Cu concentration (50 mg l−1) compared to the control treatment. Additionally, seedling growth was inhibited by 18% at 300 mg l−1 Cu with respect to the control. Copper concentration in roots and shoots was increased with increasing Cu concentration in the growth solution. The accumulation of Cu was found to be higher in roots than in the shoots. At a concentration of 300 mg l−1 Cu, the roots accumulated 27,440 mg Cu kg−1 dry weight (dw) while shoots accumulated 1282 mg Cu kg−1 dw. Seedlings were assessed for photosynthetic activity by measuring chlorophyll a fluorescence parameters: Fv/Fm and Fv/F0 values. Photosynthetic integrity was not affected by any of the Cu treatments. The X-ray absorption spectroscopic (XAS) studies showed that Cu was predominantly present as Cu(II) in Sesbania tissue. In addition, from the XAS studies it was shown that the Cu exists in a mixture of different coordination states consisting of Cu bound to sugars and small organic acids with some possible precipitated copper oxide. From the EXAFS studies, the coordination of Cu was determined to have four equatorial oxygen(nitrogen) ligands at 1.96 Å and two axial oxygen ligands at 2.31 Å. Scanning-electron microscopy studies revealed the distribution of Cu within the seedlings tissues, predominantly accumulated in the cortical and vascular (xylem) regions of root tissues. In the stem, most of the Cu was found within the xylem tissue. However, the deposition of Cu within the leaf tissues was in the parenchyma. The present study demonstrates the mechanisms employed by S. drummondii for Cu uptake and its biotransformation. 相似文献
The effect of long-term exposure to high frequency electromagnetic field (HF EMF) on some somatic and neural characteristics
was studied in neurodefective Lurcher mutant (+/Lc) and normal wild type mice (+/+). Both newborn and young adult (3 months)
animals derived from two strains (C3H, B6CBA) were exposed to HF EMF (870 MHz) from 1st to 21st day or from 91st to 120th
day respectively. In animals of both groups and controls we observed the development of body weight. Moreover, in the HF EMF
exposed adult B6CBA animals we studied spatial learning ability, motor functions and the CNS excitability. To investigate
specific energy absorption rate (SAR) in experimental animals we have done the basic 3D calculations of the electromagnetic
energy distribution in the simplified model of the mouse. The HF EMF exposed animals exhibited mild differences of body weight
between them and unexposed controls. The long-term exposure to HF EMF did not significantly influence the ability to learn
in the Morris water maze. However, significant lower swimming speed was found in the irradiated +/Lc as well as lower motor
activity of +/+ in the open field when compared to controls. No significant differences were found between HF EMF irradiated
animals and controls in examination of the CNS excitability and motor functions. 相似文献