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《Communications in Soil Science and Plant Analysis》2012,43(10):1109-1119
Abstract The ratio between non‐humified and humified fractions in pyrophosphate extracts is shown to vary during maturation of sewage sludge. The ratio is higher than 1 in the raw materials but lowers at 1 or less than 1 with the aging of sludge and is assumed to reflect quantitatively the degree of stabilization of organic matter in the sludge. Analytical isoelectrofocusing (IEF) experiments showed that humified fractions in raw sludge focalize only in the pH gradient regions lower than 5.0, whilst in older sludge samples a progressive strengthening of bands occurs in the region between pH 6.5 and 5.0, approaching at least partially IEF patterns of soil organic matter. IEF patterns are suggested to reflect the stabilization of organic matter in sewage sludge from a qualitative point of view. 相似文献
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Marc Breulmann Katrin Kuka Manfred van Afferden François Buscot Christoph Fühner Roland Müller 《Archives of Agronomy and Soil Science》2018,64(6):873-880
Due to higher proportions of labile carbon (C) compounds the suitability of biochar produced by hydrothermal carbonization (HTC) for C sequestration is questionable. We hypothesized that pre-treatment with water would reduce the biological decay of hydrochar from sewage sludge. Unwashed and washed feedstock and hydrochar were incubated in a short-term experiment. The kinetics of the biological decomposition of the materials was calculated on the basis of a double exponential model and the C sequestration potential using the CANDY Carbon Balance (CCB) model. Biological decomposition of the carbonized materials was governed by the percentage of labile C compounds. Mean residence time of a fast (MRTfast) and slow decay pool (MRTslow) of unwashed hydrochars varied clearly (MRTfast: 0.8 – 5.0 months and the MRTslow: 5.0–18.6 months). The pre-treatment with water removed labile hydrochar C and reduced the biological accessibility. MRTfast and MRTslow was increased by intensive washings (MRTfast: 5.0–7.4 months and the MRTslow: 14.9 months). High synthesis coefficients suggest that hydrochar C was humified and transferred into stabilized SOC. The results clearly show that once adsorbed components were eliminated, and as compared to pyrolysed biochar hydrochar from sewage sludge may also be useful for soil C sequestration. 相似文献
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J. J. Den Van Berg 《Land Degradation \u0026amp; Development》1993,4(4):407-413
The disposal of sewage sludge affects the environment as the sludge May, contain harmful components such as pathogenic organisms, organic compounds, heavy metals and excess phosphorus and nitrogen. Depending on the method of disposal, these effects can be immediate or time-delayed and non-linear. the effects of dumped or landfilled sewage sludge can be characterized through its leaching capability, which depends on the treatment before dumping. Treatment May, be simple dewatering or advanced incineration, wet oxidation or immobilization. Leach-ability is considered here. 相似文献
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The concentration of medically used radionuclides has been studied in sludge from the sewage treatment plant serving the borough of Malmo. In this area all nuclear medicine procedures are carried out in one hospital and almost all patients live in the borough. Therefore, the input of medically used radionuclides into the sewage system can be estimated with good accuracy. Samples of digested sludge have been taken once or twice a week during half a year. Iodine-131 (physical half life (T) = R.05 d) was detected in all samples. The 131I-activity concentration due to medical use varied between (0.03±0.01) and (0.12±0.02) nCi kg?1. The ratio between the total output of 131I via the sludge and an adherent input of the radionuclide into the sewage system was determined to (2.6 ± 0.6) × 10?3, which is equivalent to a ratio of (2 ± 1) × 10?2 for stable I. Occasionally measurable activities of 198Au (T=2.7 d) and 201T1(T=3.l d) have been found. The radioactivity concentration of medically used radionuclides in the sludge is low and constitutes no health problems for the persons involved. The sludge however has proved to be a very sensitive and suitable integrator of radioactive material released from a large urban area. 相似文献
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The Cu in the saturation extract of dried Davis sewage sludge was mainly in a complexed form. A Cu2+ specific ion electrode was used to determine the extent of complexation. The adsorption coefficient for the complexed Cu on Yolo silt loam was 4 while for Cu added as CUSO4 it was 90 L kg?1 at relevant Cu concentrations in solution. Paper electrophoresis was used to define the Cu complexes according to their mobility in an electric field. Six fractions of positive, negative and neutral charge were isolated. The portion of Cu in the sludge which was water soluble increased significantly upon drying. The large percentage of complexed Cu and its relatively low adsorption on soil suggested that sewage sludge may, under certain conditions, be a source of Cu contamination of plant systems and, in extreme cases, of ground water. 相似文献
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S. Balogh 《Water, air, and soil pollution》1996,91(3-4):249-254
The fate of heavy metals in multiple hearth sewage sludge incinerators was examined using mass balance techniques. All major process streams into and out of the incinerators were sampled in order to characterize the partitioning of Cu, Ni, Ph, and Cd into the major effluent streams, and to calculate a metals mass balance around the incinerators. The results indicate that the residual particulate matter from the incineration process becomes progressively more enriched in the more-volatile metals (Cd and Ph) with decreasing particulate size, in the order bottom ash < cyclone ash < scrubber water particulate < stack particulate. The less-volatile metals Cu and Ni are not similarly enriched. The mass balance indicates that approximately two-thirds of the Cd mass entering the incinerators is partitioned to the scrubber water stream, while the bottom ash stream receives most of the Cu, Ni, and Pb. 相似文献
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Richard W. Lahann 《Water, air, and soil pollution》1976,6(1):3-8
The application of sewage sludge to agricultural fields may result in the production of Mo-rich herbage, a cause of metabolic disorders in animals. An alternative to application of sludge to agricultural fields is sludge utilization in strip-mine reclamation. Oxidation of strip-mine spoil material causes accumulation of Mo-rich iron oxyhydroxide in stream beds and spoil piles. Strip-mine reclamation by sludge application may induce short-term increases in the concentration of Mo and other metals in waters discharged from the reclaimed area because of pH dependent ion-exchange reactions and dissolution of Mo-bearing iron oxyhydroxides. 相似文献
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Summary We studied the effect of incubating peat with lime and sewage sludge in small proportions on biological activity and N mineralization. The peat response was dependent on pH and, in acid peats, on mineralization capacity. In acid peats, the addition of sewage sludge inhibited biological activity. Only the most eutrophic peats (Herbosa) responded with accelerated mineralization. The addition of lime to acid peats favoured organic matter mineralization, shown by a greater CO2 release. The best results were obtained by adding lime and sewage sludge together. In saline peats, the best N levels were obtained without incubation. 相似文献
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A sewage sludge with the addition of two woody materials (1 : 2 ratio), tree-pruning chips and vine shoots, to provide structure were composted under controlled conditions of temperature (28°C) and humidity (70% ambient humidity). Hydrolytic enzyme activities [urease, phosphatase, N-benzoil l-argininamide (BBA) hydrolysing protease, casein-hydrolysing protease, ATP, hydrosoluble and hydrolysable polysaccharides] were determined during the aerobic incubation. Samples were taken and incubated under the same conditions in an accelerative bioreactor to test potential C mineralisation by measuring the CO2 evolved. A rapid mineralisation phase (2–3 weeks) was followed by a slow maturation (4–14 weeks) period. The slow phase and the dynamics of substrate decomposition were better indicated by the hydrolytic enzyme activities that were measured. The structuring agents slightly retarded the compositing process with tree prunings having the strongest effect. Hydrolysable polysaccharides and Folin-reactive compounds (proteins, polyphenols) released by the structure-providing lignocellulose material appear to have controlled both the intensity and the length of the maturation phase. 相似文献
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Sewage sludge in doses of 200 and 400 Mg ha−1 (dry weight) were applied in an experimental rehabilitation of a limestone quarry to improve soil physical condition. The effect of this organic waste on soil aggregation and structural stability has been tested measuring aggregate size distribution by dry- and wet-sieving procedures over a period of 28 months. We discuss the influence of the organic components of aggregates on soil structure. The main effect of sewage sludge was to increase aggregate stability to raindrop impact (splash) just after application of the former but one year later this effect decreased notably. Organic matter is distributed in different ways between macro- and microaggregates, and this parameter seems to be responsible for the structure changes observed. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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M. L. Lozano Cerezo M. L. Fernndez Marcos E. lvarez Rodríguez 《Land Degradation \u0026amp; Development》1999,10(6):555-564
In order to reclaim a clay quarry, a topsoil material was mixed with gravelly spoil at different ratios and with various rates of sewage sludge. The influence of three spoil/topsoil ratios (1:1, 2:1 and 3:1) and three sludge rates (40, 80 and 120 t ha−1) on chemical properties of the resulting material was investigated, with emphasis on heavy metal (Fe, Cu, Mn, Ni and Zn) contents. The mixtures topsoil/spoil/sludge were water saturated and incubated for 15 or 30 days in a chamber under controlled conditions. The incubated samples were analysed for pH, total carbon and nitrogen, and total, available, exchangeable and soluble heavy metals. The addition of spoil to the topsoil increased the volume of material available, by utilizing an inert material unsuitable by itself to grow plants. The addition of sewage sludge repaired the disadvantages of the spoil, increasing the pH and the organic matter contents. The total heavy metal contents in the mixtures followed the sequence Fe>>Mn>>Zn, Cu>Ni. All except Cu were within the ranges allowed for agricultural lands. The available heavy metals constituted a small fraction of total contents and decrease with time due to complexation and immobilization processes. The exchangeable and soluble fractions were almost negligible; only small amounts of Mn, Zn and Cu were detected. Therefore, the risk of contamination by heavy metals is insignificant in the conditions investigated. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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This study was conducted to measure the mutagenic potential of municipal sewage sludge amended soil. Two separate sludge samples were collected from one municipal wastewater treatment plant and applied to undisturbed soil lysimeters over a 9 mo interval. Soil and sludge samples were collected for approximately 2 yr following sludge application. Samples were solvent extracted using methylene chloride and methanol, and the bacterial mutagenicity of the resulting residue determined using the Salmonella/microsome assay. The maximum specific activity of the sludge amended soil was 416 net revertants per 10 mg of residue induced by the methanol fraction extracted from the Weswood soil collected 154 d following the first sludge application. In the Padina sand, the maximum specific activity was 320 net revertants per 10 mg of residue induced by the methanol fraction extracted from the sample collected 154 d following the first sludge application. The specific activity of the sludge amended soil was observed to decrease slowly with time. For both the Padina and the Weswood soils, mutagenic organic chemicals were detected in soil samples collected 510 d following the second sludge application. For the Weswood soil, the mutagenic activity per unit weight of soil with metabolic activation of the samples collected 510 d after the final sludge application was decreased by 15 and 76% for the methylene chloride and methanol fractions, respectively, when compared to the maximum weighted activity observed 56 d after the final sludge application. The results indicate that municipal sewage sludges may contain organic mutagens which are persistent in the soil. 相似文献
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M. Salim Akhter 《Water, air, and soil pollution》1990,51(1-2):147-152
Trace metals such as Pb, Zn, Cu, Ni, Cd and Fe were determined in sewage sludge produced at a sewage treatment plant in Bahrain (Tubli) and soils. The soils, both untreated and treated with the sludge, are used for agricultural purposes in Bahrain. The Trace-metals level showed the following range (μg g?1 dry weight); Pb, 242 to 609; Zn, 704 to 836, Cu, 329 to 512; Ni, 23 to 41; Cd, 1.8 to 3.9 and Fe, 1867 to 4284. The data show the degree to which untreated soils have already been contaminated with trace elements. The level of trace-elements found in sludge showed the following range (μg g?1 dry weight); Pb, 140 to 186; Zn, 597 to 836; Cu, 348 to 449; Ni, 47 to 53; Cd 5.7 to 9.2 and Fe, 5950 to 8520. Mean levels were generally close or lower than mean concentration reported in the United Kingdom and the United States for sludge. They were also lower than the suggested concentration limits for application of sludge on agricultural land, which is one of the most cost effective and attractive techniques for sludge disposal. Soils treated with this sludge (after 1 yr) were also analyzed and showed substantial enhancement of the available level of trace elements in the soil. This eventually will lead to an increase in the trace-element level in plants grown for human or animal consumption. This could have phytotoxic effects, and the possibility of toxic effects on live-stocks and human beings. 相似文献
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A gel filtration chromatography technique was used to separate soluble species of Cd, Cu, Co, Mn, Ni, and TI in the influent and effluent of a laboratory scale activated sludge simulation operated at a range of sludge ages from 3 to 18 days. It was found that, whilst there was no general trend for all six metals, Cd and Mn associated mainly with low molecular weight fractions; Co, Cu, and Ni with a range of predominantly high molecular weight fractions; and TI tended towards association with high molecular weight fractions which influenced metal solubility and appeared to be significant in determining metal removal. It appeared that all metals exhibited high affinity for mixed liquor suspended solids (MLSS) and that this affinity was strongest for Cu and Cd. Nickel, Co, Cu, and TI appeared to show a high affinity for polymeric microbial products produced at longer sludge ages. The gel filtration technique was found to be useful in the separation of metal species in conjunction with a sufficiently sensitive detector provided their concentrations in the original sample were relatively high. 相似文献