Textural and chemical properties of swine-manure-derived biochar pertinent to its potential use as a soil amendment

Biochars have received increasing attention in recent years because of their properties pertaining to soil fertility and contaminant immobilization as well as serving as carbon sinks. In this work, a series of biochars were produced from dried swine manure waste by slow pyrolysis at different temperatures (i.e., 673-1073 K). The characterization of the resulting biochars was examined for its relevance to its potential use as soil amendment. It was found that the pore properties, ash contents and pH values of all swine-manure-derived biochars basically increased as temperature increased, while the yield and nitrogen/oxygen contents decreased with increasing temperature as a result of pyrolytic volatilization during pyrolysis. From the organic and inorganic elements analyses, the manure-derived biochar was rich in soil nutrients such as N, P, Ca, Mg, and K. Furthermore, the pore, surface and chemical properties were also consistent with the observations of the SEM-EDS, XRD and FTIR. This result suggested that the mesoporous manure-derived biochar could be used as an excellent medium to soil environment.     

Effect of different biochars amendment on soil biological indicators in a calcareous soil

Environmental Science and Pollution Research - Previous studies suggest that biochar has potential to benefit soil when used as an amendment, but only few studies have investigated how the...     

Utilization of coal fly ash as a slow-release granular medium for soil improvement

This work proposes a new potential application of waste coal fly ash as a K fertilizer support. Fly ash was reacted with KOH to facilitate the impregnation of K as well as to enhance the bonding force. In particular, the applied process resulted in a significant slow-releasing characteristic of fertilizer elements. To examine the effect of K impregnation, a few detailed leaching tests were carried out in terms of process variables such as reaction time and temperature, sintering time and temperature, and KOH concentration. The current experiment presented an optimum preparation condition that is competitive with conventional commercial fertilizers. The manufactured ash fertilizers inhibited release of the K elements. It was also found through the continuous leaching test with pure water that the ash fertilizer had excellent moisture absorbability. However, the effects of some trace elements in fly ash on soil health and crop productivity as well as environmental considerations need to be established with long-term studies.     

一种新型土壤改良剂的制备及性能研究

以废弃蔗渣为原料提取纤维微晶,结合筛选的高效菌株制备成一种新型的土壤改良剂.通过土壤改良剂的红外光谱分析和电子扫描显微镜(SEM)微观形貌分析,土壤改良剂是由各单体在交联剂作用下形成的交联网状大分子,具有众多亲水基团的共聚体,纤维微晶呈白色条状分布,被共聚体所包裹.土壤改良剂吸水持续时间及吸水性能较蔗渣有明显提升,在去...     

Degradation of the fungicide difenoconazole in a silt loam soil as affected by pretreatment and organic amendment

Degradation of the fungicide difenoconazole was examined in a silt loam soil under controlled conditions (60% WHC, 30 degrees C) in the laboratory. Difenoconazole was applied at 0.1 and 1.0 mg kg(-1) dry soil, respectively. The experiments were run with non-pretreated and pretreated field soil, respectively, partly mixed with easily decomposable organic matter (leaf powder). In all experiments, degradation curves showed a sigmoidal shape with clear acclimation phases. Pretreatment with difenoconazole in the field decreased the acclimation phases, DT(50)- and, in some cases, DT(90)-values. The incorporation of easily decomposable organic matter decreased both DT(50)- and DT(90)-values and increased the general microbial activity significantly. We conclude that difenoconazole is metabolized by an acclimated part of the soil microflora. However, the degradation seems to be stimulated in the presence of suitable co-substrates.     

解磷微生物对煤系废弃物粉煤灰的改良效应

燃煤产生大量的粉煤灰虽会严重污染环境,但却含有植物生长必需的营养元素,将其资源化生物利用是一条很好的途径.从粉煤灰和农田土壤中分离筛选出 2 株解磷细菌 CA 和 SL,以紫花苜蓿为供试植物,通过盆栽试验研究接种解磷细菌对粉煤灰基质的改良作用.研究表明,加入解磷细菌后,对粉煤灰基质有一定的改良作用,促进了植物生长,增加了对粉煤灰中难溶性磷的吸收利用,降低了粉煤灰 pH,增加了根际细菌和真菌的数量.从粉煤灰中筛选分离出的菌株 CA的改良作用更显著,苜蓿的地上干重比对照提高了45.1%.解磷微生物的应用对于实现废弃物粉煤灰场的生态恢复提供了新的技术与潜力.     

Short-term effects of compost amendment on the fractionation of cadmium in soil and cadmium accumulation in rice plants

Purpose

We used a sequential extraction to investigate the effects of compost amendment on Cd fractionation in soil during different incubation periods in order to assess Cd stabilization in soil over time.

Methods

Pot experiments using rice plants growing on Cd-spiked soils were carried out to evaluate the influence of compost amendment on plant growth and Cd accumulation by rice. Two agricultural soils (Pinchen and Lukang) of Taiwan were used for the experiments. The relationship between the redistribution of Cd fractions and the reduction of plant Cd concentration due to compost amendment was then investigated.

Results and discussion

Compost amendment in Pinchen soil (lower pH) could transform exchangeable Cd into the Fe- and Mn-oxide-bound forms. With increasing incubation time, exchangeable Cd tended to transform into carbonate- and Fe- and Mn-oxide-bound fractions. In Lukang soil (higher pH), carbonate- and Fe- and Mn-oxide-bonded Cd were the main fractions. Exchangeable Cd was low. Compost amendment transformed the carbonate-bound form into the Fe and Mn oxide form. Pot experiments of rice plants showed that compost amendment enhanced plant growth more in Pinchen soil than in Lukang soil. Compost amendment could significantly reduce Cd accumulation in rice roots in both Pinchen and Lukang soils and restrict internal transport of Cd from the roots to the shoots. Because exchangeable Cd can be transformed into the stronger bonded fractions quickly in Pinchen soil, a reduction of Cd accumulation in rice due to compost amendment of Pinchen soil was significant by 45?days of growth. However, carbonate-bonded fractions in Lukang soil may provide a source of available Cd to rice plants, and exchangeable and carbonate-bonded fractions are transformed into the other fractions slowly. Thus, reduction of Cd accumulation by rice due to compost amendment in Lukang soil was significant by 75?days of growth.

Conclusions

The results of the study suggest that the effectiveness of compost amendment used for stabilization of Cd and to decrease the phytoavailability of Cd for rice plants is different in acidic and alkaline soils. In acidic soil, Cd fractionation redistributes quickly after compost amendment and shows a significant reduction of Cd accumulation by the plant within a few weeks. In alkaline soil, due to the strongly bound fractions of Cd being in greater quantity than the weakly bound ones, a longer period (a few months) to redistribute Cd fractions is needed.     

Potential use of DNA adducts to detect mutagenic compounds in soil

In this study, three different soils with contrasting features, spiked with 300 mg benzo[a]pyrene (BaP)/kg dry soil, were incubated at 20 °C and 60% water holding capacity for 540 days. At different time points, BaP and DNA were extracted and quantified, and DNA adducts were quantified by ³²P-postlabelling. After 540 days incubation, 69.3, 81.6 and 83.2% of initial BaP added remained in Cruden Bay, Boyndie and Insch soils, respectively. Meanwhile, a significantly different amount of DNA-BaP adducts were found in the three soils exposed to BaP over time. The work demonstrates the concept that DNA adducts can be detected on DNA extracted from soil. Results suggest the technique is not able to directly reflect bioavailability of BaP transformation products. However, this new method provides a potential way to detect mutagenic compounds in contaminated soil and to assess the outcomes of soil remediation.     

火力发电厂粉煤灰干燥特性研究

介绍了利用实验台对粉煤灰的干燥特性进行试验研究的情况 ,给出了粉煤灰的干燥曲线、干燥速率曲线和粉煤灰平衡湿含量计算式 ,分析了在干燥过程中粉煤灰的阻力特性 ,为粉煤灰干燥装置的工业化设计提供了理论依据     

蚯蚓处理污水污泥制取土壤改良剂

将污水污泥和秸秆按不同比例混合后进行30 d预堆肥处理,然后在实验室条件下接种爱胜蚓(Eisenia fetida)开展60 d蚯蚓处理实验,研究污水污泥理化性质变化规律及其影响因素,并分析最终产品(蚯蚓粪)质量。结果表明,蚯蚓处理使污水污泥pH、有机碳(TOC)、C/N和病原菌含量显著降低,电导率(EC)升高,TN、TP、TK(总钾)、碱解氮、速效磷、速效钾分别升高26.8%～40.8%、26.7%～52.4%、25.9%～44.8%、43.0%～120.0%、88.6%～406.8%、38.2%～113.2%,发芽指数(GI)达到80%以上。由于基质分解矿化引起质量损失,使蚯蚓粪中重金属相对含量增加,但仍在土地改良允许范围内。蚯蚓放养密度和物料含水率及其交互作用对蚯蚓处理效果存在显著影响,处理污水污泥的最优工况为:放养密度2.5 kg/m2、含水率60%。堆肥-蚯蚓处理组合工艺可将污水污泥转化为无害的、有价值的土壤改良剂。     

Nitrous oxide and dinitrogen emissions from soil under different water regimes and straw amendment

In a laboratory study, soil amended with and without wheat straw (2.8 g kg(-1) soil) was incubated under 70% water holding capacity (WHC), continuously flooded and flooded/drained cycle conditions at 30 degrees C for 51 days. Dinitrogen and N2O evolution and ammonia volatilisation were measured during the incubation. Extractable NH4+-N and NO3--N were determined at the end of the incubation. Entrapped N2, N2O, and dissolved NH4+-N and NO3--N in drainage water were measured in the flooded/drained cycle treatment when the floodwater was drained. The results indicated that N loss through ammonia volatilisation was undetected in all treatments due to the low soil pH value (pHH2O= 5.87) and no air movement. The recovery of urea-15N as N2 was lowest in the continuously flooded treatments (0.75% and 0.96% with and without straw amendment, respectively), highest in the 70% WHC treatments (5.65% and 4.41%, respectively), and intermediate in the flooded/drained cycle treatments (1.79% and 2.65%, respectively). The recovery of urea-15N as N2O was in the same order as that of N2, negligible in the continuously flooded treatments, 0.01% and 0.07% in the flooded/drained cycle treatments, and 1.29% and 2.23% in the 70% WHC treatments, respectively. Peak N2O evolution rates were observed after the floodwater was drained but no substantial evolution was found after the soil was reflooded following drained periods. However, peak N2 evolution rates were observed after the onset of both drainage and re-flooding. Considerable quantities of N2 but no detectable N2O were entrapped in the flooded soil.     

热镀锌厂酸洗废水及锌灰中锌回收

分别采用蒸酸法、氨络合法和硫化沉淀法分离回收热镀锌厂酸洗废水及锌灰中锌铁。分别考察了酸洗废水中盐酸的逸出特性和氨浸法回收蒸馏渣中锌的效果;利用酸洗废水的酸度浸取锌灰中的锌并用氨络合法分离酸浸出液中锌铁;利用硫化物不同溶度积选择性沉淀酸浸出液中的锌,考察了Na2S加入量、曝气时间、反应溶液pH和反应时间的影响。研究结果表明硫酸的加入能提高盐酸的蒸发率但效果不明显,氨络合法难于有效分离锌铁,但硫化物沉淀法可较好地分离锌铁,铁回收率可达97．12％,锌沉淀率达到99．99％,所得沉淀物中ZnS纯度为68．51％。     

Characterization of individual fly ash particles emitted from coal- and oil-fired power plants

Individual particles from coal- and oil-fired power plants were analyzed by scanning electron microscope equipped with an energy dispersive X-ray spectrometer to investigate size, morphology, and composition. Samples were collected on filters by dichotomous sampler in the fine ( <2.5 μm aerodynamic diameter) and coarse (2.5 to 5–10 μm) fractions. In both fractions coal fly ash particles were predominantly ( > 95%) smooth, mineral spheres. No cenospheres (perforated hollow spheres) were detected, and almost 90% of the mass concentrations occurred in the coarse fraction. Sulfur as lared as a surface layer on the mineral core; the abundances of Fe and S were highly variable. The Al/Si ratio was fairly constant for most of the spheres but not for the relatively few Fe-rich or non-spherical coal fly ash particles. Over 90% of the mass of oil fly ash occurred in the fine fraction. The size distribution of chemical and morphological properties of individual oil fly ash particles was found to be trimodal. Oil fly ash particles smaller than 0.7 μ (geometric diameter) were non-spherical and relatively pure in sulfate, and 90% of such particles were smaller than 0.5 μm; V or Ni could be detected in 50% to 60% of such particles larger than 0.3 μm. Those particles in the 0.7–3 μm range of geometric diameters were predominantly spherical and of mineral composition, highly variable in Al, Si, P, Ca, Ti and Fe; 50–60% of them contained detectable amounts of V or Ni. Larger oil fly ash particles had a lacy morphology and consisted of carbonaceous material and sulfur.     

Leaching and reduction of chromium in soil as affected by soil organic content and plants

The oxidation state of chromium in contaminated soils is an important indicator of toxicity and potential mobility. Chromium in the hexavalent state is highly toxic and soluble, whereas the trivalent state is much less toxic and relatively insoluble. A laboratory study investigated the impact of growing plants and supplemental organic matter on chromium transport in soil. Plants alone had no appreciable effect on the chromium oxidation state in soil. Soil columns with higher organic content were associated with lower ratios of chromate:total chromium than the columns with lower organic matter. Analyses of column leachate, plant biomass, and soil indicate that more chromium leaching occurred in the vegetated, low organic columns. Retention of Cr in the soils was correlated to the Cr(III) content. Plant uptake of chromium accounted for less than 1% of the chromium removed from the soil. Overall, the addition of organic matter had the strongest influence on chromium mobility.     

Effect of green manure amendment on herbicide pendimethalin on soil

Manure amendment in agricultural practice can have a large effect on herbicide dissipation because the period of manure plowing is close to the period of herbicide application. In addition, manure amendment is among the frequently encountered options in ameliorating pesticide pollution. In this research, the dissipation of the herbicide pendimethalin was examined after amendment with two common green manures, Lupinus luteus (L) or Cosmos bipinnatus (C), for 110 days in pH 5.2 and 7.7 soils (Sankengtzu [Sk] and Erhlin [Eh] soil, respectively). The microbial activity and ecology changes were examined by using Biolog EcoPlate and denaturing gradient gel electrophoresis (DGGE). In Sk soil, the half-lives of pendimethalin with L, C, and blank treatment were 49.0, 54.9, and 62.2 days, respectively, whereas that in Eh soil they were 46.3, 52.6, and 34.8 days, respectively. Pendimethalin dissipated quickly in more neutral soil (Eh soil), but the addition of manure can only increase the dissipation rate in acidic soil (Sk soil), indicating that the amendment of manures exerted different effect in pendimethalin dissipation rates in different pH soils. The application of pendimethalin and/or manure altered the microbial community activity after 24 h of incubation. After 110 days, the microbial community activities in green manure–amended soil were more similar to that with blank than pendimethalin treatment in both types of soils. In comparison with treatment C, microbial communities were more similar between treatment L and blank, indicating the superior effect over pendimethalin on microbial communities when applying Lupinus luteus. The research showed that the application of herbicide pendimethalin changed soil microbial community, and the amendment of manures exerted different effect in pendimethalin dissipation rates in different pH soils. It is assumed that the change in dissipation rates was originated from the microbial community change after different manure amendment.     

Evaluation of antibiotic mobility in soil associated with swine-slurry soil amendment under cropping conditions

Interest in identifying pools of antibacterial-resistance genes has grown over the last decade, with veterinary antibiotics (VAs) receiving particular attention. In this paper, a mesoscale study aimed at evaluating the vertical transport of common VAs—namely, fluoroquinolones, tetracyclines, sulfonamides, and lincosamides in agricultural soil subjected to drip irrigation—was performed under greenhouse conditions. Accordingly, leachates of cropped and uncropped soil, amended with swine-slurry leading to 19–38 μg kg^?1 (dry mass) antibiotics in the soil, were analyzed over the course of the productive cycle of a lettuce (42 days) with three sampling campaigns (N?=?24). High lincomycin (LCM) concentrations (30–39 μg L^?1) were detected in the leachates collected from the swine-slurry-amended soil. The highest LCM mass recovered in the leachates (30.1?±?1.63 %) was obtained from cropped experimental units. In addition, the LCM leaching constant and its leaching potential as obtained from the first-order model were higher in the leachates from the cropped experimental units. Lower concentrations of sulfadimethoxine were also detected in leachates and in soil. Enrofloxacin and oxytetracycline occurred only in soil, which is consistent with high soil interaction.     

热镀锌厂酸洗废水和锌灰中回收硫化锌

从热镀锌厂的酸洗废水和锌灰中回收硫化锌,采用X射线能谱仪(EDS),X射线衍射仪(XRD),傅里叶红外光谱仪(FTIR)和场发射透射电镜(FETEM)表征样品ZnS性质,电感耦合等离子发射体(ICP-OES)分析上清液性质,并研究该反应动力学过程。EDS和ICP分析表明,样品ZnS纯度达到85.45%,其上清液含有高浓度铁,含量为2 g/L,可用于制备复合亚铁絮凝剂,而其他重金属离子浓度均低于电镀废水排放标准。XRD分析表明,样品ZnS是立方晶型,调节pH和采用滴加方式能有效改善样品ZnS的晶型。采用Scherrer公式计算晶体粒径,结果表明,晶粒大小在3~6 nm之间。FTIR分析表明,样品ZnS呈现良好的红外透明性,且温度、pH和滴加方式对样品的红外透光性基本没有影响。FETEM结合XRD图表明,该纳米晶呈片状,近似为球形,呈多层叠加,分散性不明显,有团聚现象。动力学实验表明,逆一级动力学方程适合描述硫化沉淀的反应动力学过程,活化能为39.04 kJ/mol,沉淀过程受化学反应和扩散联合控制。     

Palygorskite as a feasible amendment to stabilize heavy metal polluted soils

The sorption behaviour of palygorskite has been studied with respect to lead, copper, zinc and cadmium in order to consider its application to remediate soils polluted with these metals. The Langmuir model was found to describe well the sorption processes offering maximum sorption values of 37.2 mg/g for lead, 17.4 mg/g for copper, 7.11 mg/g for zinc and 5.83 mg/g for cadmium at pH 5-6. In addition the effect of palygorskite amendment in a highly polluted mining soil has been studied by means batch extractions and leaching column studies. The soluble metal concentrations as well as the readily-extractable metal concentrations were substantially decreased at any concentration of palygorskite applied to soil (1, 2, 4%), although the highest decrease is obtained at the 4% dose. The column studies also showed a high reduction in the metal leaching (50% for lead, 59% for copper, 52% for zinc and 66% for cadmium) when a palygorskite dose of 4% was applied.     

Activated carbon amendment to sequester PAHs in contaminated soil: a lysimeter field trial

Activated carbon (AC) amendment is an innovative method for the in situ remediation of contaminated soils. A field-scale AC amendment of either 2% powder or granular AC (PAC and GAC) to a PAH contaminated soil was carried out in Norway. The PAH concentration in drainage water from the field plot was measured with a direct solvent extraction and by deploying polyoxymethylene (POM) passive samplers. In addition, POM samplers were dug directly in the AC amended and unamended soil in order to monitor the reduction in free aqueous PAH concentrations in the soil pore water. The total PAH concentration in the drainage water, measured by direct solvent extraction of the water, was reduced by 14% for the PAC amendment and by 59% for GAC, 12 months after amendment. Measurements carried out with POM showed a reduction of 93% for PAC and 56% for GAC. The free aqueous PAH concentration in soil pore water was reduced 93% and 76%, 17 and 28 months after PAC amendment, compared to 84% and 69% for GAC. PAC, in contrast to GAC, was more effective for reducing freely dissolved concentrations than total dissolved ones. This could tentatively be explained by leaching of microscopic AC particles from PAC. Secondary chemical effects of the AC amendment were monitored by considering concentration changes in dissolved organic carbon (DOC) and nutrients. DOC was bound by AC, while the concentrations of nutrients (NO(3), NO(2), NH(4), PO(4), P-total, K, Ca and Mg) were variable and likely affected by external environmental factors.