The impact of sludge amendment on gas dynamics in an upland soil: monitored by membrane inlet mass spectrometry

Studies of the land disposal of biosolids and municipal sewage have focused largely on the potential pollution of the soil with pathogens, toxic compounds or heavy metals. Little is known about the impact of sludge amendment on carbon source and sink concentrations in soils. In this study gas concentrations in Scottish soil cores (from limed and unlimed plots) were monitored continuously at 3 cm depth before, during and after sludge application using membrane inlet mass spectrometry (MIMS). Following sludge application to soil cores, significant and sustained increases in CH4 (for 8 days) and CO2 (for between 16 and 120 days) concentration were observed. This suggested short-term stimulation of indigenous methanogens, provision of a new methanogenic inoculum, or inhibition of methane oxidizers (for example by heavy metals or NH4 in sludge). Soil microbial fermentative activity was enhanced over periods of a few months as shown by elevated CO2 concentrations.     

Carbon monoxide uptake kinetics in unamended and long-term nitrogen-amended temperate forest soils

The effect of nitrogen (N) additions on the dynamics of carbon monoxide consumption in temperate forest soils is poorly understood. We measured soil CO profiles, potential rates of CO consumption and uptake kinetics in temperate hardwood and pine control plots and plots amended with 50 and 150 kg N ha-1 year-1 for more than 15 years. Soil profiles of CO concentrations were above atmospheric levels in the high-N plots of both stands, suggesting that in these forest soils the balance between consumption and production may be shifted so that either production is increased or consumption decreased. Highest rates of CO consumption were measured in the organic horizon and decreased with soil depth. In the N-amended plots, CO consumption increased in all but one soil depth of the hardwood stand, but decreased in all soil depths of the pine stand. CO enzyme affinities increased with soil depth in the control plots. However, enzyme affinities in the most active soil depths (organic and 0-5 cm mineral) decreased in response to low levels of N in both stands. In the high-N plots, affinities dramatically-increased in the hardwood stand, but decreased in the organic horizon and increased slightly in the 0-5 cm mineral soil in the pine stand. These findings indicate that long-term N addition either by fertilization or deposition may alter the size, composition and/or physiology of the community of CO consumers so that their ability to act as a sink for atmospheric CO has changed. This change could have a substantial effect on the lifetime of greenhouse gases such as CH4 and therefore the future of Earth's climate.     

Mobility and survival of Salmonella Typhimurium and human adenovirus from spiked sewage sludge applied to soil columns

Aims:  This study investigated the survival and transport of sewage sludge-borne pathogenic organisms in soils.
Methods and Results:  Undisturbed soil cores were treated with Salmonella enterica ssp. enterica serovar Typhimurium- lux (STM- lux ) and human adenovirus (HAdV)-spiked sewage sludge. Following an artificial rainfall event, these pathogens were analysed in the leachate and soil sampled from different depths (0–5 cm, 5–10 cm and 10–20 cm) after 24 h, 1 and 2 months. Significantly more STM- lux and HAdV leached through the soil cores when sewage sludge was present. Significantly more STM- lux were found at all soil depths, at all time periods in the sewage sludge treatments, compared to the controls. The rate of decline of STM- lux in the controls was more rapid than in the sewage sludge treatments. Survival and transport of HAdV were minimal.
Conclusions:  The presence of sewage sludge can significantly influence the transport and survival of bacterial pathogens in soils, probably because of the presence of organic matter. Environmental contamination by virus is unlikely because of strong soil adsorption.
Significance and Impact of the Study:  This study suggests that groundwater contamination from vertical movement of pathogens is a potential risk and that it highlights the importance of the treatment requirements for biosolids prior to their application to land.     

盆栽荷木、肖蒲桃和黄果厚壳桂幼苗对土壤温室气体排放影响的培育实验研究

通过对土壤65d的室内培养,比较研究了种上荷木、肖蒲桃和黄果厚壳桂幼苗并受模拟酸雨淋洗42月的盆栽土壤温室气体CO2、CH4、N2O排放的差异。结果发现,种植肖蒲桃的土壤CO2排放显著大于种植荷木和黄果厚壳桂的土壤,种植肖蒲桃和黄果厚壳桂的土壤CH4吸收显著大于种植荷木的土壤,而树种对土壤N2O的排放影响不明显。分析表明,土壤CO2的排放和对CH4的吸收的树种间差异并不完全由树种导致的土壤碳氮性质差异引起的,而导致树种对N2O的排放无差异的原因则很复杂。     

Soil microorganisms as controllers of atmospheric trace gases (H2, CO, CH4, OCS, N2O, and NO).

Production and consumption processes in soils contribute to the global cycles of many trace gases (CH4, CO, OCS, H2, N2O, and NO) that are relevant for atmospheric chemistry and climate. Soil microbial processes contribute substantially to the budgets of atmospheric trace gases. The flux of trace gases between soil and atmosphere is usually the result of simultaneously operating production and consumption processes in soil: The relevant processes are not yet proven with absolute certainty, but the following are likely for trace gas consumption: H2 oxidation by abiontic soil enzymes; CO cooxidation by the ammonium monooxygenase of nitrifying bacteria; CH4 oxidation by unknown methanotrophic bacteria that utilize CH4 for growth; OCS hydrolysis by bacteria containing carbonic anhydrase; N2O reduction to N2 by denitrifying bacteria; NO consumption by either reduction to N2O in denitrifiers or oxidation to nitrate in heterotrophic bacteria. Wetland soils, in contrast to upland soils are generally anoxic and thus support the production of trace gases (H2, CO, CH4, N2O, and NO) by anaerobic bacteria such as fermenters, methanogens, acetogens, sulfate reducers, and denitrifiers. Methane is the dominant gaseous product of anaerobic degradation of organic matter and is released into the atmosphere, whereas the other trace gases are only intermediates, which are mostly cycled within the anoxic habitat. A significant percentage of the produced methane is oxidized by methanotrophic bacteria at anoxic-oxic interfaces such as the soil surface and the root surface of aquatic plants that serve as conduits for O2 transport into and CH4 transport out of the wetland soils. The dominant production processes in upland soils are different from those in wetland soils and include H2 production by biological N2 fixation, CO production by chemical decomposition of soil organic matter, and NO and N2O production by nitrification and denitrification. The processes responsible for CH4 production in upland soils are completely unclear, as are the OCS production processes in general. A problem for future research is the attribution of trace gas metabolic processes not only to functional groups of microorganisms but also to particular taxa. Thus, it is completely unclear how important microbial diversity is for the control of trace gas flux at the ecosystem level. However, different microbial communities may be part of the reason for differences in trace gas metabolism, e.g., effects of nitrogen fertilizers on CH4 uptake by soil; decrease of CH4 production with decreasing temperature; or different rates and modes of NO and N2O production in different soils and under different conditions.     

玉渡山水库生长季温室气体排放特征及其影响因素

为了探讨温带水库温室气体排放规律,采用静态箱-色谱分析法,研究了温带地区库龄10年内的北京玉渡山水库生长季3种温室气体CO2、CH4及N2O排放特征,及其影响因子。结果表明:样地类型、测定月份与样地类型交互作用对3种温室气体通量影响极显著,5月消落带CO2通量(664.31mg·m-2·h-1)达到最大,显著高于入库口和浅水区;8月消落带CH4通量(0.87mg·m-2·h-1)及N2O通量(3.05mg·m-2·h-1)最大;8月,切除消落带样地地上植物后,3种温室气体通量均有所降低。CO2通量与地下5cm地温、氧化还原电位和水体总氮显著正相关,与地上生物量和水体pH显著负相关;CH4通量与地表温度、地上生物量、水体pH呈显著相关,与水体总氮和水体铵态氮显著负相关;N2O通量与水体总氮含量显著相关,与水体pH显著负相关。采取平均估值法初步推测,在生长季,水库消落带、入库口及浅水区CO2排放量依次为15960、2160、-70kg·hm-2;CH4排放量依次20.04、-7.05、14.8kg·hm-2;N2O排放量依次83.42、3.79、-1.54kg·hm-2;表明消落带3种温室气体的排放量均较高,为玉渡山水库3种温室气体排放的重点区域。     

Methane oxidation in landfill cover soil

Methane oxidation in the cover soil of the Khmet'evo municipal landfill in Moscow oblast was investigated. Methane emission from the experimental parcel of the site was highly inhomogeneous. At a depth of 45-60 cm, the pore gas mainly consisted of CH4 (60-70%) and CO2 (30-40%). In the upper horizons of the cover soil, the concentration of these gases sharply decreased. Techniques for estimation of the methane-oxidizing activity in the cover soil of the landfill were tested. The rate of methane oxidation in the soil, the factor limiting methane emission from the surface of the site, correlated with the cell number of culturable methanotrophic bacteria. The method of indirect immunofluorescence revealed ten known species of methanotrophic bacteria in enrichment cultures obtained from samples of the cover soil. Our results also indicate the presence of unknown psychrotolerant methanotrophs that are active at the low temperatures characteristic of Moscow oblast.     

不同水旱轮作体系稻田土壤剖面N2O的分布特征

通过原位采集淹水和排水状态下土壤剖面4个层次的气体,研究氧化亚氮（N₂O）在水旱轮作体系稻田土壤剖面中的动态分布特征.试验设置小麦-单季稻和油菜-双季稻两种轮作体系,包括施N和不施N两种施肥方式.结果表明:施用N肥极显著促进了土壤剖面N₂O的产生（P<0.01）,不同层次间N₂O浓度相关性极显著（P<0.01）,小麦、油菜生长期施N和无N处理下层30 cm和50 cm处N₂O浓度均高于表层7 cm和15 cm处;早稻无N处理则为表层7 cm和15 cm处高于下层30 cm和50 cm处（P<0.05）,其他水稻处理各层次间无显著差异.无N处理土壤N₂O峰值出现在旱作向水稻的转变期,施N处理则出现在旱作第2次追肥后,季节转变期也有较高的N₂O浓度.     

Greenhouse gas emission during storage of pig manure on a pilot scale

The greenhouse gas emissions (CO2, CH4, N2O) from a 2 ton (4.4 m3) deep litter pig manure pile (storage time 113 days during winter season) were quantified by using a tent, which covered the whole pile during the measuring periods only. The emissions were calculated in CO2 equivalents per kilogram dry matter by. Additionally the retention time (use of tracer gas SF6) and the concentrations of the gases in different parts of the pile were determined. The average retention time of the gases in the pile was less than 2 h. CH4 is assumed to have been generated only in the centre of the pile, whereas CO2 was assumed to have been generated in a wider zone. The emissions of CH4, CO2 and N2O were at the highest in the beginning when nearly the whole pile had temperatures in the range of thermophilic microorganisms. This leads to the assumption that mainly thermophilic microorganisms formed the gases. The most important gas for global warming was found to be nitrous oxide.     

两种污泥连续施用对潮土重金属含量及酶活性的影响

采用盆栽土培试验,研究了工业污泥(化工厂底泥)及城市污水处理厂剩余污泥中重金属存在的形态与含量,以及两种污泥连续施用对潮土重金属含量及酶活性的影响。结果表明,两种污泥中的重金属主要是以非交换态存在,城市污水处理厂剩余污泥中总的重金属含量比工业污泥低,而重金属的有效性比工业污泥高;污泥的施用能增加潮土中脲酶的活性,多酚氧化酶及中性磷酸酶的活性与污泥的施用量有一定相关性,并与土壤中交换态Zn、Cu含量呈一定负相关,土壤多酚氧化酶及过氧化氢酶活性可作为土壤中重金属Zn污染的指示指标;污泥的施用有提高潮土中交换态Cu、Zn及Pb含量的趋势。     

Differences on nitrogen availability in a soil amended with fresh, composted and thermally-dried sewage sludge

Anaerobically-digested sludge called fresh sludge (F), composted sludge (C) and thermally-drying sludge (T), all from the same batch, were applied to the surface of a calcareous Udic Calciustept with loamy texture. Dosage equivalent was 10 t ha(-1) of dry matter. The concentration of mineral nitrogen (ammonium and nitrate) in the soil was measured in order to estimate the effects of the post-treatments to which the different kinds of sewage sludge are subjected in relation to the availability of N in the surface layer of the soil. The most significant differences in NH(4)-N and NO(3)-N concentrations due to the transformation of the organic matter were observed during the first three weeks following soil amendment. Thermally-dried and composted sludge initially displayed higher concentrations of ammonium and nitrate in soil. Five months after the amendment, soil applied with fresh sludge showed the highest concentrations of NH(4)-N and NO(3)-N (6.1 and 36.6 mg kg(-1), respectively). It is clear that the processes of composting and thermal-drying influence the bioavailability of nitrogen from the different types of sewage sludge.     

Leaching of boron through sewage sludge amended soil: the role of clinoptilolite

A laboratory experiment was conducted to determine the release of boron from soil-sewage sludge mixtures by leaching using a clinoptilolite type natural zeolite, before land application of the sewage sludge. Soil columns were filled up with the clinoptilolite soil after mixing with sewage sludge at a rate of 30 tons ha(-1) and with two different particle sizes (0.1-0.25 and 1.0-2.0 mm) of clinoptilolite each at the concentrations of 1% and 2%. The particle size and the application rate of clinoptilolite affected both boron leaching from soil compared to the control treatment (soil and sewage sludge mixture). The total soluble boron leached from a soil column varied from 66-92% depending on the applications of clinoptilolite and reached 96% for the control treatment, following application of 80 cm depth of water in all treatments. In the cases of the 1% application rate of 0.1-0.25 and 1-2 mm sized clinoptilolite 78% and 92% of the total boron leached, respectively. While at 2% application rate of 0.1-0.25 and 1-2 mm zeolite, 66% and 87% of total soluble boron leached, respectively. Boron concentrations in the soil layers increased as application rate increased and particle size of clinoptilolite decreased because of its high adsorption capacity. Adsorption isotherms indicated that clinoptilolite had a high adsorption capacity for boron compared to the sewage sludge and soil.     

Effects of tillage and nitrogen fertilizers on CH4 and CO2 emissions and soil organic carbon in paddy fields of central China

Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha(-1)) on fluxes of CH(4) and CO(2), and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH(4) emissions by 13%-66% and SOC by 21%-94% irrespective of soil sampling depths, but had no effect on CO(2) emissions in either year. Tillage significantly affected CH(4) and CO(2) emissions, where NT significantly decreased CH(4) emissions by 10%-36% but increased CO(2) emissions by 22%-40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%-48% in the 0-5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0-20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered.     

多年冻土退化地区湿地土壤温室气体排放及其影响因子

采用野外原位实验静态箱-气相色谱法,研究了兴安岭多年冻土不同程度退化地区生长季湿地土壤温室气体CH4、CO2和N2O的排放通量特征,同时分析了环境因子对土壤温室气体排放的影响。结果表明:1)3种类型冻土区(季节性冻土区、岛状多年冻土区、连续多年冻土区,分别用D1、D2、D3表示)土壤在生长季时期表现为CO2和N2O的源;D1和D3为CH4的源,D2为CH4的汇。D1、D2、D3土壤在生长季中平均CH4排放通量分别为(0.127±0.021)、(-0.020±0.006)、(0.082±0.019)mg·m^-2·h^-1;CO2排放通量分别为(371.50±66.73)、(318.43±55.67)、(213.19±37.05)mg·m^-2·h^-1;N2O排放通量分别为(24.05±2.62)、(8.07±2.42)、(2.17±0.25)μg·m-2·h-1。土壤CO2和N2O排放通量随多年冻土退化程度的加剧呈现出升高的趋势。2)细根生物量、凋落物生物量、全碳、全氮、可溶性有机碳、总可溶性氮、土壤容重、土壤温度、土壤含水量等均影响温室气体排放,3种不同类型冻土区土壤CH4、CO2和N2O的排放差异是诸多影响因子综合作用的结果。     

Structure and function of methanotrophic communities in a landfill-cover soil

In landfill-cover soils, aerobic methane-oxidizing bacteria (MOB) convert CH(4) to CO(2), mitigating emissions of the greenhouse gas CH(4) to the atmosphere. We investigated overall MOB community structure and assessed spatial differences in MOB diversity, abundance and activity in a Swiss landfill-cover soil. Molecular cloning, terminal restriction-fragment length polymorphism (T-RFLP) and quantitative PCR of pmoA genes were applied to soil collected from 16 locations at three different depths to study MOB community structure, diversity and abundance; MOB activity was measured in the field using gas push-pull tests. The MOB community was highly diverse but dominated by Type Ia MOB, with novel pmoA sequences present. Type II MOB were detected mainly in deeper soil with lower nutrient and higher CH(4) concentrations. Substantial differences in MOB community structure were observed between one high- and one low-activity location. MOB abundance was highly variable across the site [4.0 × 10(4) to 1.1 × 10(7) (g soil dry weight)(-1)]. Potential CH(4) oxidation rates were high [1.8-58.2 mmol CH(4) (L soil air)(-1) day(-1) ] but showed significant lateral variation and were positively correlated with mean CH(4) concentrations (P < 0.01), MOB abundance (P < 0.05) and MOB diversity (weak correlation, P < 0.17). Our findings indicate that Methylosarcina and closely related MOB are key players and that MOB abundance and community structure are driving factors in CH(4) oxidation at this landfill.     

Effects of organic matter on virus transport in unsaturated flow.

The effects of natural humic material and sewage sludge organic matter (SSOM) derived from primary treated sewage sludge on virus transport by unsaturated flow through soil columns were evaluated. Bacteriophage MS-2 was applied to loamy fine sand columns 0.052 m in diameter and 1.05 m long. Virus concentrations in the influent and effluent were measured daily for 7 to 9 days. In the first experiment, virus transport through two fresh soil columns was compared with that through a column previously leached with more than four pore volumes (T) of well water. The soil water organic matter concentrations in the leachate of the fresh soil declined with time. Relative virus concentrations (C/Co) from one fresh soil column reached 0.82 in 0.9 T and then declined to 0.51 by 2.1 T. The other fresh soil column reached and maintained a steady-state relative virus concentration [(C/Co)s] of 0.47 from 1.5 to 2.5 T. The leached column reached and maintained a (C/Co)s of 0.05. Concentrations measured at 0.2-, 0.4-, 0.8-, and 1.05-m depths indicated that most virus particles were removed in the surface 0.2 m. In the second experiment, one leached column was pretreated with SSOM derived from primary treated sewage sludge and the other leached column was untreated. SSOM concentrations declined with depth. A suspension of virus and SSOM in well water was applied to both columns. Although the (C/Co)s values were similar (0.41 for the pretreated column and 0.47 for the untreated column), breakthrough was delayed for the untreated column. Both natural humic material and sewage sludge-derived SSOM increased the unsaturated-flow transport of MS-2.     

Persistence of poliovirus 1 in soil and on vegetables grown in soil previously flooded with inoculated sewage sludge or effluent.

Land disposal of sewage sludge and effluent is becoming a common practice in the United States. The fertilizer content and humus value of such wastes are useful for agricultural purposes, and the recycling of sewage onto the land eliminates many of our stream pollution problems. The potential exists for crops grown in such irrigated soil to be contaminated by viruses that may be present in the sewage. Studies were initiated to determine viral persistence in soil and on crops grown under natural conditions in field plots that had been flooded to a depth of 1 inch (2.54 cm) with poliovirus 1-inoculated sewage wastes. Lettuce and radishes were planted in sludge- or effluent-flooded soil. In one study, the vegetables were planted 1 day before flooding, and in another they were planted 3 days after the plots were flooded. Survival of poliovirus 1 in soil irrigated with inoculated sewage sludge and effluent was determined during two summer growing seasons and one winter period. The longest period of survival was during the winter, when virus was detected after 96 days. During the summer, the longest survival period was 11 days. Poliovirus 1 was recovered from the mature vegetables 23 days after flooding of the plots had ceased. Lettuce and radishes are usually harvested 3 to 4 weeks after planting.     

Persistence of poliovirus 1 in soil and on vegetables grown in soil previously flooded with inoculated sewage sludge or effluent.

Land disposal of sewage sludge and effluent is becoming a common practice in the United States. The fertilizer content and humus value of such wastes are useful for agricultural purposes, and the recycling of sewage onto the land eliminates many of our stream pollution problems. The potential exists for crops grown in such irrigated soil to be contaminated by viruses that may be present in the sewage. Studies were initiated to determine viral persistence in soil and on crops grown under natural conditions in field plots that had been flooded to a depth of 1 inch (2.54 cm) with poliovirus 1-inoculated sewage wastes. Lettuce and radishes were planted in sludge- or effluent-flooded soil. In one study, the vegetables were planted 1 day before flooding, and in another they were planted 3 days after the plots were flooded. Survival of poliovirus 1 in soil irrigated with inoculated sewage sludge and effluent was determined during two summer growing seasons and one winter period. The longest period of survival was during the winter, when virus was detected after 96 days. During the summer, the longest survival period was 11 days. Poliovirus 1 was recovered from the mature vegetables 23 days after flooding of the plots had ceased. Lettuce and radishes are usually harvested 3 to 4 weeks after planting.     

Viruses in sewage: effect of phosphate removal with calcium hydroxide (lime).

During calcium hydroxide (lime) treatment (pH 9.6 to 10.5) of wastewaters for phosphate removal there was also a two-log removal of added poliovirus (type I, Sabin) from effluents. A similar virus reduction was seen in the sludge generated in these experiments. However, in view of the limitations of techniques for virus recovery from sludge, only a small portion of the infectious virus present in lime sludge may have been detected. Storage of lime sludge at 28 degrees C for up to 48 h produced no appreciable reduction in the virus titre. Five sets of field samples of sewage, effluents, and sludge from a sewage treatment plant (Kemptville, Ont.) which utilizes lime for phosphate removal were also examined for indigenous viruses being BS-C-1 cells. All of the sample of lime sludge and 80% of the samples of both sewage and lime-treated effluent revealed virus; after chlorination only 20% of the lime-treated effluent samples were positive for virus. In contrast, in an earlier study with essentially the same experimental set up, 76% of the sample of chlorinated primary effluent were found to contain virus. Because of the easily detectable quantities of infectious virus in lime sludge and due to the lack of virus inactivation during storage of such sludge, caution must be exercised in its handling and disposal.