Effects of the application of heated sewage sludge on soil nutrient supply to plants

Abstract

We previously reported that heating sewage sludge significantly changes the rate of N mineralization. The present study was undertaken to examine the extent to which these changes affect plant growth and nutrient supply after application to different soils. A pot experiment in which komatsuna plants (Brassica campestris L. var. rapa) were grown in a Fluvisol or an Arenosol indicated that the amount of N taken up by the plants increased significantly by heating air-dried sludge at 120°C and decreased significantly by heating at 180°C. Heat-drying of the sludge at 120°C or 180°C also increased the N uptake significantly. These plant responses could be explained by the heat-induced changes in the release of inorganic N from the sludge. In contrast to N, the sludge materials containing Fe as a coagulant immobilized soil soluble P. When the sludge was applied to an Andosol, the N-supplying effects on plant growth were offset by P adsorption onto the sludge and soil. In a successive pot experiment conducted without additional sludge application, it was further suggested that frequent sludge application is required to maintain plant growth. However, it will also lead to the accumulation of sludge components in the soil because less than 40% and 15% of the sludge N and P, respectively, were apparently recovered in two harvests of the plants. In conclusion, heated sludge materials can act as an effective organic N fertilizer provided that they are applied to a suitable soil and that the short-term effects on soil productivity are balanced with the long-term effects on environmental quality.     

污泥保水功能的研究及应用初报

污泥的透水性差,难以干燥是污泥资源化利用的技术障碍。可以利用污泥的这一特性,开发污泥保水的新功能。以土培及玉米盆栽研究污泥不同含量与在土壤中不同放置方式的保水效果,对土培的含水量、失水量及失水率,盆栽土壤水分含量及植株生物量进行了系统分析。污泥含量高的处理有一定保水效果但不及保水剂处理,而其盆栽结果却优于保水剂处理。污泥在土层的不同放置试验表明,在土壤中层状放置的土培及盆栽试验结果均优于全层混合,且双层的效果最优。污泥具有较强的保水性,是有待开发的新功能。与在土壤合适的放置方式结合,可更好地发挥其保水潜力。     

干污泥和堆肥污泥施用于红壤中N素的释放特性

在红壤自然状况下,模拟了施肥沟,对红壤不同污泥施肥处理的N素释放特性进行了研究。试验结果表明,干污泥配比在10%~20%时,碱解氮、铵态氮和硝态氮累计释放量分别为:25.71%~33.48%,9.57%~14.85%和4.08%~7.65%。堆肥污泥配比在20%~33%时,其累计释放量分别为13.55%~15.65%,2.03%~4.23%和3.11%~5.37%。干污泥处理的释放量大于堆肥污泥处理的释放量,释放过程变化较堆肥污泥剧烈,铵态氮和硝态氮均有明显峰值,铵态氮最大含量532.98±10 mg/kg,释放量最大达10.95%;硝态氮含量最大为149.2±14 mg/kg,释放量最大时为3.32%。无论是从氮的肥效角度,还是氮释放的环境风险角度考虑,污泥堆肥处理后施肥方式均优于干污泥处理施肥方式。     

施用辐照处理的污水污泥对作物产量和土壤氮的影响

A field experiment was conducted to study the feasibility of irradiated and non-irradiated sewage sludge as a fertilizer for the growth of wheat and rice. The irradiated and non-irradiated sewage sludge were applied at rates of 0 (CK), 75, 150, 225 and 300 kg N ha^-1 for wheat, and 0 (CK), 112.5, 225, 337.5 and 450 kg N ha^-1 for rice, respectively. (NH₄)₂SO₄ at a rate of 150 kg N ha^-1 for wheat, and 225 kg N ha^-1 for rice were added to the control treatments. Additionally, 20 kg ¹⁵N ha^-1 in the form of (NH₄)₂SO₄ was added to each treatment for wheat to study the effect of sewage sludge on chemical nitrogen fertilizer recovery. The results showed that the irradiation of sewage sludge by gamma ray at a dosage of 5 kGy increased crop yield by 11%~27% as compared to the non-irradiated treatments. Irradiation stimulated mineralization of organic nitrogen in the sludge and improved seedling growth. It was found that addition of irradiated sludge could reduce the leaching loss of chemical nitrogen fertilizer. Both irradiated and non-irradiated sewage sludge could increase the content of soil total nitrogen. Based on the preliminary results, it was concluded that irradiated sewage sludge could partly substitute for chemical nitrogen fertilizer in crop production.     

用15N肥料标记法研究潮土中玉米氮肥的利用率与去向

【目的】特定作物体系中氮肥的去向很难做到定量化。本文以玉米为供试作物,解析潮土上玉米作物氮素肥料利用、 转移规律,探讨肥料氮、 土壤氮与作物氮之间的关系。【方法】采用15N标记和盆栽培养技术,在北京市农林科学院人工控温温室条件下进行模拟研究,设置10个施氮水平(0、 22、 44、 66、 88、 111、 133、 177、 222、 266 mg/kg N),分析植株氮素利用和土壤氮素供应特征,研究潮土种植夏玉米条件下氮素肥料的运移规律及不同氮肥剂量对夏玉米的作用效应。【结果】所有施氮处理均显著提高了玉米生物量和植株吸氮量。氮肥利用效率虽然随施氮量增加有升有降,但处理间差异不显著。夏玉米对15N标记氮肥的回收率为9.01%~67.57%,土体中15N残留率和损失率分别为21.40%~40.54%和11.04%~50.45%,均随施氮量的增加而显著增加。与N1~N3(22、 44、 66 mg/kg)施肥水平处理相比,N4(88 mg/kg)处理条件下15N肥料在土壤中残留率分别减少19.14、 12.38、 13.13个百分点;15N肥料的损失率分别降低39.41、 7.88、 13.88个百分点。氮肥施用量超过88 mg/kg时,各个处理条件下玉米植株生物量和氮肥回收率出现降低趋势,分别降低5.88%~8.0%和9.06%~27.81%;15N肥料在土壤中的残留率和损失率分别减少3.36%~17.30%和1.65%~13.57%。【结论】该试验条件下,玉米的合理施氮量为88 mg/kg时,氮素的利用率最高为67.57%,残留率和损失率最低,分别为21.40%和11.04%,对生态环境的压力较小。     

污水慢速渗滤土地处理系统的改进试验研究

传统的污水慢速渗滤土地处理系统以污水的深度处理和利用为主要目标,水力负荷较小。该试验对传统的土地处理系统进行改进,在土壤1 m深处设置排水系统,增大系统水力负荷。试验结果表明,在大水力负荷情况下,改进的污水慢速渗滤土地处理系统对污染物有较好地去除效果,出水水质优良。除总氮外各指标浓度均满足地面水环境Ⅲ类水域水质标准要求。     

Potassium Jarosite for fertilizer

Japan has scarcely any potassic resource in her country. Therefore, the shortage was severe in the second world war. In this time I had investigated the fertilizer utilization of many potassic minerals, such as liparite, alunite, glauconite and vermiculite in this country. The potassium jarosite was discovered for the first time at Gumma limonite mine by Katayama and Saito in 1947n. Since then, the many deposites were found out at such places as Suwa Mine in Nagano prefecture, Mitsui-Aso Mine in Kumamoto prefecture and several mines in the Hokkaido district.     

造纸污泥堆肥对酸性土壤铝污染的影响

通过盆栽试验,研究在砖红壤中施加富含铝盐的造纸污泥堆肥后,土壤－作物体系中的铝毒效应。试验结果表明：盆栽初期,添加造纸污泥堆肥各处理土壤中的总酸溶性铝和总单核铝浓度较CK呈显著上升趋势,并随堆肥用量的增加而增加;随着种植时间推移,各处理（除了CK）总酸溶性铝和总单核铝浓度显著降低,且在盆栽结束时各处理总酸溶性铝浓度均低于原砖红壤中总酸溶性铝浓度;在整个盆栽期间,总单核铝是土壤中活性铝的主要存在形态;添加堆肥的各处理玉米植株的根部和地上部分铝含量均显著小于CK,玉米的生长状况均优于CK,说明在酸性土壤中添加造纸污泥堆肥,能起到很好的肥效作用,且不会对玉米生长形成铝毒效应,其中10%为本试验的最佳配比;另外,土壤理化性质测定结果显示：添加造纸污泥堆肥能有效减缓土壤酸化、增加土壤有机质和有效磷含量,提高土壤质量。     

Agronomic Traits of Corn Fertilized with Sewage Sludge

Although research on the environmental impacts of using waste as a fertilizer is of great importance, the basic principle for using a product as fertilizer is that it should provide nutrients for plants without causing any harm to them. The objective of this study was to evaluate the agronomic traits (number of nodes, plant height, leaf number, yield, and protein content of grains) and the nutritional status of corn treated with sewage sludge. The experiment was conducted in the municipality of Jaboticabal in a Red Latosol. A randomized block design with four treatments (0, 55, 110, and 167.5 Mg ha^?1 of sewage sludge) and five repetitions was used. At 30 days after emergence (DAE), the dose of 110 Mg ha^?1 dry weight presented greater values for plant height, leaf number and stem diameter. At 60 DAE, the treatments did not affect the agronomic traits. No influence from the treatments tested was observed for protein content of grains and yield. The dose of 167.5 Mg ha^?1 showed greater weight of 100 seeds. All treatments showed nutritional imbalances. This study confirmed the agricultural potential of sewage sludge as a source of nutrients.     

Chemical Fractionation of Trace Elements in Biosolid‐Amended Soils and Correlation with Trace Elements in Crop Tissue

Abstract

A previous study indicated that agricultural biosolid applications increased the concentration of EPA₃₀₅₀‐digestible trace elements in soils on Pennsylvania production farms but could not indicate potential trace‐element environmental availability. This study was conducted to determine if biosolid application had altered the distribution of trace‐elements among operationally defined soil fractions and the relationship of trace element concentrations in soil and crop tissues. Biosolid‐amended and unamended soils from production farms in Pennsylvania were extracted using a modified Bureau Communautaire de Référence (BCR) sequential fractionation technique and analyzed for chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Trace‐element concentrations in crop tissues (soybean silage, sudangrass, corn grain, alfalfa hay, and orchardgrass hay) from the same farms were also determined. Fractionation results indicated that the proportion of Cr, Cu, Ni, Pb, and Zn that is potentially bioavailable is quite small in unamended soils. Biosolid applications significantly (P≤0.1) increased concentrations of Cu in all soil fractions (average increase over unamended soil=1.14, 8.27, 6.04, and 5.84 mg kg^?1 for the exchangeable, reducible, oxidizable, and residual fractions, respectively), Ni (0.41, 1.65 mg kg^?1 for the reducible and residual fractions, respectively), Pb (5.12 and 1.49 mg kg^?1 for the reducible and residual fractions, respectively), and Zn (8.28, 7.12, 4.44, and 8.98 mg kg^?1 for the exchangeable, reducible, oxidizable, and residual fractions, respectively) but did not significantly increase Cr in any soil fraction. Concentrations of Cu in all soil fractions were significantly (P≤0.01) correlated with concentrations of Cu in orchardgrass tissue (r=0.70, 0.66, 0.76, and 0.69 for the exchangeable, reducible, oxidizable, and residual soil fractions, respectively). Concentrations of exchangeable and reducible Zn were significantly correlated with Zn in sudangrass tissue (r=0.81 and 0.67), and reducible Zn was significantly correlated with Zn concentrations in orchardgrass tissue (r=0.65). Application of biosolids had little effect on bioavailability of Cr, Ni, or Pb, whereas higher loadings of Cu and Zn led to a shift toward the more labile soil fractions. Loadings of Cu and Zn were much smaller than cumulative loadings permitted under U.S. Environmental Protection Agency (USEPA) Part 503 regulations. Chemical soil fractionation was able to detect increases in labile soil Cu and Zn that relate to increased phytoavailability.     

污泥加石灰后作为肥料用于玉米生长中施肥研究

The use of sewage sludge on agricultural land provides an alternative for its disposal. Therefore, the aim of the present study was to evaluate the feasibility of using industrial sewage sludge produced in Pakistan, as an agricultural fertilizer. The agricultural soil amended with 250 g kg^-1 sewage sludge with or without lime treatment was used for the growth of the common local grain crop, maize （Zea maize）. The mobility of the trace and toxic metals in the sludge samples was assessed by applying a modified BCR sequential extraction procedure. The single extraction procedure was comprised of the application of a mild extractant （CaCl2） and water, for the estimation of the proportion of easily soluble metal fractions. To check the precision of the analytical results, the concentrations of trace and toxic metals in every step of the sequential extraction procedure were summed up and compared with total metal concentrations. The plant-available metal contents, as indicated by the deionized water and 0.01 mol L^-1 CaCl2 solution extraction fractions and the exchangeable fraction of the sequential extraction, decreased significantly （P 〈 0.05） with lime application because of the reduced metal availability at a higher pH, except in the cases of Cd and Cu, whose mobility was slightly increased. Sludge amendment enhanced the dry weight yield of maize and the increase was more obvious for the soil with lime treatment. Liming the sewage sludge reduced the trace and toxic metal contents in the grain tissues, except Cu and Cd, which were below the permissible limits of these metals. The present experiment demonstrates that liming was an important factor in facilitating the growth of maize in sludge-amended soil.     

Carbon and nitrogen mineralization of sewage sludge compost in soils with a different initial pH

Soil properties may affect the decomposition of added organic materials and inorganic nitrogen (N) production in agricultural soils. Three soils, Potu (Pu), Sankengtzu (Sk) and Erhlin (Eh) soils, mixed with sewage sludge compost (SSC) at application rates of 0 (control), 25, 75 and 150 Mg ha⁻¹ were selected from Taiwan for incubation for 112 days. The aim of the present study was to examine the effects of SSC application rates on the carbon decomposition rate, N transformation and pH changes in three soils with different initial soil pH values (4.8–7.7). The results indicated that the highest peaks of the CO₂ evolution rate occurred after 3 days of incubation, for all treatments. The Pu soil (pH 4.8) had a relatively low rate of CO₂ evolution, total amounts of CO₂ evolution and percentage of added organic C loss, all of which resulted from inhibition of microbial activity under low pH. For the Pu and Sk soils, the concentration of NH₄⁺-N reached its peak after 7–14 days of incubation, which indicated that ammonification might have occurred in the two soils with low initial pH values. NO₃⁻-N rapidly accumulated in the first 7 days of incubation in the Eh soil (pH 7.7). The direction and extent of the soil pH changes were influenced by the N in the SSC and the initial soil pH. Ammonification of organic N in the SSC caused the soil pH to increase, whereas nitrification of mineralized N caused the soil pH to decline. Consequently, the initial soil pH greatly affected the rate of carbon decomposition, ammonification and nitrification of SSC.     

Interactions of gamma‐irradiated sewage,nitrogen and phosphorus for Sorghum on a calcareous soil

Abstract

The interaction of gamma‐irradiated sewage sludge, nitrogen and phosphorus fertilizers on dry matter production, phosphorus concentration and phosphorus uptake of sorghum was examined. Three crops of sorghum were grown in the greenhouse in 19 1 plastic buckets. The phosphorus and sludge treatments were applied at the initiation of the experiment only. Nitrogen was applied to the corresponding nitrogen treatment pots before each of the three croppings.

There was a significant nitrogen x sewage interaction for dry matter production, phosphorus concentration and phosphorus uptake in each harvest. There was a significant phosphorus sewage sludge interaction in the first harvest for phosphorus uptake. All other possible interactions were not statistically significant. The 67 metric ton/ha sludge rate produced nearly the same yield as the nitrogen treatment. In the first harvest, sludge significantly increased plant phosphorus uptake from the fertilizer phosphorus. The phosphorus uptake in sorghum from 472 and 944 kg P/ha from the sludge treatments was comparable to that from 1299 and 2598 kg P/ha from triple superphosphate.     

生态塘-人工湿地-生态塘复合系统对城市河水中氮的去除效果

为对滇池流域重污染河流的治理探究出一套有效、实用污水处理方案,该试验通过中试规模的生态塘1—水平潜流人工湿地—生态塘2复合系统,在不同的水力停留时间（3 d,2 d,1 d）条件下对昆明市新运粮河水中氮的去除效果进行研究。研究表明：生态塘1和生态塘2对河水中氮的处理都能保持良好的效果,且稳定性高,抗负荷能力强,总体上要优于人工湿地。其中,生态塘1在高负荷条件下的除氮效果最好,起到了蓄洪池、沉淀池等综合作用;生态塘2的处理效果表现稳定,保证了最终出水的水质,起到了生态塘和景观池的双重功效,具有良好的处理效果和景观效益;人工湿地对氮的处理效果较差,抗负荷能力较弱。在HRT为3 d、2 d和1 d条件下,复合系统对总氮（TN）的去除率分别为39.39%、25.26%、19.62%,对NH3-N的去除率分别为51.98%、29.14%、21.18%;对TN的处理均达到了城镇污水处理厂污染物一级排放标准,对NH3-N的处理均达到了城镇污水处理厂污染物二级排放标准;1 d宜作为复合系统运行的最佳HRT参数。生态塘1－水平潜流人工湿地－生态塘2复合系统对城市河水中氮的处理效果显著,可选择作为有效治理滇池流域重污染河流的工艺之一。