Nitrogen Availability for Maize from a Rolling Pampa Soil After Addition of Biosolids

Abstract

The objective of this paper was to evaluate the influence of different rates of biosolids on the soil nitrogen (N) availability for maize and its residuality. A field experiment was developed in a typic Argiudol located in the NE of the Buenos Aires Province. Maize was sown for two consecutive years 1997–1999. Biosolids from a sewage treatment plant of Buenos Aires outskirts were superficially applied to the soil and incorporated by plowing. There were eight treatments: Check; 8, 16, and 24 Mg of dry biosolid ha^?1; 8 and 16 Mg of dry biosolid ha^?1 applied one year before, 100 and 150 kg N ha^?1 of calcium ammonium nitrate (CAN). The sampling and determinations were done during the second maize cycle. At presowing (PS), sowing (S), 6 expanded leaves (V6), 12 expanded leaves (V12), and Flowering (Fl) composite soil samples from 0–40 cm depth were obtained to determine ammonium and nitrate contents. At Fl maize plants were sampled in order to determine total biomass and N content. The N‐nitrate content in the soil was significantly increased by the biosolids application (p < 0.05), and varied for each increment depending on the biosolids rates and the phenological stage. After 30 days from the incorporation the increases of 1.19, 1.34, and 2.05% were observed for N‐nitrates for 8, 16, and 24 Mg ha^?1, respectively. The contribution of mineral N from the biosolids was 2.48, 6.46, and 5.01 kg N Mg^?1 when the rates were incremented from 0–8, 8–16, and 16–24 Mg ha^?1, respectively. The nitrogen mineralization followed a release pattern with a maximum value of 296 kg N‐nitrate ha^?1 at sowing for 24 Mg ha^?1. Since then, the release of mineral nitrogen decreased significantly till Fl. The N‐nitrates values variation with the temperature adjusted to polinomic functions. The mineral N released from the biosolids increased as a response to the increment of soil temperature and then decreased due to the maize nitrogen absorption and the potentially mineralized nitrogen exhaustion. The application of 150 kg N ha^?1 as CAN incremented significantly the soil N‐nitrate content and equalized 16 and 24 Mg of dry biosolids ha^?1 at V6. But, no synchronism between the high nitrate releasing from biosolids and the increment in the nitrogen absorption by maize was observed. This fact generates a surplus of nitrate that incremented the potential of nitrogen loss by lixiviation. We observed a residual effect from the biosolids that were applied the previous year. This contribution represented the 35% of the maize requirements and was similar to the nitrate content observed in Bio 16. The biosolids might be a valuable source of nitrogen for maize crop if the synchronism between the soil supply and maize demand is observed in order to avoid nitrates surplus.     

Effects of Biosolids Based Soil Products on Soil Physical and Chemical Properties in Urban Gardens

A study was conducted to evaluate the effect of two biosolids based soil products on soil physical properties in urban community gardens in Tacoma, Washington. The Tagro soil product is made from Class A biosolids cake mixed with sand and sawdust. The GroCo biosolids compost is produced from biosolids cake and sawdust. Both products meet regulatory requirements for unrestricted use and are locally available to gardeners. Plots were established in 3 community gardens and maintained for 2 growing seasons. Amendments were applied at 200 Mg ha^?1 dry weight in the first year of the study. Plots were split for the 2^nd year with half of the amendment plots receiving an additional 200 Mg ha^?1 of amendments. Although lower in most metals than the soils they were added to, biosolids did not have a significant effect on total soil metal concentrations. Biosolids addition increased the water infiltration rate from 10.1 ± 0.95 ml min^?1 in control soils to between 51 ± 6.1 and 212 ± 34 ml min^?1, depending on the product used. Bulk density was decreased from 1.07 ± 0.01 g cm^?3 to between 0.51 ± 0.08 and 0.77 ± 0.03 g cm^?3. Total carbon, nitrogen and available phosphorus were increased in the biosolids amended plots in comparison to the control plots. Biosolids addition resulted in decreased pH (5.35-5.75) in comparison to the control soils (6.43). The results from this study indicate that biosolids-based soil amendments can be a suitable amendment for urban community gardens.     

Comparison of Odor Emissions from Three Different Biosolids Applied to Forest Soil

The odor emissions from three types of biosolidsfrom King County, WA, were measured usingdilution-to-threshold olfactometry and mass spectralanalyses. This article describes thermal desorption andcryogenic GC/MS methods developed to characterizeodorant emissions from biosolids application to forestsoil. The major odorous compounds volatilized from twoanaerobically digested biosolids were ammonia anddimethyl disulfide, with lesser quantities of carbondisulfide, dimethyl sulfide, trimethyl amine, acetoneand methyl ethyl ketone. A third type of biosolidswas formed by centrifuge and drying one of the otherbiosolids at 190 °C. This dry biosolids producedmore odor and volatilized a more complex array ofvolatile compounds including: dimethyl disulfide,dimethyl sulfide, carbon disulfide, methylethyldisulfide, methane thiol, trimethyl amine, aceticacid, propionic acid, and butyric acid. Odor unitemissions were not found to correlate with microbialactivity, initial biosolids ammonium, organicnitrogen, and total sulfur. Variability in odoremission were explained by the number of odorouscompounds volatilized from each material, surface areaof biosolids and drying of the biosolids.     

Improving the Physical and Chemical Properties of a Disturbed Soil Using Drying-bed Biosolids

Disturbed soils might be improved by increasing organic matter content. The objective of this study was to determine if a large application of drying-bed biosolids would improve soil productivity and promote bermudagrass (Cynodon dactylon) and establishment on the Trinity clay soil. Anaerobically digested, air-dried biosolids were applied to Trinity clay (very-fine, montmorillonitic, thermic, typic, pelludert) at rates of 0, 112, 560, and 1120 Mg ha^?1. The biosolids were incorporated into the top 15 cm of the soil and bermudagrass sprigs were planted. Biosolids significantly reduced soil bulk density and soil resistance to penetration when measured during the second and third years after the application. Biosolids increased soil concentrations of organic carbon, nutrients (nitrogen, phosphorus, copper, zinc, iron) and heavy metals (cadmium, chromium, nickel, lead). Bermudagrass biomass production and nutrient uptake were increased due to biosolids, but heavy metals were not significantly transferred from soil to above-ground plant tissue.     

Alleviation of Soil Acidity and Aluminium Phytotoxicity in Acid Soils by Using Alkaline-Stabilised Biosolids

A pot experiment was carried out to study alleviation of soil acidity and Al toxicity by applying an alkaline-stabilised sewage sludge product (biosolids) to an acid clay sandy loam (pH 5.7) and a strongly acid sandy loam (pH 4.5). Barley (Hordeum vulgare L. cv. Forrester) was used as a test crop and was grown in the sewage sludge-amended (33.5 t sludge DM ha-1) and unamended soils. The results showed that the alkaline biosloids increased soil pH from 5.7 to 6.9 for the clay sandy loam and from 4.5 to 6.0 for the sandy loam. The sludge product decreased KCl-extractable Al from 0.1 to 0.0 cmol kg-1 for the former soil and from 4.0 to 0.1 cmol kg-1 for the latter soil. As a result, barley plants grew much better and grain yield increased greatly in the amended treatments compared with the unamended controls. These observations indicate that alkaline-stabilised biosolids can be used as a liming material for remedying Al phytotoxicity in strongly acid soils by increasing soil pH and lowering Al bioavailability.     

矿石废料对垃圾筛分土抗剪特性的改良研究

出于改良矿区坡面稳定性,处理垃圾筛分土、矿石废料等,进而实现缓解城市和环境压力的目的,对不同配比的矿石废料与垃圾筛分土混合物的稳定性进行研究。使用自制直剪仪,对不同体积比例的混合物进行抗剪试验,并模拟降雨,研究雨强对混合体稳定性的影响。结果表明:矿石废料占混合土体积比在20%～60%区间内时混合体稳定性最强;降雨能通过增加剪切面的垂直应力及改变剪切面含水率来降低剪切面的剪应力,从而造成坡面稳定性的下降;50%左右的矿石废料体积比具有最佳的抗剪效果,区间下限应高于30%,上限以植被恢复的存活率为参考依据。     

Phytotoxicity of Biosolids Compost at Different Degrees of Maturity Compared to Biosolids and Animal Manures

Biosolids compost is a good organic amendment but immature compost can exhibit phytotoxic behavior which can be attributed to different toxic substances. Our objective was to determine the phytotoxicity of: i) Biosolids; ii) Mix of biosolids and wood sawdust sampled a day after composting started; iii) The same material sampled at the end of the thermophilic stage; iv) cured compost; v) cow manure and vi) horse manure A germination bioassay was carried out using Lolium perenne (ryegrass) seeds: germination and root growth percentage were determined as well as electrical conductivity, pH, phenol content and volatile organic acids. In three treatments, Ni, Pb, Zn, Cu and Cd were also determined. Ammonia volatilization was determined during biosolids composting. The germination percentage varied from 67% to 95% but the inhibition of root growth appears to be a more sensitive phytotoxicity indicator (18% to 74%. Phytotoxic effects on germinating ryegrass were mainly related to extract pH and electrical conductivity. Potentially toxic elements, volatile organic acids, phenolic compounds and ammonia were not related to germination.     

Landfill Methane Oxidation in Engineered Soil Columns at Low Temperature

Though engineered covers have been suggested for reducing landfill methane emissions via microbial methane oxidation, little is known about the covers' function at low temperature. This study aimed to determine the methane consumption rates of engineered soil columns at low temperature (4–12°C) and to identify soil characteristics that may enhance methane oxidation in the field. Engineered soils (30 cm thick) were mixtures of sewage sludge compost and de-inking waste, amended with sand (SDS soil) or bark chips (SDB soil). At 4–6°C, we achieved rates of 0.09 gCH₄ kgTS^?1d^?1 (0.02 m³ m^?2d^?1) and 0.06 gCH₄ kgTS^?1d^?1 (0.009 m³ m^?2d^?1) with SDS and SDB soils, respectively. With SDS, good movement and exchange of oxygen in porous soil moderated the slowdown of microbial activity so that the rate dropped only by half as temperature declined from 21–23°C to 4–6°C. In SDB, wet bark chips reduced the soil's air-filled porosity and intensified non-methanotrophic microbial activity, thus reducing the methane consumption rate at 4–6°C to one fourth of that at 21–23°C. In conclusion, soil characteristics such as air-filled porosity, water holding capacity, quantity and stabilization of organic amendments that affect the movement and exchange of oxygen are important variables in designing engineered covers for high methane oxidation at low temperature.     

Field Method for Biosolids N Mineralization Using Porous Ceramic Cups

A new technique was developed for field determination of N mineralization from biosolids, which provides a simple, inexpensive test that yields accurate results. A residuals technique was used; mineralization was defined as the difference between the original and final mass of organic nitrogen. Biosolids were collected from a number of British Columbia wastewater treatment plants (WWTPs), placed in porous ceramic tubes and incubated under controlled conditions. Variables studied included wet versus dry biosolids, application rate, tube size, inoculation solution, and the effect of a soil addition mixed with biosolids. There was little difference in N mineralization between wet and dried biosolids, however variability was reduced using dried biosolids. No difference was observed using different amounts of biosolids. When dried biosolids were inoculated with supernatant obtained from a soil and biosolids mixture, decomposition was higher than with supernatant from the individual mediums alone. However, mineralization was fairly close with all inoculates. The addition of soil had little effect on biosolids decomposition other than resulting in a higher variability.     

Neutral Ammonium Citrate Extraction of Biosolids Phosphorus

Abstract

Matching biosolids application rates to crop phosphorus (P) needs requires quantifying the P fertilizer replacement value of biosolids. Neutral ammonium citrate (NAC) extraction of P, used for assessing available P in mineral fertilizers, was evaluated for 35 different biosolids. Biosolids NAC‐P was not statistically different (p=0.05) from total P using strong acid digestion (EPA 3051‐P). High P recovery by NAC was attributed to dissolution of P‐containing iron (Fe)/aluminum (Al) oxides under the aggressive extracting conditions (0.88 M citrate at 65°C). Citrate effectively dissolves P‐binding Fe/Al hydrous oxides, the very components that reduce phytoavailability when biosolids are land applied. Greenhouse studies with pasture grass (Paspalum notatum Flugge) grown in P‐deficient soils amended with biosolids revealed P phytoavailability was not correlated (r²=0.10) with biosolids NAC‐P. Phytoavailability was inversely correlated (r²=0.66) with biosolids total Al+Fe content. The NAC extraction, designed for commercial fertilizers, is inappropriate for quantifying biosolids phytoavailable P.     

Effect of Treated Wood on Biosolids Composting

The possibility of using construction and demolition (C&;D) waste wood as a bulking material in biosolids composting was investigated. Potential contaminants in C&;D waste wood include arsenic (As), chromium (Cr), and copper (Cu) from treated wood, and lead (Pb) from paints. Untreated and treated woodchips from C&;D wood were mixed with biosolids, composted using an aerated static pile process, and cured. There were no significant differences between untreated and treated woodchips with respect to composting process, time to stability, or product quality. Composting parameters monitored included moisture content, pH, electrical conductivity, organic matter degradation, fecal coliform levels, and stability by respirometry. Finished compost quality was evaluated in terms of potential toxic elements (PTE) levels. PTE values in treated woodchips (26 ± 35, 29 ± 41, 56 ± 46, and 5 ± 5 µg·g^?1 for As, Cr, Cu, and Pb, respectively) were higher and more variable than those in the untreated woodchips (3 ± 3, 17 ± 8, 13 ± 2, and 0.5 ± 0.0 µg·g^?1). However, both untreated and treated wood compost products met Canadian Council of Ministers of the Environment Category B values for PTE. In addition, and only molybdenum (Mo) and Cu exceeded Category A thresholds. Biosolids were the most significant contributor of Mo, while Cu contributions came from both biosolids and wood chips; some samples of pressure-treated wood showed concentrations of Cu in the range of 765 to 8,455 µg·g^?1. The results of this study suggest that treated wood from C&;D recycling facilities will not significantly degrade the quality of biosolids compost products.     

Stability Measurement of Biosolids Compost by Aerobic Respirometry

Oxygen uptake of biosolids compost was measured during both laboratory and full-scale studies. Aerobic respirometry of solid samples of compost provided a precise measure of microbial activity. There was a noticeable decreasing trend in oxygen consumption over 25 days of composting, thereby indicating increasing stability. Moisture content also was found to affect the compost stability. During 48-hour respirometer tests, the compost sample did not dry to the point where respiration was inhibited. Measurement of volatile solids reduction alone during biosolids composting with large quantities of sawdust revealed little about stability.     

Land Disposal of Centrate from Biosolids Production

Arid land and riparian plants were irrigated with a liquid wastewater stream (centrate) from biosolids production at a municipal sewage treatment facility. Centrate containing approximately 1000 mg/l ammonia nitrogen was diluted with Tucson city tap water to provide treatments of 2.5, 5, 10, 25, 50, and 100% centrate, along with a dilution water control. Plants grown in 19-l containers in a greenhouse were irrigated daily with 6.7 l of solution over a 7-week period. All species exhibited a fertilizing effect at concentrations up to 5 and 10% centrate, equivalent to approximately 50 and 100 mg/l NH₃–N, but then inhibitory above 100 mg/l. No plants survived on the 50 or 100% treatments. If centrate were to be diverted from the wastewater facility to be disposed of on the land, it was estimated that the total nitrogen content of the biosolids produced by the plant would be reduced by 11%. This reduction would have only a small impact on the value of the biosolids for soil amendment applications.     

城市垃圾填埋场水土保持治理技术探讨

以深圳市玉龙坑垃圾填埋场为例,分析了城市垃圾填埋场水土流失产生机理、特点,并提出了相应的水土保持治理措施。     

Potential of Biosolids from Shrimp Aquaculture as a Fertilizer for Broccoli Production

Shrimp biosolids (SB) are composed of shrimp fecal matter and decomposed shrimp feed and remain as debris in the bottoms of drained ponds used to culture shrimp. These biosolids are considered waste and usually disposed of in landfills. SB is a valuable source of N, P, K and a variety of other useful plants nutrients; however, SB contains high levels of Na. Field research was conducted to evaluate the potential of SB as a fertilizer source used with and without an inorganic fertilizer source (Osmocote 14N - 6P - 12K) to grow broccoli (Brassica oleracea italica). Yield of marketable heads/ha varied with SB/Osmocote (OSM) ratios. OSM at 75 kg/ha in combination with 9.0 MT SB/ha increased heads/ha significantly compared to lesser rates of each fertilizer source. This SB/OSM fertilizer regime contained a total of 263N - 116P - 99K - 99Na/ha. The biological yield increased 13% with OSM at 150 kg/ha and SB at 9.0 MT/ha, but if OSM was increased to 300 kg/ha, yield decreased significantly by 21% probably due to excessive fertilizer salts from both sources restricting plant growth. Lettuce field bioassays after broccoli production did not indicate that either fertilizer source persisted in the soil. The sodium in SB needs to be considered carefully whenever this material is used and SB should be evaluated in experimental trials before commercial use on other crops.     

Windrow Cocomposting of Municipal Biosolids and Yard Waste

A total of four windrows with yard waste:biosolids ratios ranging from 5.0:1 to 1.2:1 by wet weight were operated over a six month period. The windrows were monitored for temperature, oxygen content, bulk density, particle size, compost characteristics (including metals, nutrients, pesticides, volatile solids, and moisture content), runoff characteristics, and odor potential. Based on study results, cocomposting should be employed at a yard waste:biosolids ratio greater than or equal to 3:1 in order to minimize odor and improve compost characteristics. Leaching of several metals was observed; however, only lead was observed in the runoff at concentrations above maximum contaminant levels.     

Hydrochars from Biosolids and Urban Wastes as Substitute Materials for Peat

Peat is the most widely used substrate component and extensively used in greenhouse cultivation, landfill cover soils, urban parks and gardens, urban agriculture or green roofs, due to its excellent combination of physicochemical properties. The production of hydrochar by hydrothermal carbonization (a process at lower temperatures than pyrolysis and using wet conditions) could industrially reproduce the initial conditions of biomass humification and lead to materials with similar properties to those of peat. The objective of this work was to compare peat (PT, Control), a hydrochar prepared from biosolids (HSL), a hydrochar prepared from the organic fraction of urban wastes (HUW) and two mixtures (PT + HSL and PT + HUW) at a 50% volume rate for their potential use as substrates with multiple applications. Ryegrass was established at a rate of 40 g seeds cm⁻² in the potting mixtures. Hydrophysical and biochemical properties (microbial biomass and the enzymes dehydrogenase, β‐glucosidase and phosphomonoesterase) were analyzed for PT, HSL, HUV and their combination (PT + HSL and PT + HUW). Treatments with biosolids hydrochar increased ryegrass production by 184% (HSL) and by 216% (PT + HSL) dry weight compared to the control (peat). Biochemical properties depended strongly on hydrochar type, while the hydrophysical properties of the hydrochars were similar to those of peat. Overall, our results found hydrochar–peat mixtures (PT + HSL and PT + HUW) to be suitable for the preparation of growing media. Copyright © 2017 John Wiley & Sons, Ltd.