On-Farm Assessment of Biosolids Effects on Nitrogen and Phosphorus Accumulation in Soils

A field plot experiment in a calcareous soil with wheat and maize rotation was carried out for 2 yr. The study aimed to investigate the effects of biosolids （sewage sludge or chicken manure） application on nitrogen （N） and phosphorus （P） accumulation in soils and to develop a model for the effects of biosolids application on available P （Olsen-P） accumulation in soils, by which the quantities of biosolids that can be safely applied to agricultural soils were estimated. The results showed that heavy application of biosolids to agricultural soils based on the N requirement of a wheat-maize rotation cropping system will oversupply P. Soil total N was increased by 0.010 g kg-1 at application rate of 1 ton sewage sludge per hectare. The high ratio of N to P in grains of wheat and maize （from 4.0 to 7.6） and low ratio of N to P in biosolids （〈2） led to more surplus P accumulated in soils. Although plant yields and P uptake by plants increased with increasing quantities of applied biosolids in soils, there was still an average 2.87 mg kg-1 increase in Olsen-P in the plough layer treated with biosolids for every 100 kg P ha-1 surplus. A predictive model was developed based upon the initial Olsen-P in soils, P input rates, crop yield, soil pH, and cultivation time. From the model, it is suggested that sewage sludge could be applied to calcareous soils for 12 yr using the recommended application rate （9 tons ha-1 yr-1）. The field results will be helpful in achieving best management of biosolids application for agricultural production and environmental protection.

Understanding the Removal and Fate of Selected Drugs of Abuse in Sludge and Biosolids from Australian Wastewater Treatment Operations

Illicit and pharmaceutical drugs are considered to be emerging contaminants of concern,and much research effort has gone into assessing their occurrence in wastewater.However,little information exists on their presence in treated sludge or biosolids.In this study,we examined sludge and biosolids from a large metropolitan wastewater treatment plant(WWTP)in Australia to determine the occurrence of five drugs of abuse,including benzoylecgonine as indicator of cocaine consumption,methamphetamine and 3,4-methylenedioxy methamphetamine(MDMA)as representative illicit stimulants,and codeine and morphine as pharmaceuticals with potential environmental risk.The samples were solid-phase extracted and analyzed by liquid chromatography–tandem mass spectrometry(LC–MS/MS).Benzoylecgonine and MDMA were present in raw sludge but were notably degraded during solids treatment processes,and were not detected in the dewatered sludge(after treatment)or in biosolids.Methamphetamine,codeine,and morphine were detected in all biosolids samples at mean concentrations of 20–50 lg kg^-1.The presence of these three drugs in biosolids shows that these compounds are relatively stable in the solids and in soil,and can persist in biosolids for at least several years.A simple environmental risk assessment based on estimated risk quotients(RQs)for these compounds indicated that the potential environmental risks associated with the land application of biosolids are very low at typical Australian biosolids application rates.

Impact of nitrogen input from biosolids application on carbon sequestration in a Pinus radiata forest

Background:Forest management practices(e.g.choice of stand density,fertilisation)are just as important in carbon(C)forestry as in other types of forestry and will affect the level of C sequestration and profitability.Because C stored in wood is approximately proportional to the product of its volume and density,it is necessary to account for both volume growth and wood density when assessing the effects of fertilisation on C sequestration in pine forests.Methods:The effects of nitrogen(N)input from biosolids application on forest C sequestration were quantified from an intensively monitored biosolids field trial in a Pinus radiata plantation on a sandy soil in New Zealand.The field trial tested the application of three biosolids rates:Control(no application),Standard(300 kg N⋅ha^(-1) applied every three years),and High(600 kg N⋅ha^(-1) applied every three years),across three levels of stand density:300,450,and 600 stems⋅ha^(-1).Carbon sequestration was estimated using the C-Change model from annual plot measurements of stand density,stem height and diameter,and annual breast height wood densities obtained from increment cores.Results:By age 24 years,N-fertilised trees had sequestered 40 t C⋅ha^(-1) more than unfertilised trees,an increase of 18%.Fertilisation increased stem volume by 23%but reduced stem wood density by 2.5%.Most of the increased C sequestration occurred between age 6 and age 17 years and the Standard rate gave the same increase in C sequestration as the High rate.On average,there was no significant difference in growth rate between fertilised and unfertilised trees after the 17th growth year,but the increased growth ceased earlier at higher stand densities,and later at lower stand densities.Conclusions:This study indicates that 2–3 applications of the Standard rate would have been sufficient to achieve the increased C sequestration,with an applied N to C conversion ratio of 43–65 kg C⋅kg^(-1) N.Our results highlight that N fertilisation will become more widespread under greenhouse gas emissions trading schemes which en-courages forest management practices that improve C sequestration in young forests in New Zealand in particular and other countries in general.

Effect of a Newly Developed Pelleted Papermill Biosolids on Crop and Soil

The US is one of the leading global producers of paper industry with approximately 24 percent of the share of world paper supply. Despite diversity of the feedstock and production methods, C rich papermill biosolids (PB) is a major byproduct of paper production process. Landfilling is the predominant method of PB management. Increasing landfill cost and its potential environmental consequences have incentivized research and development efforts to find beneficial uses for PB. This sensible option reduces the overall paper production costs and increases environmental sustainability. Pelletization of PB increases its marketability by reducing transportation costs. This greenhouse study was conducted to gain a better understanding of the properties and effects of a recently developed pelletized papermill biosolids (PPB) on bell pepper (Capsicum annuum L.) and soil. Urea and PPB were each applied at four total N rates equivalent to 45, 90, 135, and 180 kg N ha﹣1 and an additional control treatments of 0 N was included. The total C and N concentration in this PPB were 379 and 14 g·kg﹣1 respectively and its C:N ratio was 27.2. Nitrogen treatment significantly (P ≤ 0.0839) influenced pepper height, dry biomass, N concentration, and N uptake. Plant height ranged from 31.2 to 44.4 cm;135 kg·ha﹣1 urea-N and PPB-N produced the tallest and shortest plants respectively. Dry biomass of the pepper that did not receive any N, those treated with urea-N or PPB-N were 5.3, 5.7 - 7.5, and 5.9 - 6.5 g·plant﹣1 respectively. Nitrogen concentration in control treatment (0 N) was 36.4 g·kg﹣1 and that of pepper treated with any N ranged from 32.0 - 40.7 g·kg﹣1. There was an inverse numerical, albeit not always statistically significant, relationship between PPB rate and plant N concentration. Generally, pepper treated with urea removed significantly more N from soil than control or PPB treated pepper. Nitrogen uptake by plants that did not receive any N and those amended with urea or PPB were 194, 229 - 270, and 155 - 164 mg·plant﹣1 respectively. Pepper N uptake and concentration data indicate that higher rates of PPB resulted in immobilization of native soil and PPB-N due to its wide C:N ratio (27.2). Nitrogen treatment significantly influenced soil pH, SOM, total C and N (P > 0.1). Soil organic matter and total C in post-harvest soil samples were 17.4 - 19.4 and 21.9 - 35.0 g·kg﹣1 respectively. The observed increase in soil total C and SOM highlights the potential beneficial use of PPB as a means to improve soil health and sequester C in soil. Narrowing the C:N ratio of PPB, by coapplication or incorporation of the mineral N into the pellets will make it an attractive organic N fertilizer.

Corn and Soil Response to a Recently Developed Pelletized Papermill Biosolids

Beneficial utilization of industrial byproducts such as papermill biosolids (PB) provides a unique opportunity to reduce the overall production cost and increase environmental sustainability. Pelletization of a byproduct enhances its marketability by improving the transportation and application. This greenhouse study was conducted to gain a better understanding of the properties and effects of, a recently developed pelletized papermill biosolids (PPB), on corn (Zea mays L.) and soil. Urea and PPB were each applied at four total N rates equivalent to 45, 90, 135, and 180 kg⋅ha−1 and an additional control treatments of 0 was also included. The PPB contained 379 and 14 g⋅kg−1 total N and C and its C:N ratio was 27. Nitrogen treatment significantly (P ⋅plant−1 where application of 180 kg⋅ha−1 of PPB-N produced the smallest plant biomass. Numerically the dry biomass of corn that did not receive any N, corn fertilized with any PPB, and corn fertilized with any urea was 38.3, 26.9 - 41.1 and 38.1 - 40.92 g⋅plant−1 respectively. Nitrogen concentration in corn plants ranged 6.2 - 11.5 g⋅kg−1. Nitrogen concentration in corn that did not receive any urea or corn that received urea was 8.7 - 11.5 g⋅kg−1 and was significantly more than corn treated with any PPB. Total N uptake (removed from soil) by the corn plant was 166 - 455 mg⋅plant−1. Total N uptake by corn that did not receive any N, corn fertilized with any PPB, and corn fertilized with any urea were 327, 166 - 278, and 379 - 455 mg⋅plant−1 respectively. The data suggest that the high C/N ratio (27.2) of PPB resulted in immobilization of PPB-N. Thus the next step will be to research the optimal rates of inorganic N that should be incorporated into this PPB to reduce its C:N to make it an effective high organic matter content N fertilizer. Nitrogen treatment significantly (P g⋅kg−1. The SOM of the treatments fertilized with 90 and 180 kg⋅ha−1 of PPB-N was 19.4 - 19.7 g⋅kg−1 and was significantly higher than soil that did not receive any N. The application of PPB significantly increased the soil total C which was 36.0 and 23.6 g⋅kg−1 in the soil amended with 180 kg⋅ha−1 of PPB-N and the control respectively. The observed increase in SOM and total C in PPB treated soil points to the potential soil health and C sequestration benefits of PPB provided that its C/N ratio can be increased by incorporating inorganic N into it.

Postharvest Quality and Safety of Potted Greenhouse Tomato Grown on Forest Soil-Biosolids substrate,Blended with NPK Fertilizer

Studies on the effects of biosolids(BS)amended substrate on food quality and safety in tomato production have not been adequately addressed.The objective of this study was to investigate the influence of composted BS and NPK fertilizer on post-harvest quality and safety of potted greenhouse tomato Solanum lycopersicum L.Potted tomatoes"Maxim F1"were grown in a randomized complete block design with four replications.Inorganic fertilizer NPK(17:17:17) fertilizer was applied at 0,100 kg ha^(-1)(5g per pot)and 200 kg ha^(-1);(10g per pot),BS was applied at 0%,10%,20%,30%,and 40%v/v,in all possible combinations.Tomato were harvested and analyzed for ascorbic acid,chlorophylls,carotenoids and total phenolic compounds;weight loss,fruit firmness,titratable acidity and total soluble solids,as well as heavy metals and microbial contaminants.Results revealed that tomato fruit at 10%BS in combination with NPK fertilizer at 100 kg ha^(-1) had the highestβ-carotene(6.1 mg 100 g^(-1)),lycopene(26.1 mg 100 g^(-1)),ascorbic acids(128.0 mg 100 g^(-1)),total phenolic acids(13.2 mg 100 g^(-1)),total soluble solids(17%).However,the same rates produced tomato fruit with lower titratable acidity(2.2%)and had heavy metal residues within the permissible level,according to International EPA standards on biosolids utilization for food crops production.Similarly,no trace of pathogenic bacteria;Salmonella,Escherichia coli,Staphylococcus was observed on the harvested tomato.This study reveals at BS 10% with NPK fertilizer at 100 kg ha^(-1) substrate as a better option of plant nutrient source for quality and safe greenhouse tomato production.

Dispersion Modeling of Particulate Matter in Different Size Ranges Releasing from a Biosolids Applied Agricultural Field Using Computational Fluid Dynamics

This paper proposes a methodology using computational fluid dynamics (CFD)-FLUENT to simulate the dispersion of particulate matter releasing from a biosolid applied agricultural field and predict the particulate concentrations for different ranges of particle sizes. The discrete phase model (Lagrangian-Eulerian approach) was used in combination with each of the four turbulence models: Standard kε (kε), Realizable kε (Rkε), Standard kω (kω), and Shear-stress transport k-ω (SST) to predict particulate matter size concentrations for distances downwind of the agricultural field. In this modeling approach, particulates were simulated as discrete phase and air as continuous phase. The predicted particulate matter concentrations were compared statistically with their corresponding field study observations to evaluate the performance of turbulence models. The statistical analysis concluded that among four turbulence models, the discrete phase model when used with Rkε performed the best in predicting particulate matter concentrations for low (u < 2 m/s) and medium (2 < u < 5 m/s) wind speeds. For high (u > 5 m/s) wind speeds, Rkε, kω, and SST showed similar performances. The discrete phase model using Rkε performed very well and modeled the best concentrations for the particle sizes (μm): 0.23, 0.3, 0.4, 0.5, 0.65, 0.8, 1, 1.6, 2, 3, 4, and 5. For particle sizes: 7.5 and 10, the performances of Rkε, kε, kω, and SST were similar.

Enhanced biological phosphorus removal using thermal alkaline hydrolyzed municipal wastewater biosolids

This study reports the feasibility of using municipal wastewater biosolids as an alternative carbon source for biological phosphorus removal.The biosolids were treated by a lowtemperature,thermal alkaline hydrolysis process patented by Lystek International Inc.(Cambridge,ON,Canada)to produce short-chain volatile fatty acids and other readily biodegradable organics.Two sequencing batch reactors(SBRs)were operated with synthetic volatile fatty acids(Syn VFA)and readily biodegradable organics produced from the alkaline hydrolysis of municipal wastewater biosolids(Lystek)as the carbon source,respectively.Municipal wastewaters with different strengths and COD:N:P ratios were tested in the study.The reactors’performances were compared with respect to nitrogen and phosphorus removal.It was observed that phosphorus removal efficiencies were between 98%–99%and 90%–97%and nitrogen removal efficiencies were 78%–81%,and 67%for the Syn VFA and Lystek,respectively.However,the kinetics for phosphorus release and uptake during the anaerobic and aerobic stages with Lystek were observed to be significantly lower than Syn VFA due to the presence of higher order VFAs(C4 and above)and other fermentable organics in the Lystek.

Impact of biosolids,ZnO,ZnO/biosolids on bacterial community and enantioselective transformation of racemic–quizalofop–ethyl in agricultural soil

The effects of biosolids,ZnO,and ZnO/biosolids on soil microorganism and the environmental fate of coexisting racemic–quizalofop–ethyl(rac-QE)were investigated.Microbial biomass carbon in native soil,soil/biosolids decreased by 62%and 52%in the presence of ZnO(2‰,weight ratio).The soil bacterial community structure differed significantly among native soil,soil/biosolids,soil/ZnO,and soil/biosolids/ZnO based on a principal co-ordinate analysis(PCo A)of OTUs and one-way ANOVA test of bacterial genera.Chemical transformation caused by ZnO only contributed 4%and 3% of the overall transformation of R-quizalofop-ethyl(R-QE)and S-quizalofop-ethyl(S-QE)in soil/ZnO.The inhibition effect of ZnO on the initial transformation rate of R-QE(rR-QE)and S-QE(rR-QE)in soil only observed when enantiomer concentration was larger than 10 mg/kg.Biosolids embedded with ZnO(biosolids/ZnO)caused a 17%–42% and 22%–38%decrease of rR-QE and rS-QE,although rR-QE and rS-QE increased by 0%–17% and 22%–58%by the addition of biosolids.The results also demonstrated that the effects of biosolids on agricultural soil microorganism and enantioselective transformation of chiral pesticide was altered by the embedded nanoparticles.

Emerging contaminants in biosolids:Presence,fate and analytical techniques

Emerging contaminants(ECs)represent a small fraction of the large chemical pollution puzzle where a wide variety of potentially hazardous chemicals reach the environment,and new compounds are continuously synthesized and released in wastewater treatment plants and ultimately in effluent and biosolids.ECs have been classified into various categories;however,this article focuses on the fate of major categories,namely pharmaceutical and personal care products(PPCPs),per-and poly-fluoroalkyl substances(PFAS),flame retardants,surfactants,endocrine-disrupting chemicals(EDCs),and microplastics(MPs).These ECs when discharged to sewer and downstream wastewater treatment plants can undergo further transformations and either degrade,persist or convert into by-products which have the potential in some cases to be more hazardous.Because of potential dangerous impacts of the availability of these contaminants in the environment,information on the fate and behavior of these pollutants is highly important to develop new strategies,such as the regulation of chemicals imported into Australia and Australian consumer goods and environmental policies to mitigate them in a sustainable way.Moreover,advanced technologies are required for the detection and identification of novel contaminants emerging in the environment at ultra low levels.The application of chromatographic techniques coupled with mass spectroscopy has provided attractive breakthroughs to detect new emerging contaminants.However,it is crucially important to understand the sensitivity and robustness of these analytical techniques when dealing with complex matrices such as biosolids.In addition,most of the literature was focused on selected compounds or a family of compounds and the existing reviews have paid less attention to examine the formation of metabolites during the wastewater treatment process and their impacts on the ecosystem.This review presents an overview of the presence of different classes of ECs around the world,their quantification from different sources like wastewater(influents or effluents),sludge and biosolids.In addition,the transformation of ECs during the treatment process,the formation of intermediate products and their impacts on the environment are also critically discussed.Three major steps of ECs analysis include sample preparation,extraction and clean-up,and analysis;hence,different methods employed for extraction and clean-up,and analytical techniques for identification are thoroughly discussed,their advantages and limitations are also highlighted.This comprehensive review article is believed to enhance the understanding of ECs in sewage sludge and would be useful to the readers of the relevant communities and various stakeholders to investigate potential technologies to maximize destruction of ECs.

The Effect of Organo-Mineral Fertilizer Applications on the Yield of Winter Wheat, Spring Barley, Forage Maize and Grass Cut for Silage

Biosolids were applied with urea to produce a granulated organo-mineral fertiliser (OMF) for application by farm fertiliser equipment to a range of agricultural crops. The recommended rates of nitrogen, phosphate and potash were calculated for the test crops using “The Fertiliser Manual”, which assesses the nutrient requirement based on previous cropping, rainfall and soil index. The OMF produced similar crop yields compared to ammonium nitrate fertiliser when applied as a top-dressing to winter wheat, forage maize and grass cut for silage in the cropping years 2010 to 2014. In 2012 the grain yield of spring barley top-dressed with OMF was significantly lower than the conventional fertiliser treatment, due to dry conditions following application. For this reason it is recommended that OMF is incorporated into the seedbed for spring sown crops and The Safe Sludge Matrix guidelines followed. The experimental work presented shows that OMF can be used in sustainable crop production systems as a source of nitrogen and phosphorus for a range of agricultural crops.

Agronomic Use of Slurry from Anaerobic Digestion of Agroindustrial Residues: Effects on Crop and Soil

In a greenhouse experiment we evaluated the application of slurry generated by a biogas reactor of agroindustrial residues. The objectives of this study were to determine the response to slurry application on dry matter production and nutrients absorption of Setaria italica (setaria), and to evaluate the effect of the slurry on soil properties. Two soils, of different texture, were mixed either with slurry or with diammonium phofsphate (DAP) at 0, 80, and160 kgN ha-1 equivalent rates. The setaria was harvested 68 days after planting, and separated into leaves plus stems, ears, and roots. Total biomass and content of N, P, K, Ca, Mg, Cu, Fe, Mn, and Zn were determined in each fraction. In the soil we determined pH, electric conductivity (EC), organic C, available P, mineral N, and exchangeable cations. Although the biomass produced and the amounts of nutrients absorbed were different in the two soils, in both of them setaria responded to the slurry application. The amounts of N absorbed from slurry and DAP were similar, indicating that the N from the slurry was readily available. The slurry application also increased the absorption of other macro and micro nutrients (P, Ca, Mg, and Zn). No significant changes in soil exchangeable cations, pH, and EC were observed at setaria harvest. In the silty soil the crop almost depleted the mineral N in all treatments, but in the sandy soil large amounts were left, especially in the treatments with slurry. This fact highlights the importance of a careful dosage of this soil amendment, to avoid the excess of mineral N, which is potential pollutant for the environment. It can be concluded that the use of slurry from the reactor had a positive effect on the nutrients availability, without negative effects on soil properties.

Accumulation of heavy metals in stemwood of forest tree plantations fertilized with different sewage sludge doses

The levels of heavy metals that accumulated in stemwood of mature trees grown for 20 years in a plantation in an abandoned peat quarry in areas that were fertilized with different amounts of domestic sewage sludge(180,360,and720 Mg ha-1on a dry basis) were compared with trees grown in a reference nonfertilized area.Included in the study was a hybrid poplar(Populus tremula x Populus tremuloides) developed for use as an energy crop,three local tree species and one introduced tree species.The concentrations of Cd,Cr,Cu,Ni,Pb and Zn in the stemwood of the trees grown in the fertilized and nonfertilized fields were determined,and found to be significantly lower than their respective concentrations in the soil.Cd and Cr were found only in several wood samples at concentrations close to the limits of detection or qualification; therefore,they were not analyzed further.A correlation analysis suggested that 75%of the correlations between the concentrations of heavy metals in the stemwood and the concentrations in the soil were negative.The ability of trees to accumulate the metals from soil in most cases decreased for Cu and Ni; however,the correlations were not as clear for Pb and Zn.The followingsequence for the levels of heavy metals found in the stemwood of the analysed trees was Zn [ Pb [ Ni [ Cu [(Cr,Cd).The results of this study showed that the levels of heavy metals in the studied wood would not exceed the permitted limits of heavy metal pollution in the air and ash when used for energy production.

Effect of Composts Combined with Chemical N Fertilizer on Nitrogen Uptake by Italian Ryegrass and N Transformation in Soil

Combining compost with sufficient chemical N fertilizer (CF) in agricultural lands is a popular practice to reduce the amount of inorganic nitrogen and accumulation of non-nutrient constituents in soils. A pot culture experiment was conducted to study the effects of 130 mg N of either solids waste compost (Scomp) or biosolids waste compost (Bcomp) complemented with 130 mg (CF, 1N) and 260 mg·N·pot-1 (CF, 2N) as 15N labeled (NH4)2SO4 (13.172 atom %) on growth and N uptake by Italian ryegrass. A separate soil incubation without plants was set up by only blends of Scomp and CF. The results from pot culture experiment show that total plant biomass and N uptake from Bcomp were significantly higher than Scomp alone. Scomp combined with CF improved yield and N uptake over those of Scomp alone. For Scomp + 1N treatment, plant nitrogen uptake derived from compost and CF accounted for 29% and 56% of added N from Scomp and CF, respectively. The incubation study indicates that 16.08 - 29.62 mg·N·kg-1·soil·day-1 from inorganic-N were immobilized into organic pools, while only 0.40 - 0.66 mg·N·kg-1·soil·day-1 from organic-N were mineralized to inorganic pools. Because a part of additional N could be tied up in organic form, combining solids compost with chemical N fertilizer therefore need to consider the effective use of compost-N.

Analysis Methods for the Determination of Anthropogenic Additions of P to Agricultural Soils

Phosphorus loading and measurement is of concern on lands where biosolids have been applied. Traditional soil testing for plant-available P may be inadequate for the accurate assessment of P loadings in a regulatory environment as the reported levels may not correlate well with environmental risk. In order to accurately assess potential P runoff and leaching, as well as plant uptake, we must be able to measure organic P mineralized by the biotic community in the soil. Soils with varying rates of biosolid application were evaluated for mineralized organic P during a 112-day incubation using the difference between P measured using a rapid-flow analyzer (RFA) and an axial flow Varian ICP-OES. An increase in the P mineralized from the treated soils was observed from analysis with the Varian ICP-OES, but not with the RFA. These results confirm that even though organic P concentrations have increased due to increasing biosolid application, traditional soil testing using an RFA for detection, would not accurately portray P concentration and potential P loading from treated soils.

Nitrogen Leaching from Saybrook Soil Amended with Biosolid and Polyacrylamide

In this study, Nitrogen leaching following surface application of biosolid with and without polyacrylamide (PAM) coating was investigated using soil column experiments. Three treatments including bare soil (C), a commercially available biosolid (BS) and PAM coated biosolid (PAM + BS), were applied to manually packed (bulk density: 1.3 g·cm-3) growth chamber soil columns (GC columns: 5 cm diameter by 40 cm long) and greenhouse soil columns (GH columns: 15 cm diameter by 40 cm long). The application rates for BS and PAM + BS were 729 and 740 kg/ha, respectively. The GC columns were incubated for 60 days in a dark chamber at 25℃ and no crop was grown in the columns. The GH columns were incubated for 60 days in a greenhouse and Ryegrass (seed rate: 252 kg/ha) was grown in these columns under 16 h daylight and at about 25℃. The columns were irrigated weekly using 270 mL DI-water for GC columns and 850 mL for GH columns and leachate was analyzed for Ammonium (NH4-N), Nitrate (NO3-N) and total Nitrogen (TN). The GH column experiments were repeated with three times greater biosolid application rate (2187 kg/ha) while keeping the PAM and Ryegrass seed rate constant. The leachate volume and NH4-N, NO3-N and TN concentration/load were not significantly different among the treatments for the GH columns but were significantly different during the incubation period. The same was true for GC columns with the exception of NO3-N and TN concentration/load which, overall, were higher for the BS and PAM + BS treatments than for the C treatment. In the beginning of the incubation, the leachate from all treatments (GC and GH) contained the highest NH4-N concentrations (>USEPA target level: 0.1 mg/L) and decreased, in some cases rapidly, to near zero. The NO3-N concentrations were highest in the middle of the incubation and greater than the USEPA target level (10 mg/L). The NO3-N concentrations were lower for cropped GH columns compared to GC columns due to NO3-N uptake by plants. The three fold increase in biosolid application rate did not increase NH4-N concentrations in leachate but did increase NO3-N and TN concentrations/loads in leachate on average 2.5 to 2.7 times. The non-significant differences among treatment means for NH4-N, NO3-N and TN concentrations/loads for the GH columns suggest that land application of biosolid (with or without PAM) to cropped silt loam landscapes at the rates considered may be safe within the context of groundwater pollution.

Potential of biochar and organic amendments for reclamation of coastal acidic-salt affected soil

Salinity and acidity have affected several hundred million hectares of land throughout the globe which poses a major threat to global food security and biodiversity.Application of organic amendments for salt-affected soils has been identified as one of the most effective ways to mitigate salinity-induced problems and considered as a green technique offering twin benefits of waste load reduction and land reclamation.However,studies on reclaiming acidic-salt affected soils are limited.Therefore,this study aimed to determine the reclamation potential of biochars and organic amendments involving Gliricidia sepium biochar produced at 300℃,500℃,and 700℃,green waste compost,and municipal sewage sludge at three different amend-ment ratios,1.0%,2.5%and 5.0%.The incubation experiment was conducted for a 4-month period with different amendment ratios applied to the coastal acidic-salt affected soil.Subsamples were extracted from incubation pots after 1 and 4 months and analyzed for soil chemical parameters(pH,EC,NO_(3)^(−),PO_(4)^(3−,total organic carbon,cation exchange capacity,sodium adsorption ratio,exchangeable sodium percentage)and microbial enzyme activity(catalase activity,and acid-and alkaline phosphatase activity).All organic amendments demonstrated enhancement of the soil properties in a significant manner.However,increasing incubation time and amendment ratio increase the changes of soil parameters by a great percentage.Therefore,the maximum amendment ratio of 5.0%and 4 months of incubation period rendered a significant improvement in the reclamation of acidic-salt affected soil.However,the biochar produced at 500℃ contributed the maximum towards the improved physicochemical and biochemical profile of acidic-salt affected soil,making it the most promising organic amend-ment for the reclamation of acidic-salt affected soil.The overall reclamation efficiency of organic amendments registered the following order of variation:700 BC<Sludge<300 BC<Compost<500 BC.

Valorization of semi-solid by-product from distillation of cellulosic ethanol into blends for heating and power

Burning down on semi-solid by-product from distillation of cellulosic ethanol to power upstream steps of its manufacturing is usual.However,this feedstock is homogenous in size and shape,hygroscopic and poorly energetic.These disadvantages make its re-use in the industrial plant very complex.Conversion of this agro-residue into high-performance blends for heating and power is,accordingly,the scientific point of this study.The pilot-scale manufacturing of composite pellets consisted of systematically pressing the residue with sugarcane bagasse at the mass ratios of 1:4,2:4,and 3:4 on an automatic pelletizer machine at 200 MPa and 125℃.The process of compaction lasted for 90 s.Durability and energy density,both increased significantly,from 95.85%to 99.55%and from 27.95 GJ m^(−3) to 32.20 GJ m^(−3) with blending at 3:4.Practically,the semi-solid by-product considerably improved the feeding,thus,enabling the layers of particles to go smoothly through the channel-forming die of the machine.Thereby,blends became stiffer and denser than pellets purely consisting of sugarcane bagasse.Preliminary evidence of the process of pelleting capable of highly valorizing the semi-solid by-product from distillation of cellulosic bioethanol into mechanically stable and energetically effective hybrid fuel grade biosolids exist.The major findings of this paper should be of great relevance to ensure safe and effective transportation and storage of biomass in indoor facili-ties where the risk for the generation of dust and fines and the subsequent off-gassing and self-firing is high.Furthermore,pelletization may optimize the co-generation of heat and steam at the large-scale bioethanol station.

Biomass-glycerol briquettes are not necessarily mechanically stable and energetically effective

The re-use of glycerol from biodiesel industry as an alternative lubricant for making high-performance briquettes is usual.However,the technical performance of this agro-industrial residue is not consistent.This study outlines,accordingly,the real risk of introducing glycerol into the co-briquetting of highly caloric by-products of energy-crops.The production of hybrid briquettes consisted of pressing mixtures of residues of sugarcane and sorghum with the liquid additive at 10,20,and 30 wt.%in bench-scale hydraulic piston presser machine.Irrespective of the blend,briquettes containing the supplement at the highest level as part of their composition ended up being much more hygroscopic(20.10%)and less energetic(3.15 GJ m^(−3)).The explanation for the negative impact of glycerol on the thermomechanical behavior of briquettes would be overconcen-tration of additive capable of effectively defying compacting biomass.The degree of compaction during co-briquetting has likely gone down quickly with a maximizing level of glycerol.As long as the additive is not able to lubricate the feedstock suitably,improbability of biomass particles to successfully bond together to form themselves into mechanically stable and energetically effective briquettes is large.Besides lower density(273.80 kg m^(−3))and higher relaxation(22.75%),briquettes with glycerol at 30 wt.%generally were aesthetically unpleasing.Practically,these products resisted no longer to handling,transportation,and storage.They lost their shape easily during emptying and shifting them,thus,releasing larger quanti-ties of biomass to the environment.Preliminary evidence of high-viscosity glycerol capable of limiting safe and effective production of high-performance briquettes for heating and power exists.

Effect of cleanup of spiked sludge on corn growth biosorption and metal leaching

A chemical leaching process was used for the cleanup of two municipal biosolids(MOS and BES)spiked with Cd,Cu,Zn or their mixture prior to agricultural use.Non-cleaned,cleaned and washed biosolids were compared as soil amendments for corn cultivation in greenhouse.Corn growth,biosorption and metal leaching were measured.Results showed that biosolid amendments tend to produce more aerial biomass.Cleanup and washing of BES biosolid significantly increased total biomass of roots and stalks,respectively.Regarding biosorption of metals,Cd accumulated in roots(0.06e1.13 mg kg^(-1))and leaves(0.06-0.63 mg kg^(-1)),but not in seeds nor in stalks.Larger amounts of Cu were detected in roots(10.7-18.2 mg kg^(-1)),stalks(1.29-3.78 mg kg^(-1))and leaves(6.77-20.2 mg kg^(-1)).However,Zn was more accumulated in roots(17.9-74.9 mg kg^(-1)),stalks(6.15-17.1 mg kg^(-1))and leaves(47.9-90.1 mg kg^(-1)).Whereas Cd and Cu decreased in the order roots>leaves>stalks,Zn decreased from leaves>roots>stalks.Cleanup and washing of MOS and BES biosolids significantly lowered biosorption of Cd(up to 84%),Cu(up to 38%),Zn(up to 63%),and other metals.Concentrations in leachate draining into outlet water varied over time,but on average were moderately low.Significant amounts of metal leached from MOS biosolid.The effects of cleanup and washing of both biosolids on biosorption and leaching depended on the initial metallic charge and the biosolid type.