Swine Manure Treatment Research Articles

Effects of Digestate from Swine Manure Digester on in Vitro Growth of Crop Fungal Pathogens: A Laboratory Study

<abstract><title><italic>Abstract. </italic></title> Anaerobic digestion is one of the most popular methods for swine manure treatment in China, and the resultant digestates are mainly used as fertilizer on arable land. Residues from anaerobic fermentation may be used to mitigate the use of chemical fungicides, but relevant information is lacking. In this lab-scale study, original digestate (OD) from a swine manure-fed digester and centrifuged supernatant liquid (SL) with different storage times (0, 7, 14, or 28 d) were added to potato dextrose agar (PDA) media at a rate of 5% to investigate the effects on in vitro mycelial growth of seven phytopathogenic fungi: Fusarium oxysporum, Sclerotinia sclerotiorum, Rhizotonia cerealis, Bipolaris sorokinianum, Rhizoctonia solani, Exserohilum turcicum, and Bipolaris maydis. Diameters of the fungal colonies were measured at 1 d intervals for 7 consecutive days, and the absolute growth rate (AGR) and growth coefficient (k) were calculated. Results showed that the colony sizes of Fusarium oxysporum, Sclerotinia sclerotiorum, Rhizotonia cerealis, Bipolaris sorokinianum, and Rhizoctonia solani on the OD-treated media were significantly smaller (p < 0.01) than the corresponding controls regardless of the storage time. Similarly, independent of storage time, SL-treated media were shown to significantly (p < 0.01) suppress AGR compared to the controls for all seven fungi except for Exserohilum turcicum, where no significant difference was observed between the 14-day-old SL treatment and control. The average k values of the fungi on the OD-treated media ranged from 29% to 143% of the values on the SL-treated media. The results of this study suggest potential use of digestate for plant disease control, which would reduce the use of chemical fungicides. Further studies are needed to investigate the fungicidal mechanism and fungicidal efficacy of OD and SL under field conditions.

Greenhouse gas emissions of an on-farm swine manure treatment plant – comparison with conventional storage in anaerobic tanks

This study aims to estimate greenhouse gas (GHG) emission reduction over a five-month period due to the implementation of a swine manure treatment plant, installed as an alternative to conventional manure storage in anaerobic tanks. The treatment plant, located in Segovia (Spain), was installed in a farrow-to-finish farm with approximately 300 sows, and was based on solid–liquid separation using screw pressing followed by coagulation-flocculation and nitrification-denitrification of the liquid fraction. Information collected during the study of the on-farm treatment plant together with the guidelines proposed by the Intergovernmental Panel on Climate Change (IPCC) was used to quantify GHG emissions for each scenario. Implementing the manure treatment plant led to a total annual GHG emission reduction of 62% (from 1204 t CO2-equiv to 456 t CO2-equiv). CO2 and CH4 emissions fell by 72% and 69%, respectively, whereas N2O emissions were similar in the two scenarios studied. It should be pointed out that only CO2 emissions from fossil fuel use were considered in the estimation. In addition, the contribution made by each of the treatment plant units to GHG emission was calculated. Carbon credit exchange might translate to a direct benefit of 0.21 € per m3 of treated manure. Reducing GHG emissions should thus be considered as a complementary factor in the development of cleaner systems for manure management, yielding both environmental as well as financial advantages.

Swine effluent treatment using anaerobic digestion at different loading rates

The industrial swine production is characterized by generation of significant effluent amounts that require treatment. The most adopted practices by Brazilian swine farmers have been wastewater storage in lagoons and its subsequent use as a biofertilizer. Nutrient accumulation in soil and water creates the need for an effective management of these residues. The anaerobic digestion process is an important alternative and low-cost treatment for organic matter reduction. However, its efficiency is limited by the digester capacity of solid degradation, especially at low hydraulic retention times. Thus, the present study aimed to verify the behavior of an upflow anaerobic digester by increasing the organic loading rate. This was accomplished in three stages using, as a parameter, volatile solids at 0.5; 1.0 and 1.5 kgVS m-3 d-1, respectively. This digester model proved to be quite robust and effective in swine manure treatment, achieving high efficiency of volatile solid removal at all stages of the study (stage 1: 61.38%; stage 2: 55.18%; and stage 3: 43.18%). Biogas production was directly related to the increasing organic load, reaching 0.14, 0.85, and 0.86 Nm³ kgVS-1add., respectively, with no significant difference (p&lt;0.05) of biogas methane concentration among the studied stages (73.7, 75.0, and 77.9%).

Evaluation of granular anaerobic ammonium oxidation process for the disposal of pre-treated swine manure.

With rising environmental concerns on potable water safety and eutrophication, increased media attention and tighter environmental regulations, managing animal waste in an environmentally responsible and economically feasible way can be a challenge. In this study, the possibility of using granular anammox process for ammonia removal from swine waste treatment water was investigated. A rapid decrease of NO2−–N and NH4+–N was observed during incubation with wastewater from an activated sludge deodorization reactor and anaerobic digestion-partial oxidation treatment process treating swine manure and its corresponding control artificial wastewaters. Ammonium removal dropped from 98.0 ± 0.6% to 66.9 ± 2.7% and nearly absent when the organic load in the feeding increased from 232 mg COD/L to 1160 mg COD/L and 2320 mg COD/L. The presence of organic carbon had limited effect on nitrite and total nitrogen removal. At a COD to N ratio of 0.9, COD inhibitory organic load threshold concentration was 727 mg COD/L. Mass balance indicated that denitrifiers played an important role in nitrite, nitrate and organic carbon removal. These results demonstrated that anammox system had the potential to effectively treat swine manure that can achieve high nitrogen standards at reduced costs.

ELECTROLYSIS OF SWINE MANURE EFFLUENTS USING THREE DIFFERENT ELECTRODES Fe-Fe, Al-Al AND Fe-Al

Swine effluent with high organic strength need to be treated to make it suitable for applying to crop/pasture fields, or discharging to any waterways. Electrocoagulation is a relatively simpler and cheaper technique over biological and chemical treatment methods currently used to treat high-strength industrial and municipal wastewater. The performance of an electrocoagulation system mainly depends on the pH, Electrical Conductivity (EC) of the medium, Chemical Oxygen Demand (COD) loading rates and catalytic activity of the electrodes used. In this research, a study was conducted to compare the pollutant removal efficiencies of three electrodes (Fe-Fe, Al-Al and Fe-Al) with three electric current levels (500, 1000 and 2000 mA) while treating swine manure effluents. The electrochemical cell consisted of two parallel rectangular plates (90×25×1.5 mm) of Iron (Fe-Fe), Aluminum (Al-Al) and Iron-Aluminum (Fe-Al, later on described as hybrid) electrodes; immersed in a beaker with 550 mL swine effluents and powered by a Direct Current (DC) supply. All studies were conducted in batches at room temperature. In general, removal efficiencies were increased with increasing current densities and electrolysis times for electrodes evaluated. Aluminum electrodes outperformed iron and hybrid (iron-aluminum electrodes) in removing Total Phosphorus (TP) at all current density levels tested. Overall, use of hybrid electrodes resulted in better COD removal. For the same treatment times (1200 s) at higher current density (21 mA cm-2), hybrid electrodes removed about 100% COD, which are about 1.9 and 1.3 times higher than those of aluminum and iron electrodes, respectively. Iron electrodes showed the highest removal efficiency (85%) for Total Organic Carbon (TOC) at 21 mA cm-2 current density and 1200 s treatment time. Overall, lower Specific Electrical Energy Consumptions (SEECs) per kg of Pollutants (TP, COD and TOC) were estimated for the aluminum electrodes than the other electrodes combination.

Utility of specific biomarkers to assess safety of swine manure for biofertilizing purposes

Swine production is an important economic activity in Brazil, and there is interest in the development of clean production mechanisms to support sustainable agro-industrial activities. The biomass derived from swine manure has good potential to be used as a biofertilizer due to its high nutrient concentration. However, the land application of manure should be based on safety parameters such as the presence of pathogens that can potentially infect animals and people. This study was designed to assess the presence of porcine circovirus-2 (PCV2), porcine adenovirus (PAdV), rotavirus-A (RV-A) and Salmonella spp. in liquid manure, as well the infectivity of two genotypes of circovirus-2 (PCV2a and PCV2b) present in liquid manure. Three swine farms were evaluated: 1) a nursery production farm (manure analyzed before and after anaerobic biodigestion), 2) a grow–finish production farm (analyzed before and after anaerobic biodigestion), and 3) a second grow–finish production farm (raw manure–affluent). PCV2, PAdV and RV-A were present before and after anaerobic biodigestion (either affluent or effluent) at all farms. Salmonella spp. were detected at farm 1 (affluent and effluent) and farm 3 (raw manure–affluent) but not farm 2 (affluent and effluent). When the ability of the anaerobic biodigestion process to reduce viral concentration was evaluated, no significant reduction was observed (P>0.05). Both the PCV2a and PCV2b genotypes were detected, suggesting viral co-infection in swine production. The results revealed infectious PCV2 even after anaerobic biodigestion treatment. The presence of Salmonella spp. and enteric viruses, especially infectious PCV2, in the final effluent from the anaerobic biodigester system suggests that the process is inefficient for pathogen inactivation. Due to the prevalence and infectivity of PCV2 and considering the successful use of molecular methods coupled to cell culture for detecting infectious PCV2, we suggest that this virus can be used as a bioindicator in swine manure treatment systems to check the efficiency of pathogen inactivation and ensure the production of safe biofertilizers from swine manure.

A new sampler for stratified lagoon chemical and microbiological assessments

A sampler was needed for a spatial and temporal study of microbial and chemical stratification in a large swine manure lagoon that was known to contain zoonotic bacteria. Conventional samplers were limited to collections of surface water samples near the bank or required a manned boat. A new sampler was developed to allow simultaneous collection of multiple samples at different depths, up to 2.3m, without a manned boat. The sampler was tethered for stability, used remote control (RC) for sample collection, and accommodated rapid replacement of sterile tubing modules and sample containers. The sampler comprised a PVC pontoon with acrylic deck and watertight enclosures, for a 12 VDC gearmotor, to operate the collection module, and vacuum system, to draw samples into reusable autoclavable tubing and 250-mL bottles. Although designed primarily for water samples, the sampler was easily modified to collect sludge. The sampler held a stable position during deployment, created minimal disturbance in the water column, and was readily cleaned and sanitized for transport. The sampler was field tested initially in a shallow fresh water lake and subsequently in a swine manure treatment lagoon. Analyses of water samples from the lagoon tests showed that chemical and bacterial levels, pH, and EC did not differ between 0.04, 0.47, and 1.0m depths, but some chemical and bacterial levels differed between winter and spring collections. These results demonstrated the utility of the sampler and suggested that future manure lagoon studies employ fewer or different depths and more sampling dates.

On-farm treatment of swine manure based on solid–liquid separation and biological nitrification–denitrification of the liquid fraction

In some regions, intensive pig farming has led to soil and water pollution due to the over-application of manure as an organic fertilizer, thereby necessitating alternative treatment technologies to help manage the large amounts of manure generated. The present study seeks to determine the effectiveness of an on-farm swine manure treatment plant consisting of a solid–liquid separation phase using screw pressing followed by a coagulation–flocculation process, and nitrification–denitrification of the liquid fraction. Each treatment unit was evaluated for its contribution towards reducing the raw manure concentration of solids, organic matter, nutrients (nitrogen and phosphorous), metals, and pathogens. The overall system presented high removal efficiencies of up to 71% of TS (total solids) and 97% of TCOD (total chemical oxygen demand). Approximately 97% TKN (total Kjeldahl nitrogen) and 89% TP (total phosphorous) removal was achieved. Metals (copper and zinc) diminished in the liquid fraction to non-detectable concentrations (<1.0 mg L−1). As regards microbial removal, total concentration reductions of 3.6 log10 for Escherichia coli and 1.8 log10 for Salmonella were achieved. Finally, the system was evaluated from a financial standpoint. Results indicate that screw pressing and coagulation–flocculation for solid–liquid separation and nitrification–denitrification of the liquid fraction is a technological alternative for reducing the environmental impact of intensive pig farming in a given area.

Inhibitory effects of ammonia on methanogenmcrAtranscripts in anaerobic digester sludge

Methanogens in anaerobic ammonia-rich digesters show differential responses to ammonia stress. The mechanism for this is poorly understood. In the present study, we determined the rates of methane production, the composition of methanogen mcrA (the gene coding for the alpha subunit of methyl-coenzyme M reductase) and their transcripts in response to ammonium addition in the anaerobic sludge retrieved from a full-scale digester treating swine manure. The rate of CH4 production substantially reduced with increased addition of ammonium. The analysis of natural (13)C abundances of CH4 and CO2 indicated that the aceticlastic methanogenesis was more sensitive than hydrogenotrophic methanogenesis. Quantitative PCR analysis revealed that mcrA copy number decreased by one order of magnitude in the treatment with a large amount of ammonium (10 g NH4+-N L(-1)) but did not change much with treatments of smaller amounts (3 and 7 g NH4+-N L(-1)) compared with the control. T-RFLP analysis of mcrA compositions showed that the structure of the methanogen community remained highly stable, with Methanosaetaceae dominating the methanogen community in all incubations. The composition of mcrA transcripts, however, showed a substantial response to the addition of ammonium. The relative abundance of Methanosaetaceae transcripts declined with increasing amounts of ammonium, whereas the transcript level of Methanobacteriales mcrA was relatively resistant. The differential responses corresponded to the shift of methanogenic pathway inferred from (13)C isotope fractionation. Our study suggests that methanogens in anaerobic sludge have a strong mcrA transcriptional response to ammonia stress without a change in the community structure.

Characterization of the methanogen community in a household anaerobic digester fed with swine manure in China

Household anaerobic digesters have been installed across rural China for biogas production, but information on methanogen community structure in these small biogas units is sparsely available. By creating clone libraries for 16S rRNA and methyl coenzyme M reductase alpha subunit (mcrA) genes, we investigated the methanogenic consortia in a household biogas digester treating swine manure. Operational taxonomic units (OTUs) were defined by comparative sequence analysis, seven OTUs were identified in the 16S rRNA gene library, and ten OTUs were identified in the mcrA gene library. Both libraries were dominated by clones highly related to the type strain Methanocorpusculum labreanum Z, 64.0% for 16S rRNA gene clones and 64.3% for mcrA gene clones. Additionally, gas chromatography assays showed that formic acid was 84.54% of the total volatile fatty acids and methane was 57.20% of the biogas composition. Our results may help further isolation and characterization of methanogenic starter strains for industrial biogas production.

Evaluation of manure-derived struvite as a phosphorus source for canola

Ackerman, J. N., Zvomuya, F., Cicek, N. and Flaten, D. 2013. Evaluation of manure-derived struvite as a phosphorus source for canola. Can. J. Plant Sci. 93: 419-424. There is growing interest in the treatment of swine manure to mitigate water quality issues related to phosphorus (P) from livestock operations. Precipitation of P as struvite (MgNH4PO4·6H2O) is a potential strategy to achieve this. The overall objective of this growth room study was to evaluate the effect of manure-derived struvite (MDS) on canola growth and P recovery efficiency. Pure struvite (PS), monoammonium phosphate (MAP), and polymer-coated monoammonium phosphate (PCMAP) were applied to canola plants in plastic pots containing 2 kg of a sandy loam soil. Biomass yields for MDS and PS were similar at all P rates (mean = 7.6 g pot-1) and significantly smaller than those for MAP and PCMAP (mean = 9.3 g pot-1). Differences in P uptake among P sources were detected at the highest P rate where P uptake was significantly greater for MAP and ...

Evaluation of manure-derived struvite as a phosphorus source for canola

Ackerman, J. N., Zvomuya, F., Cicek, N. and Flaten, D. 2013. Evaluation of manure-derived struvite as a phosphorus source for canola. Can. J. Plant Sci. 93: 419–424. There is growing interest in the treatment of swine manure to mitigate water quality issues related to phosphorus (P) from livestock operations. Precipitation of P as struvite (MgNH4PO4·6H2O) is a potential strategy to achieve this. The overall objective of this growth room study was to evaluate the effect of manure-derived struvite (MDS) on canola growth and P recovery efficiency. Pure struvite (PS), monoammonium phosphate (MAP), and polymer-coated monoammonium phosphate (PCMAP) were applied to canola plants in plastic pots containing 2 kg of a sandy loam soil. Biomass yields for MDS and PS were similar at all P rates (mean = 7.6 g pot−1) and significantly smaller than those for MAP and PCMAP (mean = 9.3 g pot−1). Differences in P uptake among P sources were detected at the highest P rate where P uptake was significantly greater for MAP and PCMAP (mean = 22.7 mg P pot−1) than for the struvite forms (mean = 16.4 mg P pot−1). Our results show that although P uptake was similar for the struvites and commercial fertilizers at P2O5 rates of 38 mg pot−1 or lower, biomass yield per unit of P taken up was smaller for the struvites. This may be due to lower initial solubility of the struvites in the alkaline (pH 7.7) soil used in this experiment, which gave an early stage growth advantage to canola fertilized with MAP and PCMAP. These results suggest that it may be necessary to supplement struvite with soluble P fertilizers, such as MAP, if applied on soils such as that tested in this study.

Application of a Series of Continuously Fed Aerated Tank Reactors System for Recycling of Swine Slurry Nutrients

Single tank aeration systems operated in batch mode or sequential batch reactors based on intermittent aeration are generally applied for swine manure treatment in order to reduce nutrient content and odor. This study evaluated the feasibility of aerobic biological treatment conducted in a serial arrangement of continuously fed aerated tank reactors configuration with swine slurry on a pilot-scale. Compared to municipal wastewater treatment swine slurry rich in nutrients and solids requires different treatment standards for the applied methods to be economically and ecologically relevant. This study presents a sequential process scheme, in which biological treatment serves as a means of achieving a pH raise. This makes it possible to separate part of the nitrogen by stripping and enhances slurry precipitating/coagulation characteristics without substantial carbon or nitrogen loss in gaseous form (which is the opposite to that in a conventional active sludge process). The system was run with a hydraulic retention time (HRT) of three to four days (whole system), and a feedback of 0.8±0.2. During treatment, total organic carbon (TOC) reduction varied between 2.4% and 14.6% and the total nitrogen concentration change was less than 3%. Nearly 50% of the total phosphorus was reduced. The results indicated that the odor of liquid manure had decreased efficiently at best to a level at which there was no odor or only very faint odor. Concurrently, manure pH rose to 8.7.

SCB-M의 돈분 처리 성능에 관한 연구

Purpose: Performance of slurry composting and biofiltration with methane production (SCB-M) using swine manure and sawdust was evaluated. The suitable specific liquid input (SLI) was determined at lab-scale SCB. Method: In lab-scale SCB, the SLI test was performed at liquid input rate of 0.04, 0.09, <TEX>$0.17cc/cm^3$</TEX> with constant sawdust volume. In pilot-scale SCB-M, the swine manure was fed to methane digester at organic loading rate (OLR) of 0.25-0.5 g VS/L/d. The effluent from methane digester was filtered using SCB. Results: The SLI at <TEX>$0.04cc/cm^3$</TEX> showed good performance in terms of retention time. In pilot-scale SCB, the removal of <TEX>$NH_3$</TEX>-N and total nitrogen (T-N) was found to be around 59% and 28%, respectively. Similarly, volatile fatty acid (VFA) and total chemical oxygen demand (TCOD) removal was found be 56% and 43%, respectively. Conclusions: For SCB-M process, the SLI of <TEX>$0.04cc/cm^3$</TEX> is recommended. The performance of swine manure treatment was improved more by using SCB-M system than using methane digester only.

Performance of two swine manure treatment systems on chemical composition and on the reduction of pathogens

Swine effluents must be correctly handled to avoid negative environmental impacts. In this study, the profiles of two swine manure treatment systems were evaluated: a solid–liquid separation step, followed by an anaerobic reactor, and an aerobic step (System 1); and a biodigester followed by serial lagoons (System 2). Both systems were described by the assessment of chemical, bacterial and viral parameters. The results showed that in System 1, there was reduction of chemicals (COD, phosphorus, total Kjeldhal nitrogen – TKN – and NH3), total coliforms and Escherichia coli; however, the same reduction was not observed for Salmonella sp. Viral particles were significantly reduced but not totally eliminated from the effluent. In System 2, there was a reduction of chemicals, bacteria and viruses with no detection of Salmonella sp., circovirus, parvovirus, and torque teno virus in the effluent. The chemical results indicate that the treated effluent can be reused for cleaning swine facilities. However, the microbiological results show a need of additional treatment to achieve a complete inactivation for cases when direct contact with animals is required.

Chemical phosphorus removal: a clean strategy for piggery wastewater management in Brazil

The intensive production of animal protein is known to be an environmental polluting activity, especially if the wastewater produced is not managed properly. Swine production in Brazil is growing, and technologies to manage all pollutants present in the wastewater effluent are needed. This work presents a case of study of phosphorus (P) removal from piggery wastewater using Ca(OH)2, and demonstrates the feasibility of this strategy for P management. The effluent of a swine manure treatment plant was treated with Ca(OH)2. According to the addition of Ca(OH)2 the pH of the effluent ranged from 8.0 to 10.0. Different conditions of sludge dewatering were evaluated, and the chemical composition of sludge was investigated. Ion chromatography analysis of effluent samples showed that 92% of total P (TP) was present as soluble P (SP) whereas 75% of SP species were present as phosphate. The efficiency of P removal was typically 90% at pH 8.5 and higher than 98% at pH 10.5. The sludge was separated by sedimentation, centrifugation or filtration and dried. The TP content of dried sludge was 9.3% (w/w). X-ray diffraction analysis of the dry sludge showed the presence of amorphous compounds of Ca and P, which is an indication that the sludge obtained from the swine manure treatment has a potential for application as biofertilizer.

Photocatalytic abatement of ammonia in nitrogen-containing effluents

The photocatalytic abatement of aqueous ammonia, the major nitrogen-containing compound in livestock manure, was investigated employing (i) a batch reactor equipped with an immersion UVA lamp, containing aqueous suspensions of different commercial TiO2 powders and (ii) a 40L prototype plug flow photo-reactor, suitable for the photocatalytic treatment of real swine and bovine manure, consisting of 9 vertical elements connected in series, internally coated with a TiO2 film, each one centrally housing a UVA lamp. A preliminary systematic investigation performed with the first photo-reactor evidenced that ammonia conversion and the selectivity toward the main oxidation products (N2, NO2− and NO3−) depend on the amount of dissolved O2, on pH and on the photocatalyst's amount and structural features. Extremely promising results, in terms of both ammonia conversion (up to the 88%) and selectivity to nitrogen gaseous species (99%), were achieved when the prototype photo-reactor was fed with suitably pre-treated manure. The TiO2-based photocatalytic treatment can thus be considered an effective remediation technology for the abatement of nitrogen-containing pollutants in surface and groundwater, originating from large-scale animal husbandries.

Culturing and molecular methods to assess the infectivity of porcine circovirus from treated effluent of swine manure

Samples were collected at the effluent of two swine manure treatment systems and were analyzed by qPCR to determine the presence and amounts of porcine circovirus (PCV2) genetic material. ST cells were inoculated with the positive samples to evaluate virus viability and for viral genotyping. Twenty-five water samples were collected monthly from treated effluent (March 2009 to December 2010). The PCV2 genome was identified by qPCR in 60% of the samples, and all of the positive samples were able to infect ST cells in vitro. Positive samples were genotyped and 60% of them were positive for both PCV2a and PCV2b, 20% were positive for genotype 2a, and 20% were positive for genotype 2b. Our results suggest that these viruses were able to resist the regular wastewater treatment, and this finding demonstrates the necessity of adding a virus inactivation step to the treatment system to guarantee the safety of water reuse.

Biosolids from Treated Swine Manure and Papermill Residues Affect Corn Fertilizer Value

Biosolids derived from treatment of animal manure or industrial effluents can be used on farms, but their fertilizer value must be assessed. A 3‐yr field study was conducted on a clay soil in Quebec, Canada, to evaluate the effect of several biosolids on silage corn dry matter (DM) yield; N‐use efficiency; and soil N, P, Cu, and Zn availability. Raw liquid swine (Sus scrofa) manure (LSM), biosolids from four swine manure treatments (aerobic digestion [AER], anaerobic digestion [DIG], filtration [FIL], anaerobic digestion followed by chemical flocculation [DIG+FLO]), combined papermill biosolids (CPB), de‐inking paper biosolids (DPB), and mineral N fertilizer (MIN) were applied before corn planting at a targeted rate of 150 kg total N ha−1. The DIG and DIG+FLO biosolids resulted in silage corn DM yield, N accumulation, and early season soil N availability comparable to LSM with an N‐use efficiency about 70% of that for MIN. The AER biosolid resulted in low DM yield with an N‐use efficiency only 10% of that for MIN; FIL and CPB had an N‐use efficiency almost 40% of that for MIN, whereas DPB caused a decline in DM yield compared to a no‐N control. The LSM‐derived biosolids increased availability of soil P (0.34 kg kg−1 excess P) and, to some extent, Cu and Zn. The CPB and DPB biosolids had little impact on soil P, but DPB markedly increased Zn availability. Manure‐derived biosolids and CPB were satisfactory N sources for silage corn while manure‐derived biosolids caused soil P enrichment when applied based on crop N requirement.

Fate of steroid hormones and endocrine activities in swine manure disposal and treatment facilities

Manure may contain high concern endocrine-disrupting compounds (EDCs) such as steroid hormones, naturally produced by pigs, which are present at μg L −1 levels. Manure may also contain other EDCs such as nonylphenols (NP), polycyclic aromatic hydrocarbons (PAHs) and dioxins. Thus, once manure is applied to the land as soil fertilizer these compounds may reach aquifers and consequently living organisms, inducing abnormal endocrine responses. In France, manure is generally stored in anaerobic tanks prior spreading on land; when nitrogen removal is requested, manure is treated by aerobic processes before spreading. However, little is known about the fate of hormones and multiple endocrine-disrupting activities in such manure disposal and treatment systems. Here, we determined the fate of hormones and diverse endocrine activities during manure storage and treatment by combining chemical analysis and in vitro quantification of estrogen (ER), aryl hydrocarbon (AhR), androgen (AR), pregnane-X (PXR) and peroxysome proliferator-activated γ (PPARγ) receptor-mediated activities. Our results show that manure contains large quantities of hormones and activates ER and AhR, two of the nuclear receptors studied. Most of these endocrine activities were found in the solid fraction of manure and appeared to be induced mainly by hormones and other unidentified pollutants. Hormones, ER and AhR activities found in manure were poorly removed during manure storage but were efficiently removed by aerobic treatment of manure.