Airton Kunz

Eficiência da interação biodigestor e lagoas de estabilização na remoção de poluentes em dejetos de suínos

Swine production is considered an activity with a high environmental impact, due to the presence of a high number of contaminants in the effluents that come out from the piggery. In this study the feasibility of a combined process biodigestor and stabilization ponds (anaerobic, facultative and maturation) connected in sequence fed with sludge from a swine manure treatment unit was evaluated. The system showed itsetf as efficient in the removal of organic matter, however it presented some limitations in removing nutrients, especially nitrogen, mainly due to the contribution of volatilization of ammonia.

Toxicity of the Colistin Sulfate Antibiotic Used in Animal Farming to Mixed Cultures of Nitrifying Organisms

Colistin is a peptide antibiotic widely used as a food additive in animal farming, specially swine and poultry, and also has recently been applied in human medicine to treat infections caused by multiresistant gram-negative bacteria strains. When orally administered, colistin is eliminated in feces virtually unaltered; thus, it may reach water bodies and wastewater treatment facilities in its active form. Apart from the risks associated with development of antimicrobial resistance and environmental toxicity issues, the presence of antimicrobials in wastewater can, additionally, interfere in biological processes commonly used to treat them. Nitrifying bacteria are among the most sensitive microorganisms to inhibitory compounds, including pharmaceuticals, and are useful as biosensors to access contaminant toxicity information in wastewater treatment plants. Therefore, in order to assess the colistin acute toxicity to the microorganisms involved in the nitrification processes, the nitritation and nitratation kinetics were monitored under different colistin concentrations. The results showed that only ammonia-oxidizing bacteria are sensitive to the antibiotic, presenting an IC50 of 10.8xa0mgu2009L−1 of colistin when used as a commercial formulation and 67.0xa0mgu2009L−1 when used as raw colistin sulfate. For nitrite-oxidizing bacteria, even the highest colistin concentration used in the assays (316xa0mgu2009L−1) was not sufficient to inhibit the process. According to these results, the colistin concentrations expected in animal farming wastewater, when its dosage is used as a growth promoter, would not be enough to keep nitrification from taking place. Nevertheless, when used in higher concentrations, such as for therapeutic purposes, it could endanger the maintenance of the process.

Aplicação de adsorção para remover amônia de efluentes suinícolas pré-tratados

+that remains in effluents from swine facilities which were submitted to physico-chemical and biological treatments. Experiments were made in batch made adding 5% (w/w) of adsorbent (0.6-1.3 and 3.0-8.0 mm) to synthetic and real swine facilities effluents. The results show that ammonium removal is influenced by adsorbent particle size and the presence of other ions in the effluent. The adsorption equilibrium was described by Langmuir as well as Freundlich isotherms and the kinetic data fitted well a pseudo-second order model.

Pathogen Inactivation and the Chemical Removal of Phosphorus from Swine Wastewater

Inactivation of pathogens present in animal manure prior to land application has justified the use of advanced technologies. However, some alternatives are expensive or not effective due to the organic material and suspended solids present in the effluent (e.g., ozone, UV light). The use of hydrated lime (calcium hydroxide, Ca(OH)2) is an attractive wastewater treatment option due to the ability of lime to kill pathogens and to extract phosphorus from manure at an alkaline pH. The present study aimed to evaluate the soluble phosphorus removal and pathogen inactivation (Escherichia coli, Salmonella enterica serovar typhymurium and Porcine circovirus type 2), in the liquid fraction and in the solid generated after Ca(OH)2 addition in swine wastewater, exposed for 3 and 24xa0h at different pH conditions: 9.0, 9.5, and 10.0. The results showed the efficiency of pH elevation with Ca(OH)2 in the removal of soluble P at pH 9.0 and the total inactivation of E. coli, Salmonella, and P. circovirus type 2 at pH 10.0. The liquid fraction (reuse water) could be safely used for cleaning the swine production facilities, and the solid fraction (precipitated P) could be used as a secondary product and fertilizer.

Swine manure post-treatment technologies for pathogenic organism inactivation

Swine manure agricultural use is a common practice in Brazil. Their physic-chemical characteristics favor its use as biofertilizer, but the presence of pathogens may become a risk to human health. This research presents a qualitative study of the main alternatives of pig manure disinfection, analyzing efficiency, advantages and limitations of each procedure. The disinfection studies reported in literature are based on the following treatments: alkaline, thermal, biological, chemical, and physical. The greater efficiencies are in thermal treatment (> 4 log: 60 °C), chemical treatment (3 to 4 log: 30mg Cl- L-1; 3 to 4 log: 40 mg O3 L-1) and physical treatment (3 a 4 log: 220 mJ UV radiation cm-2). The biological treatment (anaerobiosis) also promotes the pathogen reduction of swine manure, however with lower efficiency (1 to 2 log). The selection of the treatment should consider: implementation and operation cost, necessity of preliminary treatment, efficiency obtained and destination of the treated manure (agricultural use, water reuse). Brazilian regulation does not have specific guidelines for the microbiological quality of animal production effluents that is very important to be considered due to confined animal feeding operation transformation in the last years in the country.

Recirculation and Aeration Effects on Deammonification Activity

Deammonification process has been studied as an alternative technology for nitrogen removal. This process consists of the association between nitrifying and anammox bacteria, in which the process success is related to aeration, recirculation, and reactor configuration. Considering this, the present study aimed to evaluate the performance of an expanded granular sludge bed (EGSB) reactor on nitrogen removal by deammonification process. Established in a single reactor, it considered the effects of recirculation rate and variation of dissolved oxygen (DO) concentration in microbial community and nitrogen removal efficiency. Thus, two independent tests were conducted: (T1) high recirculation flow rate, performed at 43xa0Lxa0d−1 (Qr/Qinu2009=u200916), aeration of 30xa0mLairu2009min−1xa0L−1reactor, and conducted during 16xa0days; (T2) low recirculation flow rate performed at 6.7xa0Lxa0d−1 (Qr/Qinu2009=u20092.5), operated for 55xa0days, divided into three aeration phases: (T2a) 30xa0mLairu2009min−1xa0L−1reactor, (T2b) 20xa0mLairu2009min−1xa0L−1reactor, and (T2c) 30xa0mLairu2009min−1xa0L−1reactor. Results showed that in T1 the high recirculation rate favored nitrifying bacteria prevalence, intensified by reactor turbulence and anammox granules disintegration, changing activity from deammonification to a nitrification process. In addition, T1 reached up to 350u2009±u2009100xa0mgNxa0L−1xa0d−1 nitrogen removal rate (NRR). For T2, at low recirculation rate, deammonification process was successfully established with a NRR of 490xa0mgNxa0L−1xa0d−1 at Qr/Qinu2009=u20092.5 and air flow rate of 20xa0mLairu2009min−1xa0L−1reactor.

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<0.05) of biogas methane concentration among the studied stages (73.7, 75.0, and 77.9%).

Aplicação de efluente tratado de suinocultura para diluição de dejeto suíno e remoção de nitrogênio por desnitrificação

This study evaluated the effect of swine manure dilution with treated effluent up to 50% volumetric ratio of each part, intending to increase the denitrification by carbon feeding to the process. In studied dilution, the range of NO3--N content in the mixture was 47,9 + 14,5 mg L-1 and COD close to 17543 + 675 mg L-1, resulting in favorable denitrification activity on equalization tank due to relation COD/N-NO3- upper to 360. The NO3--N concentration was biologically reduced to 0.5 mg L-1 (around 1% of initial concentration). An improvement in solid-liquid separation efficiency using natural and synthetic organic polymers was also reached in the diluted effluent when compared to the undiluted manure.

Application of Diluted Sulfuric Acid for Manure Ammonia Extraction Using a Gas-Permeable Membrane

Tubular gas-permeable membrane (GPM) provides an alternative solution for ammonia (NH3) mitigation and recovery from liquid animal manure. A set-up consisting of a closed dairy liquid manure (LM) chamber, two sulfuric acid (H2SO4) flasks and two GPM systems was fabricated in order to investigate NH3 extraction processes using diluted H2SO4 solutions (pH values between 2 and 5.4). One GPM system was submerged below the LM surface and the other was suspended above LM surface in the headspace of the chamber. Ammonia from dairy LM was extracted and captured in acidic solution by circulating the diluted H2SO4 through both GPM systems. Results showed that the extraction of NH3 by both systems continued for few days, even though pH of the circulating acidic solution in the tubular GPM increased above the neutral pH value. By then, between 5% and 13% of the initial NH3 concentration of untreated LM were extracted by the circulating acidic solution in both systems. It was observed that the pH of acidic solution increased very quickly; especially for more diluted acid solutions. Among all experiments, the diluted acid with pH of 2 had the greatest NH3 removal and recovery as ammonium sulfate (NH4)2SO4, a potential fertilizer. However, none of the experiments with diluted acidic solutions resulted in greater extraction and recovery of NH3 from LM as compare to the strong acid (pH<0.4) used in a previous study.

Chemical Removal of Phosphorus from Swine Effluent: the Impact of Previous Effluent Treatment Technologies on Process Efficiency

Chemical phosphorus removal with hydrated lime was evaluated on effluents from different biological treatment processes applied to swine manure. The objective of this study was to establish the most suitable process for this kind of wastewater treatment. Effluents a UASB reactor, a nitrification reactor (NR), a modified Lutzak–Ettinger (MLE) reactor and a deammonification (DMX) reactor were evaluated. A comprehensive study was developed at laboratory scale to evaluate the effect of possible interferences, including alkalinity, total organic carbon, and ammonia, on phosphorus precipitation. The highest soluble phosphorus (Psol) removal efficiency and the lowest Ca:P molar ratio were obtained for the NR effluent (92% and 2.0, respectively). The good performance of the NR effluent could be attributed to the low level of ammoniacal nitrogen and alkalinity and to the presence of a relatively high concentration of calcium. Highly promising results were also obtained in field experiments, where a phosphorus removal unit was installed as the last step in a swine manure treatment system, and precipitation was applied to effluent from the NR. In this case, efficiencies of Psol removal higher than 90% were obtained. The produced sludge was rich in phosphorus and could be used as, for example, fertilizer. The results obtained in this work showed the importance of applying an efficient treatment system to swine manure for reduction of ammoniacal nitrogen, alkalinity, and carbon before chemical removal of phosphorus by precipitation with hydrated lime.