Reuse of the digestate obtained from the biomethanization of olive mill solid waste (OMSW) as soil amendment or fertilizer for the cultivation of forage grass (Lolium rigidum var. Wimmera).

The principal by-product from the two-phase olive oil production process is olive mill solid waste (OMSW). It is a highly-pollutant by-product, not only because of its characteristics, but also because of the considerable volume of OMSW which is generated, amounting to 2 to 4 million tons per year in Spain. The anaerobic digestion of this by-product is a well-studied process, and results in the generation of biogas, methane and carbon dioxide mainly of high calorific values (20-25 MJ m-3), and an effluent or digestate. The digestate of this by-product has never been characterized. This study presents an informative view on how the composition of OMSW digestate shows promising implications as a soil amendment or fertilizer due to the quality of the biomass from Lolium rigidum, a useful grass specie for the production of forage. Three OMSW digestate alternative applications or treatments were investigated: the digestate and the solid fraction of the digestate for a nutrient-poor soil amendment and the liquid fraction of the digestate as fertilizer. The results confirm that all the OMSW digestate treatments studied presented suitable characteristics for agricultural use, and showed an optimal Carbon/Nitrogen ratio with adequate values for heavy metals which are below the limits established by the Spanish and European legislation in the absence of pathogens. However, fertirrigation was the treatment that provided Lolium rigidum with the best characteristics, improving its shoot biomass, photosynthetic rate and nutritional content.

Assessing the viability of recovered phosphorus from eutrophicated aquatic ecosystems as a liquid fertilizer.

One of the most important worldwide environmental challenges is the alteration of the biogeochemical cycle of phosphorus (P). P is globally exported from terrestrial to aquatic ecosystems, causing the eutrophication of the receiving waters. In this context, magnetic microparticles (MPs) have been recently proposed for trapping P in natural eutrophicated ecosystems, as well as in treated wastewaters. The main advantage of using MPs is that both P and MPs can be recovered from the treated water. Thus, the working hypothesis of the present study is that P can be desorbed from P-loaded MPs and recovered P can be later used as a fertilizer. To test this hypothesis, the best working conditions for desorbing P from P-loaded MPs were identified; then, an experiment with different plant nutrient solutions (neutralized solutions containing recovered P and an unfertilized control) was carried out with three different plant species: Ocimum basilicum L., Cucumis sativus L. and Cucumis melo L. Finally, germination, height, root and shoot biomass and P concentration in root and shoot were compared among treatments. Our results show that the best conditions for P desorption from P-loaded MPs occurred when using 0.1 M NH4OH and using H3PO4 for neutralizing pH. The greenhouse fertirrigation pot experiment showed that the neutralized solution containing desorbed P from P-loaded MPs can be used as a liquid fertilizer, since its combination with macro and microelements significantly increased plant height, growth rate, shoot and root biomass and shoot and root P concentration. As a result, MPs can be proposed to be used for counteracting the widespread and coupled problems of the exhaustion of the P reserves and the eutrophication of aquatic ecosystems.

Accumulation of sodium and heavy metals in soil cultivated with Corymbia citriodora after the application of swine wastewater / Acúmulo de sódio e metais pesados ​​no solo cultivado com Corymbia citriodora após aplicação de água residuária de suinocultura

The confinement of pigs stands out as a great generator of swine wastewater (SW). The final destination of waste generated is currently a concern of society, since if handled improperly, it can cause serious impacts to the environment. One of the alternatives is the use of SW as a source of nutrients, which are made available to the plants, after the mineralization of organic matter. The objective of this work was to compare soil chemical attributes under two planting arrangements, in single and double lines of Corymbia citriodora. Two experiments were carried out at the Bonsucesso farm, in Uberlândia-MG, the first with C. citriodora in simple lines, with five plants per plot, spacing two meters between plants and 15 meters between rows. The second experiment was with C. citriodora in double lines, with two meters between plants in the line, three meters between lines in the plot and 15 meters between the double lines of C. citriodora. The statistical design was in randomized blocks. The treatments used were five doses of SW (0; 200; 400; 600 and 800 m³ ha-1) with five replicates. The application of SW rates was divided in the dry season, in the months of June, July and August. The chemical characteristics of the soil were evaluated in the 0-20 cm depth layer. Planting on double lines of C. citriodora provided higher soil nutrient contents. The application of swine wastewater raised the levels of potassium and heavy metals such as copper and zinc. The dose of 200 m3ha-1provided adequate levels for most nutrients present in the soil.

O confinamento de suínos destaca-se como grande gerador de águas residuárias de suinocultura (ARS). O destino final de resíduos gerados é atualmente uma preocupação da sociedade, uma vez que, se manejados de forma inadequada, podem provocar sérios impactos ao meio ambiente. Uma das alternativas é o uso da ARS como fonte de nutrientes, que após a mineralização da matéria orgânica, são disponibilizados para as plantas. O objetivo do trabalho foi comparar os atributos químicos do solo sob dois arranjos de plantio, em linhas simples e duplas de Corymbia citriodora. Foram implantados dois experimentos na fazenda Bonsucesso, em Uberlândia-MG, sendo o primeiro com C. citriodora em linhas simples, com cinco plantas por parcela, com espaçamento de dois metros entre plantas e 15 metros entre linhas. O segundo experimento foi com C. citriodora em linhas duplas, com dois metros entre plantas na linha, três metros entre linhas na parcela e 15 metros entre as linhas duplas de C. citriodora. O delineamento estatístico foi em blocos ao acaso. Os tratamentos utilizados foram cinco doses de ARS (0; 200; 400; 600 e 800 m³ ha-1) com cinco repetições. A aplicação das doses de ARS foram parceladas na estação da seca, nos meses de junho, julho e agosto. Foram avaliadas as características químicas do solo, na camada de 0-20 cm de profundidade. O plantio realizado em linhas duplas de C. citriodora proporcionou maiores teores de nutrientes no solo. A aplicação de água residuária de suinocultura elevou os teores de potássio e de metais pesados como o cobre e o zinco. A dose de 200 m3 ha-1 proporcionou teores adequados para maioria dos nutrientes presentes no solo.

Seasonal characterization of sugarcane vinasse: Assessing environmental impacts from fertirrigation and the bioenergy recovery potential through biodigestion.

Sugarcane vinasse has been widely used as a soil fertilizer in the Brazilian sucro-alcohol industry for recycling potassium and water. However, the potential negative effects from long-term soil fertirrigation represent a major drawback regarding this practice, whereas the application of biodigestion represents an efficient method for reducing the polluting organic load and recovering bioenergy from vinasse. Regardless of the predicted use for vinasse, an understanding of the potential of each option is imperative, as the seasonal alterations in the inorganic/organic fractions of vinasse directly affect its management. In this context, this study presents a detailed compositional characterization of sugarcane vinasse from a large-scale Brazilian biorefinery throughout the 2014/2015 harvest to assess the environmental effects (due to fertirrigation) and to estimate the biogas energetic potential. Calculated inputs of organic matter into soils due to vinasse land application were equivalent to the polluting load of populations (117-257inhabha-1) at least 2-fold greater than the largest Brazilian capital cities (78-70inhabha-1). Two-phase biodigestion could efficiently reduce the polluting load of vinasse (23-52inhabha-1) and eliminate the negative effects from direct sulfide emissions in the environment. However, a high risk of soil sodification could result from using high doses of Na-based alkalizing compounds in biodigestion plants. Finally, the optimized recovery of bioenergy through biogas (13.3-26.7MW as electricity) could supply populations as large as 305 thousand inhabitants, so that over 30% of the surplus electricity produced by the studied biorefinery could be obtained from biogas. Overall, applying biodigestion in the treatment of vinasse provides important environmental and energetic gains. However, the benefits of reducing the polluting organic load of vinasse through bioenergy recovery may lose their effect depending on the alkalizing strategy, indicating that the proper use of chemicals in full-scale biodigestion plants is imperative to attain process sustainability.

Fertirrigation with sugarcane vinasse: Foreseeing potential impacts on soil and water resources through vinasse characterization.

This paper reports the characterization of the polluting potential of sugarcane vinasse, the main wastewater from ethanol production. Compositional data from vinasse samples collected from sugarcane biorefineries were used to predict negative effects on the soil, water resources and crops potentially associated with fertirrigation, the primary final destination of vinasse in Brazil. High risks of soil salinization were associated with the land disposal of vinasse, as evidenced by the high levels of total dissolved solids (TDS; >4,000 mg L-1) and electrical conductivity (>6.7 dS m-1). The high TDS levels coupled with the high biodegradable organic content of vinasse (>14 g L-1) also favor organic overloading events, leading to local anaerobiosis conditions. Conversely, soil sodification should not be observed in areas fertirrigated with sugarcane vinasse, given the low Na concentrations (<66 mg L-1) relative to Mg (>145.1 mg L-1) and Ca (>458.4 mg L-1) levels. Priority pollutants (Cu, Cr, Ni, Pb and Zn) and phytotoxic elements (Al and Fe) were also found in the analyzed samples; however, relevant environmental impacts should not be associated with these particular constituents. Overall, the relatively simple methodology used herein could efficiently replace massive field data collection to provide a basic understanding of the fate of vinasse in the environment in order to highlight the priority points to be considered in the management of this effluent. In summary, the prompt implementation of treatment plants in distilleries, in addition to a continuous and broad compositional characterization of vinasse, is essential to guarantee its adequate reuse.

Toxicity of two effluents from agricultural activity: Comparing the genotoxicity of sugar cane and orange vinasse.

Vinasse, produced by several countries as a by-product of agricultural activity, has different alternatives for its reuse, mainly fertirrigation. Several monocultures, such as sugar cane and orange crops, produce this effluent. Sugar cane vinasse is already widely used in fertirrigation and orange vinasse has potential for this intention. However, its use as a fertilizer has caused great concern. Thus, ecotoxicological evaluation is extremely important in order to assess the possible effects on the environment. Therefore, the aim of this study was to evaluate the potential toxicity of vinasse of two different crops: sugar cane and orange. For this purpose, bioassays with Allium cepa as a test organism were performed with two vinasse dilutions (2.5% and 5%) to detect chromosomal aberrations and micronucleus induction. The results showed that both types of vinasse are able to induce chromosomal aberrations in meristematic cells, mainly nuclear and anaphasic bridges, suggesting genotoxic potential. The induction of micronuclei in cells of the F1 region suggests that the two residues have mutagenic potential. Thus, caution is advised when applying these effluents in the environment.

Chemical alterations in soils fertirrigated with wastewater from swine facilities / Alteraciones químicas en suelos fertirrigados con aguas residuales porcícolas / Alterações químicas em solos fertirrigados com águas residuais suinicolas

The increasing size of swine farms poses an environmental risk to water bodies, considering that manure is generally applied to croplands without appropriate agronomic criteria. Objective: the present work aimed to evaluate various chemical changes occurring in soils fertirrigated with filtrated wastewater from swine facilities (FWS). Methods: 21 drainage lysimeters filled with Dystrophic Red-Yellow Latossoil were cultivated with tomato plants in protected environments, and fertirrigated with several doses of FWS, with and without fertilizer addition. Treatments were: T1: control (provided the recommended irrigation and fertilization needs for tomato plants). Treatments T2, T3, and T4, provided 100, 150, and 200% of recommended nitrogen (N), respectively, by adding filtered swine wastewater. Treatments T5, T6, and T7 provided equivalent N percentages with fertilizer addition. The experiment was conducted in a completely randomized design (seven treatments and three replications). Results: compared with initial conditions, an increase in the concentration of available phosphorus was observed, mainly in the superficial layers. The FWS addition resulted in increments in N concentration in the superficial layers, while chemical fertilizer application resulted in larger displacements in the soil profile. Conclusion: chemical fertilization was more effective than FWS for ionizing the soil solution.

El aumento en el tamaño de las granjas porcinas supone un riesgo ambiental para los cuerpos de agua, teniendo en cuenta que el estiércol se aplica generalmente a las tierras de cultivo sin adecuados criterios agronómicos. Objetivo: el presente trabajo tuvo como objetivo evaluar los diversos cambios químicos que ocurren en los suelos fertirrigados con aguas residuales de instalaciones porcícolas (FWS). Métodos: 21 lisímetros de drenaje llenos con Latosuelo distrófico rojo-amarillo fueron cultivados con plantas de tomate en ambientes protegidos, y fertirrigados con varias dosis de FWS, con y sin adición de fertilizante. Los tratamientos fueron: T1: control (proveía la irrigación y fertilización recomendada para las necesidades de las plantas de tomate). Los tratamientos T2, T3 y T4 suministraron el 100, 150 y 200%, respectivamente, del nitrógeno (N) recomendado, mediante la adición de las aguas residuales filtradas. Los tratamientos T5, T6 y T7 proporcionaron los mismos porcentajes de N mediante la adición de fertilizantes. El experimento se realizó en un diseño completamente al azar (siete tratamientos y tres repeticiones). Resultados: al comparar con las condiciones iniciales, se observó un aumento en la concentración de fósforo disponible, sobre todo en las capas superficiales. La adición de FWS resultó en incrementos en la concentración de N en las capas superficiales, mientras que la aplicación de fertilizantes químicos resultó en grandes desplazamientos en el perfil del suelo. Conclusión: la fertilización química fue más eficaz que el FWS para ionizar la solución del suelo.

O incremento de tamanho das granjas de suínos supõe um risco ambiental para os corpos de água, tendo em conta que as fezes dos porcos aplicam-se geralmente em terras para culturas sem ter em conta critérios agronômicos adequados. Objetivo: este trabalho teve como objetivo avaliar a alteração química que ocorre em solos adubados com irrigação de água residuária de suinocultura filtrada (FWS). Métodos: 21 lisímetros de drenagem cheios com latossolo distrófico vermelho-amarelo foram cultivados com tomateiros em ambientes protegidos e fertirrigados com varias doses de FWS, com e sem adição de adubo químico. Os tratamentos foram: T1: controle (ministrou-se a irrigação e fertilização recomendada para as necessidades do tomateiro). Os tratamentos T2, T3 e T4 ministraram 100, 150 e 200%, respectivamente, do nitrogênio (N) recomendado, por médio da adição de águas residuais filtradas. Os tratamentos T5, T6 e T7 proporcionaram as mesmas percentagens de N por médio da adição de adubos químicos. O experimento se analisou com um modelo completamente aleatorizado (sete tratamentos e três repetições). Resultados: ao comparar as condições iniciais, observou-se um aumento na concentração de fósforo disponível, principalmente nas capas superficiais. A adição de FWS resultou em incrementos da concentração de N nas capas superficiais, enquanto a aplicação de adubos químicos resultou em grandes deslocamentos no perfil do solo. Conclusão: A adubação química foi mais eficaz que o FWS para ionizar a solução do solo.

Effects of wastewater from a cassava industry on soil chemistry and crop yield of lopsided oats (Avena strigosa Schreb)

This experiment was carried out in the Arenito soil of the Cidade Gaúcha county, Northwest Paraná in Brazil, in which 0, 150, 300, 450 and 600 m³ ha-1 of wastewater were applied onto soil and the crop yield and soil chemistry were investigated for lopsided oat (Avena strigosa Schreb.) plants. The crop yield from the control was 2818 kg ha-1 contrasting 3629 kg ha-1 when 300 m³ ha-1 of cassava wastewater were applied, and potassium, after haversting, was the only nutrient found in a higher concentration in the soil profile.

A utilização dos cursos de água, como drenos naturais de resíduos agroindústrias, tem contribuído para sua eutrofização principalmente como fonte de nitrogênio, fósforo e destacadamente potássio. Com o propósito de evitar o despejo deste resíduo, nos cursos de água naturais e pensando em otimizar os custos de fertilização e irrigação de culturas, realizou-se este experimento no Campus do Arenito da Universidade Estadual de Maringá, no município de Cidade Gaúcha, com a cultura da aveia preta, avaliando-se os efeitos dos níveis de água residuária (0, 150, 300, 450 e 600 m³ha-1) como também os efeitos residuais da sua aplicação no solo. O objetivo deste trabalho foi o de avaliar a influência da aplicação de diferentes níveis de água residuária de fecularia de mandioca na produção de aveia preta, bem como seu efeito residual nas propriedades químicas do solo. a aplicação de água residuária de fecularia de mandioca, proporcionou acréscimos na produtividade da cultura da aveia, obtendo-se a produtividade de 3629 kg ha-1 para o nível de 300 m³ ha-1 e 2818 kg ha-1 na testemunha quando se analisaram os valores dos elementos encontrados nas camadas, somente o potássio apresentou acréscimos nas camadas, sendo que os demais apresentaram redução.

Avaliação de critério de amostragem de solo para determinação do nitrato residual do tomateiro fertirrigado em ambiente protegido / Evaluation of soil sample criteria for the determination of nitrate residue in tomato plants fertirrigated in an unheated greenhouse

O efeito do posicionamento de amostragem para a quantificação do N-NO3 residual no solo foi determinado após o cultivo do tomateiro fertirrigado. Três experimentos foram conduzidos, em ambiente protegido, com fertirrigação por gotejamento. Em cada experimento, os tratamentos foram arranjados em parcela subdivida, com dez critérios para o manejo da adubação nitrogenada na parcela e posições de amostragem do solo na subparcela. Esses foram arranjados no delineamento experimental de blocos ao acaso. Foi determinado o teor de N-NO3 no solo de amostras retiradas no final do ciclo de cada experimento, em diferentes posições. Em todos os experimentos, o teor de N-NO3 residual no solo foi proporcional à quantidade de N aplicada nos diferentes critérios. Em condições de ambiente protegido e fertilizante nitrogenado fertirrigado por gotejamento, a melhor estratégia de amostragem do solo para a determinação do teor de N-NO3 residual foi obtida pela utilização de amostra composta tomada em posições distanciadas em 10 cm da planta na entre linha e sobre a linha de transplante.

The effect of sample positioning for quantification of residual N-NO3 in soil was determined after cultivating fertirrigated tomato plants. Three experiments were carried out in an unheated greenhouse, using drip fertirrigation. Soil N-NO3 level was determined from samples taken at the end of the cycle of each experiment. In all the experiments, the residual N-NO3 level of the soil was proportional to the amount of N applied in different criteria. Under unheated greenhouse conditions and using nitrogen fertilization by drip fertirrigation, the best soil sampling strategy for residual N-NO3 level determination was obtained by the use of a composite sample taken at a position 10 cm from the plants, between rows, and on the transplant row.

In vitro degradation of linamarin by microorganisms isolated from cassava wastewater treatment lagoons

This study aimed at isolating and characterizing of microorganisms able to use linamarin as sole carbon source. Thirty one microbial strains were isolated from manipueira, a liquid effluent of cassava processing factories. Among these strains, Bacillus licheniformis (isolate 2_2) and Rhodotorulla glutinis (isolate L1) were able to degrade 71 percent and 95 percent of added linamarin, respectively, within 7 days, showing high biodegradation activity and great potential for detoxification of cassava processing wastewaters.

In vitro degradation of linamarin by microorganisms isolated from cassava wastewater treatment lagoons.

This study aimed at isolating and characterizing of microorganisms able to use linamarin as sole carbon source. Thirty one microbial strains were isolated from manipueira, a liquid effluent of cassava processing factories. Among these strains, Bacillus licheniformis (isolate 2_2) and Rhodotorulla glutinis (isolate L1) were able to degrade 71% and 95% of added linamarin, respectively, within 7 days, showing high biodegradation activity and great potential for detoxification of cassava processing wastewaters.