Co-composting of distillery and winery wastes with sewage sludge

Compostaje de residuos vitivinícolas. Avanzando hacia una industria circular

En una vitivinicultura circular, mediante el compostaje de materia orgánica, se conservan los nutrientes, la estructura y la diversidad del suelo del viñedo, y se valorizan los residuos industriales. En este contexto, el objetivo de este trabajo fue optimizar la eficiencia y calidad de la producción de compost. En un proyecto colaborativo entre 3 bodegas, se evaluó un compostaje de volteo tradicional en conjunto con una tecnología de cubierta permeable, sustratos alternativos como residuos de tomate y manzana, así como estiércol y urea como fuente adicional de nitrógeno, y además el efecto de organismos comerciales como aceleradores del compostaje de residuos vitivinícolas. El uso de una cubierta permeable redujo el requerimiento de agua en un 17%. La adición de orujo de manzana y tomate generó un compost más estable y rico en N, en comparación con los sistemas que utilizan solo orujo. La aplicación de estiércol avícola y urea aumentó principalmente en el contenido respectivo de P y N. La inoculación adicional con microorganismos comerciales no generó diferencias en el compost. En cuanto a las poblaciones de microorganismos naturales, no se encontraron diferencias entre los tratamientos en bacterias beneficiosas fijadoras de nitrógeno como Nitrospira y Nitrosomas.

Utilización de lodos residuales en el compostaje de orujos y escobajo en la industria vitivinícola

Este estudio tiene por objetivo evaluar la factibilidad de integrar lodos provenientes de una planta de tratamiento de aguas vitivinícolas en el compostaje de orujos y escobajo. Los ensayos se llevaron a cabo en un viñedo de la zona central de Chile, se estudió la evolución del proceso de compostaje mediante el monitoreo de temperaturas, pH, humedad y densidad aparente. Se determinaron los efectos 3 distintas proporciones v/v de lodos (0, 10 y 20%), en las propiedades fisicoquímicas y el contenido de metales pesados durante la etapa mesófila inicial, termófila y mesófila tardía. Los resultados indican un incremento en el contenido de nutrientes y porcentaje de humedad al incorporar los lodos en las primeras etapas del proceso, además de mejorar la estructura física de las pilas. Sin embargo, existe un riesgo de fitotoxicidad asociado al contenido de metales pesados cuando el lodo es usado en mayores proporciones (20%). Con dosis menores (10%) se obtuvo un compost sin riesgos fitotóxicos y dentro de los parámetros establecidos por la normativa vigente en Chile. Por lo anterior, es factible integrar los lodos de la planta de tratamiento de aguas vitivinícolas, en una proporción de 10% de lodos y 90% de orujo y escobajo.

Integrated biorefinery approach to valorize winery waste: A review from waste to energy perspectives

The ever-increasing environmental crisis, depleting natural resources, and uncertainties in fossil fuel availability have rekindled researchers' attention to develop green and environmentally friendlier strategies. In this context, a biorefinery approach with a zero-waste theme has stepped-up as the method of choice for sustainable production of an array of industrially important products to address bio-economy challenges. Grape winery results in substantial quantities of solid organic and effluent waste, which epitomizes an increasing concentration of pollution problems with direct damage to human health, economy and nature. From the perspective of integrated biorefinery and circular economy, winery waste could be exploited for multiple purpose value-added products before using the biomass for energy security. This review covers state-of-the-art biorefinery opportunities beyond traditional methods as a solution to overcome many current challenges such as waste minimization in grape leaves, stems, seeds, pomace, wine lees, vinasse etc. and the biosynthesis of various high-value bioproducts viz., phenolic compounds, hydroxybenzoic acids, hydroxycinnamic acids, flavonoids, tartaric acids, lignocellulosic substrates etc.. The critical discussion on the valorization of winery waste (solid, liquid, or gaseous) and life cycle assessment was deployed to find a sustainable solution with value added energy products in an integrated biorefinery approach, keeping the environment and circular economy in the background.

Evaluating Earthworms’ Potential for Remediating Soils Contaminated with Olive Mill Waste Sediments

The olive-oil industry generates large amounts of residues that, in the past, were accumulated in evaporating ponds in many Mediterranean countries. Currently, these open-air ponds pose a serious environmental hazard because of toxic chemicals that concentrate in their sediments. Bioremediation of olive mill waste (OMW) sediments has emerged as a viable option for managing this environmentally problematic residue. Here, we postulate that inoculation of an OMW-soil mixture with earthworms may be a complementary bioremediation strategy to that using native microorganisms only. A laboratory study assessed the ecotoxicity of OMW-amended soils (10%, 20%, 40% and 80% w/w) combining earthworm biomarker responses and soil enzyme activities. The doses of 40% and 80% were toxic to earthworms, as evidenced by the high mortality rate, loss of body weight and signs of oxidative stress after 30 d of soil incubation. Conversely, doses ≤ 20% w/w were compatible with earthworm activity, as indicated by the significant increase of soil enzyme activities. Total concentrations of phenolic compounds decreased by more than 70% respect to initial concentrations in 10% and 20% OMW treatments. These results suggest that OMW sediments intentionally mixed with soils in an up to 20% proportion is a workable bioremediation strategy, where earthworms can be inoculated to facilitate the OMW degradation.

Strategies for recycling and valorization of grape marc

Grapes are one of the most cultivated fruit crops worldwide. Either for wine or juice production, grape processing generates a large amount of residues that must be treated, disposed of or reused properly to reduce their pollution load before being applied to the soil. In this review, a special focus is given to the treatment and valorization of the winemaking by-product like grape marc via anaerobic digestion, composting and vermicomposting at laboratory, pilot, and industrial scales. The impact of the final products (digestates, composts, and vermicomposts) on soil properties is briefly addressed. Moreover, the role of grape marc and seeds as a valuable source of natural phytochemicals that include polyphenols and other bioactive compounds of interest for pharmaceutical, cosmetic, and food industries is also discussed. This is of paramount importance given the fact that sustainability requires the use of management and valorization strategies that allow the recovery of valuable compounds (e.g. antioxidants) with minimum disposal of waste streams.

Chemical, Thermal and Spectroscopic Methods to Assess Biodegradation of Winery-Distillery Wastes during Composting

The objective of this work was to study the co-composting process of wastes from the winery and distillery industry with animal manures, using the classical chemical methods traditionally used in composting studies together with advanced instrumental methods (thermal analysis, FT-IR and CPMAS ¹³C NMR techniques), to evaluate the development of the process and the quality of the end-products obtained. For this, three piles were elaborated by the turning composting system, using as raw materials winery-distillery wastes (grape marc and exhausted grape marc) and animal manures (cattle manure and poultry manure). The classical analytical methods showed a suitable development of the process in all the piles, but these techniques were ineffective to study the humification process during the composting of this type of materials. However, their combination with the advanced instrumental techniques clearly provided more information regarding the turnover of the organic matter pools during the composting process of these materials. Thermal analysis allowed to estimate the degradability of the remaining material and to assess qualitatively the rate of OM stabilization and recalcitrant C in the compost samples, based on the energy required to achieve the same mass losses. FT-IR spectra mainly showed variations between piles and time of sampling in the bands associated to complex organic compounds (mainly at 1420 and 1540 cm^-1) and to nitrate and inorganic components (at 875 and 1384 cm^-1, respectively), indicating composted material stability and maturity; while CPMAS ¹³C NMR provided semi-quantitatively partition of C compounds and structures during the process, being especially interesting their variation to evaluate the biotransformation of each C pool, especially in the comparison of recalcitrant C vs labile C pools, such as Alkyl /O-Alkyl ratio.

Plant tests for determining the suitability of grape marc composts as components of plant growth media

Five grape marc composts prepared by different procedures (composting and vermicompost at several scales) were tested as potential components of plant growth media. The five composts had high organic matter content (>90%), low electric conductivity (<1 dS m(-1)) and a pH between 7 and 8. Different chemical and biochemical analyses performed indicated the higher stability of those composts submitted to a longer composting process or to a vermicomposting process (lower water soluble organic matter, respiration and dehydrogenase activity). In order to determine the suitability of the composts as substrate components, plant growth tests were performed by blending the composts with peat or commercial substrate at two compost rates (25% and 50%). The mixtures were sown with barley (Hordeum vulgare L.) and grown under controlled conditions in an incubation chamber. No prejudicial effects derived from the use of composted grape marc were observed, whatever the procedure of composting used. The results showed that four out of the five composts would be suitable for use in plant growth substrates elaboration, as they did not reduce productivity with respect to the control substrates.

Carbon and nitrogen mineralization in a vineyard soil amended with grape marc vermicompost

Vineyard soils in many areas suffer from low organic matter contents, which can be the cause of negative effects such as increasing the risk of erosion, so the use of organic amendments must be considered a good agricultural practice. Even more, if grape marc is recycled as a soil amendment in the vineyards, benefits from a good waste management strategy are also obtained. In the present study, a grape marc from the wine region of Valdeorras (north-west Spain) was used for the production of vermicompost, and this added to a vineyard soil of the same area in a laboratory study. Mixtures of soil and grape marc vermicompost (2 and 4%, dry weight) were incubated for ten weeks at 25°C and the mineralization of C and N studied. The respiration data were fitted to a first-order kinetic model. The rates of grape marc vermicompost which should be added to the vineyard soil in order to maintain the initial levels of organic matter were estimated from the laboratory data, and found to be 1.7 t ha(-1) year(-1) of bulk vermicompost (if the present mean temperature is considered) and 2.1 t ha(-1) year(-1) of bulk vermicompost (if a 2°C increment in temperature is considered), amounts which could be obtained recycling the grape marc produced in the exploitation.

Valorization of winery waste vs. the costs of not recycling

Wine production generates huge amounts of waste. Before the 1990s, the most economical option for waste removal was the payment of a disposal fee usually being of around 3000 Euros. However, in recent years the disposal fee and fines for unauthorized discharges have increased considerably, often reaching 30,000-40,000 Euros, and a prison sentence is sometimes also imposed. Some environmental friendly technologies have been proposed for the valorization of winery waste products. Fermentation of grape marc, trimming vine shoot or vinification lees has been reported to produce lactic acid, biosurfactants, xylitol, ethanol and other compounds. Furthermore, grape marc and seeds are rich in phenolic compounds, which have antioxidants properties, and vinasse contains tartaric acid that can be extracted and commercialized. Companies must therefore invest in new technologies to decrease the impact of agro-industrial residues on the environment and to establish new processes that will provide additional sources of income.

Influences of winery-distillery waste compost stability and soil type on soil carbon dynamics in amended soils

The application of organic materials to replenish soil organic matter and improve soil structure and fertility has become a common agronomic practice. This research deals with the effects of soil amendment with winery and distillery waste composts on organic carbon (C) mineralisation in two arable soils. A sandy-loam and clay-loam soil were treated and incubated with a number organic materials obtained from the co-composting of different proportions of grape stalk, grape marc, exhausted grape marc and vinasse, with sewage sludge or animal manure. Moreover, the effect of compost stability on C mineralisation dynamics was studied by applying organic materials from different stages of the composting process. The results obtained showed that the addition of exogenous organic matter stimulated microbial growth, enhanced soil respiration and increased water-extractable C contents in both soils, particularly in the days immediately following amendment. The initial composition of the different organic materials used, especially for the mature samples, and the texture of the receiving soil did not influence significantly the C mineralisation final values, with around 11-20% of the added organic C being mineralised over the first 140 days. However, the contribution of organic amendment to the labile organic C pool, maximum rates of soil respiration, as well as the extent of initial disturbance of the soil microbiota were all found to be related to the degree of organic matter stability. Moreover, irrespective of the type and stability of the organic amendment, the mineralogical composition of the receiving soil was found to significantly influence its resilience in such systems.

Feasibility of composting combinations of sewage sludge, olive mill waste and winery waste in a rotary drum reactor

Representative samples of the following biowastes typically generated in Castilla La Mancha (Spain) were composted using a pilot-scale closed rotary drum composting reactor provided with adequate control systems: waste from the olive oil industry (olive mill waste; OMW), winery-distillery waste containing basically grape stalk and exhausted grape marc (WDW), and domestic sewage sludge. Composting these biowastes was only successful when using a bulking agent or if sufficient porosity was supported. OMW waste composting was not possible, probably because of its negligible porosity, which likely caused anaerobic conditions. WDW was successfully composted using a mixture of solid wastes generated from the same winery. SS was also successfully composted, although its higher heavy metal content was a limitation. Co-composting was an adequate strategy because the improved mixture characteristics helped to maintain optimal operating conditions. By co-composting, the duration of the thermophilic period increased, the final maturity level improved and OMW was successfully composted. Using the proposed reactor, composting could be accelerated compared to classical outdoor techniques, enabling easy control of the process. Moisture could be easily controlled by wet air feeding and leachate recirculation. Inline outlet gas analysis helped to control aerobic conditions without excessive aeration. The temperature reached high values in a few days, and sufficient thermal requirements for pathogen removal were met. The correct combination of biowastes along with appropriate reactor design would allow composting as a management option for such abundant biowastes in this part of Spain.

Utilization of a factorial design to study the composting of hydrolyzed grape marc and vinification lees

Hydrolyzed grape marc (HGM) is the solid residue generated after the acid hydrolysis of grape marc to obtain hemicellulosic sugars for biotechnological purposes. In this work, HGM containing cellulose and lignin was composted together with vinification lees to obtain plant substrates on a laboratory scale. The effects of temperature (in the range of 20-50 degrees C), concentration of vinification lees (5-100 g/100 g of hydrolyzed grape marc), and concentration of CaCO(3) on the final properties of the composted HGM were studied by means of an experimental plan with factorial structure. The interrelationship between dependent and operational variables was established by models including linear, interaction, and quadratic terms. The most influential variable on the C/N ratio and P, K and Mg contents of composted substrates was the vinification lees concentration followed by the temperature, whereas on Na content and electrical conductivity the most influential variable was the temperature followed by the vinification lees concentration. The results of the incubation experiments indicated that optimal conditions for obtaining plant substrates can be achieved by composting 1:1 mixtures of hydrolyzed grape marc and vinification lees, in the presence of 5 g of CaCO(3)/100 g of HGM. During composting the pH of the mixtures increased from 5.1-6.7 to 7.1-8.1, salinity and water-soluble carbon were reduced in most cases, and the initial phytotoxicity disappeared in all of the mixtures tested.

Estimation of phosphorus content and dynamics during composting: use of near infrared spectroscopy

The content and chemical forms of P in compost are essential variables for its proper management with an agricultural purpose, especially considering the increasing P over-fertilization in agrosystems. In this study, the estimation of P content and dynamics in different composting scenarios was developed using near infrared reflectance spectroscopy (NIRS) coupled with a statistical tool for calibration, a penalized signal regression. Samples were analyzed on total P and partitioned using NaOH-solution (31)P NMR spectroscopy quantifying pyrophosphate, orthophosphate, orthophosphate diesters, phospholipids, and orthophosphate monoesters pools. According to the results obtained, total P content (r(2)=0.99 and root mean square error of cross-validation=0.53) and P forms can be estimated during composting using NIRS, as well as in the mature product, orthophosphate and orthophosphate monoesters being the most abundant P forms throughout the experiment. Penalized signal regression allows detecting the significant wavenumbers in each composting period, and also with the different P pools in the composting pile depending on time.

Study of the composting process of winery and distillery wastes using multivariate techniques

Physico-chemical, chemical and biological parameters were studied throughout the composting process of four winery and distillery composts and the data set of compost characteristics was analysed using multivariate techniques: factorial analysis (FA) and linear discriminant analysis (LDA), in order to classify the different parameters studied and thus, to establish those that better describe the composting process of this type of wastes. Through factorial analysis (FA) of the parameters studied throughout the composting process, four components that explained 85.6% of the variability were established. The parameters associated to compost maturity, agronomic character, water-soluble fraction and ammonia and temperature increment were grouped in the components F1, F2, F3 and F4, respectively, which can reduce the number of determinations needed to ascertain the maturity and quality of the composts. In addition, the linear discriminant analysis on the factorial components makes possible to classify the four composts with a percentage of success around 95%.