Research article
Mesophilic and thermophilic anaerobic co-digestion of winery wastewater sludge and wine lees: An integrated approach for sustainable wine production

https://doi.org/10.1016/j.jenvman.2016.03.029Get rights and content

Highlights

  • Amounts of winery wastes generated by an Italian cellar were evaluated.

  • Anaerobic co-digestion integrated to winery wastewater management is feasible.

  • Mesophilic process was steady and produced 0.38 m3 of biogas per kgCOD per day.

  • Thermophilic process needed trace elements augmentation to improve stability.

  • Dewaterability properties of both digestates were considered.

Abstract

In this work, winery wastes generated by a cellar producing approximately 300,000 hL of wine per year was monitored for a period of one year. On average, 196 L of wastewater, 0.1 kg of waste activated sludge (dry matter) and 1.6 kg of wine lees were produced per hectoliter of wine produced. Different winery wastes, deriving from different production steps, namely waste activated sludge from wastewater treatment and wine lees, were co-treated using an anaerobic digestion process. Testing was conducted on a pilot scale for both mesophilic and thermophilic conditions. The process was stable for a long period at 37 °C, with an average biogas production of 0.386 m3/kg CODfed. On the other hand, for thermophilic conditions, volatile fatty acids accumulated in the reactor and the process failed after one hydraulic retention time (23 days). In order to fix the biological process, trace elements (iron, cobalt and nickel) were added to the feed of the thermophilic reactor. Metals augmentation improved process stability and yields at 55 °C. The pH ranged between 7.8 and 8.0, and specific gas production was 0.450 m3/kg CODfed, which corresponded to dry matter and COD removals of 34% and 88%, respectively. Although the observed performances in terms of biogas production were good, the thermophilic process exhibited some limitations related to both the necessity of metals addition and the worse dewaterability properties. In fact, while the mesophilic digestates reached a good dewatering quality via the addition of 6.5 g of polymer per kg of dry matter, the required dosage for the thermophilic sludge was greater than 10 g/kg of dry matter.

Introduction

The winemaking process produces large volumes of waste streams, including solid organic waste, wastewater, greenhouse gases, and packaging waste (Lucas et al., 2010). Winery wastewater is a major waste stream resulting from a number of activities that include tank, floor and equipment washing; barrel cleaning; wine and product losses; bottling facilities; filtration units; and rainwater captured in the wastewater management system (Ioannou et al., 2014). The quantification of the produced wastewater is difficult, and it depends on the cellar dimensions and the technologies applied. In general, wastewater production ranges from 0.7 to 14 L per liter of wine produced (Andreottola et al., 2009), but specific studies conducted in different countries demonstrated that typical values are approximately 2–6 L of wastewater per liter of wine produced (a short review of winery wastewater in the main production countries is available in Supplementary Material).

This effluents generally presents a considerable level of COD, the major part of which is soluble (Beck et al., 2005) and highly biodegradable (Andreottola et al., 2005) due to the presence of ethanol, sugars, and organic acids (Malandra et al., 2003, Mosteo et al., 2008, Petruccioli et al., 2000, Vlyssides et al., 2005).

Because of its characteristics, this stream is generally treated using either aerobic or anaerobic processes (Ioannou et al., 2014). Among biological processes, the activated sludge process is the most commonly employed because of its high efficiency and simplicity. It can remove 98% of COD and cope with large variations in the hydraulic and pollution load (Beck et al., 2005, Fumi et al., 1995, Petruccioli et al., 2000).

The removal of organic material generates considerable quantities of excess sludge, normally in the range 0.21–0.28 kg MLVSS (mixed liquor volatile suspended solids) per kg of COD removed (Brucculeri et al., 2005, Torrijos and Moletta, 1997). Ruggieri et al. (2009) estimated that dewatered wastewater sludge represents 12% of the total organic solid waste produced by wineries and that its management via external companies is expensive and often difficult. An alternative to valorize this waste stream could be the use of an anaerobic digestion process. Anaerobic digestion (AD) is a mature technology and it is applied to treat different types of organic wastes (municipal solid wastes, sewage and waste activated sludge, agro-industrial residues, livestock effluents, etc.) and to reduce their biodegradability while simultaneously recovering bio-energy. The combination of the conventional activated sludge process (CAS) and AD is a common practice in municipal wastewater treatment plants and limits the external management costs for sludge disposal thanks to a reduction in the sludge volume. Biogas is a renewable source of energy that is usable inside the same production process and/or wastewater treatment plant, which reduces the energy requirements (Shen et al., 2015). Moreover, digestate, the effluent from the anaerobic process, can be reused in agricultural fields because of the presence of nutrients such as N, P, and K together with stabilized C and humic substances. AD removes pathogens and polyphenolic compounds with different efficiencies based on the operating conditions used. Pathogen reduction is affected by temperature, retention time and fed substrates (Poudel et al., 2010, Sahlström et al., 2004), whereas the efficiency of polyphenol degradation is mainly determined by the operational temperature (Cavinato et al., 2014, Levén and Schnürer, 2005).

Once AD is implemented for winery wastewater WAS, other winemaking process residues (e.g., wine pomace, pressed cake, or lees) should be co-treated to increase the biogas production, to improve the reactor utilization and to make the anaerobic process more economically advantageous.

Wine lees (WL) in particular are an interesting co-substrate because of their biodegradability and availability throughout the year. Like wastewater, WL contain a high organic content and their disposal requires the appropriate treatment. The composition of WL depends on the winemaking technology, although, according to de Bustamante and Temiño (1994), the main characteristics are an acidic pH (between 3 and 6), a COD greater than 30,000 mg/L, potassium in concentrations greater than 2500 mg/L, and phenolic components in quantities up to 1000 mg/L.

This paper considers the production of winery waste activated sludge and lees and their anaerobic co-digestion under both mesophilic and thermophilic conditions. The study assesses the process feasibility at pilot scale and evaluates the effluent quality in terms of pollutant removal and dewatering capacity. The suggested approach is schematically represented in Fig. 1.

Section snippets

Winery wastewater treatment plant

Waste activated sludge was collected in a cellar where a wastewater treatment plant was operating. The cellar was located in the northeast of Italy and produced approximately 300,000 hL of wine per year. It processed and bottled both self-produced and bought wines; therefore, the working period is not restricted to the grape harvest, but rather, it is distributed throughout the year. Therefore, there is no real seasonal variation in the output. Considering the wine production and winery

Substrates characterization

The substrates fed to the reactors were waste activated sludge from secondary sedimentation tank of plant treating winery wastewater and wine lees, both of which originated from the same cellar.

The solids in the dewatered WAS generally ranged from 129.0 to 193.7 g TS/kg. However, outliers were detected due to technical reasons (conditioner doses and filter press setting, Table 2). The volatile solids to total solids ratio (VS/TS) in the winery was higher (88%) than for typical sludge from

Conclusions

The cellar monitored in this work, which produced approximately 300,000 hL of wine per year, generated 196 L of wastewater, 0.1 kg of WAS (dry matter) and 1.6 kg of lees per hl of wine produced. Anaerobic co-digestion WAS and lees was feasible, both in mesophilic and thermophilic conditions, when operating with an OLR of 3.2 kg COD/(m3d) and an HRT of 23 d. The mesophilic process was stable over a long period in terms of the stability parameters (pH 7.46, 400 mg Nsingle bondNH4+/L and 2248 mg CaCO3/L) and

Acknowledgments

The authors would like to thank Vinicola Serena srl for its collaboration and ATS scarl and the Treviso City Council for their hospitality at Treviso WWTP.

References (52)

  • B. Jin et al.

    Impacts of morphological, physical and chemical properties of sludge flocs on dewaterability of activated sludge

    Chem. Eng. J.

    (2004)
  • T.I. Lafka et al.

    On the extraction and antioxidant activity of phenolic compounds from winery wastes

    Food Chem.

    (2007)
  • L. Levén et al.

    Effects of temperature on biological degradation of phenols, benzoates and phthalates under methanogenic conditions

    Int. Biodeter. Biodegr

    (2005)
  • F. et al.

    Dewaterability of anaerobic digestate from food waste: relationship with extracellular polymeric substances

    Chem. Eng. J.

    (2015)
  • M.S. Lucas et al.

    Treatment of winery wastewater by ozone-based advanced oxidation processes (O3, O3/UV and O3/UV/H2O2) in a pilot-scale bubble column reactor and process economics

    Sep. Purif. Technol.

    (2010)
  • L. Malandra et al.

    Microbiology of a biological contactor for winery wastewater treatment

    Water Res.

    (2003)
  • A.B. Moldes et al.

    Negative effect of discharging vinification lees on soils

    Bioresour. Technol.

    (2008)
  • K.P.M. Mosse et al.

    Physicochemical and microbiological effects of long- and short-term winery wastewater application to soils

    J. Hazard. Mater

    (2012)
  • R. Paradelo et al.

    Evolution of organic matter during the mesophilic composting of lignocellulosic winery wastes

    J. Environ. Manage

    (2013)
  • M. Petruccioli et al.

    High-rate aerobic treatment of winery wastewater using bioreactors with free and immobilized activated sludge

    J. Biosci. Bioeng.

    (2000)
  • a. Ramos-Cormenzana et al.

    Antimicrobial activity of olive mill wastewaters (alpechin) and biotransformed olive oil mill wastewater

    Int. Biodeter. Biodegr

    (1996)
  • L. Ruggieri et al.

    Recovery of organic wastes in the Spanish wine industry. Technical, economic and environmental analyses of the composting process

    J. Clean. Prod.

    (2009)
  • L. Sahlstrom

    A review of survival of pathogenic bacteria in organic waste used in biogas plants

    Bioresour. Technol.

    (2003)
  • L. Sahlström et al.

    Bacterial pathogen incidences in sludge from Swedish sewage treatment plants

    Water Res.

    (2004)
  • Y. Shen et al.

    An overview of biogas production and utilization at full-scale wastewater treatment plants (WWTPs) in the United States: challenges and opportunities towards energy-neutral WWTPs

    Renew. Sust. Energy Rev.

    (2015)
  • M. Torrijos et al.

    Winery wastewater depollution by sequencing batch reactor

    Water Sci. Technol.

    (1997)
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