David Bolzonella

University of Verona | UNIVR · Department of Biotechnology

Carboxylic acids have become interesting platform molecules in the last years due to their versatility to act as carbon sources for different microorganisms or as precursors for the chemical industry. Among carboxylic acids, short-chain fatty acids (SCFAs) such as acetic, propionic, butyric, valeric, and caproic acids can be biotechnologically prod...

Cigarette Butts are one of the most diffused and toxic waste in urban contexts. They are composed by a cellulose acetate filter, used to retain toxic compounds during the smoking of cigarette, and eventual tobacco's residues. This work had the ambitious to exploit cigarette butts in a biorefin-ery scheme to produce fermentable sugars and bioethanol...

Anaerobic digestion allows for the proper management of agro-waste, including manure. Currently, more than 18,000 anaerobic digestion plants are under operation in EU, 80% of which are employed in the rural context. Tariff schemes for power generation from biogas produced during anaerobic digestion of agricultural feedstocks in Germany, Italy and A...

Orange peels (OPs) were valorized in a lab-scale biorefinery loop for the recovery of limonene and the subsequent production of volatile fatty acids (VFAs) and activated carbon (AC). Solid/liquid extraction of limonene was optimized using n-hexane at 85 °C with an OPs-to-solvent ratio of 2:1, allowing for a limonene recovery yield of 1.20% w/w. The...

Pasta is one of the most appreciated Italian products around the world. The 31% of the global production of pasta is made by Italian companies: here, about 120 companies assure an annual production of 5.3 million tons of pasta. The pasta not compliant with the required selling standards (for example size, weight) is usually crushed, grounded to pow...

The unsustainable environmental impact of fossil derived fertilizers and the depletion of raw materials for their production make the research of alternative sources for fertilizers production one of the main priorities of the international agenda. Agricultural digestate, especially if derived from livestock manure, is considered a potential candid...

Protein hydrolysates obtained from discarded biomass can be further upgraded into high market value products, in the optic of a circular bioeconomy. In this work, residues from the cultivation of alfalfa, soybean and rice, and bovine wet blue shavings were fermented with mixed microbial cultures obtaining high concentrations of volatile fatty acid...

Dairy products, extra virgin olive oil, red and white wines are excellent food products, appreciated all around the world. Their productions generate large amounts of by-products which urge for recycling and valorization. Moreover, another abundant waste stream produced in urban context is the Organic Fraction of Municipal Solid Wastes (OFMSW), who...

Food wastage is an ethical and environmental wrong practice. Considering a circular economy optic, food waste is a carbon rich substrate, suited for anaerobic fermentation to produce not only biogas, but also high-value chemical compounds, such as Volatile Fatty Acids (VFAs), that can be recovered in order to synthetize polyhydroxyalkanoates (PHAs)...

50.3 M tons of wastes are annually produced at urban level in the EU-27. Sewage sludge, Organic Fraction of Municipal Solid Wastes (OFMSW) and food industrial wastewaters, are the major typologies of wastes produced at urban level. OFMSW and sewage sludge account for the 28% and 23% of the EU-27 wastes streams, respectively. Their abundance and the...

The increase in human population determines a higher proteins request to sustain the feed demand for animals and aquaculture. Single Cell Proteins (SCPs) consist of mixed protein from pure and mixed culture of bacteria, fungi, algae, and yeast, which are grown and harvested to accomplish the food requirement of human and animals. This work investig...

This work investigates an innovative process to valorise agricultural digestate by the exploitation of solar energy. Digestate has been located in a lab-scale greenhouse to evaporate the liquid phase. Digestate vapours, rich in ammonia, are sent in a Drechsler trap, filled with 38% w/w sulfuric acid solution, through three solar air fans. A concent...

Yeast species have been spontaneously participating in food production for millennia, but the scope of applications was greatly expanded since their key role in beer and wine fermentations was clearly acknowledged. The workhorse for industry and scientific research has always been Saccharomyces cerevisiae. It occupies the largest share of the dynam...

The purification and concentration of volatile fatty acids (VFAs) after acidogenic fermentation represent the key steps for their industrial use. In this study, different batch adsorption tests were performed on single VFAs using powdered activated carbon (PAC), Lewatit VP OC 1065, Amberlyst A21, and VFA mixtures using Lewatit and Amberlyst. Adsorp...

Spent coffee grounds are rich in high-value compounds, such as saturate and unsaturated fatty acids, and polysaccharides. Therefore, this work investigated a cascade biorefinery to produce: i) biodiesel from coffee oils, ii) cellulose- and hemicellulose-derived fermentable sugars and iii) biomethane from the residual solid fraction after sugars ext...

The bio-based production of added-value products and energy from waste streams while minimizing environmental impacts is a crucial aspect within the circular economy’s principles. A two-phases anaerobic digestion process to produce volatile fatty acids (VFA) and biogas production in an energetically feasible manner from the organic fraction of muni...

This research investigated for the first time the influence of the single fractions (proteins, lipids, starch, cellulose, fibers and sugars) composing Household Food Wastes on Volatile Fatty Acids (VFA). A production at different pH (uncontrolled, 5.5 and 7.0): both the amount and profile of VFA were investigated. It was found that fractions rich i...

Currently, centralised plants are the most favoured approach for the anaerobic treatment of the organic fraction of municipal solid waste (OFMSW). However, centralised solutions imply certain environmental impacts, which prevent large-scale implementation of the anaerobic digestion (AD). As a result, we are digesting <5% of organic waste both in Eu...

Household Food Wastes (HFW) are the most abundant organic wastes at urban level with a worldwide annual production of about 2 billion tons. This material can be the right feedstock for a carboxylate biorefinery platform. This work investigated the influence of different operational parameters (pH, temperature, Organic Loading Rate) on the Volatile...

The “European Strategy for plastics” approved by the European Union aims at drastically reducing the use of plastic materials derived from fossil resources, especially single use plastic (SUP). As a consequence, the adoption of biodegradable plastics is forced by different national regulations, especially in France and Italy which banned the usage...

In this study, the production of polyhydroxyalkanoated PHA-rich microbial biomass as a novel feed additive in aquaculture was investigated at a lab-scale. Bio-based volatile fatty acids (VFAs), obtained from the acidogenic fermentation of agricultural residues in existing anaerobic digestion plants, were used as carbon and energy to cultivate the P...

A thermophilic post-hydrolysis process was applied to the effluent digestate of an anaerobic digester treating agro-waste to further solubilize biorecalcitrant organic polymers and, by recirculating back hydrolysate to the anaerobic reactor, increase the biogas production. The thermophilic reactor operated at 3 days hydraulic retention time determi...

A pilot scale biorefinery platform for the treatment of agro-waste and the production of hydrogen, methane and volatile fatty acids was studied in real environment. The system adopted was a two stage anaerobic process where hydrogen and volatile fatty acids were produced in the first phase (fermentation) and methane in the second one (digestion). T...

Spent Coffee Grounds worldwide production is estimated at around 6 M tons only at industrial level. The abundance and the heterogeneity of this substrate make it an ideal substrate for a biorefinery approach based on the “cascade biorefinery hierarchy”. Currently, the major part of spent coffee grounds is sent to incineration and landfill disposal,...

The present paper discusses issues, scenarios, new ideas and processes with the specific purpose of quantitatively evaluating the feasibility of applying industrial symbiosis (IS) to regions where Waste-to-Energy (WtE) processes are not fully utilised (e.g. many Mediterranean regions), in order to exploit the potential synergies between 1) wastewat...

A combined two-levels control method has been developed and tested on a long term operation of a two-phases pilot-scale anaerobic process for the concurrent production of volatile fatty acids, hydrogen and methane. The latter was designed for the treatment of food waste of urban origin (namely, the organic fraction of municipal solid waste). The op...

Anaerobic digestate supernatant can be used as a nutrient source for microalgae cultivation, thus integrating phytoremediation processes with high value products storage in microalgae biomass. Microalgae are able to use nitrogen and phosphorous from digestate, but high nutrient concentration can cause growth inhibition. In this study, two microalga...

The second edition of Wastewater and Biosolids Management has 40% new material including a comprehensive study guide and one new chapter entitled ‘The contribution of Decision Support System (DSS) to the approach of safe wastewater and biosolid reuse’. The study guide contains the title of the chapter, the purpose, the expected results, key concept...

High‐temperature bioconversion of lignocellulose into fermentable sugars has drawn attention for efficient production of renewable chemicals and biofuels, because competing microbial activities are inhibited at elevated temperatures and thermostable cell wall degrading enzymes are superior to mesophilic enzymes. Here, we report on the development o...

This study investigated the advantages of the anaerobic codigestion process of two urban organic waste: the organic fraction of municipal solid wastes and the waste activated sludge produced during biological wastewater treatment. In particular, a comparison between mono and double stage anaerobic digestion for biogas and biohythane (hydrogen and m...

The impact of temperature (20, 35, 45, 55, 70 °C) on volatile fatty acid (VFA) production from biowaste collected at a mechanical-biological treatment plant was analysed. Additionally, relevant streams of the treatment plant were characterised to assess seasonality effects and conceive the integration of a fermentation unit. Batch fermentation test...

Six million tons of Coffee Spent Grounds (SCG) are produced every year all around the world. Their physical and chemical characterization, rich in high value molecules and organic compounds, make SCG ideal for the recovery of bioactive molecules and bioenergy production according to the “cascade biorefinery approach”. This work investigates the eff...

The new European Union directives on waste management encourage the adoption of the “pyramidal hierarchy” for the extraction or synthesis of high added value compounds rather than the conventional mere biogas production. This approach was applied to Orange Peels (OPs), rich in limonene, a molecule used as additive in the cosmetical market. Soxhlet...

Digestate represents the semi-liquid byproduct of the anaerobic digestion process. It was estimated that 56 Mtonnes of digestate are annually produced only in Europe. Digestate composition depends on the initial total solids (TS) mixture fed to the digester and by its origin (manure, food wastes, agricultural residues, wastewater sludge). Typical v...

The hydrolytic effect of a commercial enzymes mixture, containing mainly cellulose-degrading and hemicellulose-degrading enzymes, was studied during the mesophilic anaerobic digestion of two different mixtures of maize (Zea mays L.) and triticale (× Triticosecale Wittm. ex A. camus). Laboratory-scale trials demonstrated that, for the crop mixtures...

This study focuses on the application of the concept of circular economy, with the creation of added-value marketable products and energy from organic waste while minimizing environmental impacts. Within this purpose, an urban biorefinery technology chain has been developed at pilot scale in the territorial context of the Treviso municipality (nort...

Anaerobic digestion (AD) is the most adopted biotechnology for the valorization of agricultural biomass into valuable products like biogas and digestate, a renewable fertilizer. This paper illustrates in the first part the actual situation of the anaerobic digestion sector in Italy, including the number of plants, their geographical distribution, t...

Although the organic fraction of municipal solid waste (OFMSW) and sewage sludge (SS) originate from the same urban area and contain similar organic matter, they are collected separately and handled with different technologies. In this work, a combined treatment of OFMSW-SS mixture was investigated at pilot scale, by using a three-steps mixed micro...

The problem of waste disposal has recently focused on practices for waste recycling and bio-resources valorization. Organic waste produced in urban context together with biological sludge produced in wastewater treatment plants (WWTPs) can be used as renewable feedstock for the production of building blocks of different products, from biopolymers t...

Recycled organic wastes (OW) can be a valuable P source; however, their P-fertilising capacity is still poorly known. In this study, we selected three anaerobic digestates [wastewater sludge (D 1), winery sludge (D 2), and bovine-slurry/energy crops (BD)] and two animal effluents [bovine slurry (BS) and swine slurry (SS)] to test their P-release an...

The new “Bioeconomy Strategy” document, which was issued by the European Commission in October 2018, encourages the exploitation of organic wastes according to a pyramidal hierarchy in which the extraction of valuable biomolecules, which will be used as they are or as precursors of high added value compounds, is a priority in biofuel production. Th...

Wine production is one of the leading sectors of the food processing industry. The wine industry produces a large amount of wastewater characterized by a high strength in terms of organic pollution and large variability throughout the year. Most of the organic matter is soluble and easily biodegradable. On the other hand, nitrogen and phosphorous a...

Biohythane from food waste

Volatile fatty acids (VFAs) are a class of largely used compounds in the chemical industry, serving as starting molecules for bioenergy production and for the synthesis of a variety of products, such as biopolymers, reduced chemicals and derivatives. Because of the huge amounts of food waste generated from household and processing industry, 47 and...

The integrated-multistage process proposed herein is a practical example of a biorefinery platform, where the organic fraction of municipal solid waste (OFMSW) is used as value source for polyhydroxyalkanoates (PHA) and biogas production. Technical and economical feasibility of this approach have been demonstrated at pilot-scale providing a possibl...

Agricultural waste is a huge pool of untapped biomass resources that may even represent economic and environmental burdens. They can be converted into bioenergy and bio-based products by cascading conversion processes, within circular economy, and should be considered residual resources. Major challenges are discussed from a transdisciplinary persp...

Stable operation of high-rate thermophilic sludge anaerobic reactors is sometime hard to achieve because of the nature of the anaerobic digestion (AD) process itself and the combination of biological and chemical reactions. An interesting and innovative way to handle AD data resides in multivariate statistical approaches since a more accurate analy...

Enzymatic hydrolysis represents the crucial phase in bioethanol production. Its aim is to convert pretreated lignocellulosic polymers in hexose sugars for fermentation into bioethanol. To be economically advantageous, the enzymatic hydrolysis should operate with a high concentration of dry matter. The drawback of this is the increase in the reactio...

This study focused on the treatment of psychrophilic anaerobic digestate from pig slurry digestion through a single-stage Sequencing Batch Reactor (SBR) accomplishing the autotrophic nitrogen removal (ANR). In period 1, the combination of the high sludge retention time (>50 days) and the presence of significant concentrations of biodegradable organ...

Biohythane is a hydrogen-methane blend with hydrogen concentration between 10 and 30% v/v. It can be produced from different organic substrates by two sequential anaerobic stages: a dark fermentation step followed by a second an anaerobic digestion step, for hydrogen and methane production, respectively. The advantages of this blend compared to eit...

Large amounts of residual grass originating from the management of landscape and natural areas are produced in Europe. This material, which is not competing for land use like energy crops, and is only partially recovered for animal feeding, can be profitably used for sustainable bioenergy production. In this study we demonstrated through a GIS base...

An interesting and innovated alternative to handle anaerobic digestion (AD) data resides in multivariate statistical approaches since a more accuracy analysis can be performed and fault or abnormal schemes detections can be enhanced. In this paper, principal component analysis (PCA) was the basic multivariate tool used to compare single and two sta...

DOWNLOAD LINK: https://authors.elsevier.com/a/1V-ue3QCo9NGJR - This study compared the performances of single and two-stage anaerobic digestion processes of food waste. The processes were monitored by taking into account both the steady state process performances and the transient conditions. In addition to a conventional univariate analysis, a mu...

The sustainable production of fertilizers, especially those based on phosphorus, will be one of the challenges of this century. Organic wastes produced by the agriculture, urban and industrial sectors are rich in nutrients which can be conveniently recovered and used as fertilizers. In this study five full scale systems for the recovery of nutrient...

The anaerobic digestion in double stage is a known and adopted system, but the process productivity and optimization still remain an aspect to investigate. The accumulation of organic acids (produced during fermentative metabolism) in the first stage generally decrease the pH below the optimal values (5.5). A pre-evaluation strategy by control char...

This book introduces the 3R concept applied to wastewater treatment and resource recovery under a double perspective. Firstly, it deals with innovative technologies leading to: Reducing energy requirements, space and impacts; Reusing water and sludge of sufficient quality; and Recovering resources such as energy, nutrients, metals and chemicals, in...

The effects of co-digestion of separately collected organic fraction of municipal solid waste and mixed sludge in a 95,000 equivalent inhabitants municipal wastewater treatment plant (WWTP) was studied for 18 months. It was observed that the treatment of 10,000 kg per day of organic waste increased the organic loading rate of digesters from 0.73 to...

Wastewater treatment plants in many countries use anaerobic digesters for biosolids management and biogas generation. Opportunities exist to utilise the spare capacity of these digesters to co-digest food waste and sludge for energy recovery and a range of other economic and environmental benefits. This paper provides a critical perspective for ful...

This paper deals with the optimization of anaerobic digestion of winery wastes considering the behavior of biogas production rate between two consecutive reactor feeds. Processes operating at different hydraulic retention times (23 and 40 d) were monitored and the specific biogas productions were comparable (0.386 and 0.378 m³/kgCODfed for retentio...

More sustainable scenarios in the bioenergy sector can be achieved when biomass exploitation is based on eco-efficient supply chains. Regarding this, grass as a by-product obtained from landscape management could provide a large quantity of biomass potentially utilizable in the Anaerobic Digestion (AD) supply chain.This study assessed the energy an...

The aim of this study was to verify the efficiency of a separate hydrolysis step by testing different working temperatures (37° to 55 °C) and hydraulic retention times (two, four and six days) and by evaluating readily biodegradable carbon production. The fermentation products included primarily acetic, propionic and butyric acids. These acids can...

Microalgae are fast-growing photosynthetic organisms which have the potential to be exploited as an alternative source of liquid fuels to meet growing global energy demand. The cultivation of microalgae, however, still needs to be improved in order to reduce the cost of the biomass produced. Among the major costs encountered for algal cultivation a...

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 productio...

Anaerobic digestion is one of the most attractive technologies for the treatment of industrial, civil and agricultural organic waste because of its capacity to reduce the biodegradable matter while recovering renewable energy in the form of methane. However, this bioprocess sometime suffers of problems in the interspecies electron transfer between...