Stefano Papirio

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Verified

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• PhD in Civil and Environmental Engineering
• Professor (Associate) at University of Naples Federico II

This study shows biofuels and biocommodities, i.e., hydrogen, volatile fatty acids (VFAs), and methane, can be produced in semi-continuous bioreactors from spent coffee grounds (SCG). The semi-continuous reactor operated first on untreated SCG (Reactor 1) followed by feeding ultrasound-pretreated SCG (Reactor 2) to improve the hydrolysis of the sub...

Single cell protein (SCP) is emerging as a viable alternative to conventional protein sources thanks to their low environmental footprint and resource upcycling potential. This study investigated the production of SCP from hemp (Cannabis sativa L.) biomass residues (HBRs) and cheese whey (CW) in an innovative one-stage sequential anaerobic–aerobic...

Hydrogenotrophic denitrification driven by granular sludge is an eco-friendly alternative to conventional separation-based techniques, which ensure process stability, high NO 3 ⁻ removal efficiency and minimal greenhouse gas emissions.

Consumption of coffee produces large amounts of waste in the form of spent coffee grounds (SCG), a lignocellulosic material rich in carbohydrates, proteins, and polyphenols. This abundant feedstock is promising in terms of biofuels and value-added product generation. This study investigated the impact of pretreatments, such as alkaline (NaOH), ultr...

The efficient management of municipal sewage sludge (MSS) daily produced worldwide by biological wastewater treatment process is nowadays of utmost importance. Classic treatment/disposal methods are affected by efficiency and/or safety...

Conventional mining of economically and strategically important critical rare earth elements (REEs) (such as neodymium, lanthanum and dysprosium), and chalcogens (such as selenium and tellurium) are associated with a huge economic and environmental cost. Therefore, the need to recover REEs as well as chalcogens from different waste streams includin...

The production of single cell protein (SCP) using lignocellulosic materials stands out as a promising route in the circular bioeconomy transition. However, multiple steps are necessary for lignocellulosics-to-SCP processes, involving chemical pretreatments and specific aerobic cultures. Whereas there are no studies that investigated the SCP product...

This study aimed to model simultaneous nitrification and denitrification (SND) and shortcut (partial) SND processes coupled to phosphorus removal in lab-scale moving bed biofilm reactors based on data collected during two different experimental campaigns. Modeling was performed using BioWin 6.0 to accurately predict the experimental results. A sens...

Treating excess municipal sewage sludge (MSS) by means of thermochemical processes could enable its conversion into high-value microbial protein (MP) through syngas. Nevertheless, the variable composition and content of inhibitory compounds of the latter hinders the application potential of such a biorefinery scheme. Through a series of short- (48...

Recovering phosphorus from sewage sludge is a strategic, circular approach to ensure long-term phosphorus availability for future generations, supporting sustainability and resource preservation.

Overabundant agro-industrial side streams such as lactose-rich effluents from dairy activities offer multiple valorisation opportunities. In the present study, a food-grade mixed culture of bacteria and yeasts was tested under different operational conditions for the treatment and the valorisation of cheese whey permeate (CWP), the residue of whey...

Aerobic granular sludge is an interesting alternative to the conventional activated sludge (CAS) system and modified-Ludzack–Ettinger (MLE) process for biological wastewater treatment, as it allows a more cost-effective and simultaneous removal of carbon (C) and nitrogen (N) compounds in a single stage. In this study, (micro)aerobic C and N removal...

The need to ensure adequate levels of both human and environmental health protection calls for the identification of efficient wastewater treatment processes that target the removal of conventional pollutants as well as emerging contaminants, including synthetic dyes. This study explores the potential of ozone for use in the decolorization of both...

The request for alternative sources of energy has led to evaluating untapped routes for energy production, such as using abundant and low-cost waste materials, e.g., lignocellulosic wastes, as the substrate for biological processes aimed at biofuel production. This study focused on peanut shells (PS) valorisation via anaerobic digestion (AD). Two e...

Livestock digestate provides nutrients and organic matter to the soil while increasing agricultural sustainability. Nevertheless, nitrogen (N) losses due to the nutrient surplus in regions characterized by intensive animal farming activities still represent an unsolved issue. For this purpose, digestate needs proper treatment and management to avoi...

The issue of polycyclic aromatic hydrocarbons (PAHs) is widespread in marine sediments involving ecological systems and human health. Sediment washing (SW) has proven to be the most effective remediation approach for sediments polluted by PAHs, such as phenanthrene (PHE). However, SW still raises waste handling concerns due to a considerable amount...

PAHs are largely spread in the aquatic environment, and the drawbacks of conventional remediation techniques as well as the expenditures for alternative disposal of polluted sediments lead to seek more effective, environmentally–friendly and sustainable approaches. Therefore, the present review shows a critical overview of the literature evaluated...

The anaerobic digestion of sewage sludge is highly sensitive to high zinc concentrations. Although sulfate-reducing bacteria (SRB) activity can negatively affect methanogenesis, SRB-mediated metal sulfide precipitation can alleviate zinc toxicity. A series of mesophilic anaerobic batch experiments was performed for the biomethane potential of three...

This study proposes the phytoremediation of phenanthrene (PHE)-, pyrene (PYR)-, and copper (Cu)-contaminated soil by Cannabis sativa L. The experimental campaign was conducted in 300 mL volume pots over a 50 d period using different initial polycyclic aromatic hydrocarbon (PAH) concentrations, i.e., 100 (PC1), 200 (PC2), and 300 (PC3) mg ƩPAHs kg−1...

Nitrogen is the most crucial element in the production of nutritious feeds and foods. The production of reactive nitrogen by means of fossil fuel has thus far been able to guarantee the protein supply for the world population. Yet, the production and massive use of fertilizer nitrogen constitute a major threat in terms of environmental health and s...

The swift and successful transition towards a fossil fuel-free economy is amongst the most complex challenges ever faced by humanity, implicating intricate connections and trade-offs with the so-called water–energy–food nexus [...]

This work evaluated for the first time the employment of hydrothermal alone (i.e. at 60, 80 and 100 • C) and combined ultrasonic-hydrothermal pretreatments on hazelnut shell (HS) to promote the energetic valorization of HS through anaerobic digestion. The highest cumulative biomethane yield of 137 mL CH 4 ⋅g VS − 1 was achieved performing biochemic...

Local open markets, trading fruits and vegetables, are widespread in Mediterranean countries, such as Tunisia and Jordan, producing large amounts of organic waste. Applying an anaerobic digestion process on this substrate makes it crucial to evaluate the waste mixture composition and seasonal variability properly. In this study, after defining an a...

Polycyclic aromatic hydrocarbons (PAHs) are widespread in marine environments, having negative implications on both ecological systems and human health. At the same time, research on highly–efficient and environmentally–friendly alternatives compared to conventional remediation techniques must be stepped up. In this work, for the first time, a nove...

The recurrent dredging of marine sediments needs the use of ex–situ technologies such as sediment washing (SW) to effectively remove polycyclic aromatic hydrocarbons. Notwithstanding, the large volumes of generated spent SW effluents require adequate treatment by employing highly–efficient, inexpensive and environmentally–friendly solutions. This s...

Lignocellulosic residues (LRs) are one of the most abundant wastes produced worldwide. Nevertheless, unlocking the full energy potential from LRs for biofuel production is limited by their complex structure. This study investigated the effect of N-methylmorpholine N-oxide (NMMO) pretreatment on almond shell (AS), spent coffee grounds (SCG), and haz...

As Guest Editors, we take great pleasure to have you informed that the Special Issue entitled "Agricultural Wastes Utilization and Recycling for N Recovering and Manufacturing of Biofuel" is open for submission. The official submission deadline is 31 May 2023. Detailed information can be found at: https://www.mdpi.com/journal/sustainability/speci...

This study proposes the phytoremediation of a pyrene (PYR)-contaminated soil by Cannabis sativa L. The experimental campaign was conducted along a 60 days period using three different initial PYR concentrations (i.e., 50, 100 and 150 mg·kg TS⁻¹ of soil) in 300 mL volume pots under greenhouse conditions (18–25 °C and 45–55% humidity). After 60 days...

The environmental impact of the dairy industry is heavily influenced by the overproduction of nitrogen- and carbon-rich effluents. The present study proposes an innovative process to recover waste contaminated nitrogen from anaerobic digestate while treating excess cheese whey (CW) and producing high-quality, clean single cell protein (SCP). By rel...

This study provided important insights on the anaerobic digestion (AD) of hazelnut skin (HS) by operating a fed-batch AD reactor over 240 days and focusing on several factors impacting the process in the long term. An efficient reactor configuration was proposed to increase the substrate load while reducing the solid retention time during the fed-b...

Lignocellulosic materials (LMs) are abundant feedstocks with excellent potential for biofuels and biocommodities production. In particular, nut and coffee wastes are rich in biomolecules, e.g. sugars and polyphenols, the valorisation of which still has to be fully disclosed. This study investigated the effectiveness of ultrasounds coupled with hydr...

This study investigates the dark fermentation of fruit and vegetable waste under meso-philic conditions (30-34 °C), as a valorization route for H2 and volatile fatty acids production, simulating the open market waste composition over the year in two Mediterranean countries. Specifically , the study focuses on the effect of the (i) seasonal variabil...

In line with the emerging circular bioeconomy paradigm, the present study investigated the valorisation of abundant hemp biomass residues (HBRs) such as hurds (HH) and a mix of leaves and inflorescences (Mix), and other organic wastes (i.e., cheese whey and grape pomace) through the volatile fatty acid (VFA) production in mono- and co-acidogenic fe...

The aim of this study was to develop a mathematical model to assess the effect of soluble microbial products production and external carbon source addition on the performance of a sulfur-driven autotrophic denitrification (SdAD) process. During SdAD, the growth of autotrophic biomass (AUT) was accompanied by the proliferation of heterotrophic bioma...

Lignocellulosic materials (LMs) are the most abundant residues on the planet and have a huge potential for methane production. Several strategies have been tested to enhance the methane potential of LMs, with a particular emphasis on environmentally friendly and economically convenient pretreatments. This chapter revisits the potential of two chemi...

The continuous dredging of sediments contaminated by polycyclic aromatic hydrocarbons such as phenanthrene (PHE) has required the employment of high–efficiency technologies, including sediment washing (SW). However, the large amount of generated spent SW effluents requires the development of effective, eco–friendly and cost–saving approaches, which...

Autotrophic denitrification with biosulfur (ADBIOS) provides a sustainable technological solution for biological nitrogen removal from wastewater driven by biogenic S⁰, derived from biogas desulfurization. In this study, the effect of different biofilm carriers (conventional AnoxK™ 1 and Z-200 with a pre-defined maximum biofilm thickness) on ADBIOS...

In the emerging context of circular bioeconomy, industrial hemp (Cannabis Sativa L.) biomass is a valuable resource for the sustainable implementation of second-generation biorefineries. Potentially, all the main hemp components can find application within different biorefinery approaches, adding value to the conventional production of hemp fibres...

The adoption of prolonged solid retention times during the biological treatment of urban wastewaters is a well-known strategy to reduce sewage sludge production. However, it also results in the production of a biological sludge with low percentages of biodegradable organic matter, also characterized by high humification degrees, which may hamper th...

Soil contamination by pyrene has increased over the years due to human-related activities, urgently demanding for remediation approaches to ensure human and environment safety. Within this frame, phytoremediation has been successfully applied over the years due to its green and cost-effectiveness features. The scope of this review includes the main...

Lignocellulosic materials are the most abundant biomass on the planet, representing a great opportunity for energy valorization. This work investigated the effect of methanol-organosolv pretreatment on the methane production from hazelnut skin (HS), spent coffee grounds (SCG), and almond shell (AS). The pretreatment on the three lignocellulosic mat...

This study proposes new perspectives for the management and biorefinery of wastes deriving from the agri–food sector such as chestnut shell (CS), which was here used as an organic feedstock for biomethane production through anaerobic digestion (AD). 1–5% alkaline (i.e. NaOH and KOH), hydrothermal (i.e. at 100 °C) and combined hydrothermal–alkaline...

The contamination of sediments by polycyclic aromatic hydrocarbons (PAHs) has been widely spread for years due to human activities, imposing the research and development of effective remediation technologies for achieving efficient treatment and reuse of sediments. In this context, the amendment of biochar in PAH–contaminated sediments has been lat...

Brewery spent grain (BSG) is an industrial waste stream with large potential for biorefining purposes. This work evaluated the production of volatile fatty acids (VFAs) by a two-step process using BSG as renewable feedstock by combining a single direct hydrolysis step (without removing the acid or potential inhibiting compounds) with an acidogenic...

The comparative performance of an inverse fluidized bed reactor (IFBR) having high density polyethylene beads as carrier materials for biofilm formation and a continuous stirred tank reactor (CSTR), both maintaining autotrophic denitrification using biogenic sulphur (ADBIOS) in the absence and presence of nickel (Ni²⁺), was studied. The reactors we...

Mitigating ammonia emissions from the livestock sector offers the opportunity to combine environmental protection with resource recovery through emerging circular bioeconomy approaches. In this work, we tested the potential of low-rate stripping techniques to enable techno-economically feasible nitrogen recovery and valorization from buffalo manure...

Graphical abstract J o u r n a l P r e-p r o o f 2 Highlights  Fe(II)-driven autotrophic denitrification was investigated in packed-bed reactors  Higher nitrate loading rates enhanced denitrification performances in PBR1  The highest specific nitrate removal rate was 14.3 mg NO3-/g VS/h  At constant nitrate loading rate, denitrification efficie...

Circular management of carbon and nutrients is at the basis of future environmental sustainability and global food security. However, direct resource recovery and upcycling from wastes poses safety concerns related to source contamination. By carefully evaluating the potential integrations of existing and emerging bio-technologies, we put forward n...

This study offers new insights and promising perspectives in view of the energy valorization of hazelnut skin (HS) as a potential feedstock for renewable biomethane production. The process originally comprised the coupling of chemical pretreatments and individual dosing of cobalt (Co), nickel (Ni) and selenium (Se) as enhancement strategies of the...

The aim of the present study was to investigate the effect of gradually increasing glucose concentrations (from 5.6 to 111 mmol L⁻¹) on the fermentative H2 production with and without bioaugmentation. A stirred tank reactor (STR) was operated at 70 °C and inoculated with a hyperthermophilic mixed culture or a hyperthermophilic mixed culture bioaugm...

Industrial hemp stands out as a promising candidate for clean and sustainable biomass-to-bioenergy systems due to its multipurpose, high biomass yield and resource efficiency features. In this study, different hemp biomass residues (HBRs) were evaluated as a potential feedstock for renewable biomethane production through anaerobic digestion (AD). T...

Cheese whey (CW) and hemp hurds (HH) represent typically overabundant biowastes of food and agricultural production, and their circular management is crucial to improve both sustainability and profitability of the agri-food chain. By combining experimental biochemical methane potential (BMP) tests and literature data, the techno-economic aspects of...

This study proposes a comparison of different ex situ technologies aimed at the removal of polycyclic aromatic hydrocarbons from marine sediments in terms of performances, costs and energy balance. In accordance with the principles of water-energy nexus, anaerobic bioremediation, soil washing and thermal desorption were investigated under low liqui...

This study proposes the supplementation of digestate, fresh organic fraction of municipal solid waste (OFMSW) and a nutrient solution during the anaerobic biostimulation of marine sediments contaminated by polycyclic aromatic hydrocarbons (PAHs). The experimental activity was conducted with four PAHs (i.e. phenanthrene, anthracene, fluoranthene and...

Cost-benefit Analysis of Environmental Health Interventions clearly articulates the core principles and fundamental methodologies underpinning the modern economic assessment of environmental intervention on human health. Taking a practical approach, the book provides a step-by-step approach to assigning a monetary value to the health benefits and d...

Cost-benefit Analysis of Environmental Health Interventions clearly articulates the core principles and fundamental methodologies underpinning the modern economic assessment of environmental intervention on human health. Taking a practical approach, the book provides a step-by-step approach to assigning a monetary value to the health benefits and d...

This study focused on continuous-flow hydrogen production byThermotoga neapolitanaat a hydraulic retentiontime (HRT) decreasing from 24 to 5 h. At each HRT reduction, the hydrogen yield (HY) immediately dropped,but recovered during prolonged cultivation at constant HRT. Thefinal HY in each operating period decreasedfrom 3.4 ( ± 0.1) to 2.0 ( ± 0.0)...

Increasing total solids in anaerobic digestion can reduce the methane yield by highly complex bio-physical–chemical mechanisms. Therefore, understanding those mechanisms and their main drivers becomes crucial to optimize this waste treatment biotechnology. In this study, seven batch experiments were conducted to investigate the effects of increasin...

High-solids anaerobic digestion (HS-AD) of the organic fraction of municipal solid waste (OFMSW) is operated at a total solid (TS) content ≥ 10% to enhance the waste treatment economy, though it might be associated to free ammonia (NH3) inhibition. This study aimed to calibrate and cross-validate a HS-AD model for homogenized reactors in order to a...

The recovery of iron and other heavy metals by the formation of Fe(III) (hydr)oxides is an important application of microbially-driven processes. The mineral characterization of the precipitates formed during Fe(II)-mediated autotrophic denitrification with and without the addition of Cu, Ni, and Zn by four different microbial cultures was investig...

Hydrogen is a strong inhibitor of dark fermentation. We aimed at directly correlating the hydrogen production by Thermotoga neapolitana with the supersaturation of hydrogen in the liquid phase (H2aq), which is often disregarded. Different agitation speeds, biogas recirculation and bubble induction by AnoxK™ K1 carrier were tested to prevent the sup...

This study focused on the supersaturation of hydrogen in the liquid phase (H2aq) and its inhibitory effect on dark fermentation by Thermotoga neapolitana cf. capnolactica by increasing the agitation (from 100 to 500 rpm) and recirculating H2-rich biogas (GaR). At low cell concentrations, both 500 rpm and GaR reduced the H2aq from 30.1 (±4.4) mL/L t...

This study evaluates the main effects of including ‘non-ideal’ bio-physical-chemical corrections in high-solids anaerobic digestion (HS-AD) of the organic fraction of municipal solid waste (OFMSW), at total solid (TS) between 10 and 40%. As a novel approach, a simple ‘non-ideal’ module, accounting for the effects of ionic strength (I) on the main a...

Rice straw is an abundant and sustainable substrate for anaerobic digestion (AD), but it is often deficient in essential trace elements (TEs) for proper microbial growth and metabolism. A lack of TEs leads to AD imbalances and suboptimal biogas yields. However, the total TE concentration is not a sufficient indicator of the amount of TEs available...

In this study, mono-digestion of the organic fraction of municipal solid waste (OFMSW) and co-digestion of OFMSW with beech sawdust, simulating green waste, were used to investigate the maximum operational total solid (TS) content in semi-continuous high-solids anaerobic digestion (HS-AD). To alleviate substrate overloading in HS-AD, the effluent m...

This study focused on the effect of feed glucose and acetic acid on biohydrogen production by Thermotoga neapolitana under continuous-flow conditions. Increasing the feed glucose concentration from 11.1 to 41.6 mM decreased the hydrogen yield from 3.6 (± 0.1) to 1.4 (± 0.1) mol H2/mol glucose. The hydrogen production rate concomitantly increased un...

Hierarchical three-dimensional (3D) porous architecture FeIIFeIII layered double hydroxide (LDH) multiwall was grown on carbon-felt (CF) substrate via solvothermal process. The as-deposited FeIIFeIII LDH/CF cathode was composed of highly oriented and well crystallized interconnected nanowalls with high electrical conductivity and excellent catalyti...

During high-solids anaerobic digestion (HS-AD) of the organic fraction of municipal solid waste (OFMSW), an important total solid (TS) removal occurs, leading to the modification of the reactor content mass/volume, in contrast to ‘wet’ anaerobic digestion (AD). Therefore, HS-AD mathematical simulations need to be approached differently than ‘wet’ A...

A local sensitivity analysis was performed for a chemically-synthesized elemental sulfur (S0) based two-step denitrification model, accounting for nitrite (NO2−) accumulation, biomass growth and S0 hydrolysis. The sensitivity analysis was aimed at verifying the model stability, understanding the model structure and individuating the model parameter...

In this study, the biokinetics of autotrophic denitrification with biogenic S0 (ADBIOS) for the treatment of nitrogen pollution in wastewaters were investigated. The used biogenic S0, a by-product of gas desulfurization, was an elemental microcrystalline orthorhombic sulfur with a median size of 4.69 µm and a specific surface area of 3.38 m2/g, whi...

Acid mine drainage and mining wastewaters contain, depending on the source, elevated concentrations of metals, e.g. nickel (Ni2+), and oxyanions, e.g. selenate (SeO42−) and sulfate (SO42−). This study compared the performance of two reactor configurations, a biotrickling filter (BTF) and an upflow anaerobic sludge blanket (UASB) reactor, for the tr...

Fe(II)-mediated autotrophic denitrification in the presence of copper (Cu), nickel (Ni) and zinc (Zn) with four different microbial cultures was investigated in batch bioassays. In the absence of metals, complete nitrate removal and Fe(II) oxidation were achieved with a Thiobacillus-dominated mixed culture and Pseudogulbenkiania sp. 2002 after 7 d....

Electro-Fenton (EF), an advanced oxidation process, can be combined with a biological process for efficient treatment of wastewater containing refractory pollutants such as pharmaceuticals. In this study, a biological process was implemented in a sequencing batch reactor (SBR), which was either preceded or followed by EF treatment. The main goal wa...

This work investigated the effect of three different chemical pretreatment methods on the biogas production from the anaerobic digestion of wheat straw. The lignocellulosic material was separately pretreated using i) the organic solvent N-methylmorpholine N-oxide (NMMO) at 120 °C for 3 h, ii) the organosolv method, employing ethanol as the organic...

The hydrolysis of elemental sulfur (S0) coupled to S0-based denitrification and denitritation was investigated in batch bioassays by microbiological and modeling approaches. In the denitrification experiments, the highest obtained NO3−-N removal rate was 20.9 mg/l·d. In the experiments with the biomass enriched on NO2−, a NO2−-N removal rate of 10....

The biomethane potential from the anaerobic digestion of rice straw, hazelnut skin and cocoa bean shell was investigated after applying an organosolv pretreatment. The pretreatment of the three lignocellulosic materials was performed at 150 and 180°C for 60 min using 50% (v/v) ethanol as organic solvent. Afterwards, the untreated and pretreated fee...

The dewaterability of sludge from two conventional activated sludge (CAS) and three membrane bioreactor (MBR)-based wastewater treatment plants was investigated prior to and after anaerobic digestion. The concentration and composition of extracellular polymeric substances (EPS) mostly affected the dewaterability of all raw sludge samples. A better...

The effect of trace elements (TEs) addition and NaOH pretreatment on the anaerobic digestion of rice straw was investigated in batch tests. Co, Ni and Se were added to the raw rice straw at different dosages. The NaOH pretreatment was applied to the rice straw both alone and in combination with the addition of TEs, in order to evaluate potential sy...

Fe(II)-mediated autotrophic denitrification with four different microbial cultures under different pH and EDTA/Fe(II) conditions was investigated in batch bioassays. Initially, the highest nitrate removal (72%) was achieved with an activated sludge inoculum. The use of pure cultures of Pseudogulbenkiania strain 2002 and Thiobacillus denitrificans r...

Many industrial activities result in heavy metal dispersion in the environment worldwide. Heavy metals are persistent contaminants, which get into contact with living organisms and humans creating serious environmental disorders. Metals are commonly removed from wastewaters by means of physical-chemical processes, but often microbes are also enroll...