Elena Ficara

Politecnico di Milano | Polimi · Department of Civil and Environmental Engineering

Algae are on the rise. There has never been a better time for exploring the potential of algae for biomass production, valorisation, and bioremediation. Research into new species, bioactive compounds, production and processing of biomass, bioremediation performance and development of cost- and energy-efficient large-scale cultivation are all in ful...

This study aims at evaluating the process efficiency of an outdoor pilot-scale microalgae-based wastewater treatment system. Experimental results from two monitoring campaigns were analysed, showing that the system removed on average 85.1 % and 36.2 % of the influent ammoniacal nitrogen and orthophosphate, respectively, with an associated algal pro...

This study aims at evaluating an innovative biotechnological process for the concomitant bioremediation and valorization of wastewater from textile digital printing technology based on a microalgae/bacteria consortium. Nutrient and colour removal were assessed in lab-scale batch and continuous experiments and the produced algae/bacteria biomass was...

Microalgae and other phototrophic microorganisms can be cultivated to produce food and valuable bioproducts, also allowing to remove nutrients from wastewater and CO2 from biogas or polluted gas streams. Among other environmental and physico-chemical parameters, microalgal productivity is strongly influenced by the cultivation temperature. In this...

Research data produced within the CARIPLO IMAP and Perform Water 2030 projects were processed using the SimaPro software to carry out the Life Cycle Assessment according to ISO 14040-44 of an innovative process of treated effluents’ polishing. The study aims to evaluate the integration of a microalgae culture as a side-stream process into the basel...

In this work, the nutrients and eutrophication problem are integrated into a nature-based solution by incorporating microalgae-based nutrient removal from wastewater and collecting the residue in an anaerobic digestion plant to produce biogas that is directly exported to an existing gas-fired power plant and closes the bioresource loop. El Burullus...

Exploiting the combination of algae and bacteria in High Rate Algal/Bacterial Ponds (HRABP) is an emerging approach for wastewater remediation and resource recovery. In this study, the advantage of adding a solid/liquid separation system to uncouple Hydraulic Retention Time (HRT) and Solid Retention Time (SRT) is explored and quantified. A long-ter...

Algae-bacteria (AB) consortia can be exploited for effective wastewater treatment, based on photosynthetic oxygenation to reduce energy requirements for aeration. While algal kinetics have been extensively evaluated, bacterial kinetics in AB systems are still based on parameters taken from the activated sludge models, lacking an experimental valida...

In the context of circular economy and sustainable production of materials, this project investigated the feasibility of producing sustainable polyhydroxyalkanoates (PHA) from microalgae and sludge used in the treatment of municipal wastewater. The overall process was studied looking at the main steps: microalgae production, fermentation of the bio...

The efficiency of an outdoor pilot-scale raceway pond treating the wastewaters generated by a large-scale piggery farm in Northern Italy was evaluated. The biomass productivity over 208 days of experimentation was 10.7 ± 6.5 g TSS·m⁻²·d⁻¹, and ammoniacal nitrogen, orthophosphate, and COD average removal efficiencies were 90%, 90%, and 59%, respecti...

The results of a first campaign of sampling and analyses of emerging micropollutants in the influent (municipal centrate) and effluent of a pilot MBP raceway are reported. The algal population was chiefly made of Chlorella spp. and the pilot worked satisfactorily for the removal of nitrogen. 14 emerging micropollutants were analysed. Average remova...

The efficiency of an outdoor pilot-scale raceway pond treating the wastewaters generated by a large-scale piggery farm in Northern Italy was evaluated. The biomass productivity over 208 days of experimentation was 10.7 ± 6.5 g TSS⋅m− 2 ⋅d− 1 , and ammoniacal nitrogen, orthophosphate, and COD average removal efficiencies were 90%, 90%, and 59%, resp...

Anaerobic co-digestion in wastewater treatment plants is looking increasingly like a straightforward solution to many issues arising from the operation of mono-digestion. Process modelling is relevant to predict plant behavior and its sensitivity to operational parameters, and to assess the feasibility of simultaneously feeding a digester with diff...

Implementation of onsite bioremediation technologies is essential for textile industries due to rising concerns in terms of water resources and quality. Partial nitritation-anaerobic ammonium oxidation (PN/A) processes emerged as a valid, but unexplored, solution. In this study, the performance of a PN/A pilot-scale (9 m³) sequencing batch reactor...

Metal-based flocculants are commonly used for biomass harvesting in microalgae-based bio-refineries. Besides the high separation efficiency, additional aspects should be considered, related to the toxicity of metals for the algal biomass. Partitioning tests for commonly used flocculants (i.e., FeCl3 and Al2(SO4)3) showed that metals were mostly tra...

The treatability of seven wastewater samples generated by a textile digital printing industry was evaluated by employing 1) anammox-based processes for nitrogen removal 2) microal-gae (Chlorella vulgaris) for nutrient uptake and biomass production 3) white-rot fungi (Pleur-otus ostreatus and Phanerochaete chrysosporium) for decolorization and lacca...

Harvesting has been recognized as a major bottleneck in any microalgae-based technology, making it a relevant research topic in the field. Among applicable technologies, electrocoagulation-flotation (ECF) has been devoted a lot of attention as an effective alternative to conventional metal salts addition. This paper reports and comments the relevan...

The first objective of this study is to assess the predictive capability of the ALBA (ALgae-BActeria) model for a pilot-scale (3.8 m2) high-rate algae-bacteria pond treating agricultural digestate. The model, previously calibrated and validated on a one-year data set from a demonstrative-scale raceway (56 m2), successfully predicted data from a six...

This paper proposes a new model describing the algae-bacteria ecosystem evolution in an outdoor raceway for wastewater treatment. The ALBA model is based on a mass balance of COD, C, N and P, but also H and O. It describes growth and interactions among algae, heterotrophic and nitrifying bacteria, while local climate drives light and temperature. R...

This study aimed at examining and comparing the nutrient removal efficiency, biomass productivity and microbial community structure of two outdoor pilot-scale photobioreactors, namely a bubble column and a raceway pond, treating the liquid fraction of an agricultural digestate. Bacterial and eukaryotic communities were characterized using a metabar...

The demand for aquafeed is expected to increase in the coming years and new ingredients will be needed to compensate for the low fish meal and oil availability. Microalgae represent a promising matrix for the future aquafeed formulation, however, the high production cost hinders its application. The use of microalgae from biorefinery would reduce t...

The role of P content on the treatment and valorization of the liquid fraction of digestate, namely centrate, through microalgae-based technologies was evaluated in this study. The performance of four column photobioreactors, which were fed on diluted centrate with corrected (10 mg N/ mg P) and not modified (129 mg N/ mg P) N:P ratio, were monitore...

Tetraselmis suecica was cultivated in a semi-continuously operated tubular photobioreactor fed on aquaculture wastewater (AW) testing two hydraulic retention times (HRT): 10 and 7 days (RUN_1 and RUN_2, respectively). The integrated mechanistic model BIO_ALGAE was validated with experimental data in order to simulate the biomass production and nutr...

This study aims at demonstrating the feasibility of using microalgae-bacteria consortia for the treatment of the sidestream flow of the supernatant from blackwater dewatering (centrate) in an urban wastewater treatment plant in Northern Italy. A 1200 L raceway reactor was used for the outdoor cultivation of a diverse community of Chlorella spp., Sc...

The use of phototrophic organisms in wastewater treatment is gaining increasing interest, due to the possibility of exploiting photosynthetic oxygenation, thus lowering treatment costs and environmental impacts. Mixed consortia of phototrophic organisms and aerobic bacteria rapidly develop in photobioreactors receiving wastewaters; in this case, th...

This study aimed at evaluating the effects of different environmental conditions (irradiance, temperature, pH and dissolved oxygen) on a microalgae-bacteria consortium cultivated in a pilot-scale open pond and fed on the liquid fraction of anaerobic digestate. A standardized photo-respirometry protocol was followed to evaluate the activity of micro...

The inhibitory effects of free ammonia (FA) on microalgae/cyanobacteria in wastewater-treating photobioreactors (PBR) can strongly reduce their treatment efficiency, increasing the operational costs and undermining the stability of the system. Although FA-promoting conditions (high pH, temperature and ammoniacal nitrogen concentration) are commonly...

Milk whey processing wastewaters (MWPWs) are characterized by high COD and organic nitrogen content; the concentrations of phosphorus are also relevant. A microalgal-based process was tested at lab scale in order to assess the feasibility of treating MWPW without any dilution or pre-treatment. Different microalgal strains and populations were teste...

Abstract Microalgal meal are a promising matrix to replace Fish Meal (FM) and Fish Oil (FO) in aquafeed production thanks to their nutritional and nutraceutical properties as protein and lipid source as well as supplement of microelements and bioactive compounds (Camacho-Rodríguez et al.2017; Becker 2007), however their high production cost is a m...

The increasing amount of source separated organic fraction of municipal solid wastes (OFMSW) treated by anaerobic digestion for energy recovery requires the implementation of cost-efficient processes for the treatment of the produced digestate, especially in terms of nitrogen removal. The autotrophic nitrogen removal process, based on the coupling...

To define a reliable and simple model to be used to develop control strategies meeting specific biogas production goals by tuning the feeding pattern thus achieving a more flexible bio-energy production. The AMOCO model was extended to the co-digestion of corn silage, cattle manure and cheese whey. Model parameters identified with an LFT method and...

The problem addressed in this paper is the efficient operation of anaerobic digesters for biogas production. We improve the generality of a literature model (the AMOCO) to account for two hydrolysis steps. We introduce an LFTbased parameter identification technique, ans demonstrate the achievable match improvements by validating the model versus ex...

BACKGROUND Secondary effluent wastewaters still contain resources including water and nutrients that must be safely reused and recovered. In this study, the combined role of microalgae as disinfectant and nutrient removal agents was evaluated for the potential application of a microalgae‐based process as a cost‐effective tertiary treatment. Nutrien...

This study was carried out to assess the efficiency of a pilot-scale bubble-column reactor to remove nitrogen in centrate from the biosolid dewatering of a municipal wastewater treatment plant whilst producing biomass for agricultural purposes. The column was inoculated with a mixed community of Scenedesmus and Chlorella spp. and operated outdoor i...

Background Microalgae‐bacteria based processes are among the most promising low‐cost technologies to treat livestock wastewaters. The current literature reports the need for pretreatment or dilution of piggery wastewater for adequate microalgal growth. The aim of the study is to optimize the potential of microalgal‐bacterial communities to treat un...

This paper addresses the efficiency of a microalgae-based agricultural digestate treatment at pilot-scale in an outdoor raceway pond (880 L, pH-dependent CO2 dosage) and in a bubble column (74.5 L, air-bubbling). Specifically, nitrogen removal, evolution of the algae-bacteria consortium, and the actual process applicability in the Po Valley climate...

Anaerobic digestion (AD) is an established process for the treatment of organic wastes and the production of renewable energy. However, high amounts of digestate produced by regional AD plants require enhancement for further use. This study investigates a conceptual model for the digestate enhancement by using a downstream gasification. It is based...

Experimental laboratory methods and techniques have matured to the degree that they have become accepted as reliable tools in wastewater treatment research and practice. For sector professionals, especially the new generation of young scientists and engineers entering the wastewater treatment profession, the quantity, complexity and diversity of th...

Biogas production has been suggested as a valid valorization solution for microalgal/bacteria biomass (MAB) grown on wastewater. This research is aimed at assessing the feasibility to use MAB grown in an outdoor raceway fed on piggery wastewater for biogas production. Batch and continuous anaerobic tests were conducted on the sole MAB and on a blen...

Respirometric techniques are useful tools to evaluate bacterial activities in activated sludge processes due to their fast execution and the possibility to obtain several kinetic parameters from a single test. Using such techniques in microalgae-bacteria consortia treating wastewater could allow a better understanding of mutual interactions between...

This work concerns the possibility of using phycoremediation of piggery wastewater (PW) in order to remove nitrogen and to send the produced algal biomass to anaerobic digestion. A semi-continuous culturing test was performed in 150 mL glass test tubes (4.5 cm diameter, 20 cm high), in four replicates, and run for 90 days. Light was provided artifi...

Studies were performed on the use of the solid fraction of digestate (D) for the production of lignocellulolytic enzymes (endo- and exo-glucanase, xylanase, β-glucosidase and laccase) by fungi, in comparison with wheat straw (benchmark) (W). To date, this is the first report on the use of such an inexpensive substrate in a liquid environment. Subme...

The liquid fraction of digestate produced by agricultural biogas plants is rich in macro and micronutrients that are valuable for the culturing of microalgae. Nonetheless, the high ammonium concentration may cause toxicity and the high optical density may reduce light penetration, negatively affecting the biomass production rate. Dilution with fres...

This paper presents a knowledge-based planning of the most proper treatment schemes for drinking water supply (DWS) systems, jointly applying statistical tools and experimental tests. Milan city was chosen as case of study, being its DWS system composed of more than 20 DWS units, widespread in the urban area. First, multivariate statistical techniq...

This paper discusses the possibility of including the culturing of microalgae within a conventional wastewater treatment sequence by growing them on the blackwater (BW) from biosolid dewatering to produce biomass to feed the anaerobic digester. Two photobioreactors were used: a 12 L plexiglas column for in-door, lab-scale tests and a 85 L plexiglas...

The aim of this research was to evaluate the applicability of the anammox process for removing nitrogen from the supernatant originating from the anaerobic digestion of the organic fraction of municipal solid waste (OFMSW). The short term inhibitory potential of this concentrated wastewater was evaluated by means of batch tests in terms of maximum...

Production of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. A workshop was held in June 2015 in Leysin Switzerland to agree on common solutions to the conundrum of inconsiste...

Anaerobic digestion is a key process for urban solid waste management converting organic waste into biogas, mainly composed of methane and carbon dioxide, and a residue called digestate which is generally separated into solid and liquid fractions. Based on an overview of the abundant literature published on municipal solid waste and lignocellulosic...

Over the past twenty years, the knowledge and understanding of wastewater treatment has advanced extensively and moved away from empirically-based approaches to a fundamentally-based first-principles approach embracing chemistry, microbiology, and physical and bioprocess engineering, often involving experimental laboratory work and techniques. Many...

In the agricultural sector of many European countries, biogas production through anaerobic digestion (AD) is becoming a very fast-growing market. Anaerobic digestion is a simple and robust process that biologically converts an organic matrix into biogas and digestate, the latter corresponding to the anaerobically non-degraded fraction. So far, dige...

In this paper, a reduced order model of anaerobic digestion is first proposed, with the main goal to develop an efficient tool for process monitoring and control. Then, in order to perform parameter estimation, the model has been rewritten in a linear fractional transformation (LFT) formulation, using a symbolic tool originally developed for linear...

The anaerobic digestion model No.1 (ADM1) developed by the IWA Task Group for mathematical modelling of anaerobic digestion processes Batstone et al. [1] is a structural model which describes the main biochemical and physicochemical processes. For such purposes, other models have been proposed to describe anaerobic processes with a reduced set of p...

Owing to their complexity, accurate and detailed models of anaerobic digestion cannot be used for online monitoring and control. To this aim reduced order models have to be considered. In this chapter, a modification of the well-known AMOCO model is first proposed in order to widen its field of applicability. Then, to perform parameter identificati...

The reduction of biological excess sludge production using ozone is a well-known technology and is applied in several full-scale plants around the world. Nevertheless, optimisation of the process is not yet adequately documented in the literature. Operational parameters are usually chosen by assuming a direct proportionality between ozone dose and...

The recent discovery of the metabolism of anammox bacteria (ANaerobic AMMonium OXidation) has revolutionized the understanding of the nitrogen cycle. Unlike the conventional process of nitrification and denitrification, by which the nitrogen removal from wastewater is usually performed, the anammox bacteria catalyze the oxidation of ammonium to mol...

This study investigated the effect of enzymatic and combined alkaline-enzymatic pretreatments on chemical composition and methane production from ensiled sorghum forage. Four commercial enzymatic preparations were tested and the two yielding the highest sugars release were added to evaluate any hydrolytic effect on both untreated and alkaline pretr...

The integration of a photobioreactor for algal culture in the process scheme of WWTPs could have positive effects on mass and energy balances. The algal biomass could grow on N rich liquids, such as centrates from sludge dewatering, improving N removal and reducing the overall energy consumption, and then undergo anaerobic digestion generating biog...

The liquid fraction of digested material is rich in ammonium and may require nitrogen removal. The aim of this research was to evaluate the applicability of the anammox process for the biological N removal from a supernatant coming from the anaerobic digestion of a mixture of piggery manure, poultry manure, and of agro-wastes. The supernatant was p...

The paper reports the results of an experiment to assess the feasibility of including a photobioreactor within the design of a wastewater treatment plant, growing microalgae on the centrate from anaerobic sludge dewatering. The growth of algal biomass would take advantage of the available nitrogen and provide a substrate for biogas production by an...

This paper focuses on the production of bio-hydrogen by dark fermentation of de-proteinized (by membrane ultra-filtration) cheese whey, an abundant waste stream of the food industry. This waste stream contains mainly lactose, which was also used as reference substrate in bio-hydrogen production tests. Those tests were conducted in batch by using a...