scholarly journals Microalgal Systems for Wastewater Treatment: Technological Trends and Challenges towards Waste Recovery

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8112
Author(s):  
Etiele G. Morais ◽  
Nathana L. Cristofoli ◽  
Inês B. Maia ◽  
Tânia Magina ◽  
Paulo R. Cerqueira ◽  
...  
Keyword(s):  
Scale Up ◽  
Economic Feasibility ◽  
Environmental Benefits ◽  
Growth Media ◽  
Future Prospects ◽  
Nitrogen And Phosphorus ◽  
Microalgal Biomass ◽  
Main Challenge ◽  
Valuable Compounds ◽  
Organically Grown

Wastewater (WW) treatment using microalgae has become a growing trend due the economic and environmental benefits of the process. As microalgae need CO2, nitrogen, and phosphorus to grow, they remove these potential pollutants from wastewaters, making them able to replace energetically expensive treatment steps in conventional WW treatment. Unlike traditional sludge, biomass can be used to produce biofuels, biofertilizers, high value chemicals, and even next-generation growth media for “organically” grown microalgal biomass targeting zero-waste policies and contributing to a more sustainable circular bioeconomy. The main challenge in this technology is the techno-economic feasibility of the system. Alternatives such as the isolation of novel strains, the use of native consortia, and the design of new bioreactors have been studied to overcome this and aid the scale-up of microalgal systems. This review focuses on the treatment of urban, industrial, and agricultural wastewaters by microalgae and their ability to not only remove, but also promote the reuse, of those pollutants. Opportunities and future prospects are discussed, including the upgrading of the produced biomass into valuable compounds, mainly biofuels.

scholarly journals Comprehensive Utilization of Marine Microalgae for Enhanced Co-Production of Multiple Compounds

Marine Drugs ◽  
2020 ◽  
Vol 18 (9) ◽  
pp. 467
Author(s):  
Ruijuan Ma ◽  
Baobei Wang ◽  
Elvis T. Chua ◽  
Xurui Zhao ◽  
Kongyong Lu ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Production Efficiency ◽  
Metabolic Flux ◽  
Marine Microalgae ◽  
Economic Feasibility ◽  
Thermochemical Conversion ◽  
Microalgal Biomass ◽  
Comprehensive Utilization ◽  
Potential Applications ◽  
Valuable Compounds

Marine microalgae are regarded as potential feedstock because of their multiple valuable compounds, including lipids, pigments, carbohydrates, and proteins. Some of these compounds exhibit attractive bioactivities, such as carotenoids, ω-3 polyunsaturated fatty acids, polysaccharides, and peptides. However, the production cost of bioactive compounds is quite high, due to the low contents in marine microalgae. Comprehensive utilization of marine microalgae for multiple compounds production instead of the sole product can be an efficient way to increase the economic feasibility of bioactive compounds production and improve the production efficiency. This paper discusses the metabolic network of marine microalgal compounds, and indicates their interaction in biosynthesis pathways. Furthermore, potential applications of co-production of multiple compounds under various cultivation conditions by shifting metabolic flux are discussed, and cultivation strategies based on environmental and/or nutrient conditions are proposed to improve the co-production. Moreover, biorefinery techniques for the integral use of microalgal biomass are summarized. These techniques include the co-extraction of multiple bioactive compounds from marine microalgae by conventional methods, super/subcritical fluids, and ionic liquids, as well as direct utilization and biochemical or thermochemical conversion of microalgal residues. Overall, this review sheds light on the potential of the comprehensive utilization of marine microalgae for improving bioeconomy in practical industrial application.

scholarly journals Sustainable Syntheses and Sources of Nanomaterials for Microbial Fuel/Electrolysis Cell Applications: An Overview of Recent Progress

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1221
Author(s):  
Domenico Frattini ◽  
Gopalu Karunakaran ◽  
Eun-Bum Cho ◽  
Yongchai Kwon
Keyword(s):  
Microbial Fuel Cells ◽  
Noble Metals ◽  
Raw Materials ◽  
Nanoparticle Synthesis ◽  
Economic Feasibility ◽  
Electrolysis Cell ◽  
Microbial Electrolysis Cells ◽  
Electrolysis Cells ◽  
Bioenergy Generation ◽  
Valuable Compounds

The use of microbial fuel cells (MFCs) is quickly spreading in the fields of bioenergy generation and wastewater treatment, as well as in the biosynthesis of valuable compounds for microbial electrolysis cells (MECs). MFCs and MECs have not been able to penetrate the market as economic feasibility is lost when their performances are boosted by nanomaterials. The nanoparticles used to realize or decorate the components (electrodes or the membrane) have expensive processing, purification, and raw resource costs. In recent decades, many studies have approached the problem of finding green synthesis routes and cheap sources for the most common nanoparticles employed in MFCs and MECs. These nanoparticles are essentially made of carbon, noble metals, and non-noble metals, together with a few other few doping elements. In this review, the most recent findings regarding the sustainable preparation of nanoparticles, in terms of syntheses and sources, are collected, commented, and proposed for applications in MFC and MEC devices. The use of naturally occurring, recycled, and alternative raw materials for nanoparticle synthesis is showcased in detail here. Several examples of how these naturally derived or sustainable nanoparticles have been employed in microbial devices are also examined. The results demonstrate that this approach is valuable and could represent a solid alternative to the expensive use of commercial nanoparticles.

scholarly journals Advances in Circular Bioeconomy Technologies: From Agricultural Wastewater to Value-Added Resources

Environments ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 20
Author(s):  
Nidhi Mehta ◽  
Kinjal J Shah ◽  
Yu-I Lin ◽  
Yongjun Sun ◽  
Shu-Yuan Pan
Keyword(s):  
Membrane Separation ◽  
Value Added ◽  
Fulvic Acids ◽  
Chemical Precipitation ◽  
Environmental Benefits ◽  
Nitrogen And Phosphorus ◽  
Piggery Wastewater ◽  
Agricultural Wastewater ◽  
Treatment Processes ◽  
Electrokinetic Separation

This review systematically outlines the recent advances in the application of circular bioeconomy technologies for converting agricultural wastewater to value-added resources. The properties and applications of the value-added products from agricultural wastewater are first summarized. Various types of agricultural wastewater, such as piggery wastewater and digestate from anaerobic digestion, are focused on. Next, different types of circular technologies for recovery of humic substances (e.g., humin, humic acids and fulvic acids) and nutrients (e.g., nitrogen and phosphorus) from agricultural wastewater are reviewed and discussed. Advanced technologies, such as chemical precipitation, membrane separation and electrokinetic separation, are evaluated. The environmental benefits of the circular technologies compared to conventional wastewater treatment processes are also addressed. Lastly, the perspectives and prospects of the circular technologies for agricultural wastewater are provided.

scholarly journals Processing Methodologies of Wet Microalga Biomass Toward Oil Separation: An Overview

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 641
Author(s):  
Vânia Pôjo ◽  
Tânia Tavares ◽  
Francisco Xavier Malcata
Keyword(s):  
Food System ◽  
Lipid Extraction ◽  
High Energy ◽  
Economic Feasibility ◽  
Alternative Source ◽  
Microalgal Biomass ◽  
Energy Demands ◽  
Chemical Profiles ◽  
System Sustainability ◽  
Industrial Level

One of the main goals of Mankind is to ensure food system sustainability—including management of land, soil, water, and biodiversity. Microalgae accordingly appear as an innovative and scalable alternative source in view of the richness of their chemical profiles. In what concerns lipids in particular, microalgae can synthesize and accumulate significant amounts of fatty acids, a great fraction of which are polyunsaturated; this makes them excellent candidates within the framework of production and exploitation of lipids by various industrial and health sectors, either as bulk products or fine chemicals. Conventional lipid extraction methodologies require previous dehydration of microalgal biomass, which hampers economic feasibility due to the high energy demands thereof. Therefore, extraction of lipids directly from wet biomass would be a plus in this endeavor. Supporting processes and methodologies are still limited, and most approaches are empirical in nature—so a deeper mechanistic elucidation is a must, in order to facilitate rational optimization of the extraction processes. Besides circumventing the current high energy demands by dehydration, an ideal extraction method should be selective, sustainable, efficient, harmless, and feasible for upscale to industrial level. This review presents and discusses several pretreatments incurred in lipid extraction from wet microalga biomass, namely recent developments and integrated processes. Unfortunately, most such developments have been proven at bench-scale only—so demonstration in large facilities is still needed to confirm whether they can turn into competitive alternatives.

scholarly journals Optimisation of microalgal cultivation via nutrient-enhanced strategies: the biorefinery paradigm

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Gonzalo M. Figueroa-Torres ◽  
Jon K. Pittman ◽  
Constantinos Theodoropoulos
Keyword(s):  
Kinetic Model ◽  
Growth Dynamics ◽  
Value Added ◽  
Cost Effective ◽  
Predictive Modelling ◽  
Nitrogen And Phosphorus ◽  
Predictive Capacity ◽  
Microalgal Biomass ◽  
Microalgal Cultivation ◽  
Lipid Formation

Abstract Background The production of microalgal biofuels, despite their sustainable and renowned potential, is not yet cost-effective compared to current conventional fuel technologies. However, the biorefinery concept increases the prospects of microalgal biomass as an economically viable feedstock suitable for the co-production of multiple biofuels along with value-added chemicals. To integrate biofuels production within the framework of a microalgae biorefinery, it is not only necessary to exploit multi-product platforms, but also to identify optimal microalgal cultivation strategies maximising the microalgal metabolites from which biofuels are obtained: starch and lipids. Whilst nutrient limitation is widely known for increasing starch and lipid formation, this cultivation strategy can greatly reduce microalgal growth. This work presents an optimisation framework combining predictive modelling and experimental methodologies to effectively simulate and predict microalgal growth dynamics and identify optimal cultivation strategies. Results Microalgal cultivation strategies for maximised starch and lipid formation were successfully established by developing a multi-parametric kinetic model suitable for the prediction of mixotrophic microalgal growth dynamics co-limited by nitrogen and phosphorus. The model’s high predictive capacity was experimentally validated against various datasets obtained from laboratory-scale cultures of Chlamydomonas reinhardtii CCAP 11/32C subject to different initial nutrient regimes. The identified model-based optimal cultivation strategies were further validated experimentally and yielded significant increases in starch (+ 270%) and lipid (+ 74%) production against a non-optimised strategy. Conclusions The optimised microalgal cultivation scenarios for maximised starch and lipids, as identified by the kinetic model presented here, highlight the benefits of exploiting modelling frameworks as optimisation tools that facilitate the development and commercialisation of microalgae-to-fuel technologies.

A cascade biorefinery for the valorization of microalgal biomass: biodiesel, biogas, fertilizers and high valuable compounds

2021 ◽  
Vol 59 ◽  
pp. 102433
Author(s):  
F. Monlau ◽  
S. Suarez-Alvarez ◽  
A. Lallement ◽  
G. Vaca-Medina ◽  
G. Giacinti ◽  
...  
Keyword(s):  
Microalgal Biomass ◽  
Valuable Compounds

scholarly journals Assessment of Chlorella sorokiniana Growth in Anaerobic Digester Effluent

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 478
Author(s):  
Elvira E. Ziganshina ◽  
Svetlana S. Bulynina ◽  
Ayrat M. Ziganshin
Keyword(s):  
Agricultural Waste ◽  
Ammonium Phosphate ◽  
16S Rrna Gene Sequencing ◽  
Experimental Period ◽  
Chlorella Sorokiniana ◽  
Growth Media ◽  
Rrna Gene ◽  
Anaerobic Digester Effluent ◽  
Rrna Gene Sequencing ◽  
Valuable Compounds

Microalgae are considered a potential source of valuable compounds for multiple purposes and are potential agents for bioremediation of aquatic environments contaminated with different pollutants. This work evaluates the use of agricultural waste, unsterilized and anaerobically digested, to produce biomass from a strain of Chlorella sorokiniana. Furthermore, the presence of bacteria in these wastes was investigated based on the bacterial 16S rRNA gene sequencing. The results showed a specific growth rate ranging between 0.82 and 1.45 day−1, while the final biomass yield in different digestate-containing treatments (bacterial-contaminated cultures) ranged between 0.33 and 0.50 g L−1 day−1. Besides, substantial amounts of ammonium, phosphate, and sulfate were consumed by C. sorokiniana during the experimental period. The predominant bacteria that grew in the presence of C. sorokiniana in the effluent-containing treatments belonged to the genera Chryseobacterium, Flavobacterium, Sphingomonas, Brevundimonas, Hydrogenophaga, Sphingobacterium, and Pseudomonas. Therefore, this microalga can tolerate and grow in the presence of other microorganisms. Finally, these results show that anaerobically digested agricultural waste materials are a good substitute for growth media for green microalgae; however, phosphate and sulfate levels must also be controlled in the media to maintain adequate growth of microalgae.

scholarly journals Quality perception of organically grown tomatoes (Lycopersicon esculentum Mill.) in Vienna, Austria

2016 ◽  
Vol 5 (2) ◽  
pp. 16-20
Author(s):  
PK Ng’ang’a ◽  
CR Vogl
Keyword(s):  
Fruit Size ◽  
Quality Standards ◽  
International Markets ◽  
Sweet Taste ◽  
Structured Interviews ◽  
Quality Perception ◽  
Main Challenge ◽  
Human Health Damage ◽  
The Government ◽  
Organically Grown

Austria is one of the major organic tomato producing countries for local and export marketing. These tomatoes are produced in parts of Austria especially around Vienna where their production system has to meet stringent organic quality standards in both local and international markets. These quality standards may put considerable strain on farmers and are normally formulated without famers’ participation so may not be wholly representative of the farmers’ quality interpretation. The aim of this paper is therefore to determine the Austrian organic tomatoes growers’ perception and practice of quality and challenges. Qualitative semi-structured interviews were carried out among 28 organic tomatoes farmers in Vienna, Austria. Findings suggest that quality of organic tomatoes is mainly perceived in terms of both informal values (big fruit size, long shelf life, food security and amount of income received from tomato sales) as well as formal norms (non- application of chemicals, human health, damage free, sweet taste, red colour, and juiciness). There were no gendered differences in quality perception among the growers. High costs of production inputs were identified as the main challenge to attaining quality in organic tomatoes. Following these findings, there is need for effective participation of growers in formulation of standards as well as subsidizing of production inputs by the government. The Austrian tomato growers as well as local and international retailers should work closely to increase the price received by the Austrian organic tomato growers so that it more adequately covers their production costs.Int. J. Agril. Res. Innov. & Tech. 5 (2): 16-20, December, 2015

scholarly journals Economic Feasibility of Solar Irrigation Pumps: A Study of Northern Bangladesh

2022 ◽  
Vol 11 (1) ◽  
pp. 1-13
Author(s):  
Md. Tawhidul Islam ◽  
Md. Elias Hossain
Keyword(s):  
Food Security ◽  
Solar Energy ◽  
Food Production ◽  
Agricultural Land ◽  
Economic Feasibility ◽  
Environmental Benefits ◽  
Primary Data ◽  
Environmental Benefit ◽  
Service Model ◽  
The Government

Bangladesh is the most densely populated country in the world. With a total population of around 165 million, the country has constantly been facing food security challenges and other problems. Therefore, increasing food production is one of the feasible solutions to this challenge, and proper agricultural land use for food production bears critical importance. Adopting sustainable irrigation systems and viable technologies would be vital for ensuring efficient use of agricultural land in Bangladesh to safeguard the country's food security. Solar irrigation pumps (SIPs) can be a reliable option in this regard. However, Bangladesh has experienced a prolonged growth rate of SIP installation in the last decade.  The countryhas set a target to install 10000 SIPs by the year 2027, albeit it is a tiny share of the 1.57 million conventional irrigation pumps operating in the country. This study aims to investigate the economic feasibility of the SIPs operating in the northern region of Bangladesh in terms of estimating financial feasibility and environmental benefits. The study is mainly based on primary data collected from the users of SIPs from two Upazilas of Dinajpur and Rangpur districts. A total of 14 SIPs, categorized into large, medium, and small pumps, are selected randomly from the available SIPs in the study areas. The financial analysis reveals that small SIPs are the most profitable option (20% IRR) for investment. Large SIPs are moderately profitable (10% IRR), and their profitability can be improved (10.50% IRR) by introducing additional uses of solar energy. However, medium SIPs are the worst (5% IRR) option for investment. In the study areas, large and medium SIPs are designed for the 'fees for service model', and small SIPs are designed for the 'fees for ownership model'. It is found that the 'fees for ownership model' is more profitable than the 'fees for service model'. Moreover, the net environmental benefit for all SIPs is found almost equal to the given subsidy for installing them. Also, the net environmental benefit per kilowatt peak (kWp) is highest for the small SIPs. This paper recommends that additional use (e.g., husking, grinding, supply excess electricity to grid, and so on) of solar energy can improve the profitability of investmenton SIPs. Further, the government should continue giving grants for installing SIPs and promote 'fees for ownership model' (small SIPs) for personal use. It would speed up the dissemination rate of SIPs and help increase the country's agricultural production and improve the environmental conditions.

scholarly journals Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models

2014 ◽  
Vol 14 (23) ◽  
pp. 32233-32323 ◽  
Author(s):  
M. Bocquet ◽  
H. Elbern ◽  
H. Eskes ◽  
M. Hirtl ◽  
R. Žabkar ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Atmospheric Chemistry ◽  
Hybrid Methods ◽  
Model Performance ◽  
Chemical Data ◽  
Current Status ◽  
Model Parameters ◽  
Chemical Transformations ◽  
Future Prospects ◽  
Main Challenge

Abstract. Data assimilation is used in atmospheric chemistry models to improve air quality forecasts, construct re-analyses of three-dimensional chemical (including aerosol) concentrations and perform inverse modeling of input variables or model parameters (e.g., emissions). Coupled chemistry meteorology models (CCMM) are atmospheric chemistry models that simulate meteorological processes and chemical transformations jointly. They offer the possibility to assimilate both meteorological and chemical data; however, because CCMM are fairly recent, data assimilation in CCMM has been limited to date. We review here the current status of data assimilation in atmospheric chemistry models with a particular focus on future prospects for data assimilation in CCMM. We first review the methods available for data assimilation in atmospheric models, including variational methods, ensemble Kalman filters, and hybrid methods. Next, we review past applications that have included chemical data assimilation in chemical transport models (CTM) and in CCMM. Observational data sets available for chemical data assimilation are described, including surface data, surface-based remote sensing, airborne data, and satellite data. Several case studies of chemical data assimilation in CCMM are presented to highlight the benefits obtained by assimilating chemical data in CCMM. A case study of data assimilation to constrain emissions is also presented. There are few examples to date of joint meteorological and chemical data assimilation in CCMM and potential difficulties associated with data assimilation in CCMM are discussed. As the number of variables being assimilated increases, it is essential to characterize correctly the errors; in particular, the specification of error cross-correlations may be problematic. In some cases, offline diagnostics are necessary to ensure that data assimilation can truly improve model performance. However, the main challenge is likely to be the paucity of chemical data available for assimilation in CCMM.

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