scispace - formally typeset
Search or ask a question
Journal ArticleDOI

A review on microalgal culture to treat anaerobic digestate food waste effluent

TL;DR: In this article, the authors reviewed the anaerobic digestion of food waste, the composition of its digestate and trends in the treatment of ADFE with emphasis on treatment using microalgae.
Abstract: Food waste constitutes a significant portion of waste in the world. Indeed, it is estimated that about one-third of edible human food is wasted globally. Anaerobic digestion has been identified as a promising technology for the treatment of food waste as it generates a significant amount of energy and can remove a substantial portion of the organics. However, this process has not been adequately applied due to technical and economic challenges. Most importantly, anaerobic digestion of food waste produces waste in the form of Anaerobic digestate food effluent (ADFE), with high amounts of nutrient such as ammonium (up to 3000 mg L−1 NH3-N). It has been established that this effluent can be used as a substrate for the cultivation of microalgae allowing both a means of its treatment and its possible valorization. This paper reviews the anaerobic digestion of food waste, the composition of its digestate and trends in the treatment of ADFE with emphasis on treatment using microalgae. Potential microalgal cultivation methods applicable to the treatment of anaerobic digestate, especially ADFE, and possible optimization of the cultivation methods are also reviewed critically. Further, understanding of the cultivation of microalgae in ADFE is required to aid in better design of its treatment process and valorization to improve its economics.
Citations
More filters
Journal ArticleDOI
TL;DR: Anaerobic digestion (AD) is a widely used technology to valorise food waste for biogas production yet a considerable amount of digestate remains underutilised.

100 citations

Journal ArticleDOI
TL;DR: In this paper, a review on ammonium and its importance in algal nutrition, but also on its problematic presence in aquatic systems such as wastewaters is presented, focusing on the exploitation of microalgae in ammonium removal and the role of ammonium in micro-algae metabolism.
Abstract: In plant cells, ammonium is considered the most convenient nitrogen source for cell metabolism. However, despite ammonium being the preferred N form for microalgae, at higher concentrations, it can be toxic, and can cause growth inhibition. Microalgae’s tolerance to ammonium depends on the species, with various taxa showing different thresholds of tolerability and symptoms of toxicity. In the environment, ammonium at high concentrations represents a dangerous pollutant. It can affect water quality, causing numerous environmental problems, including eutrophication of downstream waters. For this reason, it is important to treat wastewater and remove nutrients before discharging it into rivers, lakes, or seas. A valid and sustainable alternative to conventional treatments could be provided by microalgae, coupling the nutrient removal from wastewater with the production of valuable biomass. This review is focused on ammonium and its importance in algal nutrition, but also on its problematic presence in aquatic systems such as wastewaters. The aim of this work is to provide recent information on the exploitation of microalgae in ammonium removal and the role of ammonium in microalgae metabolism.

57 citations


Cites background from "A review on microalgal culture to t..."

  • ...Sustainability 2021, 13, 956 6 of 17 According to Chuka-Ogwude [53], under high levels of ammonia, Fv/Fm values decreased with the rising NH3-N concentration due to the disruption of the photosynthetic apparatus....

    [...]

  • ...According to Chuka-Ogwude [53], under high levels of ammonia, Fv/Fm values decreased with the rising NH3-N concentration due to the disruption of the photosynthetic apparatus....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the properties of food waste digestate and the worldwide regulations on digestate for soil conditioning were summarized, and the principles, mechanisms, and application prospects of various post digestion treatment processes were reviewed and discussed, including dewatering, drying, and biological stabilization.

45 citations

Journal ArticleDOI
TL;DR: Aim of this work is in identifying the state of the art of the strategies to manage the digestate from the anaerobic processing of the organic fractions of municipal solid waste.

44 citations

Journal ArticleDOI
TL;DR: Results indicate that MUR 273 displayed tolerance levels similar to that obtained with MUR 268 which had previously undergone long-term acclimation in digestate and could potentially be used in the treatment and valorization of the anaerobic digestate of food waste with significantly less dilution.
Abstract: Anaerobic digestate of food waste as a waste product of anaerobic digestion contains a significant amount of nutrients making its direct disposal prohibitive due to environmental regulations. However, the nutrients in this waste are a valuable feedstock for waste-to-product endeavours such as microalgae cultivation coupled to the treatment of the digestate. A limitation to this path is the high toxic concentration of ammonia nitrogen in the digestate which limits microalgae growth, leading to the requirement for significant dilution before use. This study focused on the bioprospecting and sourcing of species capable of sustained growth in very high concentrations of ammonia nitrogen. Ten local strains of microalgae were isolated, comprising mainly of unicellular species, a colonial species, and a filamentous species. Three unicellular species were chosen (Chlorella sp., MUR 271; Scenedesmus obliquus (Tetradesmus obliquus), MUR 272; and Oocystis sp., MUR 273) and screened alongside previously isolated strains (Scenedesmus quadricauda, MUR 268; Chlorella sp., MUR 269; and Scenedesmus dimorphus (Tetradesmus dimorphus) MUR 270) which had undergone long-term acclimation in digestate. The most tolerant of the newly isolated strains was MUR 273 (Oocystis sp.), capable of proliferation in up to 600 mg L−1 NH3-N concentration in digestate. The maximum specific growth rate, μmax, of MUR 273 was 0.36 ± 0.01 day−1 at 150 mg L−1 NH3-N. The results indicate that MUR 273 displayed tolerance levels similar to that obtained with MUR 268 which had previously undergone long-term acclimation in digestate and could potentially be used in the treatment and valorization of the anaerobic digestate of food waste with significantly less dilution.

38 citations

References
More filters
Journal ArticleDOI
TL;DR: The only way to eliminate Nr accumulation and stop the cascade is to convert Nr back to nonreactive N2, which leads to lag times in the continuation of the cascade.
Abstract: Human production of food and energy is the dominant continental process that breaks the triple bond in molecular nitrogen (N2) and creates reactive nitrogen (Nr) species. Circulation of anthropogenic Nr in Earth’s atmosphere, hydrosphere, and biosphere has a wide variety of consequences, which are magnified with time as Nr moves along its biogeochemical pathway. The same atom of Nr can cause multiple effects in the atmosphere, in terrestrial ecosystems, in freshwater and marine systems, and on human health. We call this sequence of effects the nitrogen cascade. As the cascade progresses, the origin of Nr becomes unimportant. Reactive nitrogen does not cascade at the same rate through all environmental systems; some systems have the ability to accumulate Nr, which leads to lag times in the continuation of the cascade. These lags slow the cascade and result in Nr accumulation in certain reservoirs, which in turn can enhance the effects of Nr on that environment. The only way to eliminate Nr accumul...

2,647 citations

Book
01 Jan 2011
TL;DR: The Swedish Institute for Food and Biotechnology (SIK) as mentioned in this paper conducted two studies on global food losses, one for high/medium-income countries and one for low income countries, to serve as a basis for the international congress Save Food!, 16-17 May 2011, at the international packaging industry fair Interpack2011 in Dusseldorf, Germany.
Abstract: This publication is based on studies carried out from August 2010 to January 2011 by The Swedish Institute for Food and Biotechnology (SIK) on request from the FAO. The two studies on global food losses (one for high/medium-income countries and one for low income countries) have been carried out to serve as a basis for the international congress Save Food!, 16-17 May 2011, at the international packaging industry fair Interpack2011 in Dusseldorf, Germany. The study highlights the losses occurring along the entire food chain, and makes assessments of their magnitude. Further, it identifies causes of food losses and possible ways of preventing them. The results suggest that roughly one-third of food produced for human consumption is lost or wasted globally, which amounts to about 1.3 billion tons per year. This inevitably also means that huge amounts of the resources used in food production are used in vain, and that the greenhouse gas emissions caused by production of food that gets lost or wasted are also emissions in vain.

2,628 citations

Book
12 Dec 2018
TL;DR: The What a Waste 20: A Global Snapshot of Solid Waste Management to 2050 as discussed by the authors aggregates extensive solid waste data at the national and urban levels and provides information on waste management costs, revenues, and tariffs; special wastes; regulations; public communication; administrative and operational models; and the informal sector
Abstract: By 2050, the world is expected to generate 340 billion tons of waste annually, increasing drastically from today’s 201 billion tons What a Waste 20: A Global Snapshot of Solid Waste Management to 2050 aggregates extensive solid waste data at the national and urban levels It estimates and projects waste generation to 2030 and 2050 Beyond the core data metrics from waste generation to disposal, the report provides information on waste management costs, revenues, and tariffs; special wastes; regulations; public communication; administrative and operational models; and the informal sector

1,937 citations

Journal ArticleDOI
TL;DR: S syntrophically fermenting bacteria synthesize ATP by substrate-level phosphorylation and reinvest part of the ATP-bound energy into reversed electron transport processes, to release the electrons at a redox level accessible by the partner bacteria and to balance their energy budget.
Abstract: Fatty acids and alcohols are key intermediates in the methanogenic degradation of organic matter, e.g., in anaerobic sewage sludge digestors or freshwater lake sediments. They are produced by classical fermenting bacteria for disposal of electrons derived in simultaneous substrate oxidations. Methanogenic bacteria can degrade primarily only one-carbon compounds. Therefore, acetate, propionate, ethanol, and their higher homologs have to be fermented further to one-carbon compounds. These fermentations are called secondary or syntrophic fermentations. They are endergonic processes under standard conditions and depend on intimate coupling with methanogenesis. The energetic situation of the prokaryotes cooperating in these processes is problematic: the free energy available in the reactions for total conversion of substrate to methane attributes to each partner amounts of energy in the range of the minimum biochemically convertible energy, i.e., 20 to 25 kJ per mol per reaction. This amount corresponds to one-third of an ATP unit and is equivalent to the energy required for a monovalent ion to cross the charged cytoplasmic membrane. Recent studies have revealed that syntrophically fermenting bacteria synthesize ATP by substrate-level phosphorylation and reinvest part of the ATP-bound energy into reversed electron transport processes, to release the electrons at a redox level accessible by the partner bacteria and to balance their energy budget. These findings allow us to understand the energy economy of these bacteria on the basis of concepts derived from the bioenergetics of other microorganisms.

1,749 citations

Journal ArticleDOI
TL;DR: A helical tubular photobioreactor system, the BIOCOIL™, has been developed which allows these algae to be grown reliably outdoors at high cell densities in semi-continuous culture.

1,296 citations