Efficient Nitrogen Recovery from Agro-Energy Effluents for Cyanobacteria Cultivation (Spirulina)

The present study aimed to obtain an efficient liquid nitrogen fertilizer from the by-product of anaerobic digestion for its subsequent use in the production of cyanobacteria (Spirulina). A simple recovery technology was tested based on the stripping and acid absorption, modifying temperature (50 and 70 degrees C) and pH (10 and 12), of the ammonia nitrogen contained in the digestate produced in a large-scale plant treating livestock manure and grass silage. The results demonstrated how, at a relatively low temperature (50 degrees C), using sulfuric and citric acid solution, it is possible to recover nitrogen from a digestate in the form of ammonium sulfate and ammonium citrate with yields of 70% and 72.1% respectively. By carrying out Spirulina growth tests, promising results were obtained under semicontinuous production, with a maximum dry biomass daily productivity of 0.344 g L-1 day(-1) with ammonium sulfate and 0.246 gDW L-1 day(-1) with ammonium citrate. The results showed that nitrogen can be efficiently recovered on site by using the organic acid, digestate and waste heat from anaerobic digestion for Spirulina biomass production

An outlook on modern and sustainable approaches to the management of grape pomace by integrating green processes, biotechnologies and advanced biomedical approaches

Grape pomace is the main solid residue of wine industry, mainly composed of seeds, skins and stalks, all containing high amounts of valuable phytochemicals. Considering its high potential, in this review, an outlook on different resources and products, which can be obtained by the recovery of grape pomace is provided. Special attention has been devoted to the analysis of chemical, physical and biotechnological processes to be applied and also to the high value compounds and products, such as supplements, nutraceuticals and cosmeceuticals, that can be manufactured. In particular, in the first part of the review, an update on the composition of grape pomace has been provided along with the analysis of its traditional fate. In the second part, the more modern and green approaches tested to the sustainable management of grape pomace are reported and discussed

Combining Different Approaches for Grape Pomace Valorization: Polyphenols Extraction and Composting of the Exhausted Biomass

Grape pomace represents 60%, by weight, of the solid side-streams of the wine-making process. The quantities produced, seasonality, and the presence of polyphenols pose economic and environmental issues that require proper management approaches based on the principles of sustainability and circular economy. The present work focuses on the combined application of solid-liquid extraction of polyphenols from ground grape pomace using a hydroethanolic mixture and the composting of the exhausted pomace. The obtained results support the possibility of recovering approximately 76.5 g of extract per kg of dry grape pomace (or 1.8 g of total phenols per kg of dry grape pomace). The composting process was not affected by the extraction process. On the contrary, the composting process was enhanced by the pomace particle size reduction, in terms of final biostability and content of humic acids

Extraction of the antioxidant phytocomplex from wine-making by-products and sustainable loading in phospholipid vesicles specifically tailored for skin protection

The present study is aimed at valorizing grape pomace, one of the most abundant winery-making by-products of the Mediterranean area, through the extraction of the main bioactive compounds from the skin of grape pomace and using them to manufacture innovative nanoformulations capable of both avoiding skin damages and promoting skincare. The phytochemicals were recovered through maceration in hydroethanolic solution. Catechin, quercetin, fisetin and gallic acid, which are known for their antioxidant power, were detected as the main compounds of the extract. Liposomes and phospholipid vesicles modified with glycerol or Montanov 82® or a combination of both, were used as carriers for the extract. The vesicles were small (~183 nm), slightly polydispersed (PI ≥ 0.28), and highly negatively charged (~−50 mV). The extract was loaded in high amounts in all vesicles (~100%) irrespective of their composition. The antioxidant activity of the extract, measured by using the DPPH (2,2-Diphenyl-1-picrylhydrazyl) test, was 84 ± 1%, and slightly increased when loaded into the vesicles (~89%, P < 0.05). The grape pomace extract loaded vesicles were highly biocompatible and able to protect fibroblasts (3T3) from the oxidative stress induced by hydrogen peroxide

Emissions from mechanically-biologically treated waste landfills at field scale

Modern waste management tends towards greater sustainability in landfilling, with the implementation of strategies such as the pretreatment of solid waste. This work assesses the behaviour of rejects from a refining stage of mechanically-biologically treated municipal solid waste at the landfill. The main results of 18 months' monitoring of an experimental pilot cell with waste from a full-scale plant are presented. This first stages are expected to be the most problematic period for this type of waste. The evolution of the temperature and the composition of leachate and gas at various points within the cell are included. During the first weeks, pollutant concentrations in the leachate exceeded the reference ranges in the literature, coinciding with a rapid onset of methanogenic conditions. However, there was a quick wash, reducing concentrations to below one third of the initial values before the first year. pH values influenced concentrations of some pollutants such as copper. These results indicate that, right from the beginning of disposal, such facilities should be prepared to treat a high pollution load in the leachate and install the gas emissions control elements due to the rapid onset of methanogenesis.This work is funded by the Spanish Ministry of Economics and Competitiveness through the CTM2012-35055 project. The project is financed jointly by the European Regional Development Fund, FEDER (operational period 2007-2013). The authors wish to thank the Government of Cantabria, through the public company MARE, and TirCantabria, the landfill operator company, for their collaboration

Dynamic transformations of nitrogen during mechanical-biological pre-treatment of municipal solid waste

Mechanical–biological pre-treatment (MBP) of municipal solid waste (MSW) has gained evidence as a practice capable of accomplishing the requirements for environmental sustainable landfilling. In particular, MBP is effective in reducing the ammoniacal nitrogen content in the leachate. However, few data are available on the modifications of the nitrogen forms occurring during MBP and on the role played by processes such as nitrification and generation of refractory organic compounds. The dynamic transformations of nitrogen were investigated during the MBP. MSW was mechanically and biologically pre-treated; samples were collected at different stages of the process and analysed to investigate the evolution of nitrogen forms; batch and column leaching tests were performed as well. The results indicate that nitrification is negligible and volatilization can only partially explain the low ammoniacal nitrogen content in the leachate. Incorporation of ammoniacal nitrogen into a refractory organic form was assessed and is likely to play an important role. The maximum content of refractory organic nitrogen in the solid waste was achieved after about 60 days of aerobic pre-treatment; therefore, the minimal duration of the MBP should be about 8–9 weeks in order to optimize the ammoniacal nitrogen incorporation, unless the waste is characterized by a low C/N ratio

Semi-continuous biological hydrogen production through anaerobic digestion of mixture of waste by anaerobic digestion of mixture of waste with specified average residence time, and feeding equivalent volume of fresh mixture into reactor

NOVELTY - Semi-continuous biological hydrogen production includes anaerobic digestion of mixture of waste in a hydrogen production reactor with an average residence time of the mixture in the hydrogen production reactor of 2-4 days, obtained through daily removal of a portion corresponding volume of mixture in the reactor; and feeding an equivalent volume of analogous fresh mixture into the reactor. USE - Method for semi-continuous biological hydrogen production (claimed). ADVANTAGE - The method can produce high quantities of hydrogen, with constant production of the element in time, which can be integrated with other processes for biochemical transformation of organic waste to provide a process whose end products are all useful and re-usable. DETAILED DESCRIPTION - Semi-continuous biological hydrogen production comprises anaerobic digestion at 30-40 degrees C of a mixture of waste having not greater than 10 wt.% solids, containing biodegradable organic fractions of urban waste, both from separate refuse collection and from mechanical sorting, by vegetation waters deriving from olive oil production and by active sludge from urban sewage purification. The method is conducted with an average residence time of the mixture in the hydrogen production reactor of 2-4 days, obtained through daily removal of a portion corresponding to approximately 1/n of the volume of mixture in the reactor, where n indicates the number of days of desired average residence time, and feeding an equivalent volume of analogous fresh mixture into the reactor. INDEPENDENT CLAIMS are included for: (1) anaerobic hydrogen production reactor (13) of the continuous stirred-tank type, equipped with inlet port(s) and outlet port(s), both gas-tight, with instruments to control pH and temperature of the reaction mixture present in the reactor, and with gas-tight ports to take samples of gas or reaction mixture; and (2) a plant (10) for the combined production of hydrogen and methane, constituted by the reactor and a second gas-tight reactor (14) for methane production, connected in series by gas-tight ports and feed systems, so that an outlet port of the hydrogen production reactor is connected to an inlet port of the second reactor