Session 52 - Biowaste

[CEST2019_00966] Expansion of the 3T method for the assessment of various Energy-from-Waste technologies
by Vakalis S., Moustakas K., Malamis D., Loizidou M.

The term “energy from waste” refers to technologies that utilize waste streams for energy production. However, for the energy production by means of thermal treatment of non-hazardous waste it is usually the term “waste-to-energy” that is commonly used. The Waste Framework Directive 2008/98/EU separates the waste management strategies into Recovery Operations and Disposal Operations (ANNEXES I and II respectively). Waste-to-energy technologies that use waste as fuel for energy generation are considered Recovery Operations, i.e. R 1. When the scope is the destruction/ reduction of the waste before landfilling, the waste-to-energy technologies are considered Disposal Operations, i.e. D 10. This issue has been of high importance because each waste-to-energy facility can potentially fall into both categories according to the assessment tool that sets the bar. In order to address this issue European Commission integrated the R1 formula in the second revision of the Waste Framework Directive of 2008 and improved it in the Directive 2015/1127/EU that entered into force from July 31st, 2016. It should be stated for the record that the R1 formula has been a very helpful tool for assessing waste-to-energy plants and has set the general framework. The problems with the use of the R1 formula start from the fact the formula is not thermodynamically consistent since it is self-proclaimed to be more a “utilization efficiency” formula rather than a pure energy efficiency.

Session: 52, Room: D, at Sat, 09/07/2019 - 16:45 to 17:00
Oral presentation in Biowaste

Sewage Sludge Use In Agriculture Is Promoted By The European Union Since The Normative Of Cleaning Waters Related To The Compulsory Use Of Depuration Plants In All Cities Over 2000 Inhabitants Was Finally Implemented In 2005. The University Of Santiago De Compostela (Usc) Has Been Conducted Long-Term Experiment Research About The Application Of Different Sewage Sludge Doses In Silvopastoral Systems. Main Results Shown That Sewage Sludge Can Be Successfully Used As Fertilizer For Both Tree And Pasture Development, With Reduced Toxicity For Animals When Plant Production Is Considered In Both Very Acidic And Acidic-Neutral Soils. This Paper Provides An Overview Of The Main Findings In Acidic Soils Of The Long-Term Results After Application Of Sewage Sludge In Soils.

Session: 52, Room: D, at Sat, 09/07/2019 - 16:30 to 16:45
Oral presentation in Biowaste

In the present study, PHA production from ovine cheese whey (oCW) through a 3-step process (dark fermentation, biomass selection and PHA accumulation process) was investigated. Different operating pHs were adopted during the fermentation step and no external nutrients were supplied at any step of the process. Results showed that the production of PHA from oCW is a promising valorisation approach.

Session: 52, Room: D, at Sat, 09/07/2019 - 16:15 to 16:30
Oral presentation in Biowaste

Sewage sludge (SS) is a by-product of wastewater treatment. Anaerobic digestion is a worldwide technology used in SS stabilization and pre-treatment step is used to improve its biodegradability. Once SS is stabilized they are named biosolids (BS). Biosolids composition makes them attractive as a soil amendment. But also, BS could be a source of contamination. Therefore, the objective of this study was to evaluate the nutrient leaching in loamy-silty soil of BS stabilized with conventional and advanced anaerobic digestion. Thus, two biosolids from conventional and advanced anaerobic digestion were evaluated in soil leaching columns using loamy-silty soil to evaluated phosphorus and nitrogen flux. The results show that the leaching rate of nutrients is not influenced by the pre-treatment, but the application rate of biosolids influences the leaching rate of nutrients.

Session: 52, Room: D, at Sat, 09/07/2019 - 17:00 to 17:03
Flash presentation in Biowaste

In this study, hydrothermal pretreatment in combination with HCl, at a chemical loading of 2 g /100 g TS was carried out as a pretreatment method to enhance anaerobic digestion of willow sawdust. Regarding hydrothermal pretreatment, various temperatures (130.5-230oC) and process times (15.5 -60 min) were studied, using a Central Composite Design so as to optimize pretreatment conditions and the methane potential.

Session: 52, Room: D, at Sat, 09/07/2019 - 15:30 to 15:45
Oral presentation in Biowaste

Sunflower residues are a prominent substrate of renewable source for biogas production during anaerobic digestion (AD). However, due to its recalcitrant structure, pretreatment is necessary to increase its biodegradability. The objective of the present work was to evaluate the effect of the NaOH pretreatment on the methane production from sunflower residues. The residues were separated into stalks and heads after seed removal. It was observed that pretreatment caused an increase in the biochemical methane potential (BMP) during batch tests, but a decrease was recorded during continuous experiments.

Session: 52, Room: D, at Sat, 09/07/2019 - 16:00 to 16:15
Oral presentation in Biowaste

Anaerobic digestion has been recognized as the most demanding process for the valorization of organic solid waste towards the generation of valuable intermediates, that can be converted into a methane rich-gas to meet the current needs for renewable energy. In this regard, press-extrusion has raised as a promising mechanical pretreatment to enhance methane production by increasing the organic loading rate to the digester as well as by adequately mixing the liquid and the solid fractions from this pretreatment. This study aimed at verifying the significance of both the organic loading rate and the mixing ratio between the liquid and solid fraction from press-extrusion by using a factorial design of experiment. Results were discussed and statistically elaborated to identify the operating conditions to be further tested for the optimization of the integrated process.

Session: 52, Room: D, at Sat, 09/07/2019 - 15:45 to 16:00
Oral presentation in Biowaste