•The high output of MSS highlights the need for alternative routes of valorization.•Evaluation of 3 sludge-to-energy valorisation methods through SWOT analysis.•Pyrolysis is an energy and material ...recovery process resulting to ‘zero waste’.•Identification of challenges and barriers for MSS pyrolysis in Greece was investigated.•Adopters of pyrolysis systems face the challenge of finding new product markets.
For a sustainable municipal sewage sludge management, not only the available technology, but also other parameters, such as policy regulations and socio-economic issues should be taken in account. In this study, the current status of both European and Greek Legislation on waste management, with a special insight in municipal sewage sludge, is presented. A SWOT analysis was further developed for comparison of pyrolysis with incineration and gasification and results are presented. Pyrolysis seems to be the optimal thermochemical treatment option compared to incineration and gasification. Sewage sludge pyrolysis is favorable for energy savings, material recovery and high added materials production, providing a ‘zero waste’ solution. Finally, identification of challenges and barriers for sewage sludge pyrolysis deployment in Greece was investigated.
•The study aims to contribute in the debate on waste to energy methodologies.•SRF valorization in dedicated thermal plant and in cement kilns was assessed.•Environmental protection, industrial ...ecology and symbiosis were considered.•Use of SRF in cement kilns is a sustainable solution rather electricity production.
A debate is still open on issues of waste to energy methodologies aiming to answer to questions of particular relevance, such as whether the concept of SRF/RDF production can be applied directly to MSW through the Mechanical–Biological Treatment (MBT) process, when selective collection acts as a virtual pre-treatment of the same, or if the use of SRF/RDF as alternative fuel in cement kilns is the most sustainable solution. In this study, two scenarios were analyzed and compared: (a) the use of SRF in a new dedicated thermal plant for electricity production and (b) the use of SRF as an alternative fuel in an existing cement plant. The comparative assessment was based on principles of Sustainable Waste Management embracing technical and cost issues, environmental protection, industrial ecology and symbiosis. The application of SWOT analysis showed that the use of SRF in cement kilns is more sustainable compared to its use in a new dedicated plant for electricity production.
An approach for biomass flash pyrolysis in a circulating fluid bed (CFB) reactor with continuous solids regeneration is described in this study. The unit is capable of performing conventional and ...catalytic biomass pyrolysis with the proper solid selection. The production of improved quality liquid products in a direct step through catalytic pyrolysis is investigated in this work. Both conventional and catalytic biomass pyrolysis can be effectively performed in this CFB unit. Flash pyrolysis conditions were achieved and liquid product yields of ∼70
wt% (on biomass feed) were obtained. The effect of specific operating variables including the type of inorganic solid material and the solid/biomass ratio was established on the final liquid product quality and yield. Solid materials considered included silica sand, a commercial fluid catalytic cracking catalyst and a ZSM-5 additive. Catalytic biomass pyrolysis generally leads to the production of additional water, coke and gases compared to conventional pyrolysis. However, the obtained liquid product quality and composition is improved.
A new procedure is proposed for the effective conversion of biomass flash pyrolysis liquids (BFPLs) to transportation fuels. First, the hydrotreatment of a BFPL was studied, both in a thermal and in ...a catalytic mode. The thermal hydrogenation of BFPLs, a modification of the VEBA Combi Cracking process, is a low cost and low severity hydrogenation process without any operational problems. It has been proved to be the less sensitive hydrotreatment process with respect to BFPLs. The liquid product of this process cannot be used in the refinery without further upgrading. However, its heavy fraction, mixed with an aromatic hydrocarbonaceous feedstock (LCO) was considered as a potential FCC feedstock. The direct introduction of BFPLs in the FCC process was so far infeasible, because of their particularly high tendency to coke formation. Commercially available cracking catalysts were found to have an acceptable performance. Acceptable levels of coke on catalyst (<1
wt%) and gasoline yields (23–25
wt%) were obtained. Commercial ReUSY catalysts with a Re
2O
3 content of 0.6, characterized by a narrow pore size distribution (
D=36
Å), were found to be more appropriate for this application. The obtained bio-gasoline meets the EU specifications and is characterized by a high RON value of 96.
Used tires (UTs) are an abandon solid waste in Greece and worldwide which can be effectively transformed to valuable products and energy via pyrolysis. In this study, current status of both European ...and Greek Legislation on waste management with a special insight in tires is reported. The established Joint Alternative Management System (JAMS) for the alternative management of tires is described, along with the adopted valorization routes. The adopted Energy recovery routes in Greece are discussed with focus on pyrolysis. The main drawbacks of pyrolysis are identified and solutions are proposed for their effective implementation in the near future. Tires energy and material recovery are particularly favorable, with substantial benefits of energy savings, material recovery and high added materials production. Based on the existing extensive expertise in the pyrolysis of tires, an effort was made in order to identify the non-technical barriers for the further exploitation of pyrolysis as a promising valorization route in Greece. A SWOT analysis was further developed for the comparison of pyrolysis with combustion and the results are also presented.
Abstract
Study question
Are there differentially expressed genes (DEGs), in the testicular tissue of azoospermic males which could uncover tissue specific gene expression signatures, associated with ...idiopathic azoospermia?
Summary answer
The current findings link for the first time the pathophysiology of idiopathic azoospermia to the immune system and open a new era for further investigation
What is known already
Azoospermia is the most severe form of male infertility and affects 10% of the infertile men and 1% of the general male population which equals to several million men all over the world. A causal genetic factor is established in only 25% of the cases while in the remaining 75% there is no diagnosis and is termed idiopathic. Published data demonstrate that in idiopathic azoospermia heterogeneous genetic factors are the underlying cause. Clarifying the genetic basis of azoospermia will immensely improve our current clinical and treatment approaches for patient care at the levels of diagnosis, therapy, treatment, and safety
Study design, size, duration
During June 2020 and June 2021 testicular samples from 26 consented IVF patients were included in this study. The samples were divided in 7 pools based on the presence of testicular spermatozoa found. In particular, Pools 1-3 included testicular samples with high, average and very low presence of spermatozoa, Pools 4 & 5 samples with no spermatozoa found, and Pools 6-7 included only CF carriers. Pools 6 &7 were used as controls.
Participants/materials, setting, methods
Total RNA was isolated using the RΝeasy plus universal mini kit (Qiagen) and quantified using a photometer. Next, RNA sequencing was performed by Novogene, using the Illumina NovaSeq platform and the DEGs that were identified were processed using Gene Ontology (GO) functional enrichment analysis, pathway enrichment analysis and protein-protein interaction (PPI) network reconstruction using the Gene Ontology Resource, the KEGG database and the STRING database respectively.
Main results and the role of chance
In total RNA from up to 39.664 genes was detected and significant differences in gene expression (DEGs, log2fold change≥2, p-value < 0.05) were identified in the 7 pools analyzed. The top 10% of the protein coding DEGs from each comparison was further analyzed. Up to 1.900 protein coding genes were found to be common in at least two comparisons and exhibit consistent expression profiles. In particular, 920 genes were overexpressed in the “good quality” testicular samples (high & average presence of spermatozoa) while 940 genes were overexpressed in the “low quality” testicular samples (rare or no spermatozoa found). GO analysis revealed that the sexual reproduction, male gamete generation spermatogenesis, cilium movement and fertilization biological processes were enriched in the “good quality” testicular pools while the biological processes response to stimulus, response to stress, response to cytokine and defense response were overrepresented in the “low quality” testicular samples. The PPI network of the DEGs was reconstructed and hub proteins with a putative key role in the pathogenesis of azoospermia were identified.
Limitations, reasons for caution
While transcriptomics analysis is becoming a powerful analysis tool there are still technical limitations which may impact the accurate representation of the DEGs profiles found. The data obtained in this study represent the whole testicular tissue samples analyzed and they are not cell-type specific
Wider implications of the findings
The findings of this study demonstrate that in the “low quality” testicular samples, there is a significant under-expression of testis-specific genes directly involved in spermatogenesis and fertilization processes, an over-expression of the genes involved in the body’s immune defense system and advance our understanding in the pathophysiology of idiopathic azoospermia.
Trial registration number
Τ1EDK-02787
