Enzym zymatic atic pret etre reatm atment nt of organ anic - PowerPoint PPT Presentation

Enzym zymatic atic pret etre reatm atment nt of organ anic ic residu dual al solids ds for anaer erobic bic digesti stion on Maria ia Ramos s Suar arez ez Dr. D. Puri and Dr. S. Heaven @MariaRSuarez M.Ramos-Suarez@soton.ac.uk

UK Statistics on Waste (2018), Department for Environment, Food & Rural Affairs

CH 4 ORS Biorefinery 18,700 tonnes products -2,240,000£ 3

Anaerobic digestion H 2 CO 2 NH 3 NH 4 Alcohols H 2 S SOLUBLE WASTE Carbonic MOLECULES -Carbohydrates acids -Sugars CH 4 -Proteins -Amino acids CO 2 -Lipids Volatile fatty -Fatty acids acids Acetic acid Hydrolysis Methanogenesis Acidogenic fermentation

Anaerobic digestion Advantages Drawbacks cks • • Mature technology CH4 global warming potential • = 23x CO 2 potential Single end-product • • Reactor instability In situ product recovery • • Econ onomica omically y unfe feasib sible Absence of product inhibition without subsidies (0.4 €/kg ) • Thermodynamically favourable • Mild conditions -> environmentally friendly. Acidogenic fermentation PHAs 2.0€/kg Organic Lipids for VFAs Matter biodiesel Microbial fuel cells Biogas 0.4 €/ kg Faster process – more economic!

ORS composition

Pretreatments Chemical mical Physica ical Oxydative reactions: Ozonation, alkali and Thermal treatments, microwaves, acid pretreatments, etc. ultrasound, etc. Effective Effective Toxic compounds generation/expensive High energy consumption/expensive Biological ogical Use of biological agents such as microorganisms or enzym ymes es Effective/Environmentally friendly Complex treatment (specific to substrate) Economic solution

Pretreatment – batch experiemnts 5% enzyme loading, 17h at 50°C, 1.6% TS Complex A: cellulase/β -glucosidase/hemicellulase Complex B: cellulase/β -glucanase/hemicellulase /xylanase/arabinase

Pretreatment – batch experiemnts 17h at 50°C, 0.2% TS

Pretreatment prior to AD 5% enzyme loading 50°C for 24h, 6.8% TS

Semi continuous AD HRT=14 days OLR=3.5 g VS/L day Enzyme AD pretreatment + AD Cost of landfill (£/tonne ORS) 107.00 88.72 Cost of enzyme (£/tonne ORS) 0.00 40.21 Benefits from CH4 (£/tonne ORS) 11.63 13.71 - 95.37 -115.22 Balance (£/tonne ORS)

Conclusions Enzym ymat atic ic Under er the ORS coul uld d be pret etreat eatme ment nt tested ed better er suit ited ed for with h condit ditions ions, , AD + a VFA factor ory carbohydr ohydrase ases enzym ymatic atic compl plex ex pret etreat eatme ment nt is impr prov oved ed not an methane ane yiel eld d economic nomic by 18% solution ion Future work Influence ence of pH DOE for Dewater erab abil ilit ity y and other er enzym ymatic atic tests and variab iables es on pret etreat eatme ment nt separ aration ation VFA produ oduct ction ion and subseq equent ent methods ods acido dogenic genic ferment entation ation