9th World Convention on Recycling and Waste Management October 22-23, 2018 Osaka, Japan

Adina Anghelescu-Hakala is a Senior Research Scientist at VTT Technical Research Centre of Finland and has a 26-year extensive expertise in polymer chemistry.She has obtained her PhD in Polymer Chemistry in 2001 from Technical University “Gheorghe Asachi” Iasi, Romania. After completing PhD, she worked as a PostdoctoralResearcher at University of Helsinki, Laboratory of Polymer Chemistry and as a Principal Scientist at “Petru Poni” Institute of Macromolecular Chemistry,Bioactive and Biocompatible Polymers Department, Iasi, Romania. She has received Ecoinvent Award in 2003, Iasi, Romania. She has 53 peer-reviewedpublications (28 in journal articles and 25 in conference proceedings), 10 patents, 2 patent applications and 12 invention disclosures. Her main competence areasare natural and synthetic polymers for ecological applications including treatment of waste water and water treatment chemicals, natural and synthetic polymers for biomedical applications, stimuli-responsive nanomaterials, controlled radical polymerization techniques and chemical modifi cation of biopolymers.

Statement of the Problem: Biodegradable polymers are potential solutions to the environmental problems generated by plastic waste. Every year, 8 million tons of new plastics are dumped into oceans. With growing market volumes of innovative bio-based and biodegradable plastics such as Poly(Lactic Acid (PLA), the recycling of these materials is becoming a more viable option. PLA has attracted particular attention as a substitute for conventional petroleum-based plastics. To increase sustainability and management of plastic waste, new methods to close the recycling loop of PLA are needed. Recycling approaches have limitations in that materials can only undergo a fi nite number of processing cycles before their properties are deteriorated. Production of PLA from recycled components allows substantial energy savings compared to using virgin raw materials.

Methodology: PLA depolymerization by hydrolysis leads to production of high quality LA which can be used to reproduce PLA polymers. This avoids the expensive and complex process of glucose fermentation, which is used to obtain virgin Lactic Acid (LA). In this work, combined chemical and biochemical methods for PLA depolymerization to high value and quality components are developed. Th e hydrolyzed PLA products were characterized by: (1) GC/MS: Evaluation of monomeric and oligomeric content; (2) Chiral GC: Evaluation of D and L-LA enantiomers content; and (3) SEC: Calculation of molecular weight and molecular weights distribution.

Findings: Th e PLA hydrolysis proceeds with higher rates in alkaline conditions with formation of LA monomer without changes in the original composition of D, L isomers. Acidic hydrolysis of PLA produces a mixture of monomeric and oligomeric forms and their composition depends on the reaction conditions.

Conclusion: By alkaline hydrolysis of PLA, LA monomer can be produced and repolymerized aft er conversion in acid form. By hydrolysis of PLA in acidic conditions, oligomeric precursors suitable for further biochemical/enzymatic depolymerization can be produced

Christian J Engelsen is a Senior Scientist at SINTEF. His research fi eld of interest is in processing and treatment of various waste types, integration of mineral waste into cementitious systems, technical and environmental performance. He is a Specialist in metal and CO2 binding mechanisms to cementitious systems and materials effect on drinking water. He has 20 years of experience with treatment and recycling of construction and demolition waste and is currently leading an Indo-Norwegian institutional cooperation between Central Public Works Department (Ministry of Housing and Urban Affairs) and SINTEF. He has published more than 90 scientifi c papers in journals, book chapters, conference proceedings and technical reports. He has managed or has been key scientific  personnel in more than 150 contract research projects.

Statement of the Problem: Construction and Demolition waste (C&D waste) is one of the biggest waste streams in most countries. The heavy inorganic part (from concrete and masonry) could be processed and refined into recycled aggregates. This type of aggregates could substitute natural aggregates in a range of user applications like road construction, landscaping and concrete production. This will save natural resources, decrease transportation, reduce landfi lling and bind CO2 through increased

carbonation. The purpose of the study is to calculate the binding potential in the Indian concrete.

 

Methodology & Theoretical Orientation: Carbonation of concrete

normally occurs when air or water-borne CO2 dissolves in the concrete pore water and react with Ca2+ to form stable CaCO3. Upon carbonation, the pH of the concrete pore water is decreased

to around 9. Carbonation mainly involves decalcifi cation of the Ca-bearing hydrate phases when diff erent polymorphs of CaCO3 are formed. In addition, the Mg-bearing hydrate phases (OH-hydrotalcite and CO3-hydrotalcite) will also carbonate by

forming MgCO3 and Al(OH)3.

 

Findings: Applying the cement chemistry of the hydrate phases, a realistic binding of 200 kg CO2/ton cement has been calculated for Indian concrete. It has been assumed an average clinker factor of 0.75. Furthermore, accounting for a total annual Indian cement consumption of 300 million tons, the emission during cement production is 180 million tons, i.e. 600 kg CO2/ton cement. Due to carbonation, 10-20% of the emission are re-absorbed in service life, i.e. the remaining binding potential is around 18-36 million tons. If 10% of the cement consumed in concrete is recycled, minimum 5 million tons of CO2 may potentially be bound due to the recycling.

 

Conclusion & Significance: Th e binding of CO2 to concrete materials due to carbonation is signifi cant. Th e CO2 binding

potential can be further utilized by recycling of C&D waste.

Min-Hao Yuan has received his PhD in Environmental Engineering from National Taiwan University in 2011. He has also been trained from the leading universities in Japan, University of Tokyo and Tokyo Institute of Technology and the University of Michigan-Ann Arbor, USA. He was also awarded several merit-based fellowships from Taiwan, Japan and USA. He is currently working as an Assistant Professor in Department of Occupational Safety and Health, China Medical University. His research focus is about green technology and safety science with a wide range of green technology, cleaner production and safety engineering for sustainable energy industries and pollution prevention.

Since the more stringent regulations on ammonia for industrial wastewater has implemented, recovery of ammonia from ammonia-rich wastewater has attracted much attention because of the idea of a circular economy. For example, the practice of semiconductor industry by using membrane distillation has generated solution of ammonium sulfate ((NH4)2SO4) more than 2000 tons/month by a company. However, (NH4)2SO4 can be re-used for only industrial propose, resulting in shortcoming in their circular economy route. Th is study employs vacuum stripping using a Rotating Packed Bed (RPB) to recover ammonia from ammonium sulfate wastewater into a high quality of anhydrous ammonia (Anhydrous NH3) and sodium sulfate (NaSO4), which both anhydrous NH3 and NaSO4 have a wide variety of industrial uses. Th e results showed that the required operation time to achieve removal effi ciency above 90% and concentration of NH4-N below 5000 ppm has been reduced from 12 to 8.3 h at the initial condition of 2000 L/day (2.08 tons/day) and initial NH4-N concentration of 60,000-70,000 ppm, temperature of 55 °C and pH>13. Th erefore, this study provides a new pathway for circular economy solutions for high-quality ammonium products recovered from the ammonia-rich industrial wastewater.