RESEARCH INTERESTS
My research interest is in “organic waste-to-resource recycling via bioconversion processes” within the field of Environmental Engineering. The research projects may be sub-divided into several bioenvironmental engineering processes and systems, with the multiple purposes of resource recovery and protection of soil, water and air quality. Composting and anaerobic digestion are now commonly used to recycle agricultural and municipal wastes. Research efforts are required to balance the preference to return nutrients in the residues to soils while making the feedstock available for renewable energy.
Anaerobic fermentation for bioenergy production
The reduction of greenhouse gas emissions and lessening our reliance on dwindling non-renewable fossil fuel reserves requires the development of sustainably produced alternate fuels without compromising food supplies. One possibility is to develop a process to convert the agri-food wastes (potential important sources of pentose and hexose sugars as carbohydrate substrate) to hydrogen, a mobile energy supply and a likely future energy carrier. Hydrogen can be used efficiently and sustainably for combined heat and power generation in fuel cells; it has higher energy conversion efficiency and potentially lower carbon footprint when compared to methane. The research aims at investigating techniques to increase the hydrogen production rate during anaerobic fermentation. The objectives are to determine the best pretreatment techniques (thermal, microwave or chemical) for seed sludge and substrate, which can inhibit methane forming bacteria; to control and optimize the operational parameters with an aim to select for hydrogen-producing microorganisms and hence achieve process optimization; to increase hydrogen production rate via using continuous fermentation process in various types of bioreactors; and to use membrane technology for minimizing the accumulation of inhibitory metabolic products and purifying the biogas. Another research project concerns the development of a worksheet-based calculator for anaerobic fermentation of agri-food wastes, and comprises of technology options and engineering economics as the main components. The anticipated software product would allow for the evaluation of emerging technologies aside from well-established ones. The goal is to recommend a viable anaerobic fermentation system for the production and utilization of bioenergy and the digestate.
Composting and biofertilizer production
Reducing air emissions (mainly ammonia, odors and volatile organic compounds) from composting and enhancing compost quality for improved marketability remain to be the major challenges facing the composting industry today. Research is focused on the reduction of these emissions, and the production of a value-added compost/biofertilizer. Preventive means are used for reducing the odor and ammonia emissions during the active phase of composting, while maximizing nitrogen retention in the finished product. This would help to reduce the footprint required for odor treatment via biofiltration. One method is to form struvite and other crystals that have low solubility in water and hence constitute slow-release inorganic ingredients in the finished compost. Another method is to use chemical and biological additives in the form of specialized yeast strains, zeolite or alum for biodegrading odors and VOCs and adsorbing ammonia. The finished compost may go through further downstream processing such as densification (via granulating or pelletizing) and blending with other organic ingredients so as to improve its marketability. Another research project pertains to the compostability of controlled-microstructure biodegradable polymers.
Odor monitoring and biofiltration for odor control
In the research project, odor concentration as a composite indicator of odor strength is determined via olfactometry and odor panel tests. This odor sensory method remains the most valid for odor evaluation today along with GC/MS techniques, while electronic nose techniques have yet to be developed for complex odors such as those emitting from composting facilities, farms, landfills and wastewater treatment plants. A dynamic dilution olfactometer has been assembled in our laboratory, which is in compliance with international standard in regard to quality requirements for the olfactometer and performance, odor panel procedure and data analysis. Accurate odor emission measurements and subsequent dispersion modeling would enable the best management practices to be devised using integrated preventive and control measures for different agricultural and industrial operations. Research on odor control has been focused on the biofiltration technology as applied to composting, pulp mill and farm odors in recent years.
RECENT SELECTED PUBLICATIONS
- Won, S.G. and A.K. Lau.2008. Feasibility of anaerobic fermentation of dairy wastewater and sucrose-rich wastewater for biological hydrogen production. Proceedings 6th ORBIT International Conference, Wageningen, the Netherlands, October 13-15.
- Lau, A.K., W.W. Cheuk and K.V. Lo. 2008. Degradation of greenhouse twines derived from natural fibers and biodegradable polymer during composting. In press, J. Environ. Manage. DOI: 10.1016/j.jenvman.2008.03.001
- Lau, A.K., S. Bittman and D. Hunt. 2008. Development of ammonia emission factors for the land application of poultry manure in the Lower Fraser Valley of British Columbia. In press, Can. Biosys. Eng.
- Zhang, W. and A.K. Lau. 2007. Reducing ammonia emission from poultry manure composting via struvite formation. J. Chem. Technol. and Biotechnol. 82(6): 598-602.
- Lau, A.K. and K. Cheng. 2007. Removal of odor using biofilter from duck confinement buildings. J. Environ. Sci. Health Part A. 42(7): 955-960.
- Zhang, W., A.K. Lau and Z.P. Wen. 2008. Preventive control of odor emissions through manipulation of operational parameters during the active phase of composting. Accepted for publication in J. Environ. Sci Health Part B – Pesticides, Food Contaminants and Agric. Wastes.
- Lemus, G.R., A.K. Lau, R.M.R. Branion and K.V. Lo. 2004. Bench-scale study of the biodegradation of grease trap sludge with yard trimmings or synthetic food waste via composting. J. Environ. Eng. Sci. 3: 485-494.
- Shelford, T., A.K. Lau, D.L. Ehret and S.T. Chieng. 2004. Comparison of a new plant-based irrigation control method for with light-based irrigation control for greenhouse tomato production. Can. Biosys. Eng. 46: 1.1-1.6.
- Lau, A.K., S. Bittman and G.R. Lemus. 2003. Odor measurements for manure spreading using a sub-surface deposition applicator. J. Environ. Sci. Health B38 (2): 233-240.
- Pang, S.F., A. Chu, A. Lui, S. Li and A.K. Lau. 2003. A contemporary eco-fertilizer with promising benefits. Supplement to Nature 426 (6968): 2 pp.
- Zhang, W. and A.K. Lau. 2008. Effects of bioadditive on the thermal performance, odor emissions and compost quality for poultry manure composting. Acceptable for publication in Int. J. Env. Waste Manage. subject to revisions.
- Ra, C.S. and A.K. Lau. Swine wastewater treatment using submerged biofilm SBR process: Enhancement of performance by internal circulation through sand filter. Manuscript submitted to Water Research. (2008)
- Lau, A.K., S. Bittman, D. Hunt and M. Wong. Ammonia emission from land-applied poultry manure on grassland. Manuscript submitted to Soil Wat. Air Pollution. (2008)
- Fraser, B.S., A.K. Lau, T. Forge and K. Paisley. 2004. Co-composting of biosolids and poultry manure at the District of Kent wastewater treatment plant. B.C. Water & Waste Association Annual Conference, May 3-6, Whistler, BC.
- Lau, A.K., S. Bittman, A. Black, and L. van Vliet. 2004. Reduction of GHG emissions for dairy production and poultry manure composting systems and its impact on agricultural sustainability. Final workshop on “Greenhouse Gas Emissions from Canadian Agriculture” of the Climate Change Funding Initiative in Agriculture, Jan 19-20, Winnipeg, MB.
OTHER AFFILIATIONS/MEMBERSHIPS
- American Society of Agricultural and Biological Engineers/Canadian Society for Biological Engineering
- Composting Council of Canada
- Water Environment Federation/British Columbia Water and Waste Association
TEACHING
- CHBE 362/363 - Chemical/Process Engineering Laboratory
- CHBE 459 - Chemical and Biological Engineering Economics
- CHBE 480 - Hazardous Waste Processing Technology
- APSC 262 - Technology and Society II
