UBC BIOREACTOR TECHNOLOGY GROUP COMMUNITY DRIVEN BIOSOLIDS RESEARCH Dr. Cigdem Eskicioglu, P.Eng. Leader of UBC Bioreactor Technology Group Associate Professor, School of Engineering, UBC s Okanagan Campus RDCO, Governance and Services Meeting, May 14, 20155
SLUDGE/BIOSOLIDS WASTE OR RESOURCES? Accounts for 50 60% of the operation cost of treatment plant Stringent sludge reuse/disposal regulations Contains valuable organic matter The energy contained in wastewater and biosolids exceeds the energy needed for treatment by 10-fold (WERF) (http://urbanfoodproducer.blogspot.ca/2011/05/biosolids-intersection-of-public-health.html)
ONSITE SLUDGE STABILIZATION OPTIONS Biological Processes: - Anaerobic Digestion - Aerobic Digestion - Sequential Anaerobic/Aerobic Digestion - Sequential Anoxic/Aerobic Digestion - Composting Chemical Processes: - Alkaline stabilization Physical Processes: - Thermal Drying Bioreactor Technology Group Depending on digester temperature, sludge residence time, chemical dose, biosolids classify as Class A or B Biosolids or Compost
ANAEROBIC DIGESTION A bioreactor process in which anaerobic microorganisms consume biodegradable organic solids to produce methane and carbon dioxide in oxygen free environment requires heat to 35 o C or 55 o C Volume Reduction Energy Production Pathogen Removal Fertilizer Anaerobic Digester in UK (http://www.stuartmichael.co.uk/index.asp?cslincoln)
AEROBIC DIGESTION A bioreactor process in which aerobic microorganisms in sludge consume organic solids and oxygen to produce carbon dioxide in the presence of oxygen produces heat Oxygen CO 2 Municipal sludge Digestate Volume Reduction Pathogen Removal Biomass Fertilizer
AEROBIC VS. ANAEROBIC DIGESTION Advantages Anaerobic digestion (large size WWTP) Generates biogas (65-70% methane) as by-product Low energy input (no oxygen requirement) Digested biosolids are richer in nitrogen Disadvantages Complexity in operation (i.e. handling explosive gas, boilers, H 2 S, sensitive methane formers) High ammonia in digestate (>1200 mg/l); side-stream treatment needed Higher odor potential Harder to dewater digestate Aerobic digestion (small to medium size WWTP; 20,000 40,000 m 3 /d) Easy to control Lower ammonia concentrations in digestate (<500 mg/l) Less odor generation compared to anaerobic digestion Easier to dewater digestate Less capital cost No biogas production Energy intensive to supply oxygen Needs heating for cold climates ph drop as a result of nitrification (NH 3 NO 3 ) Westside Regional Wastewater Treatment Plant (WWTP) has 10,000 m 3 /d
RISKS ASSOCIATED WITH CONTAMINANTS IN BIOSOLIDS Heavy Metals: - Copper and Zinc can cause diseases (i.e. Alzheimer s and anemia) after certain concentrations - Chronic exposure to Cadmium can cause kidney dysfunction, bone fracture, hypertension - High concentration of Led can cause mutagenesis, carcinogenesis - Generally bound to soil within the surface layer (0-30 cm) and present low risk to groundwater Pathogens: - Potential disease outbreak Health risks are function of biosolids contaminant concentration (regulated by OMRR), land application rate/duration (determined by land application plan) along with soil-water partition coefficients
RISKS ASSOCIATED WITH CONTAMINANTS IN BIOSOLIDS Other substances (emerging micro-pollutants): - Surfactants [nonylphenol (NP) and their ethoxylates (NP1EO, NP2EO)] - Pesticides - Brominated flame retardants [penta-brominated BDE-99, deca BDE-209, 1,2-bis(2,4,6,-tribromophenoxy) ethane (BTBPE)] - Natural/synthetic hormones - Dioxins/furans - Pharmaceuticals and personal care products (PPCPs)[triclosan, triclocarboan] Not regulated due to lack of research demonstrating risk to humans or environment
UBC S TECHNOLOGY GROUP Harvesting energy (biogas), creating fertilizer from organic waste (i.e. biosolids, manure, kitchen waste) Waste minimization, diversion from landfills Odor monitoring and mitigation
STATE OF THE ART LAB INFRASTRUCTURE Automated fermenters with mechanical mixing, temperature control, ph, DO probes for culture growth Large capacity, temperature controlled incubators
ANALYTICAL CAPABILITIES/ SERVICES Gas chromatographs for biogas composition (i.e. CH 4, CO 2, N 2, O 2, H 2 S, mercaptans) Micro- and nano-scale Liquid chromatograph triple quadrupole mass spectrometer for emerging micro-pollutants (i.e., hormones, personal care products, drugs) particle size analyzers imaging
RESEARCH PARTNERS NSERC Strategic NSERC Collaborative NSERC ENGAGE Mitacs - City of Kelowna - BC Ministry of - Regional District of Central - Fortis BC - Opus Dayton - Fraser Valley Biogas Environment - Paradigm Okanagan Knight - Sun-Rype Other - OBWB Environmental Products - Regional Technologies - CH Four Biogas District of - BiozAgri Products Okanagan - Metro Vancouver Similkameen
RESEARCH PROBLEMS THAT WE ARE TRYING TO SOLVE - Enhancing solids destruction beyond 55% in digesters to lower biosolids volume land applied - Enhancing methane generation by co-digesting biosolids with yard waste, kitchen waste, waste from wineries/orchards - Reduction in solids residence time and digester volume (foot print) - Removal of ammonia from anaerobic digester effluents - Reduction of odour causing volatile sulfur compounds in biosolids - Fate of emerging micro-pollutants in sludge digestion processes - Human health risk assessment of pollutants in biosolids (recent)
UBC OKANAGAN & REGIONAL DISTRICT OF CENTRAL OKANAGAN (RDCO) NSERC COLLABORATIVE RESEARCH DEVELOPMENT (CRD) PARTNERSHIP
MODULE 1) LAB TESTING DIGESTERS AT BIOREACTOR TECHNOLOGY GROUP Anaerobic Biogas generation Anaerobic T ph Aerobic/Anoxic DO AIR Biosolids volume reduction Upgrade to Class A biosolids Ammonia removal Co-digestion sludge with yard waste T ph T ph Digesters will be fed waste sludge from Westside Regional WWTP Project Duration: June 2015 June 2016
MODULE 2) HEALTH RISK ASSESSMENT OF HEAVY METALS Probabilistic Health Risk Analysis was performed to asses Cd, Cu, Zn ingested through food crops grown on farm lands fertilized by biosolids 8 yrs. of historical data from Westside Regional WWTP was used Land application rate of 5-100 t/ha is assumed One-time and long term (30 years) application duration was evaluated No potential risk to the human health even at longterm biosolids land application scenario at 100 t/ha fertilizer application rate due to Cd, Cu, Zn.
Next Steps Bench-scale digester testing will start in couple of months, A group of micro-pollutants (i.e. antibiotic, pain killer, epilepsy and anti-inflammatory drugs) will be monitored in influent and effluent stream of digesters along with conventional pollutants (i.e. solids, pathogens, metals), Data gathered will be used for other human and environment risk assessment studies in the future. THANK YOU RDCO, NSERC CRD PROGRAM! THANK YOU FOR LISTENNING! For Contact Email: Cigdem.Eskicioglu@ubc.ca