Treatment of High Strength Vegetable Processing Wastewater with a Sequencing Batch Reactor

The feasibility of an aerobic sequencing batch reactor was studied at the lab scale to treat the high organic loading present in two vegetable processing wastewaters. Hydraulic retention time (HRT) was varied to evaluate its effect on the removal efficiency of chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TP). The results showed that a longer HRT promoted the removal of TP, while the liquid drawn per cycle had a larger effect on the COD removal efficiency. An increase in the COD/TKN and TKN/TP ratio decreased the removal efficiency of TKN and TP respectively. The optimized configuration was able to reduce the wastewater loadings to acceptable sewer discharge limits, making it possible eliminate the sewer surcharge fees

The Development of Technology-supported Approaches to the LO Process for Accredited Engineering Programs

Tracking graduate outcomes is a new requirement for engineering education in Canada.  Working closely with curriculum developers and educational technologists, the School of Engineering at the University of Guelph has shown it is possible to put in place an effective process.  The process requires engaged participants, an open-mindedness and integrated technologies to collect and report the data.  Combining people, process and technology provides a way for data analysis to satisfy accreditation requirements and internal quality education metrics.  This paper describes the approach taken and identifies strengths, challenges, and opportunities to be successful, and support the ultimate goal of curriculum improvement

Determining a Bioventing Scale-Up Factor

Bioventing is an increasingly popular means of removing hazardous petroleum products from sites contaminated by industry and underground gasoline storage tanks. A mesoscale bioventing reactor system was used to determine the rate of bioremediation and compared to previous work completed on smaller scale reactors. Ten 4kg reactors with two different soil types were spiked with synthetic gasoline to an initial concentration of 4000mg/kg soil. Vacuum was then applied at a rate of 1mL/min, with sufficient water levels monitored and maintained to induce bioventing conditions. Gas chromatography was used to determine concentrations of synthetic gasoline in soil every two days for each soil type. Results indicate a smaller scale up factor for sandy soils (Delhi), than for clayey soils (Elora). Furthermore it was observed that slower decay rates exist as reactor size increases, suggesting that conservative estimates are needed when transferring lab results to the field

Hybrid Treatment System to Remove Micromolecular SMPs from Fruit Wastewater Treated with an MBR

Fruit processors want to reduce their environmental footprint by implementing the recycling of treated wastewater. Observations of a membrane bioreactor (MBR) and reverse osmosis (RO) system showed that the RO quickly fouled due to elevated levels of soluble microbial products (SMPs), an inert micromolecular composition in the form of dissolved organic matter (DOM) in the MBR effluent. Bench scale experiments were completed using enhanced coagulation and granular activated carbon sorption. Results showed that enhanced coagulation removed only 20% of the DOM, which was insufficient to protect the RO membrane. However, sorption studies with GAC showed that 98% of the dissolved SMP-DOM could be removed, the fraction of DOM from microbial activities. Results also showed that when enhanced coagulation preceded the sorption stage, GAC column run time could be extended by about 15%. The resulting BMP minimizes RO membrane fouling in the agri-food sector and opens further water recycling opportunities.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Large Scale Bioventing Degradation Rates of Petroleum Hydrocarbons and Determination of Scale-up Factors

Bioventing is a cutting edge, non-destructive treatment method that uses indigenous soil microorganisms in-situ to remediate petroleum hydrocarbons in the unsaturated soil zone. Transferring the application of this technology to a field environment still has some uncertainties due to scale-up challenges. In order to identify the scale-up factor, a 80 kg soil reactor system was developed, consisting of a custom made reactor, climate chamber, low flow venting system and an off gas capture device. Sandy and clayey soils were tested with known concentrations of spiked synthetic gasoline. Various environmental conditions were monitored which included: moisture levels, pH, microbial levels, nutrient and oxygen levels. Results show a second stage degradation rate similar to the degradation rate obtained from research conducted with a 4 kg reactor, giving an average scale-up factor of 2.3±0.4. The completed research shows that working with a 80 kg laboratory reactor is feasible, yet not always necessary for the development of scale-up factors. A complimentary study with aged soil contaminants was preformed and yielded degradation rates that were significantly reduced

Developing a Robust Bioventing Model

Bioventing is a widely recognized technique for the remediation of petroleum hydrocarbon-contaminated soil. In this study, the objective was to identify an optimal mathematical model that balances accuracy and ease of implementation. A comprehensive review of various models developed for bioventing was conducted wherein the advantages and disadvantages of each model were evaluated and compared regarding the different numerical methods used to solve relevant bioventing equations. After investigating the various assumptions and methods from the literature, an improved foundational bioventing model was developed that characterizes gas flow in unsaturated zones where water and non-aqueous phase liquid (NAPL) are present and immobile, accounting for interphase mass transfer and biodegradation, incorporating soil properties through a rate constant correlation. The proposed model was solved using the finite volume method in OpenFOAM, an independent dimensional open-source coding toolbox. The preliminary simulation results of a simple case indicate good agreement with the exact analytical solution of the same equations. This improved bioventing model has the potential to enhance predictions of the remediation process and support the development of efficient remediation strategies for petroleum hydrocarbon-contaminated soil

FRUIT AND VEGETABLE WASH-WATER CHARACTERIZATION, TREATMENT FEASIBILITY STUDY AND DECISION MATRICES

On average, it is estimated that up to 5 liters of wastewater is generated per kg of produce in post-harvest processing of fruit, leafy greens and root vegetables. The typical wastewater parameters vary in concentration (solids content, COD, BOD, nitrogen, phosphorus) based on the produce being processed. The challenge for producers and regulators is that the selection of the appropriate treatment technology is challenging, so decision matrices were developed to narrow down the treatment selections. Wash-waters for different types of fruit and vegetables from two different operation types, washing only vs. washing and processing. Bench-scale treatments selected for testing included settling, coagulation and flocculation with settling, centrifuge, dissolved air flotation, electrocoagulation, screening, and hydrocyclone. The developed decision matrices summarize the removal effectiveness of the different treatments for typical wastewater parameters and serve as a reference tool in understanding wash-water treatment technologies and their effectiveness in treating various wash-waters

Fruit and vegetable wash-water characterization, treatment feasibility study and decision matrices

On average, it is estimated that up to 5 liters of wastewater is generated per kg of produce in post-harvest processing of fruit, leafy greens and root vegetables. The typical wastewater parameters vary in concentration (solids content, COD, BOD, nitrogen, phosphorus) based on the produce being processed. The challenge for producers and regulators is that the selection of the appropriate treatment technology is challenging, so decision matrices were developed to narrow down the treatment selections. Wash-waters for different types of fruit and vegetables from two different operation types, washing only vs. washing and processing. Bench-scale treatments selected for testing included settling, coagulation and flocculation with settling, centrifuge, dissolved air flotation, electrocoagulation, screening, and hydrocyclone. The developed decision matrices summarize the removal effectiveness of the different treatments for typical wastewater parameters and serve as a reference tool in understanding wash-water treatment technologies and their effectiveness in treating various wash-waters.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author