Vermifiltration of Dairy Wastewater for Reuse: The Earthworm Revolution Item Type text; Electronic Thesis Authors Patton, Catherine Marie Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 28/09/2021 06:36:09 Item License http://rightsstatements.org/vocab/InC/1.0/ Link to Item http://hdl.handle.net/10150/625118 VERMIFILTRATION OF DAIRY WASTEWATER FOR REUSE: THE EARTHWORM REVOLUTION By CATHERINE MARIE PATTON ____________________ A Thesis Submitted to The Honors College In Partial Fulfillment of the Bachelors degree With Honors in Chemical Engineering THE UNIVERSITY OF ARIZONA M A Y 2 0 1 7 Approved by: ____________________________ Dr. Kimberly Ogden Department of Chemical and Environmental Engineering Acknowledgements: Thank you to Manuel Vasquez, Kimberly Ogden, Jack Garrett, and Tiffany Hawks. Special thanks to Veikko Kanto for assistance and funding with experimental design; Mary Kay Amistadi for ICP-MS testing, lab supplies, and for being the best boss; and Charly Amling for cutting an unwieldy glass vessel. You all are wonderful! Wastewater treatment is a problem of great importance to arid climates like the American Southwest, but common processes often require many treatment chemicals and high energy use. The purpose of this project was to design a process to remediate 600,000 gallons/day of wastewater from the Shamrock Dairy treatment plant in Phoenix, AZ. Vermifiltration was chosen as a chemical-free and low energy treatment process to remove BOD, COD, and TSS. A vermifiltration experiment was run confirming high contaminant removal (~85% TOC) in an 8 hour retention time. The process design included solid liquid separation, vermicomposting, cooling, and vermifiltration. A full economic and environment analysis was done, leading to the recommendation that the process be built without the solid liquid separation and vermicomposting, and that research on worm species such as the Indian Blue Worm (Perionyx excavates) be done to investigate their ability to remediate wastewater in the 25-30°C temperature range for reduced cooling requirements. With these improvements the process would be an economically sustainable and very environmentally friendly solution for remediation of dairy waste water. The main objective of this project is to design a process to treat 600,000 gallons of dairy wastewater per day. The contaminant levels are reduced to the City of Phoenix Water and Sewer wastewater disposal standard. The treated water is clean enough to dispose without incurring fines. The contaminants of concern are biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), arsenic, lead, selenium and cadmium. The wastewater treatment system consists of a solid liquid separator, a vermicompost bed and six vermifiltration beds. This process is based on vermicompost and vermifiltration research done by Sinha et al. and Kumar et al. using Red Wiggler worms (Eisenia fetida). Vermifiltration is used for the design because of its high contaminant removal and low energy requirements. The vermifiltration beds remove up to 98% of BOD, 90% of COD, 90-95% of TSS, and most heavy metals (Sinha et al.) The removal of contaminants is dependent on the hydraulic retention time (HRT). Experimentation shows 81% TOC removal for an 8-hour HRT and potential for 90% or higher removal at an 11-hour HRT (Appendix B). Energy requirements for this process mainly come from pumping and cooling. Cooling is the main contributor to energy requirements with a total duty of 13,480,000 kWh/year. The proposed process has few safety hazards, with no hazards under normal operating conditions. Hazards inherent to the system result from abnormal feed conditions or equipment failure. Equipment failure is most likely due to increased solids composition of the feed stream. This could result in safety hazards associated with clogging and pressure buildup in the units. Vermifiltration is inherently an environmentally friendly process in that it has relatively low power consumption and requires no hazardous chemicals. The main environmental impact of the process comes from the emission of carbon dioxide due to mineralization within the vermifiltration and vermicompost beds and due to power requirements for cooling. Mineralization accounts for the release of approximately 16,000 metric tons of CO2 per year. Energy use accounts for the release of approximately 563 metric tons of CO2 per year. The CO2 emissions due to mineralization could be greatly reduced with the use of a CO2 scrubber. The vermifiltration system is not economically feasible as currently designed. Further research is needed to find a species of worm suitable for use in the Phoenix, AZ. This will reduce the need for significant cooling. It is recommended that Indian Blue worms be investigated for this purpose, as they can withstand temperatures up to 35°C and have an optimum temperature range of 21-30°C. Assumptions made include the retraining of workers and that the process is added to the existing plant in its footprint. It is also assumed that the exiting storage tank and main fed line pump can be reused. Based on this model the process designed may be economically sustainable with further research. This vermifiltration system is not viable as designed with the use of Red Wigglers, but could be with further research using different species of worms. The process should exclude the solid liquid separator and vermicompost bins for cost feasibility. Kara Kanto Wrote GUI code for experiment Wrote control system code for experiment Designed and built circuits for experimental apparatuses Designed and built (and modified when needed) experimental apparatuses Preformed experiments and collected effluent samples Wrote Experimental Design (Appendix A) Contributed to BFD/PFD Contributed to Lab Report (Appendix B) Wrote lab notes Edited report Printed and bound report Catherine Patton Wrote summary Contributed to Introduction Contributed to BFD and PFD 1, created PFD 2 Contributed to ASPEN simulation, specifically inlet heat exchanger modeling Wrote Description of Process Contributed to Process Rationale Heat Exchanger design, description, optimization, and safety analysis Contributed to building experimental setup Performed experiments with group Contributed to Cost Analysis Contributed to Environmental analysis Edited report Connor Stahl Contributed to BFD Contributed to overall ASPEN simulation Cost analysis calculations Wrote economic analysis section Created stream tables Contributed to equipment table Created utility table Created CO2 emissions table and pie charts Contributed to mass balance Worked with solid-liquid separator Created Economic Analysis Appendix and Mass Balance Appendix Created Meeting Log Appendix Calliandra Stuffle Contributed to Mass Balance Contributed to Introduction Contributed to PFD 1 Contributed to Process Rationale Contributed to building experimental setup Performed experiments with group Performed lab sample prep and analysis Data analysis Wrote Lab Report - Appendix B Vermicompost design, description, optimization, and safety analysis Contributed to Environmental Conclusion 1. Introduction ...........................................................................................................................2 1.1 Overall Goal ..........................................................................................................................2 1.2 Current Market Information...................................................................................................2 1.3 Project Premises and Assumptions ........................................................................................2 2. Process Description, Rationale and Optimization ................................................................4 2.1 Block Flow Diagrams ............................................................................................................4 2.2 Process Flow Diagrams .........................................................................................................5 2.3 Equipment Tables ..................................................................................................................7 2.4 Stream Tables ........................................................................................................................9 2.5 Utility Tables ...................................................................................................................... 11 2.6 Written Description of Process ............................................................................................ 11 2.7 Rationale for Process Choice ............................................................................................... 12 3. Equipment Description, Rationale, and Optimization ....................................................... 14 3.1 Solid Liquid Separator ......................................................................................................... 14 3.2 Heat Exchangers.................................................................................................................. 14 3.3 Vermifiltration ...................................................................................................................