Grantee Research Project Results
Final Report: Photobioreactor for Hydrogen Production from Cattle Manure
EPA Grant Number: SU832485Title: Photobioreactor for Hydrogen Production from Cattle Manure
Investigators: Khandan, Nirmala , Gnaneswar, Gude Veera , Ramana, Gadhamshetty Venkata , Maganti, Anand , Smith, Geoffrey , Deng, S. , Vishwanathan, Venkat
Institution: New Mexico State University - Main Campus
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 30, 2004 through May 30, 2005
Project Amount: $9,996
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2005) RFA Text | Recipients Lists
Research Category: P3 Challenge Area - Air Quality , Pollution Prevention/Sustainable Development , P3 Awards , Sustainable and Healthy Communities
Objective:
Hydrogen is clean non-polluting energy carrier. Hydrogen if produced from renewable resources can be a sustainable alternative to traditional energy carriers. The cost of hydrogen production can be minimized if waste materials can be used as feedstock in its production. This project aims to investigate the feasibility of cattle manure as feedstock for hydrogen production. Under this research, a new 2-stage bioreactor is developed for this purpose. The first stage is anaerobic fermentation of manure, using heat treated anaerobic sludge as the seed. The second stage is photofermentation of the effluent from the first stage, using Rhodobacter sphaeroides as the seed. The first stage is an attached growth reactor while, the second is a completely mixed stirred reactor to maximize light transmission.
The deliverables of the ongoing research are a prototype reactor for hydrogen production from cattle manure; verification of the extent to which organic fraction of cattle manure can be stabilized by the proposed process; development, calibration, and validation of a mechanistic process model for proposed process; and establishment of operational and performance characteristics of the proposed system for biohydrogen production
Summary/Accomplishments (Outputs/Outcomes):
Participating students at New Mexico State University designed and fabricated a prototype bioreactor for biohydrogen production by “dry digestion” of cattle manure. Preliminary studies on this prototype confirmed that proposed 2-stage bioprocess can solubilize solid organic wastes. The following parameters were monitored during these tests: volatile fatty acids (VFA), chemical oxygen demand (COD), pH, ammonia, heterotrophic count, and fecal coliform. Evaluation methods consisted of development, calibration, and validation of a mechanistic process model for process optimization and scale-up. Key findings from this project can be summarized as follows:
- Anaerobic sludge can be enriched to solubilize organic content of cattle manure
- pH in the first stage remained below 6.0 throughout the tests indicating minimum methanogenic activity in the reactor
- Preliminary process model for first stage was able to predict well COD generation
- Identified pH and hydrogen partial pressure as key parameters essential for process optimization
Conclusions:
Cattle manure is a relatively cheap and abundant resource that can serve as feed-stock for biohydrogen production. This study evaluated the feasibility of microbial hydrogen production from cattle manure by anaerobic fermentation followed by photosynthesis in a 2-satge reactor. The proposed process can be an environmentally acceptable approach for stabilizing organic solid wastes such as cattle manure
Initial problems in reactor fabrication and operation were rectified and the prototype was refined and modified to improve the design. Preliminary tests on the prototype confirmed that the reactor is capable of solubilization of organic content of cattle manure. The experience gained from these tests has enabled us to identify and resolve some of the major technical barriers in biohydrogen production. Process optimization should take us close to final goal of continuous biohydrogen production from cattle manure.
A mathematical model for hydrolysis and anaerobic fermentation in the first stage of the reactor has been developed. This model has been calibrated and validated using experimental results from a related but separate study. Details of these modeling studies have been peer-reviewed and accepted for publication.
This was an exciting project for students and enabled students from various disciplines to participate in a real-world project that addresses sustainability, solid waste management, environment, energy, and people. This project entailed interdisciplinary work involving applied microbiology, materials engineering, process engineering, reactor development, and mechanistic process modeling, with faculty advisors from civil engineering, chemical engineering, and biology departments.
The proposed project can help advance laboratory studies reported in the literature to a near-application level system for solid waste management and biohydrogen generation. Broader impacts of this research is to develop a process for renewable hydrogen production and at the same time recover valuable energy from waste streams, that otherwise would have consumed energy for their disposal. Biological principles involved in this project have been used to develop an exercise project in a graduate level course taught by the PI in Fall 2005.
Supplemental Keywords:
Agriculture, anaerobic, energy, engineering, fermentation, modeling, renewable, sustainable development, waste treatment, photo reaction, RFA, Scientific Discipline, Sustainable Industry/Business, POLLUTION PREVENTION, Environmental Chemistry, Sustainable Environment, Energy, Technology for Sustainable Environment, Environmental Engineering, energy conservation, waste to fuel conversion, advanced oxidation process, agricultural byproducts, animal waste, hydrogen fuels, energy efficiency, energy technology, alternative energy source, renewable energyThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.