Progress Report

CICEET Progress Report for the period 9/16/05 Through 3/15/06

Project Title: Wastewater Treatment to Minimize Nutrient Delivery from Dairy Farms to Receiving Waters
Principal Investigator(s): Katharine F. Knowlton
Additional Investigator(s): Nancy G. Love and Greg M. Mullins
Project Start Date: September 1, 2003 (due to delays in receiving funding, actual start date was December 1, 2003)

Project Objectives for This Reporting Period
Objectives
The overall goal of this work is to evaluate the effectiveness of wastewater treatment strategies to alter the N:P composition for dairy waste. Objectives are:

  1. To experimentally measure the stoichiometric and kinetic parameters that have the greatest effect on model simulation of wastewater treatment of dairy manure,
  2. To use these parameters and measured wastewater characteristics to simulate EBPR with separated dairy manure,
  3. To construct, operate, and evaluate the two most promising BNR reactors to validate the model and key parameters, and
  4. To characterize nutrient runoff from soils typical of the York River watershed, following land application of dairy manure and wastewater treatment products, in collaboration with the Chesapeake Bay Virginia NERR site.

As this is the last reporting period for this project prior to the generation of the final report, the effort on all of the above objectives will be addressed.

Tasks to meet objectives
Project tasks have been rescheduled, as outlined in the revised project schedule in section III.E. below. We are currently operating the pilot plant system at the Virginia Tech Dairy Center.

The simulations were completed, and the EBPR pilot-plant system was reconfigured to operate according to the preferred condition identified by the simulator. As noted in previous reports, start up of the EBPR reactor was the limiting factor during the laboratory study, because the lab reactor was not started with biomass from an EBPR plant. We avoided the same problem with the pilot-scale system by starting with seed from an EBPR plant in North Carolina, and EBPR was achieved. The rainfall simulation plan for objective 2 was conducted.

Progress on Tasks
Task 1.1 Fermentation and wastewater analysis.
The laboratory phase of this experiment is complete.

Task 1.2 Parameter estimation.
The parameter estimation exercise is complete.

Task 1.3 Simulate optimum operating performance of EBPR system.
The model simulations are complete.

Task 1.4 Construct pilot-scale fermentor and EBPR system at Virginia Tech Dairy.
This task is complete.

Task 1.5 Operate and evaluate the pilot-scale treatment system.
Complete.

Task 2.0
Model has been run, refining it now based on data we have.

Task 3.0
Complete.

Task 4.0 Perform rainfall runoff simulation studies of both the wastewater and biosolids generated by the pilot plant system.
Complete.

Difficulties
We encountered difficulties in the operation of the laboratory-scale EBPR reactor. These difficulties related to the initiation of nitrification, which reduces the efficiency of EBPR. Many studies of EBPR on agricultural wastes in the literature add nitrification inhibitors to eliminate this potential. We did not want to add an inhibitor, because it would never be done in a full-scale facility. We implemented step feed early in the project to prevent nitrification in the bioreactor, but continued to have problems, so we adjusted the cycle times with the step feed. This eventually minimized the degree to which nitrification occurred and efficient EBPR was achieved. Once achieved, the parameter estimation experiments were reinitiated.

Another difficulty we encountered was the lack of volatile fatty acid (VFA) production potential in the pilot-plant influent. This resulted in poor P removal and we ended up investigating the reasons for this with two fermentation potential studies, which are presented in Section II. From the fermentation potential studies, we learned that the wastewater generated from fresh dairy manure used during the lab-scale system had substantially higher fermentation potential than the wastewater generated from the fresh dairy barn manure that is flushed into the full-scale treatment system and feeds the pilot-plant. We have sufficient buckets from the pilot plant study in storage to complete this study, so the manure source was changed to the material collected during the laboratory-scale study. Once the wastewater was changed, the amount of VFAs in the EBPR reactor feed increased and, shortly thereafter, the EBPR process started to work.

Project Objectives for Next Reporting Period

Objectives
All objectives are complete, except for final revisions needed in the model simulation. These will be completed in the next month, and a final report submitted in July.

Preliminary Data
Data on Dairy Wastewater Composition, lab scale reactor performance, parameter estimation, pilot scale performance, and runoff will be summarized in the final report.

Dissemination
Publications: none

Workshops: Results of this project were presented at the Virginia Tech Feed and Nutritional Management Cow College in Blacksburg, VA in January, 2005. Approximately 75 dairy industry consultants were present, and the project was well received.

Conferences: 5

Presented:
K. F. Knowlton, N. G. Love and M. Muftugil. Wastewater treatment to reduce the phosphorus content of dairy manure. pp. 129-134 In Proceedings of the Virginia Tech Cow College, Blacksburg, VA. January 2005.

Weaver, C. C., Muftugil, M. B., Kozarek, J., Wolfe, M. L., Knowlton, K. F. and Love, N. G. Utilization of a Fermentor to Support Enhanced Biological Phosphorus Removal with Dairy Wastewater. Presentation at Undergraduate Research Day, Virginia Tech, October 14, 2004.

Muftugil, M. B., Love, N. G. and Knowlton, K. F. Using Enhanced Biological Phosphorus Removal (EBPR) to Alter the Nitrogen:Phosphorus Ratio of Dairy Manure and to Minimize Nutrient Delivery to Receiving Waters. Presentation at Innovative Uses of Agricultural Animal Manure, Biosolids and Paper Mill Residuals, June 29 ­ July 1, 2005 Omni Chicago Hotel, Chicago, Illinois USA.

Muftugil, M. B., Love, N. G. and Knowlton, K. F. Using Enhanced Biological Phosphorus Removal to Minimize Nutrient Delivery from Dairy Farms to Receiving Streams. Submitted to the Virginia Water Environment Association/American Waterworks Association Joint Annual Meeting, Virginia Beach, Virginia, September 2005.

Muftugil, M. B., Love, N. G. and Knowlton, K. F. Using Enhanced Biological Phosphorus Removal to Minimize Nutrient Delivery from Dairy Farms to Receiving Streams. Submitted to the Water Environment Federation WEFTEC 2005, Washington DC, October 2005.

Manuals, Protocols: None
Outreach Activities: See workshop description above.
Contact with End Users: See workshop description above.
Patent, Copyright, Invention Disclosure Activity: none

Expenditures
All funds are expended.