Progress 10/01/03 to 09/30/06

Outputs
A pilot plant was installed and operated at a dairy/ farm in Waianae, Hawaii in August, 2004. It includes and anaerobic Bio-nest process and an aerobic EMMC (Entrapped Mixed Microbial Cell) - Biobarred process. After one year investigation, the design and operational criteria for various strength of milk parlor wastewater and level of target effluent TCOD (Total Chemical Oxygen Demand) have been developed. The integrated bioreactor of two-stage anaerobic Bio-nest (HRT of 15 hours) and EMMC-Biobarred (HRT of 12 hours) is proposed for medium strength wastewater (TCOD ~3,800 mg/l after the primary settling tank) treatment with treated wastewater for reuse. Accordingly, the treatment cost of $1.1 per 1000 gallon (3.8 m3) of wastewater or about $91 for each ton weight of TCOD removal is estimated for this option. At this level of cost, it is considered as an economic alternative for the milk parlor wastewater treatment/ reuse among the existing technologies. This is especially suitable for the land limited condition. Also, it was concluded from the development of a pseudo-steady model for the anaerobic Bio-nest reactor for the treatment of milk parlor wastewater, the medium influent concentration range TCOD of 4g/L-7g/L provides a very stable process performance regarding the wastewater clean up and bioenergy utilization based on the economic consideration. However, a long term operation behavior for this pilot plant and the economic evaluation for the various alternatives including the direct treatment of diluted milk parlor wastewater are under investigation now.

Impacts
In the U. S., lagoon/ pond system is one of the most dairy wastewater treatments because it costs less to construct and can be simply operated and maintained. However, it still has many problems to meet the more strict environmental regulations. Especially, when the intensifying livestock operation is practiced under the land limited condition. Success of this research project will provide an appropriate cost-effective pretreatment unit process for potential reuse of treated wastewater for flusing the dairy operational facilities and for possible recovery of bioenergy (as methane gas) for the on-farm energy use. Ultimately, it will make a great contribution for the sustainable agriculture with sound environment protection.

Publications

• Kongsil P. (2006). Engineering and economic evaluation of innovative bioreactor for milk parlor wastewater treatment/ reuse. MS Thesis, University of Hawaii at Manoa, 215pp.
• Cho, E. S., Kongsil, P, and Yang, P. Y. (2006). Alternative technology for milk parlor wastewater treatment/ reuse. Presented at Hawaii Water Environment Association, 28th Annual Conference, February 9-10 2006, Honolulu, Hawaii.
• Cho, E. S., Kongsil, P. and Yang, P. Y. (2006). Development of a land limited dairy wastewater treatment/ reuse by integrating biological pretreatment alternatives to the existing lagoon/ pond system. Presented at 7th IWA specialist conference of waste stabilization ponds, September 25-27, 2006, Bangkok, Thailand.

Progress 10/01/04 to 09/30/05

Outputs
A pilot plant for treating milk parlor wastewater and reuse was constructed and operated in February 2005. It consists of a primary settling/equalization tank (12m3), two anaerobic tanks (10m3 each), an intermediate holding tank (5m3) and an aerobic tank (5m3). In spite of many natural causes for the delay of starting up of the treatment system, the system is still able to be investigated for the process performance of various HRT's (Hydraulic Retention Time) applied between 20 and 50 hrs. Based on the result for this period of the operation/investigation, the average removal of TCOD (Total Chemical Oxygen Demand) and SCOD (Soluble Chemical Oxygen Demand) for anaerobic Bio-nest process are 75% and 60%, respectively. For the aerobic EMMC process (operated at HRT of 12 h), the average removals for TCOD, SCOD and TN (Total Nitrogen) are 55%, 25%, and 25%, respectively. The biogas production rate for the anaerobic Bio-nest process is about 0.2-0.5 l/l/d with about 70% methane content. Necessary development of design and operation criteria with economic analysis for this pilot plant is still in progress. In order to assist and predict the design and operation of the anaerobic Bio-nest process, a modified pseudo-steady state model was developed. This will assist us to determine the suitable input TCOD concentration for the wastewater clean-up and bioenergy utilization based on the economic consideration. Also, a long term operation behavior for the pilot plant and the EMMC technology for the treatment raw and anaerobically treated milk parlor wastewater at the laboratory scale are under investigation now.

Impacts
Currently, most of dairy producers and other animal producers are using the anaerobic lagoon system to manage their wastewater. Because of many problems of operating the lagoon system for animal wastewater management, especially, for the concentrated animal feeding operation (CAFOs), the alternative of animal wastewater management needs to be developed. In order to relieve the current improper management of the lagoon system, this pilot plant study is designed to be integrated with existing lagoon system for wastewater treatment and utilization (gas for energy, treated water for reuse/irrigation and digested study for soil conditioners/fertilizer). Success of this research will make a great contribution to sustainable agriculture with sound environment protection. The animal producers will be able to co-exist with neighbors peacefully.

Publications

• Cho, E.S., Kongsil, P. and Yang, P.Y. 2005. Engineering an innovative bioreactor with existing lagoon system for dairy wastewater treatment/reuse - A case pilot plant study. Presented at the Symposium on the State of the Science: Animal Manure and Waste Management, January 5-7, 2005, San Antonio, Texas.

Progress 10/01/03 to 09/30/04

Outputs
Field Investigation: A field investigation was done in November 2003. Three dairy farms and their waste management systems were investigated and evaluated. The main problems are undersized pond system, which causes poor quality of effluent, groundwater pollution, polluted runoff, and odor generation. Installing a proper biological pretreatment is essential to solve these problems. In this project, the proposed location was discussed with Mountain View Dairy in January, 2004, and decided in April. Reactor System: A pilot plant will consist of a primary settling/equalization tank, two anaerobic tanks, an intermediate holding tank and an aerobic tank. The primary settling/equalization tank of 16.7 m3 is used to overcome the operational problems and to improve the performance of the downstream process by pre-removal of high solids concentration and reduction of shock loading caused by variations in the influent wastewater strength. Construction is under going in the field. Two anaerobic tanks are made of isophthalic polyester (Harrington Industrial Plastics LLC). Each tank has a volume of 10 m3 with a 182.9 cm inside diameter and 381 cm depth. The water volume of each tank is about 8.4 m3. On the top of each reactor, there is a vent for gas collection and a safety valve. Two gas meters (Measurement Control Systems, AM-250) are installed to measure the biogas from each Bio-nest anaerobic tank. For the intermediate holding tank, the dome vertical tank of 1.89 m3 (Mr. Sandman, Inc., Model#JS-120) is 119.38 cm inside diameter and 182.88 cm depth. It is placed between the second Bio-nest tank and the aerobic EMMC tank. The part of effluent suspended solids from the Bio-nest tank will be removed in this intermediate tank before going to the aerobic EMMC tank. The EMMC tank of 3.8 m3 (sandman #TC7272IA) will be fabricated with 30% packing ratio of EMMC carriers. Making the EMMC carrier is under going. Start-up and operation of anaerobic Bio-nest system: Two anaerobic Bio-nest tanks were seeded with the anaerobic sludge taken from an anaerobic digester at Hawaii-American Water Company in Honolulu, Hawaii. The Bio-nest reactors were allowed to acclimate at ambient temperature without feeding for about 2 weeks and then wastewater of about 3.8 m3 was fed in an upflow pattern to the Bio-nest reactors twice in a week, corresponding to about a HRT of 15 days. All the reactors started to produce biogas with organic removal. No data or results are available at this time due to uncompleted installation of pilot plant.

Impacts
Success of this research will make a great contribution to sustainable agriculture with environment protection, achievement of economic prosperity, the improvement of a high quality of human society. Environmental effects: Improper management of dairy wastewater can be significant cause for surface water impairment, air pollution and groundwater contamination. The development of integration system of two anaerobic Bio-nest reactors and an aerobic EMMC reactor will improve water quality with reduction of runoff pollutant, contamination of groundwater. Furthermore, the potential for water quality degradation from nitrogen and oxygen consumption can be reduced through the aerobic EMMC treatment applied. This system can also improve air quality by removing ammonia. Much of odor is due to high levels of ammonia causing the negative impact with respect to acid rain and the formation of airborne particles of NH4NO3 that contribute to the PM10s. Sociological benefits: Sustainable agriculture appears to be important means due to increased public awareness. The application of this project will reduce environmental degradation and protect environmental health by providing proper wastewater treatment. The public benefit by reducing the transport of pollutions and pathogens from farms. Economical effects: since stringent requirements are imposing added cost on the animal farmers, the integration system of this project which is land limited, simple and cost effective process will provide farmers benefits by reducing disposal problem.

Publications

• No publications reported this period

Progress 10/01/02 to 09/30/03

Outputs
No progress to report. This project was initiated on October 1, 2003.

Impacts
No impact to report. This project was initiated on October 1, 2003.

Publications

• No publications reported this period