|Pan, Zhongli - John|
Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2003
Publication Date: 1/1/2004
Citation: Zhang, R., Yang, P., Pan, Z., Wolf, T., Turnbull, J. 2004. Treatment of Swine Wastewater with Biological Conversion, Filtration, and Reverse Osmosis - A Laboratory Study. Transactions of the ASAE. 47(1):243-250 Interpretive Summary: Waste management is a major challenge for every animal feeding operation. Nearly 40% of feed dry matter and up to 70% of nutrients fed to the animals is excreted in manure, and increasingly significant amounts of labor and capital are being invested in efforts to better manage this organic material. Liquid manure handling and storage systems are commonly used on livestock farms. Most of the water used on livestock farms and later added into the manure system is originated from building and equipment washing activities. In the areas where water resources are limited and/or disposal of a large quantity of wastewater is problematic; reclamation of clean water from animal wastewater may become necessary. Production of biogas as fuel and nutrient-rich liquid as fertilizer products at the same time of achieving water reclamation will help with the economics of wastewater treatment. The overall goal of this research was to develop an energy efficient, integrated animal wastewater treatment system for water reclamation as well as biogas and organic fertilizer production. The objective was to investigate the technical feasibility of combining biological treatment processes (anaerobic digestion and aerobic treatment), sand filtration and reverse osmosis membrane separation in one treatment system.
Technical Abstract: An integrated wastewater treatment system was studied in the laboratory for treatment of swine wastewater to achieve energy recovery, fertilizer production, and water reclamation. The system consisted of one Anaerobic Sequencing Batch Reactor (ASBR), one or two aerobic Sequencing Batch Reactors (SBR1 and SBR2), one sludge settling tank, one sand filter, and one reverse osmosis (RO) unit. The system was tested with swine wastewater of about 15,000 mg/L VS. The COD and solids in the wastewater were reduced by 89-97% and total coliforms and E coli were reduced by 1 log CFU after treatment with ASBR and SBRs. The nitrogen in oxidized forms (NO2-N and NO3-N) was 14% or 53% of total nitrogen in the wastewater after it passed through SBR1 or SBR1 and SBR2, respectively. The sand filter was used to further reduce the COD and solids, especially suspended solids, prior to RO treatment. Two types of spiral wound RO membranes were tested and compared. The RO was found to be highly effective in separating nutrient and salt elements from water. After RO treatment, over 70% of NH3-N, NO2-N and NO3-N, and over 90% of other elements, such as P, K, Cl, Ca, Mg, Na, Zn, Fe, and Cu, were concentrated in a liquid effluent that had 10% volume of original wastewater. The reclaimed water needs to be further evaluated for its uses.