INNOVATIVE ANIMAL MANURE TREATMENT TECHNOLOGIES FOR ENHANCED ENVIRONMENTAL QUALITY
Location: Coastal Plain Soil, Water and Plant Conservation Research
Title: Development of Anaerobic Ammonium Oxidation (Anammox) Technology Using Immobilized Biomass from Swine Manure
Submitted to: Recycling of Agricultural Municipal and Industrial Residues
Publication Type: Proceedings
Publication Acceptance Date: July 6, 2006
Publication Date: August 15, 2006
Citation: Vanotti, M.B., Szogi, A.A., Kunz, A., Gonzalez, M. 2006. Development of anaerobic ammonium oxidation (Anammox) technology using immobilized biomass from swine manure. In: Petersen, S.O., editor. Proceedings of 12th Recycling of Agricultural Municipal and Industrial Residues (RAMIRAN), September 9-12, 2006, Aarhus, Denmark. p. 143-146.
The isolation of anammox adapted to animal wastewater environments can be of significant importance to farming systems because excess ammonia in modern, industrial-type livestock production is a global problem and the use of conventional biological N removal methods is usually hindered by cost; thus, we think that the more economical anammox-based treatment can greatly facilitate adoption of advanced wastewater treatment technologies by farmers.
The anammox cultures were successfully established using continuous-flow unit processes and biomass carriers seeded with sludges of manure origin. The sludges containing anammox bacteria were obtained from three swine farms: Two were located in North Carolina, USA, and the other in Santa Catarina, Brazil. The sludges were obtained from diverse environments in the swine farms: an aerobic nitrification tank treating anaerobically-digested swine manure, an anoxic denitrification tank treating liquid swine manure after solid-liquid separation, and sediment in an old (inactive) anaerobic lagoon used to treat swine manure. Laboratory bioreactors were seeded with the manure sludges after acclimation with nitrate solution to remove endogenous carbon.
In a first phase of the research, two sequential experiments were conducted over a 5-year period (2000-2005) to investigate conditions to 1) isolate anammox from the swine sludges and 2) optimize anammox treatment. The bioreactors were operated in continuous flow and contained polyvinyl alcohol (PVA) hydrogel biomass carrier beads for immobilization and enrichment of the slow growth microorganisms. A distinct red biomass growth, which is typical of the anammox planctomycete bacteria, developed in the reactors only when high N (300 mg/L) and salt strength concentration was used in the synthetic enrichment medium. Under these conditions and protocol, it took about 100 days for the anammox reaction to develop from farm sludges obtained in both USA and Brazilian farms. Removal of NO2- and NH4+ was simultaneous at the following stoichiometric ratios: NH4+ + 1.24 NO2- -> 1.00 N2 + 0.24 NO3-
Nitrogen removal rate obtained during first-phase development was 0.7-0.8 kg N/m3/day, which is in the range of industrial bio-treatment applications. In a second phase of the research, new reactors were seeded directly with the anammox red sludge biomass produced before. As biomass carrier, the reactors used either a polyester non-woven material coated with pyridinium type polymer or a net type acryl-resin fiber material, both materials designed to enhance retention of microorganisms. Removal of NO2- and NH4+ at typical ratios of the anammox reaction occurred from day one of operation of the reactors. Nitrogen removal rates increased exponentially with time in the reactors seeded with the anammox enriched sludge. These findings overall may lead to development of more economical treatment systems for livestock wastewater and other effluents containing high ammonia concentration.