Aquaculture CRSP 21st Annual Technical Report
Use of Clinoptilolite Zeolites for Ammonia-N Transfer and Retention in Integrated
Aquaculture Systems and for Improving Pond Water Quality before Discharge
Tenth Work Plan, Appropriate Technologies Research 5 (10ATR5)
Ted R. Batterson and Christopher F. Knud-Hansen
Department of Fisheries and Wildlife
Michigan State University
East Lansing, Michigan, USA
Yang Yi and Yuan Derun
Aquaculture and Aquatic Research Management
School of Environment, Research, and Development
Asian Institute of Technology
Pathumthani, Bangkok, Thailand
Five experiments were conducted at the Asian Institute of Technology (AIT, Thailand) during February–July 2002 to assess the potential of crushed (1–2 mm diameter) clinoptilolite zeolite to: 1) transfer ammonia-N from animal manures to fertilize aquaculture ponds, 2) moderate ammonia concentrations in fertilized culture water, and 3) remove ammonia-N from discharged pond water. The clinoptilolite used in this study was found to absorb about 1.91 g N kg-1 when soaked in an ammonium chloride solution, but absorbed very little nitrogen when soaked in a solution of urea. When soaked in either fresh swine or chicken manure slurries, the clinoptilolite absorbed about 0.43 g N kg-1 after one week—with most of the absorption occurring within the first two days of immersion. Other molecules in the manures likely out-competed ammonium ions for ion exchange sites in the clinoptilolite. Nevertheless, plastic mesh bags containing crushed clinoptilolite soaked in swine manure and replaced weekly were able to provide sufficient N to culture waters to promote algal production and Nile tilapia yields similar to tanks fertilized with urea. Results indicate that clinoptilolite technologies applied to livestock-fish integrated systems could increase on-farm nitrogen utilization efficiencies by capturing and recycling manure-N before it is otherwise lost through ammonia volatilization or nitrate leaching, and to use that nitrogen as a fertilizer to promote algal productivity in culture ponds. Unfortunately, a simple economic analysis does not encourage this approach for small-scale farmers. In addition, the anticipated effect of moderating ammonia levels in culture water by clinoptilolite was not obvious in the experiments. It was also found that clinoptilolite did not significantly reduce nitrogen levels (both total ammonia and total nitrogen) of aquaculture discharge water. These results were likely due to the relatively low ammonia concentrations in the water and the limited contact time with the clinoptilolite. Adequately assessing the potential for clinoptilolite to capture and recycle nitrogen from aquaculture wastewater will require further research.
Animal manures have long been used for pond fertilization because they contain the three major algal nutrients: nitrogen (N), phosphorus (P), and carbon (C). A major concern with putting manures into ponds, however, is the biochemical oxygen demand (BOD) from the microbial decomposition of organic matter. Too much manure with too little pond aeration can cause serious depletion of dissolved oxygen (DO) and significant mortalities of culture organisms. The research described below examined the use of clinoptilolite zeolites as a vehicle for transferring manure-N into a pond without including the detrimental BOD in the process.
Natural zeolites are aluminosilicate minerals found in volcanogenic sedimentary rocks worldwide (Mumpton, 1999). Natural zeolites possess several important properties including adsorption, cation-exchange, dehydration-rehydration, and catalysis. Considerable scientific research in the last few decades has identified broad applications for natural zeolites in construction materials, soil improvements for water and nutrient retention, treatment of water and wastewater for removal of heavy metals and nutrients, dietary supplements for farm-raised animals, health care, and other beneficial uses (Mumpton, 1999).
Clinoptilolite zeolites, (Na3K3)6(Al12Si30O72).24H2O, are one of about 40 types of naturally existing zeolites. Clinoptilo