1	Water Quality Effects of Waste Water Lagoon Conversion to Fish Ponds Gary Burtle Animal & Dairy Science University of Georgia
2	Options for Lagoon Conversion (From Worley 2004) Complete Closure and Fill (reclaim land surface) Breach the Lagoon Berm Convert to Farm Pond Livestock Watering Irrigation Storage Fish Pond
3	NRCS Standard for Closure Unless sludge is removed, it shall not be used for fish production Fencing and warning signs shall be used until the water is safe for swimming and livestock watering Site should be restored to control erosion or the esthetic value of the site
4	Agitate and Pump (Worley 2004)
5	Floating Pump or Dredge (Worley 2004)
6	Geotubes for Sludge Removal (Filling) – from Worley 2004
7	Sludge Removal Sludge composition Does it contain oyster shell, dirt, or debris? Dewatering Irrigate or Geobag dewatering Odors Low humidity, calm winds, wind direction Releasing nutrients to surface or groundwater Keep water in the lagoon over sludge
8	Closure Plan Time schedule Starting from notification of DNR Dewatering method Sludge handling Analysis of sludge and soil Application methods Intended purpose after closure
9	Stabilizing the Lagoon Bottom Certify that the sludge has been removed Analysis for Nitrogen, Phosphorous, Potassium, Copper and Zinc Based on lime requirement, add lime Use plants to remove nutrients, hay For larger lagoons Establish grass on the bank slopes and surrounding area
10	The Ammonia Nitrogen Plume (Volland et al. 2003, J. Hazardous Substance Research) Expected to be 4 to 12 feet deeper than lagoon bottom after 20 years of use As high as 900 mg/kg at 6 inches Maximum of 25 mg/kg after sludge and soil removal Swine lagoons have deepest plume Sandy soil have deeper plumes than heavy clays Exposure of lagoon bottom allows further leaching to lower depths
11	Removing Lagoon Bottom
12	Water Quality Criteria for Ammonia (U.S. EPA 1999 Update) Aquatic life limits between 0.5 and 7.0 mg/L, depending on water temperature Chronic ammonia toxicity within this range is higher at warm temperatures Acute ammonia toxicity is higher when pH is high Early life stages are harmed by ammonia above 4.3 mg/L
13	Reshaping the Lagoon Banks Slopes not steeper than 3:1 Cover clay areas with topsoil to allow vegetation to establish Divert water from watershed to allow pond to remain filled or utilize well to fill pond Follow NRCS standards for Fresh Water Storage 378, 397, 399, and 436
14	Filling the Lagoon with Water Remove any brush that has grown in the empty lagoon Fill and possibly flush the lagoon to irrigation fields Perform analysis of ammonia or total nitrogen in the water Keep pond fenced and posted until analyses are on target Stock fish when maximum limits are reached
15	Water Quality Targets *For swimming and fishing
16	Dissolved Oxygen Criteria Maintain 3-5 ppm Dissolved Oxygen High nutrient concentrations will cause dense algal blooms to develop As nutrients reach target maximum, dissolved oxygen changes will stabilize Mechanical aerators can be used to protect fish after stocking
17	Summary Sludge must be removed Soil analyses are used to certify nutrient removal Restore lagoon to esthetic conditions Monitor water to determine when to stock fish