Legislative Update Septage Land Application Site Monitoring. Date

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1 Legislative Update Septage Land Application Site Monitoring Date

2 Background Land application has been the primary method for disposal of septage in Florida (at 90 sites) Septage application sites are regulated by the DOH (Chapter 64E 6) and permits have been issued through local environmental health offices In 2011, Florida Legislature issued a requirement that the land application of septage would be discontinued by January 1, 2016 In 2015, DEP began a study to monitor the effects at 12 of these sites to help Legislature better understand the issue (assistance from Florida Onsite Wastewater Association) 1/18/2017 2

3 Chronology of Activities Late 2014 Study plan developed in spring/summer of 2014 to evaluate environmental impacts 2015 session Request by Legislature for more information on environmental impacts at existing sites Summer fall, 2015 Implemented bi monthly monitoring at 12 sites 2016 Session DEP update to Legislature November 2016 DEP completed monitoring 2017 Session DEP Final report to Legislature 1/18/2017 3

4 Land Application Site Study Objective: Monitor water quality at 12 representative land application sites, document site conditions, and provide a report to the legislature. Scope: Identify representative sites, obtain access Install 4 monitoring wells at each site, describe soils and geology Collect water samples for analysis, measure ground water depth and movement; measure seasonal variation Evaluate influences on observed results Provide periodic updates to management Final report to legislature by Session /18/2017 4

5 Distribution of Land Application Sites 1/18/2017 5

6 Locations of 12 Study Sites 1/18/2017 6

7 Site Characteristics Area Max = 470 Min = 3 Median = 28 Average = Application Area (Acres) STUDY SITES: AREA (ACRES) Max=78 Min= 2 Median= 9 Average= All Sites 12 Study Sites 0 1/18/2017 7

8 Site Cover/Agricultural Practices Site ID Area (Acres) County Vegetative Cover Agricultural Use A 28 Levy Bahia grass Hay production B 40 Marion Bahia grass, weeds Hay production C 28 Hernando Oak tree nursery, bahia grass, weeds Nursery plant harvesting D 3 Pasco Bahia grass Livestock pasture E 30 Polk Bahia grass, saw palmetto, and small trees Livestock pasture F 5 Polk Bahia grass Livestock pasture G 4.5 Putnam Bahia grass Livestock pasture, hay production H 2 Polk Bahia grass Livestock pasture, hay production I 8 Polk Non-agricultural plants Livestock pasture, hay production J 9 Levy Bahia grass and weeds Hay production K 33 Marion Bahia grass and weeds Pasture, hay production L 78 Polk Orange trees and weeds Orange grove 1/18/2017 8

9 Site Characteristics-Soils Soil texture and drainage class are related to nitrogen leaching potential Excessively drained, well drained soils (high leaching) Somewhat well drained (moderate leaching) Somewhat poorly drained to very poorly drained (low leaching) Site soil characteristics 3 sites (Sites B, C, K) had high leaching soils 5 sites (Sites A, F, H, J, L) had moderate leaching soils 4 sites (Sites D, E, G, I) had low leaching soils 1/18/2017 9

10 Groundwater Monitoring Contractors Drilling a Monitoring Well Typical Monitoring Well 1/18/

11 Groundwater Conditions The aquifer monitored is either the surficial (sand and clay) or Floridan (limestone) at these sites, depending on location At 7 sites (D,E,F,G, H, I, L), it is the surficial At 5 sites (A, B, C, J, K), it is the Floridan Depending on site, depth to groundwater ranges from 4 to 84 feet below land surface At sites D, E, F, I, and L, depth to groundwater is 10 feet or less, At sites B, C, and K, depth to groundwater is 40 or greater, At sites G, H, and J, depth to groundwater is between 10 and 40 feet Groundwater flow direction influences results at most of the sites, based on differences in water quality between wells (wells on downgradient side have higher levels of N and P) 1/18/

12 Ground Water Flow Example 1/18/

13 Water Quality Sampling Water quality samples were collected bi monthly from 4 wells at each site from Summer 2015 to Fall 2016 (most sites have been sampled 10 times) Sampling parameters: Nitrogen species (nitrate, ammonia, organic nitrogen) Phosphorus Chloride Bromide, Potassium, Sulfate Nitrogen isotopes This update provides information on laboratory results through September 2016 Key parameters: Nitrogen (N) and Phosphorus (P) 1/18/

14 Nitrogen in Groundwater 1/18/

15 Nitrogen Results Nitrate is the primary form of nitrogen found in all groundwater samples collected As a point of reference, Florida s groundwater standard for nitrate is 10 milligrams per liter At 5 sites, average nitrogen concentration is >10 mg/l and at 8 sites, the highest reported concentration exceeded 10 mg/l At all but one site, the dominant source of nitrogen at sites with higher levels appears to be septage At 3 sites, average nitrogen levels were 1 mg/l or lower 1/18/

16 Comparison of Site Average and Background Phosphorus Phosphorus level (mg/l) Site Average Phosphorus Level Background Phosphorus for County A G D F E K H J B C I L Site ID 1/18/

17 Phosphorus Results Phosphorus typically does not leach to groundwater unless the amount applied exceeds the capacity of the soil. Sandy soils have a relatively low capacity to adsorb phosphorus. Natural background phosphorus levels for groundwater can be used as references for sites At all sites but 2 (I and L), average phosphorus level is higher than the background levels for the counties they are in At 4 sites (A, D, G and H), average phosphorus levels are >10 times the background levels Phosphorus is bound to soil. At sites with highest concentrations, phosphorus adsorptive capacity of the soil may have been exceeded allowing applied phosphorus to leach to groundwater 1/18/

18 Summary Results from this study are being evaluated and a final report will be provided to the Florida Legislature before the 2017 legislative session For more information contact: Richard Hicks DEP Groundwater Management Section richard.w.hicks@dep.state.fl.us /18/