North Ranch Bio-Recycling Facility Glenn Mutti-Driscoll, LHG April - - PowerPoint PPT Presentation

April 9, 2018

Soil Water and Groundwater Nitrate Data, North Ranch Bio-Recycling Facility

Glenn Mutti-Driscoll, LHG

Unsaturated Zone Transport

Regional Aquifer ~4 year Unsaturated Zone Travel Time Soil Nitrogen Pool

Groundwater Flow Direction

Monitoring Locations and Recent Nitrate Concentrations

Soil Water and Groundwater Nitrate Concentrations

Groundwater Nitrate Concentrations Part II

Surface Water Nitrate Concentrations

Monitoring Locations and Recent Nitrate Concentrations

 Groundwater nitrate exceedances have historically occurred

and continue to occur on property.

 Offsite groundwater nitrate concentrations are generally low

and near background concentrations, suggesting that dilution is mitigating factor

 Offsite surface water concentrations are low, onsite

concentrations can be elevated but generally infiltrate

 Groundwater nitrate concentrations expected to decrease in

several years due to decreased surface loading and improved crop management

 Proposed storage impoundment should help improve

groundwater nitrate concentrations since material is not being applied in winter when plants can’t take it up

North Ranch Nitrate Summary

Unsaturated Zone Transport

Regional Aquifer Perched Water Tables Clay ~4 year Unsaturated Zone Travel Time Soil Nitrogen Pool

North Ranch Early Fall Soil Nitrate Data

 In 2007 USGS sampled for 61

compounds common to domestic and industrial wastewater analyzed, including surfactants, food additives, fragrances, antioxidants, flame retardants, plastecizers, industrial solvents, disinfectants, fecal sterols, PAHs, and high-use domestic pesticides

 Published guidance designates surface NO3-N above 30

mg/kg post fall harvest as excessive, between 20 and 30 as high, and between 10 and 20 mg/kg in the fall as medium. Soil nitrate levels below 20 mg/kg in 5 of 7 fields indicate treatment capacity higher than that application. Land Profile recommends an end-of-season goal of 20 mg/kg surface soil NO3-N.

 Soil nitrate peaked at excessive levels in 2013 (Field 3) and 2014

(Fields 1, 4, 10, 11), indicating excessive application and prompting reductions in application by Bio Recycling. On review of the agronomic rate calculation, Bio Recycling determined that higher than anticipated retention of ammonia from filtrate likely contributed to excessive soil nitrate levels.

No fields had greater than 30 mg/kg NO3-N, a level considered excessive. The reduced nitrogen application rate accomplished in 2015 and 2016 was clearly the correct response to excess soil nitrate evident in 2013 and 2014.

2016 Soils Report

 In 2016, surface soil NO3-N trended lower for a second year,

averaging 14.0 mg/kg compared to 24.5 mg/kg in 2015, 57.0 mg/kg in 2014, and 26.2 mg/kg in 2013.

 Surface soil NO3-N ranged from 4.5 to 25.0 mg/kg in 2016.  Average subsoil NO3-N trended lower at 4.7 mg/kg and

ranged from 2.0 to 8.8 mg/kg.

2016 Soils Report

 Intro

 Licensed HG with PGG  Presenting water quality monitoring data

 Soil to Regional Water table

 Surficial soil nitrogen pool  After leaches goes through vadose zone, like conveyor belt generally  Some clay perching layers present making flow occur both vertically and

horizontally

 Takes ~4 yrs to hit Water Table (some uncertainty- USGS estimated 2-4 yrs

from 3H/He samples, tried CFC, C14, and SF6 as well but inconclusive. Site loading review suggests 2-7 years, with a 4.1 yr avg)

 GW Flow

 Direction based on DTW measurements from 13 surveyed wells  Travel time 5.5 to 9 yrs from MW-6 to Williams (some uncertainty in measured

hydraulic parameters)

 2016 Q4 Conc map-

 high at 1 and 4, also 5,6. Upgrad wells and offsite no exceedances  2 soil water lysimeters (tip at 24.5ft bgs). 2015 spike at L-1 likely reflects high

mineralization rate in 2014 that did not spur plant uptake.

 4 surface water monitoring locations, will be 2 additional under new permit

Outline

 Sampling locations with elevated concentrations

 Monitor quarterly  High variability. 1 & 4 typically exceed, 5 and 6 more variable and sometimes

• exceed. No other wells do.

 Some seasonality, with Q3 to Q4 GW peaks  Most recent quarter has decrease in N at lysimeters, is consistent with

decreases measured with soil sampling, presumably several years until the lower loading measurable at water table. Currently proposed approach should result in lower GW concentrations, mostly a matter of time until vadose zone flushed

 Low Concentration wells

 Upgradients and offsite domestics  Plume appears be getting diluted prior to reaching nearby residential wells

 Surface water monitoring

 Never exceeded at wetlands on Webb Hill rd at SW-1(only 21% of site drains

that way, also ¾ mile travel distance)

 SW-3 on property, no outlet  SW-2A and SW-2B: seasonal ponds, generally just infiltrate down  No SW contamination offsite  As part of permit conditions, new locations SW-4 and SW-5 added

Outline 2

Wria 16 monitoring, maybe 14 as well

Proposed USGS Mason County Model Data Collection

https://wa.water.usgs.gov/projects/masoncounty/maps.htm

 Tool for understanding of groundwater flow paths and likely

receptors at a regional scale

 Not typically focused on individual sites due to scale  Focus on multiple aquifer systems and their interactions  Generally have lower well densities than local models or compliance

monitoring well networks (model cell sizes 500 feet to 3000 feet)

 Compiles and creates baseline data that act as a framework

for local hydrogeologic evaluations

 Groundwater recharge  Water balance and aquifer fluxes  Regional groundwater flow directions in different aquifers  Surface water-groundwater interactions  Deep aquifer-shallow aquifer interactions

Regional Model Applications

Soil Nitrogen Cycle

Global Nitrogen Cycle

Groundwater Flow Review

From: https://water.usgs.gov/edu/watercyclegwdischarge.html

 Nitrate is highly soluble and generally non-sorbing  Generally impractical to implement wide-scale groundwater

remediation techniques designed for point sources

 Best Management Practices (BMP) modification most common  Cross Injection System (CIS) Enhanced denitrification is growing

 Generally requires large scale production wells

Remediation

Best Management Practices

Remediation

Best Management Practices

Remediation

 Modification of BMPs is the general approach, designed to limit

loss of nutrients to the subsurface

 BMP modification problematic because:

 Bound N in soil  Groundwater lags  Difficulty of evaluating efficacy of BMPs  Difficulty in enforcing implementation of BMPs

 Have been successful in the Malheur GWMA (Oregon)

 Based on local studies

 Substantial denitrification occurs in the unsaturated zone  Denitrification converts nitrate (NO3-) to gaseous forms of N  Requirements include oxygen-depleted conditions, a suitable

electron donor, and microbes with the metabolic capacity for denitrification

 Suitable microbes are generally ubiquitous under agricultural

land use.

 Oxygen-depleted conditions (< 2 mg/L dissolved oxygen) and

the availability of electron donors.

 Electron donors include carbon, reduced inorganic iron, and

reduced sulphur

Denitrification

Remediation

 Enhanced denitrification requires electron donors - acetate

and hydrogen most effective

 Localized enhanced denitrification can be implemented

around high flux zones around production wells (cross injection system)

Enhanced Denitrification

Remediation

 Carbon Wall  Septic Tank Retrofit  Drain Field Retrofit  Pump & Treat (aka irrigation)  Slow release fertilizers  Legumes in rotation  Cover cropping in winter  Manure lagoon liners  Manure application at

agricultural rates

Nitrogen Reduction Technologies

 Anaerobic Digestors  Manure Export as

Compost/fertilizer

 No-till  Lower fertilization after high N

crops

 Crop type  Reduced N inputs/timed N

inputs (split applications)

 Irrigation efficiency paired

with nutrient application efficiency