North Carolina Piedmont Nutrient Load Reducing Measures Technical - PowerPoint PPT Presentation

North Carolina Piedmont Nutrient Load Reducing Measures Technical Report Project Update Victor D’Amato Jonathan Smith Andrew Anderson and Natalie Carmen

Project Approach - Schedule Activity May June July August September Task 1 Selection of Measures - Kick off and NSAB meeting Task 2 Data Sources - Data protocol - Data collection - Data assessment - Data summary Task 3 Technical Report - Method/tool development - Draft report - NSAB presentation - Final report

Project Approach – Tasks  Task 1. Selection of Measures ● May 13 th NSAB meeting: kick off/presentation attended by Vic, Jonathan ● Will begin putting together data protocol (Task 2) in preparation ● Prepared to discuss key questions to be addressed prior to data collection ● Coordination with PTRC/DWQ  Task 2. Data Sources ● Data protocol technical memo (by May 20 th ) – criteria for accepting data – NC Piedmont applicability – Data QA/QC and other characteristics ● Data collection – collect data sources/references ● Data assessment – assess sources versus acceptance criteria ● Data summary (by June 14 th ) – summarize assessment and recommend data sources to use

Project Approach – Tasks  Task 3. Technical Report ● Method/tool development – data processing and analysis ● Draft report (by August 9 th ) ● NSAB presentation (September 6 th ) – Summarize draft report, comments received and proposed revisions and other actions to be taken ● Final report (by September 20 th )

Today’s Presentation  Executive Summary  For each measure:  Background and Introduction ● ● Orientation to and Project Parties and Roles ● Project Overview summary of content  Data Sources and Assessment in draft report ● (Load Reducing Measure)  (Load Reducing Measure) ● Major issues ● Background identified ● Baseline Load Characterization ● Potential Management Practices ● Remaining work to ● Management Practice Performance Summary and Validation finalize report ● Other Recommendations ● Question/answer  Program Implementation Recommendations  References

Remedy Malfunctioning Septic System – Background  “Malfunctions” and load delivery characteristics vary spatially and temporally  New malfunctions occurs as old malfunctions are remedied  Malfunction types ● Illicit septic tank effluent discharge ● Illicit graywater (e.g., from laundry) discharge ● Demonstrated drainfield malfunction  Remedy types ● Repair to properly functioning septic system ● Repair with properly functioning TS-II (nitrogen-reducing) onsite system ● Connection to permitted major NPDES system ● Replacement with a discharging TS-II system  Credits awarded based on rates of different types of malfunctions and remedies implemented

Remedy Malfunctioning Septic System – Program Elements  New “survey program” for jurisdictions to establish malfunction rates and accounting for malfunctions and remedies ● 20% of systems inspected per year ● Normalize seasonal differences ● Apply malfunction rate improvement to all systems in jurisdiction  Remedies resulting from malfunctions identified via traditional methods (complaints, required inspections, home transfers)  Systems (functioning and malfunctioning) otherwise eliminated by connection to sewer  Averaging across multiple systems captures expected range in malfunction intensity and remedy performance

Remedy Malfunctioning Septic System – Malfunction Types  Illicit septic tank effluent discharge ● TN load of 11 lb/yr-person (assumes no reduction in septic tank) ● TP load of 1.8 lb/yr-person  Illicit graywater (e.g., from laundry) discharge ● TN load of 0.70 lb/yr-person ● TP load of 0.98 lb/yr-person ● Based on published data post detergent phosphate reduction  Demonstrated drainfield malfunction ● TN load of 1.1 lb/yr-person ● TP load of 0.036 lb/yr-person ● Based on combination of Piedmont water quality data and malfunction accounting methodologies used in other watershed studies

Remedy Malfunctioning Septic System – Remedy Types  Repair to properly functioning septic system ● TN load of 0.55 lb/yr-person (95% reduction of STE load) ● Zero TP load (100% reduction) ● Based on combination of Piedmont water quality data, Chesapeake and others ● Currently conducting additional literature review and review of Piedmont water quality data to estimate functioning and malfunctioning system loads  Repair with properly functioning advanced (TS-II) onsite system ● TN load of 0.22 lb/yr-person (60% + 95% = 98% reduction of STE load) ● Zero TP load (100% reduction in soil)  Connection to permitted NPDES system ● Assume all load transferred to point source sector, but awaiting DWQ input  Replacement with TS-II equivalent discharging system ● TN load of 4.4 lb/yr-person ● TP load of 1.8 lb/yr-person

Remedy Malfunctioning Septic System – Credit Summary TN load reduction credits Properly Properly functioning Connection to major Connection to a TS- Remedy (R) functioning septic TS-II system (R2) NPDES system (R3)* II Discharging system (R1) System (R4) (lb/cap/year) (lb/cap/year) M alfunctioning System (M) (lb/cap/year) (lb/cap/year) Direct STE discharge (M1) 10.45 10.78 11.0 6.6 Direct graywater/laundry 0.15 0.48 0.70 -- discharge (M2) Demonstrated drainfield 0.55 0.88 1.1 -- malfunction (M3) TP load reduction credits Properly Properly functioning Connection to major Connection to a TS- Remedy (R) functioning septic TS-II system (R2) NPDES system (R3) II Discharging system (R1) System (R4) (lb/cap/year) (lb/cap/year)* M alfunctioning System (M) (lb/cap/year) (lb/cap/year) Direct STE discharge (M1) 1.8 1.8 1.8 -- Direct graywater/laundry 0.98 0.98 0.98 -- discharge (M2) Demonstrated drainfield 0.036 0.036 0.036 -- malfunction (M3)

Remedy Discharging Sand Filter – Background  Describes several different types of systems with varying characteristics  Only a portion have actually been identified and permitted  Accounting can be done on a system-by-system basis but there are benefits for jurisdictions to combine program with that for septic systems  Discharging system types ● Gravity-dosed single pass sand filters with regular discharges ● Gravity-dosed single pass sand filters with no or infrequent discharges ● Recirculating filters and TS-II equivalent treatment systems ● Malfunctioning (surface failing) systems  Remedy types ● Upgrade to recirculating filters or TS-II treatment systems ● Connection to major NPDES system ● Replacement with properly functioning septic system ● Replacement with properly functioning TS-II onsite system

Remedy Discharging Sand Filter – System Types  Gravity-dosed single pass sand filters with regular discharges ● TN load of 7.4 lb/yr-person (33% load reduction) ● TP load of 1.8 lb/yr-person (no load reduction) ● Based on Durham/DWQ data and some published data  Gravity-dosed single pass sand filters with no or infrequent discharges ● TN load of 7.4 lb/yr-person (33% load reduction) ● TP load of 0.9 lb/yr-person (50% load reduction)  Recirculating filters and TS-II treatment systems ● TN load of 4.4 lb/yr-person (60% load reduction) ● TP load of 1.8 lb/yr-person (no load reduction)  Malfunctioning systems ● TN load of 7.4 lb/yr-person (33% load reduction) ● TP load of 1.8 lb/yr-person (no load reduction)

Remedy Malfunctioning Septic System – Remedy Types  Upgrade to recirculating filters and TS-II treatment systems ● TN load of 4.4 lb/yr-person (60% load reduction) ● TP load of 1.8 lb/yr-person (no load reduction)  Connection to major NPDES system ● Assume all load transferred to point source sector, but awaiting DWQ input  Repair to properly functioning septic system ● TN load of 0.55 lb/yr-person ● Zero TP load  Repair with properly functioning advanced (TS-II) onsite system ● TN load of 0.22 lb/yr-person ● Zero TP load

Remedy Malfunctioning Septic System – Credit Summary TN load reduction credits Upgrade to TS-II Connection to major Replacement with Replacement with Alternative (A) treatment system NPDES system (A2)* properly functioning properly (A1) septic system (A3) functioning TS-II (lb/cap/year) onsite system (A4) Discharging System (D) (lb/cap/year) (lb/cap/year) (lb/cap/year) Single-pass filter with 3.0 7.4 6.9 7.2 regular discharges (D1) Single-pass filter with no or 3.0 7.4 6.9 7.2 infrequent discharges (D2) TS-II or equivalent treatment -- 4.4 3.9 4.2 system (D3) Malfunctioning discharging 3.0 7.4 6.9 7.2 systems (D4)

Remedy Malfunctioning Septic System – Credit Summary TP load reduction credits Upgrade to TS-II Connection to major Replacement with Replacement with Alternative (A) discharging NPDES system (A2)* properly functioning properly treatment system septic system (A3) functioning TS-II (lb/cap/year) (A1) onsite system (A4) Discharging System (D) (lb/cap/year) (lb/cap/year) (lb/cap/year) Single-pass filter with -- 1.8 1.8 1.8 regular discharges (D1) Single-pass filter with no or -- 0.9 0.9 0.9 infrequent discharges (D2) TS-II or equivalent treatment -- 1.8 1.8 1.8 system (D3) Malfunctioning discharging -- 1.8 1.8 1.8 systems (D4)