MPCA Remediation Policy

Transcription

1 Remediation MPCA Remediation Policy Remediation is defined as the act or process of correcting a fault or deficiency in a system without changing system structure or form. Consortium of Institutes for Decentralized Wastewater Treatment (2009) What is Remediation

2 When systems are struggling. Effluent surfacing Effluent ponding When is this applied? System Terms 1 2 Horizontal Flow 3

3 There are two basic performance standards for remediation technologies, the remediation practice(s): Restores the infiltration rate into and through the soil below the infiltrative surface to remediate or mitigate the existing malfunction to accommodate the applied flows; and Does not result in harm to the onsite system. MPCA Standards Non Failing [Proper Separation] Treating [Watertight] Discharging below surface What is System Structure?

4 Can t be Many solutions change system type System Type? Need to Check them all Need to Fix them all Be careful Identifying the Problems & Solutions

5 Hydraulic Overload Organic Overload Soils ID Poor Workmanship System Problems User System Components Surface water Hydraulic overload

6 Timer Holding tank Hybrid System Lowering Hydraulic Loading Maximum dose 25% of the D. Flow Overloading Minimum dose 4-5 times Lateral volume Plugging Technology Related Too fast~ Too Big~ Other flows Dosing

7 User Non Performing BOD TSS FOG Organic overload BOD 5 Residential Range: mg/l Typical Value: mg/l Septic tank Range: mg/l Typical Value: mg/l ATU Range: mg/l Typical Value: mg/l Septic tank: < 120 mg/l Infiltration > 175 mg/l Moving towards High strength

8 COD is the equivalent amount of oxygen needed to break down organic matter using strong oxidizing agents Approximation of BOD Faster than BOD Generally somewhat higher than BOD Measure of biological inhibitors - troubleshooting Chemical Oxygen Demand (COD) Everything Soda fountains Soft serve ice cream Alcohols Food waste Greasy foods FOG Where does it BOD 5 come from

9 Fats, Oils & Grease (FOG) Animal or vegetable-based FOG Residential kitchens Degradable by microorganisms Petroleum-based FOG Industry/automotive repair Bath oils, moisturizing cream, tanning oils Not readily broken down by microorganisms Constituent Fats, Oils & Grease State at Room Temperature Comments Fats Solid Non-toxic to the system, animal fats, scum build-up Oils Liquid Non-toxic to the system, vegetable oils, hard to separate Grease Solid or liquid Residual material on appliances; petroleum products, moisturizers, bath oils, toxic to the wastewater system Room temperature assumes 74 degrees F A degreaser will move all components through a system

10 Fats, Oils, and Greases (FOG) Range: mg/l Typical Value: 15 mg/l Temperature Hot Cold Toxic Acid Base Medical Non Performing

11 Temperature Calculate mass loading to a system Concentration of constituent in the wastewater Mass (lb) = C (mg/l) x Q (gpd) x ,000,000 Estimated Mass loading based on number of people Mass (lb) = P (# of people) x O L (lbs /capita- day) Mass = 5 people x 0.17 #/per.-day = 0.85 lbs Mass = 5 people x 0.25 #/per.-day = 1.25 lbs Mass Loading

12 Mass (lb) = C x Q x ,000,000 C= Concentration [mg/l] = 334 mg/l Q= Flow [Measured or Estimated] = 443 gpd 334 mg/l x 443 gpd x ,000,000 Mass Loading: Measured Residential strength Calculate mass loading to a system Concentration in wastewater Volume of wastewater Mass (lb) =140 mg/l x 600 gpd x ,000,000 Mass (lb) = 0.70 lbs per day Commercial strength {Measured} Mass (lb) = C (mg/l) x Q (gpd) x8.35 1,000,000 Mass (lb) = 500 mg/l x 600 gpd x , Mass Loading Calculation Mass (lb) = 2.5 lbs per day

13 0.70 #/day 1,000 sqft of STA.07 # 1,000 sqft #/sqft System loading #/sqft Organic Loading

14 4 Bedroom Home {7080 assumptions} 600 gpd : 170 mg/l BOD 600 gpd x 170 mg/l x ,000,000 = 0.85 # of BOD = 1,700 sqft Organic Loading Research Data N= 284 Removed 11 values between 4,100 and 20,100 mg/l 9 values TSS/FOG Relative Frequency 20% 18% 16% 14% 12% 10% 8% 6% 4% 2% 0% Concentration (mg/l) 2800 data gamma Gamma Value Lesikar et. al (2006)

15 Good Estimates from Data Parameter Value (mg/l) % Data Covered BOD TSS FOG Lesikar et. al (2006) Flow Open [Lunch & Supper] Seats [20 seats] Employees [5 employees] GPD BOD 1,500 mg/l x 675 gpd x ,000,000= New restaurant

16 8.45 #/day Screw up 675 gpd 1.2 gpd/sqft sqft ~ 600 sqft 8.45 # 600 sqft.01 #/sqft Organic Loading Organic inputs Dairy Pop/ Alcohol Design for loading Adding technology Aerobic treatment FOG~ Plugging Managing Watching flushing Organic Loading

17 BOD Recoverable Lowering BOD Lowering Organic Loading TSS NON- organic Plugging Lowering Organic Loading

18 FOG Slow to fix {Source} Capture issues Flow pattern Temp. Degreaser Lowering Organic Loading Hydraulic load reduces Organic loading Low flow ~ Higher BOD Low BOD ~ Higher Flow Water saving fixtures Related values

19 Soil Identification Sizing Separation: Limiting Condition ID Bedrock Redox features What is Wrong?

20 Subsoil Red soils Topsoil Mounding Redox over Dry Redox Features Texture Perc test Fill soils Sizing: Texture/Structure

21 Wrong identification Black topsoil/ Redox features Wrong elevations NO elevations Separation Materials Dirty rock Dirty sand Watertightness Pump applications Electrical Type IV Systems Poor Workmanship

22 System Considerations 1 2 Horizontal Flow 3 The plan or design should: Identify the results of the failure assessment; Discuss the proposed course of action, including site-specific mitigation measures for containing and/or decontaminating sewage surfacing areas, and other measures for preventing the public from being exposed to inadequately treated sewage; Provide detailed information about the remediation practice. The manufacturer s recommended method for product use must be included in this information; Discuss alternatives or options considered; and Provide detailed subsequent follow-up action, including items contained in the Operation, Monitoring and Maintenance section of this document, including the following information: Remediation Plan

23 Operating Permit Length of time monitoring the remediation practice and its effects will occur; Who is responsible for doing the on-going monitoring; Required documentation of an agreement between the Service Provider and system owner; and the Entity responsible for monitoring and reporting requirements to submit to the local permitting authority. Management Plan This is a GOOD Idea Tracking systems Tracking fixes Informing owners What about a Permit

24 For a period of at one year, the system should be monitored to determine if the malfunction is resolved. Monitoring should document the timing of the malfunction and the remedial action done. The primary observations or measurements to make and record include: Whether the symptom of malfunction (surfacing or backing up) stops; Depth of effluent ponding in the monitoring ports in trenches, beds, atgrades and mounds. Wastewater flow When a monitoring inspection is done, or any other observation, reveals the remediation practice is not correcting the malfunction (surfacing or backing up continues or effluent ponding in observation ports do not diminish), the owner of the system must take appropriate action, according to the direction and satisfaction of the local permitting authority (and operating permit). These actions include: Discontinue the use of the remediation practice; Potential interim use of another remediation practice; Temporarily pump and haul; and Replace the system. The manufacturer should have product specific user s manuals to ensure O&M remediation products are used appropriately. Identify Problems Designer Inspector Advanced? Who really can do this

25 Douglas County Project Big Picture Risk Site Risk~ Priority System Risk Site : Owner : Technology Frequency The LGU needs to have a plan Questions