Seeing is Believing - Convincing System Owners to Take Action. Kelly Galloway, P.Eng. Stratford, PE Canada

Transcription

1 Seeing is Believing - Convincing System Owners to Take Action Kelly Galloway, P.Eng. Stratford, PE Canada kelly@dynamicmonitors.com

2 Case Study: Nursing & Assisted Living Facility Prince Edward Island, Canada

3 Facility and Sewage System: 35 bed nursing care + 15 bed assisted living Septic system 12 years old Cost in 2004: $125,000 for engineering & construction

4 Initial Symptoms of a Problem Alarms going off in 2 nd septic tank with effluent filter, Feb Alarms persisted (monthly) Septic installer/plumber thought septic tanks were dead. 4

5 Septic System Overview 2 x 3000Igal septic tanks Zabel A100 effluent filter in 2 nd tank Igal dosing tank with duplex pumps 5

6 Septic System Overview Raised-bed, soil absorption system (SAS) 5 pressure-dosed, gravel trenches. KRain 6605 mechanical indexing valve. 6

7 Raised-bed, Soil Absorption System Inspection port 50mm (2 ) Pressure distribution pipe 7

8 Investigation Methodology & Scope When problems started, what types? Pumping and maintenance history. Detailed staff interviews: operations, routines cleaning, floor waxing, painting kitchen grease traps and cleaning water softeners, water treatment systems laundry 8

9 Investigation Methodology & Scope Inventory potential toxic chemicals/products: quaternary ammonium (quat) cleaning products antibacterial cleaning products antibacterial personal hygiene products pharmaceutical use and disposal chemotherapy treatment 9

10 Investigation Methodology & Scope Examination of sewage system components Assess daily flows versus original design Examination of septic/pump tank effluent Laboratory testing of effluent: Inorganic chemistry, physical, engineering Microbiological parameters 10

11 Facility Operations, Cleaning Linens, towels laundered off-site Resident s clothes washed on-site using cold water Bleach used sparingly 11

12 Facility Operations, Cleaning Floors stripped and waxed once or twice per year. Excess liquid disposed of outside. 12

13 Facility Operations, Cleaning Painting of rooms takes place monthly Latex paint used Brushes cleaned into sinks. 13

14 Quaternary Ammonium ( Quats ) Stable, water-soluble, organic salts Difficult to break down = long biocidal effect Inhibit microbial activity at only 5 to 15 mg/l concentration in wastewater. 14

15 Quaternary Ammonium ( Quats ) Inhibit microbial activity at only 5 to 15 mg/l. Use Low Level Quat test strips to dip and test septic tank effluent. 15

16 Avmor Dazodet Plus Floor Cleaner (Quat, used ~6 months) Do not allow product to reach sewage system, even in small quantities. 16

17 Kitchen Dishwasher Water temperature 128 F to 140 F Uses 100ppm chlorine instead of Quat disinfectants 17

18 Check for Grease Trap Drain Cleaners Propylene glycol based grease trap cleaner in use. 18 Dissolves grease and sends it downstream to septic system.

19 Sump Pumps Discharging into Septic There are 2 sumps pumps at the facility 19 Plumber determined both discharge into the septic system!

20 Check for Water Softeners Backwash brine harm the microbiology Cause septic tank to discharge more solids, grease, oil. None in use 20

21 Check Personal Hygiene Products 21

22 Pharmaceuticals Unused medications are not flushed. Disposed of properly along with sharps. 22

23 Chemotherapy & Antibiotics Excreted in the urine of patients. Chemotherapy drugs in particular can be extremely toxic to microbial activity. No residents or staff have been receiving chemotherapy or ongoing antibiotic treatment. 23

24 Water Meter Data 36% higher than average daily design flow 24

25 Examination of Septic Tanks Nothing unusual in pumping history (tanks appeared normal) Septic tank effluent was thin looking Light brown suspended solids which settled out 25

26 Examination of Septic Tanks No foaming or sudsing No unusual or strong odors 26

27 Laboratory Test Results on Septic Tank Effluent - Chemistry higher than desired => can increase soil clogging 27

28 Laboratory Test Results on Septic Tank Effluent - Microbiology Bacteria populations appeared to be within the normal range 28

29 Effluent Filter Before Cleaning 29

30 Effluent Filter After Cleaning Alarms less frequent, but not stopped entirely 30

31 Check Inspection Port Effluent Levels Breakout had occurred, May 2015 Checked 10 inspection ports, Oct No effluent ponding at that time Signs of prior high levels in some ports 31

32 Distributing Valve Stuck Distributing valve appeared to be stuck on zone (outlet) #3 Maintenance neglected, lot of debris inside, rubber flap disk worn. Valve cleaned and disk replaced. 32

33 Trying to Flush Plugged Drainfield Distribution Pipes Before 33

34 Flushing Drainfield Distribution Pipes (After Unplugging) 34

35 Standpipe Residual Head Test (After Distribution Pipes Clean) 35

36 Case Study: Nursing & Assisted Living Facility Conclusions & Recommendations

37 Conclusions Routine maintenance which had been seriously neglected Indications of system overloading. Several products identified which could be having a negative impact on performance and longevity of the septic system. 37

38 Conclusions Wastewater nutrient ratios (BOD5 :TKN ratio) higher than typical range for residential wastewater. Can increase soil clogging and ponding 38

39 Conclusions Alarms Frequent high level alarms reduced by thorough cleaning of Zabel filter. However, on-going alarms may be coinciding with excess flow from the sump pumps. Filter may need to be upsized 39

40 Recommendations Stop using deleterious products Can be difficult to change procedures. Read water meter, pump controller ETMs & counters weekly Note any correlations with rainfall, snowmelt which could be indicative of I&I 40

41 Recommendations Disconnect sump pumps from septic system Stop using grease trap drain cleaning product If cleaning the grease trap regularly is too onerous, consider other options. 41

42 Recommendations Stop using Quaternary Ammonia products Use bleach, iodine or hydrogen peroxide cleaners and sanitizers instead of Quats Switch from anti-bacterial to plain soap. Avoid toothpaste/mouthwash containing Triclosan as an active ingredient Do not wash paint brushes (even latex) into sinks or into drains. 42

43 Preventative Maintenance & Monitoring Perform on annual basis! 43

44 Preventative Maintenance & Monitoring Check inspection ports periodically, especially during winter/spring. 44

45 Drainfield Sensors Continuous monitoring 24/7/365 Automatic monitoring ponding levels Uploaded to Cloud Alerts & notifications

46 Preventative Maintenance & Monitoring Check distributing valve for: broken spring debris inside Rotating to all zones 46

47 Distributing Valve Remote Monitor Continuous monitoring of valve operation Confirms even distribution Alerts valve malfunction

48 END OF FORMAL PRESENTATION 48

49 IVM6000 Valve Monitor 49