Acceptable Unacceptable

Transcription

1 1. Introduction to forms 2. Different types of Pretreatment tanks. 3. Identify unacceptable conditions. 4. Evaluate the baffles & effluent screens 5. Measure sludge & scum, identify if tank needs cleaning. Acceptable Unacceptable By: You Other Who? Septic tank Trash tank Processing tank The main function of these tanks is to separate the solids from the clear effluent. Pump Vault: need an additional form. 1

2 Water tight containers Concrete Plastic/ Fiberglass Gravity separation/ detention time Heavy sinks Lighter floats % daily flow Screen assisted Anaerobic digestion Components LIDS RISERS INLET TEE SCUM CLEAR LAYER OUTLET TEE W/ EFFLUENT SCREEN A smaller septic tank % daily flow Designed to deal with big pieces (trash) Some Aerobic Treatment Units (ATU s) use a trash tank or trash compartment as part of their treatment unit SLUDGE Anaerobic component of a treatment train Aerobically treated effluent is recirculated into the anaerobic tank Used in Nitrogen reduction systems NH 4 + NO 3 - N 2 Recirc. filters are typical units that use processing tanks a. Evaluate presence of odor within 10 feet of perimeter of system None Mild Strong Sour Chemical b. Source A. Material Concrete Fiberglass Plastic B. Capacity (gallons) C. Compartments D. Capacity for compartments 2

3 Tank INSIDE dimensions Operating depth is measured at OUTLET L x W x1 x7.5 gal/cuft 12 = gal/inch [gpi] 7 x 4 x 1 = 28 x 7.5 gal/cuft = = 17.5 GPI Depth x 17.5 gpi = Capacity 60 x 17.5 gpi = 1,050 gal Operating Capacity Actual 7.48 gallons per Cu FT Tank Inside Dimensions using inches Operating depth measured at invert of outlet pipe GPI= Length x Width x 1 / 231 ci/gal Number of compartments Capacity of each compartment 84 in x 48 in x 1in= 4032 ci/231ci/gal= GPI Tank cap = GPI x Operating Depth OD= 60 X 17.45GPI= 1047 Gallons Cap. Accurate for 1 compartment tank only! 3

4 a. Access Location: Inlet Outlet Center b. Located at grade? c. How deep is tank buried? d. Risers e. Evidence of infiltration on risers? f.lids securely fastened? STAINS G. Lid in operable condition? 4

5 A. Audio B. Visual C. Remote telemetry D. Electronic Alarm A. Liquid level in respect to outlet (inches): At Above Below In: Above At Below B.Maximum liquid level of the tank C. Height at which alarm is activated D. Evidence liquid level has been higher E. Evidence level dropped without pumping: F. Evidence of continuous inflow: G. Date of last pumpout: H. Presence of flocculant in clear zone: 5

6 SCUM LAYER CLEAR LAYER SLUDGE LAYER Thick scum plugs the sludge judge, less of a problem with the dip-stick Measure depth with a scum hook Separate the scum Insert the sludge judge or dipstick Add the sludge and scum measurements together for total solids in the tank I. Evaluation of layers in tank Compartment number Scum (in.) Clear Zone (in.) Sludge (in.) Odor Color Other Should be pumped when total solids reach 25-33% of tank capacity. If A is less than 3 If B is less than 12 If recommended, did it happen? Measure solids in the tank 60 deep 6 of Scum 18 of Sludge = x 100 = 40 % 6

7 Year 1: 10% full Year 2: 22% full Year 3: What do you think? Has Customer changed use? Pumping at year 2 may make sense System risk forms part of the decision to pump out Enzymes Bacteria Other? Customer has false security A. Inlet baffle in place B. Outlet baffle in place C. Compartment baffles in place Dual Chamber Septic Tank Scum Clear Zone Sludge 7

8 D. Effluent screen: Manufacturer Model E. Is screen accessible to ground surface: F. If screened, percent plugged G. Was screen cleaned Wash accumulated material back into the septic tank If cleaned other than at the time of pumping Remove and take elsewhere to clean, or Clean over inlet end of the tank Be sure no solids flow out of the tank while screen is removed 8

9 Screen is washed off directly into the septic tank This is being done at the inlet end of the tank to protect against cleanings going directly out the outlet Some units have protection against outflow or an extra screen that that operates during cleaning. Often, a tool is needed to remove the screen for cleaning and then to replace it into the housing Note that riser opening allows easy access to filter 1. Gloves 2. Use of providers hose with back-flow preventer Unsafe behaviors? 1. No goggles. 2. Bending over bad on the back. 3. Splash back hazard. a. Watertight (no visual leaks) b. Rebar exposed a. Watertight (no visual leaks) 9

10 c. Corrosion present d. Spalling present e.cracks present f. Root intrusion Gallons removed Date 1. Working backup lights and horn 2. Bucket for drips Hose over sidewalk is a trip hazard Regulatory agencies, designer or manufacturer may require sampling. The type of analysis and the sampling protocol is set by the requesting parties Similar operation to septic tanks Water tightness is imperative Pump when the tank is full Remote telemetry may help with management No treatment 10

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