The High Stength Sandfilter - Wcowma Onsite … High Stength Sandfilter Minimum Dose for equal...

The High Stength

Sandfilter

Minimum Dose for equal

distribution

Equation

Dose time = A + 3 B

Time Dose Equation

Measure the time required to

equally pressurize system

A= Time from pump “ON” to first

squirt

(compensate for time when no

water is coming out of the orifices)

B = Time from first squirt

to full pressure

Multiply that time by three

This will ensure water is at

equal squirt during

67%

of the run time

By this technique you we

should be able to establish a

minimum Dose size and

maintain equal distribution

Example:

360 gpd system

Time from pump being turned

ON until the first squirt shows

up is 5 seconds

A= 5 seconds

Time from the first squirt until

equal squirt is 10 seconds.

B= 10 seconds

Therefore

Minimum Dose = A + 3B

= 5 + 3 x 10

“ON Time” = 35 seconds

Set 35 seconds in the controller

Set a short OFF time

(10 Min?)

Measure drawdown over

several doses

Shows - 23.2 gallons per dose

For a 360 gpd system there

would be 15 doses

(360 divided by 23.2)

Therefore our “OFF” time is

24 divided by 15 = 1.6 hours or

1 hour 36 minutes OFF

Minimum Dose Size will be

effected by;

Design and distribution method

Ideas to minimize pump size

and dose volume

Keep tanks close to

dispersal area

Keep transport lines and

manifolds full between doses

Use chambers

on all pressurized systems to

minimize the number

of orifices needed

SURGE CAPACITY

For Time Dosing

• Pump tank needs to have enough capacity

to handle surge.

• 1,000 gallon minimum for typical

residential application

Typical 1,000 Gal Pump Chamber

Typical 500 Gal Pump Chamber

MOST IMPORTANT

Control Flow to limit

hydraulic output

DON’T FLOOD YOUR

System/Soils

Presentation

of a

Demonstration

System:

High Strength

Sand Filter

This is not a

scientific paper and

minimal data is

being presented

Hypothesis

micro-dosing

for

MACRO-ORGANISMS

BIG CRITTERS

EAT

small critters

Red Worms in Gravel Filters and

various system components

Shallow Soil Systems

At Grade Systems

Drip irrigation

Worm bin

Ghosts in Canada

Process is designed to provide an

environment that will allow macro

organisms to exist in the same area

as aerobic micro organisms, without

hydraulically over loading them.

Fall back position was that the system

is designed to rebuilt easily and cost

effectively.

Kitchen Staff

Education

Design 2000 gpd

Tanks are cheap,

put in extra grease traps

Time control of flow

70 doses per day

(every 20 minutes)

Hemlock Bark

layer above pea gravel

and sandfilter

High Strength Site Plan

High Strength Filter Profile

Chambers and Burlap

13 years Later

Flow characteristics

• 1,000 – 1,500 Gallons per day

• 4500 Gpd Peaks

• BOD5 500 TO 1100 mg/l

Construction costs

• $50,000 initial cost (7 existing 1,000 gal.

tanks were used) $21,000 saving.

• $50,000 saved not installing the aerobic

treatment portion of the system

Average Annual Fixed cost

• Approx $4,675.00 per year

• Grease Trap Pumping $3,500.00

• Quarterly inspections $800.00

• Electricity for pumps $375.00

• These costs would be incurred regardless what system was installed.

Rebuild Cost

• Approx $15,000.00

• $7,500 Labor

• $3,000 Pumping

• $4,500 materials

• Average annual cost with rebuild & repairs

Approx. $6,000.00 per year

Approx cost for sewer hook-up

• $33,000.00 hook-up fee

• $12,000 per year sewer fee

• Break even after the third year

• $60,000 saved over 13 year period

Energy Cost savings

• 2 hp blower 24/7

• 11 cents/Kw

• $1,440 per year (electricity alone) X 13 yrs

• $18,000 energy savings

Saved Maintenance Cost

• Commercial aerobic systems typically require a quarterly inspection and maintenance of the treatment portion of the system

• Approximately $1,400 per year X 13 yrs

• $18,200 saved

13 year - Impact Zones

Slime Zone

Recirculating Gravel Filter

SEPTIC TANK

RECIRCULATING

GRAVEL

FILTER

DRAINFIELD

RECIRCULATING /

MIXING TANK

Gravel Filter Profile

All four conditions must be met to satisfy media criteria.

1. Particle Size Distribution:

Sieve Particle Size Percent Passing

3/8 inch 9.50 mm 100

No. 4 4.75 mm 0 to 95

No. 8 2.36 mm 0 to 2%

No. 30 0.60 mm 0 to 0.1%

2. Effective Size: 3 mm to 5 mm.

3. Uniformity coefficient: less than or equal to 2.

4. Filter media must be washed.

Recirculating Gravel Filter Media

Recirc. Tank Profile

Flow Splitter Ball Valve

Observation

Port

To Drainfield

Buoyant Ball

Good Seal

Basket

20/80 splitter

Recirculating Gravel Filter

(Modified)

No Splitter Valve

Chamber distribution

RGF disabled alarm