Building a Continuous Flow Wastewater Treatment Plant

Motivations for this Project

Full-scale WWTP = continuous flow

Previous groups unsuccessful

Anticipated Hurdles

Movement of solids

Adequate residence time

Coordinating necessary valves with available ports

Peristaltic pump

FRIDGE

reactor

BOD

BOD

. .

..

Air flow regulator

aerationwaste

waste

Settling basin

sludge recycle

sludge recycle

to drain

Treated effluent

aeration and stirring

Clean water (to dilute BOD)

1

2

4

3

5

A

Centrifugal pump

B

CONTROLSPort 1: airflow into accumulatorPort 2: airflow out of accumulatorPort 3: centrifugal pump on/offPort 4: treated effluent removalPort 5: organic feedPort 6: clean water (feed dilution)

6

clean water

air source

Controls

o BOD flow in

o Water flow in

o Sludge recycle

o Effluent Removal

o Default

Only Conditions5

pump in short bursts to better regulate flow (low flow rates are less accurate)

Solids retention

Increase residence time

Control StatesAirflow

into accumulator

Airflow out of

accumulator

Centrifugal pump

Sludge removal

Organic feed

Clean water

BOD flow in

H2O flow in

Sludge recycle

Sludge removal

Default

Port: 1 2 3 4 5 6

State Change “Rules” Limited by software capabilities

Can not run continuous while loops Sludge recycle and BOD feed not independent

Simulate a continuous flow reactor Reactor always stirring and aerating Sludge recycle/disposal and BOD addition states

change based on

Our Major Problem Solids did not settle

Resulted in contaminated effluent

Attempted Solutions Addition of ferric chloride (coagulant)

Big flocs….that floated

Removed plastic ‘shield’ from clarifier Limited sticking to walls

Mixing of solids in clarifier Outflow pipe facilitated re-suspension Better flocculation = better settling

VSS Analysis Volatile Suspended Solids

Measure of effluent quality

Filtration Evaporation Combustion

ResultsOrganics in Effluent

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Brett'seffluent

Dale'seffluent

Our normal Oursuperclean

NRP

VS

S (

mg

/10

ml)

Brett's effluent

Dale's effluent

Our normal

Our superclean

% Removal of Solids (from Reactor to Effluent)

84

86

88

90

92

94

96

98

100

Brett Dale Our potential Our normal

NRP

% R

emo

val

Conclusions Semi-continuous

flow achieved Mixing promotes

clarification Solids retention and

movement possible Continuous flow not

possible with equipment provided

Future Research and Improvements

Clarifier dimensions Long and shallow

A second peristaltic pump for sludge recycle Better control with more accurate flow rates Approaching continuous flow

Larger activate sludge tank Increase residence time

Any Questions?

This would not have even have been remotely POSSIBLE without the help of…

Monroe Weber-Shirk, The handy guys in the basement shop, Jeff, Matt Fountain, Nick Wobbrock, Roslyn, Alex, Peter, John’s big ball of putty, All the other people in the lab, Jesus, NSF, Secretary of Defense Donald Rumsfield, My dog Kelsey, M. Todd Walter, Accel computing facility, Alexander the Great, Bill Gates, Labview, My parents, Edward Norton, Ned Nederlandy, The Big Guy Upstairs (Bisogni), The High-Noon Runner’s Club, Jill’s late-night massages, Dairy Bar, Farva, Harry Potter, Dave’s hair, The oven, Vietnam, Spicy Italian Bagels…