Water Quality Engineering projectChristian Sanchez | Russell E Di Fiori | Pasadena City College

Problem / Question

How effective is your bio-reactor and how well did it perform removing nitrates from water?

Hypothesis• In theory the specific reactor that was built should be efficient

enough to remove most if not all nitrate from water being cycled through the reactor. This is accomplished by removing Oxygen in the water by forcing it down through the inner coiled pipe, depletion of oxygen gives the bacteria perfect condition to thrive.

Project Overview

Building a reactor scaled down to process a small amount of water was a bit challenging. The actual build wasn’t so difficult but having to tune the reactor down to the flow rate was a bit more challenging, at first the results showed high nitrate levels but this was expected as the water had not yet been filtered throughout the Bio reactor. Having the water go through 75 ft. of tubing made it possible for the removal of oxygen, as the water is forced down through the tube levels of oxygen becomes lower and lower until it reaches the bottom once it reaches the bottom it then fills up all the way to the top and exits though the exhaust port. The inside was filled with wood chips although I found that it made the water a bit dirty but results showed it worked.

Variables / Research

What type of media was going to used to have production of bacteria? For my reactor I choose woodchips which I thought would be the best bet to have a surface area for bacteria to thrive.

What type of design was going to be used? For my reactor a basic design was made with an intake, exhaust port water flows in and water flows out using no pump gravity only.

Nitrate levels? Nitrate levels would have to be tested weekly for results.

Materials

Materials (detailed list) Quantity (be specific)

4 x 25 inch PVC pipe 1

PVC end caps 2

Intake Valve 1

Exhaust Valve 1

3/8 inch pipe 75 FT

Wood Chips Small bag

5mg/L water 3 Gal.

Procedure

Step 1• Gather

materials to build the reactor this took some pre – build planning.

Step 2• Put together

the reactor.• Inside we

have 75 ft of coil wrapped up.

Step 3• Test the

reactor for effectiveness and that it actually works. SUCCESS!

Step 4• Over a

period of time we need to test the results (Nitrate levels)

Data / Observations

• Initial results shows a very high levels of nitrate which seem to be normal since no actual filtration had been started.

• A slight fix in the reactors exhaust port to have the water slow down to 22 ml/min seemed to show me better results. Results proved that slowing down the water was a good method better filtrating the water.

• Before the Third test I decided to slow it down a bit more to about 15ml/min and this show an excellent drop in the nitrate. Water with high concentration of Nitrate (14.6mg/l) was added and results showed that it still dropped to 10mg/l after water was introduced.

• Water flow was kept at the same speed and this eventually lead to a pretty low level of nitrate in the water thus showing that this reactor was a success.

Results

Test 1 Test 2 Test 3 Test 40

5

10

15

20

25

21.60 mg/l

10.38 mg/l

4.4 mg/l4

Nitrate Levels

Nitrate Levels

• Initial Results showed 21.6 mg/L (starting results)

• First test shows 14.2 mg/L

• Second test shows a slight decrease at 10mg/L

• Third Test even greater success at 4.40 mg/L

• One final test shows 4.00 mg/L

Conclusion

• Bio-Reactor proved to be efficient enough to remove most of the nitrate in the water being tested. Depleting the oxygen of the water before it even going through the media was a very good way of having the nitrate levels drop over time. Overall I was very satisfied with the reactor in both the way it looked and the efficiency that this reactor had. It also shows signs that it can ultimately process a lot more water than was currently processing.