Qwik-Zyme L Study

by Justin Hall of UW-Steven’s Point.

Monitoring the effectiveness of removal of fatty acids in wastewater with and without the addition of Qwik-Zyme L biocatalyst.

Summary

The presence of fats, oils, and greases (FOG) is a major concern for the municipal wastewater treatment plants. Presence of FOG in waste water treatment systems can lead to buildups which can cause blockages and ineffective wastewater treatment. The point of entry of these FOG can be from numerous sources such as; industry, restaurants and homeowners. Regardless of the source, once it reaches the treatment facility it can be difficult to remove.

The presence of these FOG, especially in colder weather conditions can cause for less desirable wastewater flora to form such as the filaments Microthrix parvicella and Nocardia. This is because the ‘good’ bacteria that are responsible for the treatment of wastewater have a difficult time breaking down fats, oils and grease. Filamentous bacteria can also be responsible for the presence of foam in wastewater treatment processes because of their ability to float on the surface.

The objective of this study was to determine the effectiveness of the Qwik-Zyme L (QZL) biocatalyst, a wastewater additive developed and produced by AquaFix Inc. The addition of QZL, according to product labeling, aids in the removal of fats, oils and greases from wastewater. This study was developed at the Wisconsin Institute for Sustainable Technology (WIST) at the University of Wisconsin – Stevens Point. A total of nine different sources of fats were tested. Seven sourced from non-animal, with two sourced from animal products.

This study tested the removal of fatty acids from spiked wastewater samples over a 24-hour period. Wastewater with the QZL added was compared to wastewater without the addition of the biocatalyst. Analysis of the fatty acid loss after the treatment period indicated that the addition of the QZL biocatalyst was effective in aiding in the removal of fatty acids.

Results

Only trace amounts of short chained fatty acids (SCFA) were observed during the study. Due to no quantifiable levels of SCFA having been detected their results will not be individually listed.

The following graphs illustrate the degradation of the fatty acids present in the wastewater over a 24-hour time period.

Canola Oil

Table 1: Fatty acid removal for canola oil as a percentage.
Time No Biocatalyst QZL
4:00 4.0% 36.3%
9:00 10.0% 45.7%
22:30 46.4% 81.5%
27:30 60.6% 100.0%
Figure 1: Fatty acid removal for canola oil.

Coconut Oil

Table 2: Fatty acid removal for coconut oil as a percentage.
Time No Biocatalyst QZL
3:00 21.3% 52.0%
11:00 44.8% 88.2%
21:00 59.5% 100.0%
27:00 79.2% 100.0%
Figure 2: Fatty acid removal for coconut oil.

Peanut Oil

Table 3: Fatty acid removal for peanut oil as a percentage.
Time No Biocatalyst QZL
4:00 15.2% 46.6%
9:00 16.2% 55.0%
21:30 69.1% 90.9%
26:30 92.8% 100.0%
Figure 3: Fatty acid removal for peanut oil.

Sesame Oil

Table 4: Fatty acid removal for sesame oil as a percentage.
Time No Biocatalyst QZL
3:00 13.5% 22.9%
11:00 22.6% 49.9%
21:00 35.2% 77.8%
27:00 44.8% 83.6%
Figure 4: Fatty acid removal for sesame oil.

Shaving Cream

Table 5: Fatty acid removal for shaving cream as a percentage.
Time No Biocatalyst QZL
4:30 9.6% 27.9%
12:00 21.8% 59.5%
22:00 49.0% 100.0%
28:00 50.9% 100.0%
Figure 5: Fatty acid removal for shaving cream.

Olive Oil

Table 6: Fatty acid removal for olive oil as a percentage.
Time No Biocatalyst QZL
4:00 4.0% 36.3%
9:00 10.0% 45.7%
22:30 46.4% 81.5%
27:30 60.6% 100.0%
Figure 6: Fatty acid removal for olive oil.

Vegetable Oil

Table 7: Fatty acid removal for vegetable oil as a percentage.
Time No Biocatalyst QZL
2:15 22.1% 31.8%
10:30 40.7% 71.3%
21:30 72.0% 83.9%
26:00 74.2% 92.4%
Figure 7: Fatty acid removal for vegetable oil.

Bacon Grease

Table 8: Fatty acid removal for bacon grease as a percentage.
Time No Biocatalyst QZL
4:30 13.6% 21.2%
10:00 22.5% 46.6%
21:00 50.6% 74.8%
28:00 64.7% 86.3%
Figure 8: Fatty acid removal for bacon grease.

Milk Fat

Table 9: Fatty acid removal for milk fat as a percentage.
Time No Biocatalyst QZL
5:00 17.6% 36.5%
9:00 43.3% 57.8%
20:00 69.2% 85.2%
28:00 74.8% 89.9%
Figure 9: Fatty acid removal for milk fat.

COD Removal

Table 10: COD results for wastewater not treated with QZL Biocatalyst.
Initial Final
Fat Source Unfiltered Filtered Unfiltered Filtered
Canola Oil 3841.2 410.0 2693.0 117.4
Coconut Oil 3779.0 415.0 2961.2 104.3
Peanut Oil 4217.0 379.8 1987.6 130.4
Sesame Oil 4219.6 431.9 2741.6 90.4
Shaving Cream 4218.1 391.0 3112.9 117.5
Olive Oil 4913.2 438.7 2917.3 177.9
Vegetable Oil 4693.5 433.1 2840.4 74.2
Bacon Grease 3716.0 427.9 1990.3 100.4
Milk Fat 4014.9 414.6 2044.5 91.8
Table 11: COD results for wastewater treated with QZL Biocatalyst.
Initial Final
Fat Source Unfiltered Filtered Unfiltered Filtered
Canola Oil 3841.2 410.0 2655.1 121.3
Coconut Oil 3779.0 415.0 2714.0 61.2
Peanut Oil 4217.0 379.8 2111.3 70.6
Sesame Oil 4219.6 431.9 3141.5 70.0
Shaving Cream 4218.1 391.0 2917.4 105.1
Olive Oil 4913.2 438.7 2413.8 77.6
Vegetable Oil 4693.5 433.1 3008.9 7471.7
Bacon Grease 3716.0 427.9 2114.9 75.3
Milk Fat 4014.9 414.6 1788.3 70.5

Conclusion

In all of the fat sources tested the addition of the QZL biocatalyst aided in the removal fatty acids from wastewater. The biocatalyst appears to aid in the reduction of the fatty acids relatively quickly, increasing the rate of fatty acid removal during the first hours of treatment.

The first samples for fatty acid testing were drawn at about four hours into treatment. Table 12 shows the percent removal at the first sampling for fatty acids.

Table 12: Percent removal of fatty acids at first sample draw.
Fat Source Blank QZL Difference
Canola Oil 4.0% 36.3% 32.3%
Coconut Oil 21.3% 52.0% 30.7%
Peanut Oil 15.2% 46.5% 31.3%
Sesame Oil 13.5% 22.9% 9.4%
Shaving Cream 9.6% 27.9% 18.3%
Olive Oil 4.0% 36.3% 32.3%
Vegetable Oil 22.1% 31.8% 9.7%
Bacon Grease 13.6% 21.2% 7.6%
Milk Fat 17.6% 36.5% 18.9%
Average 13.4% 34.6% 21.2%
In each instance the addition of the QZL biocatalyst out preformed the blank wastewater. The average increase in removal of fatty acids at the approximately four-hour mark was 21.2%. The total fatty acid removal was 13.4% in wastewater with no biocatalyst and 34.6% in the wastewater with the QZL biocatalyst added.

The effectiveness of the QZL biocatalyst continued for the duration of the treatment. At the end of the treatment period (approximately 24-28 hours) the fatty acid concentrations dropped below quantifiable limits in five of the nine fat sources. Table 13 shows the percentages of total fatty acids removed at the end of each treatment.

Table 13: Percent fatty acid at end of treatment period.
Fat Source Blank QZL Difference
Canola Oil 60.6% 100.0% 39.4%
Coconut Oil 79.2% 100.0% 20.8%
Peanut Oil 92.8% 100.0% 7.2%
Sesame Oil 44.8% 83.6% 38.8%
Shaving Cream 50.9% 100.0% 49.1%
Olive Oil 60.6% 100.0% 39.4%
Vegetable Oil 74.2% 92.4% 18.2%
Bacon Grease 64.7% 86.3% 21.6%
Milk Fat 74.8% 89.9% 15.1%
Average 67.0% 94.7% 27.7%
There was a 27.7% increase in fatty acid removal at the end of the treatment period. 67.0% of the total fatty acids were removed in the wastewater with no biocatalyst, compared to 94.7% with biocatalyst added.

Appendix A – Experimental Conditions

Wastewater for this study was obtained from the Stevens Point, Wisconsin municipal wastewater treatment facility. Once in the laboratory, the wastewater was ‘washed’ to remove excess nutrients. Details of this procedure and others can be found in the methods section of this report.

MiniBio Reactors from Applikon Biotechnology were used to control conditions of the wastewater as listed in Table 14.

Table 14: Experimental conditions.
Parameter/Condition Target
COD (Filtered) 400 mg/L
pH 7.80
DO 3.0 mg/L
Temperature Not controlled
Stirring Speed 300 RPM
MLSS 2000 mg/L
QZL Dose 10 gal per 100,000 gal
A 2.5% solution of sodium carbonate, and 0.05M hydrochloric acid were used to control pH.

SmartBOD was added as a source of COD. 10,000 mg/L COD solutions were made and added to the wastewater to obtain the target of 400 mg/L COD.

Temperature was monitored during the study but not controlled. The ambient temperature of the laboratory where the experiments were conducted is usually between 19 and 22°C.

The study looked at a total of nine different sources of fats, seven from non-animal sources with the remaining two from animal. These were; olive oil, peanut oil, canola oil, shaving crème, coconut oil, vegetable oil, sesame oil, milkfat and bacon grease.

For each fat source tested the QZL biocatalyst was compared to a blank, or a wastewater sample with no biocatalyst added, with all other conditions remaining the same. Each test was completed in triplicate.

Appendix B – Test Methods

The reactors were tested for MLSS, chemical oxygen demand (COD), long-chained fatty acids (LCFA) and short-chained fatty acids (SCFA). Table 15 Lists the methods used for each analysis.

Table 15: List of methods used.
Test Method
Short-Chained Fatty Acids (SCFA) In House
Long-Chained Fatty Acids (LCFA) In House
Chemical Oxygen Demand (COD) SM 5220 D
Mixed Liquor Suspended Solids (MLSS) SM 2540 D

Short-Chained Fatty Acids

Samples for SCFA were filtered through a 0.22 µm membrane filter and analyzed on a DIONEX ICS-3000 chromatography system equipped with an ICE-AS1 column.

Long-Chained Fatty Acids

15 mL of wastewater was removed from the reactor vessel. This sample was then washed 3x with 5mL of hexane. Samples were centrifuged between hexane washings. The hexane fractions were collected in a separate tube and the hexane removed.

Once the hexane was removed 2.5 mL of 2.5% sulfuric acid in methanol was added as a derivatizing agent. Samples were placed in an incubated shaker table for 3 hours at 60°C. LCFA were back extracted by adding 1 to 2 mL of Hexane and vortexing.

The LCFA sample in hexane was ran on an Agilent 7890A GC system equipped with a FID detector and a DB-5 column.

MLSS Washing

Prior to using the mixed liquor obtained from the wastewater treatment facility it was ‘washed’ to remove excess nutrients. MLSS was poured into a 2L graduated cylinder and allowed to settle. Once settled the water was decanted and brought back to 2L with deionized water. This was done a total of three times.

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