Product selection and treatment programs must be designed around several variables. Controlling bacteria in a production system is often a very dynamic and daunting task. Performing a time kill study with various biocides at several concentrations is the best way to initially devise a treatment plan. Once a product has been selected, prolonged biocide batch treatments are often the most common means of maintaining microbial activity. This is mostly due to the economic factors of maintaining a continuous elevated biocide concentration. Batch treatments at high concentrations for a given amount of time are often more economical than continuous programs; they also reduce the chance of selecting out biocidal resistant strains of bacteria.
BIOCIDE PROGRAM MONITORING
After a biocide program has been initiated it is very important to monitor and trend the results of microbial cultures. Continuous batch treatment programs may have to be increased in frequency and duration if microbial cultures begin to increase with time. Continual monitoring of the program’s effectiveness through cultivation is the most important aspect of its success.
FINE TUNING BIOCIDE PROGRAMS
If APB and SRB bottles are not turning but failures occur with the cause looking like microbial, contact the coastal technical team about different serial dilution bottle i.e. IOB and DNA speciation of bacteria.
Bacteria Serial Dilution Bug Bottles
A series of sealed vials that each contain 9 mL of sterilized nutrient media for growing and detecting bacteria.
In the serial dilution method, the first media vial in a series is inoculated with 1 mL of the field sample. After thorough mixing, 1 mL of the sample from the first vial (by pushing syringe up and down, not allowing a lot of air bubbles) remove 1 ml from the first bottle and add that 1 ml to the second media vial in the series.
Continue same procedure till all six bottles have been inoculate.
When the sixth one is finished mixing, remove 1 ml and dispose of it.
Use different syringe for each set of six bottles, even for the different SRB and APB sets.
Bottles are incubated for a 28-day period
Determine the correct serial dilution bottles based on the chloride count of the water
BIOCIDE SELECTION AND EFFECTIVE CONCENTRATION VIA TIME KILL STUDY
Below are the procedures to be followed to effectively select a product for microbial control at optimal dosage rates. The procedure utilizes a serial dilution method and 28-day incubation.
1) Obtain the biocide needed for testing. 100 mL of sample should be sufficient.
2) Identify a system with known microbial contamination
3) Materials required for test set-up:
a) SRB and APB serial dilution bottles
i) 1 bottle of each (SRB and APB) per chemical per concentration and 12 of each (SRB and APB) for the initial and final blanks (i.e. standard test matrix includes 4 concentrations: 25, 50, 100, and 250 ppm)
b) Prescription bottles for produced water sample collection and inhibitor prep
c) 3 mL disposable syringes for bug bottle inoculation
4) Label 2 prescription bottles as initial blank and final blank, respectively. Label two sets of 6 SRB and APB bottles as Blank Initial 1-6 and Blank Final 1-6. Label all other prescription bottles with the appropriate name of the product and the concentration. Label corresponding SRB and APB bottles for each “treated” prescription bottle.
5) Catch a 100 mL sample of produced water in the prescription bottle labeled Blank Initial and cap.
LEADING WITH BIOCIDES
Contact Coastal Chemical to learn how we can assist with biocides.