Microbiological culture process in wastewater treatment operation

Microorganisms exist in the aquatic environment a lot, but to shorten the culture time, we must add a sufficient amount of microbial sludge to make the substrate and the available substrates in the microbial sludge. The following are the steps of microbial culture:

Step 1: Add the pre-calculated microbial sludge concentration to the tank, the supplied sludge concentration ranges from  10%  to  15%  of the total sludge concentration required for the system. The entire culture period will be controlled in terms of the concentration of input wastewater, the balance of nutrients needed for the growth of microorganisms, etc.

– Day 1:  Put microbial sludge (this must be a special type of sludge with good growth and development suitable for wastewater) into the tank and then add probiotics. Turn on the aeration blower continuously. After 4 hours, check the parameters of the input wastewater, pH, DO, Temperature, SV30, record and save the initial data.

– Day 2: turn off the aerator to settle for 2 hours, then withdraw the upper water (sludge separated water) out, add new wastewater with a flow rate of 20% of the total treated wastewater flow per hour, aeration. aeration and continued aerobic probiotic supplementation. After 8 hours, check the parameters of input wastewater, pH, DO, color, smell of sludge, check SV30 parameters. Record the parameters to check microbial growth.

– Day 3: turn off the aerator to settle after 2 hours and let the clear water out of the tank, add new wastewater with a flow rate of 20% of the total wastewater treatment volume per hour, aerate and continue to add yeast. aerobic microorganisms into the tank. After 8 hours, check the parameters of input wastewater, pH, DO, color, smell of sludge, check SV30 parameters. Record the parameters to check microbial growth.

– Day 4: turn off the aerator to settle after 2 hours and let clear water out of the tank, add new wastewater with a flow rate of 20% of the total treated wastewater per hour, aerate and continue to add yeast. aerobic microorganisms into the tank. After 8 hours, check the parameters of input wastewater, pH, DO, color, smell of sludge, check SV30 parameters. Record the parameters to check microbial growth.

– Day 5: turn off the aerator to settle after 2 hours, drain all the water inside out, refill with new water, aerate and check the parameters of the input wastewater, pH, DO, color, and odor of the wastewater. mud, check parameter SV30. After 5 days of monitoring, if the concentration of SV30 increases, and the characteristics of the microbial sludge are good in terms of organoleptic. We proceed to increase the wastewater flow load to 30% of the total wastewater flow/hour.

– Day 6: Check input wastewater parameters, temperature conditions, pH, DO are stable. Take a sample of the wastewater to check the flocculability and settling of the sludge, if it is still in good growth (SV30 concentration is about 15-20% of the cup volume). We proceed to supply wastewater continuously but with a wastewater flow load of about 30% of the total wastewater flow/hour. Turn on the gas supply system running in Auto mode.

– Day N: Continue to monitor and check the parameters, if the sludge concentration continues to increase, we proceed to increase the capacity of the system until  Full load (during this period of time it is necessary to increase the capacity of the system). Pay attention to parameters like SV30, SVI, F/M and sludge age).

Step 2:  If the system is stable, monitor and check the amount of water coming out every day to ensure that the water output always meets the output standards.

Parameter SV30 is the volume of sludge settled after 30 minutes, the purpose of measuring this parameter is to evaluate the concentration of activated sludge through the following criteria:

– The ability of mud to form cotton

– Sludge settling capacity

– Water treatment capacity (sensory assessment)

Prepare 01 1000 ml measuring cylinder and 01 sampling device, then proceed to select a sampling location in a suitable aerobic biological tank. Sampling at a selected location at a depth of 20-30% from the bottom height of the tank. Scoop a sufficient amount of sample and pour it into a 1000 ml freezer tube. Then press the meter after 30 minutes to record the volume of settled sludge after 30 minutes and evaluate the sense of the sludge (measurement unit is ml/l).