2. (a) In order to treat industrial wastewater coming from rice noodles manufact
ID: 292999 • Letter: 2
Question
2. (a) In order to treat industrial wastewater coming from rice noodles manufacturing factory, propose an appropriate biological treatment process. Justify the adoption of the proposed reactor and also highlight the challenges with a process flow diagram. (b) Elaborate the advantages of a sequencing batch reactor over membrane bioreactor. (c) Technicians need to check VSS concentration in the return activated sludge (RAS) at least once every shift, and then make appropriate RAS flow rate adjustment (if necessary), in order to maintain VSS concentration. Assumptions: . Technician A recorded RAS flow rate as 240 m*/d and VSS concentration in RAS as 5,500 mg/L in his shift. Technician B (the next one on-duty) measured VSS concentration in RAS as 4,800 mg/L Consider the above assumptions and calculate the new RAS flow rate to be adjusted by Technician B. (d) The MLSS concentration in the aeration tank is 2,450 mg/L. The sludge settle-ability test shows that the sludge volume, settled for 30 minutes in a 1 litre graduated cylinder is 270 ml. Calculate the sludge volume index (SVI), and estimate the SS concentration in the RAS and the required return sludge ratio.Explanation / Answer
1. Activated sludge treatment with aerobic system is best suited as it is the effluent coming from the food industry and will have lots of live microbes so the biochemical oxygen demand will start get reducing from the source of effluent itself.
Scheme of the ETP will be following
1. Inlet collection plus equalisation tank with aeration diffused system bod reducing will start from here itself.
2. Neutralisation tanks to make pH slightly alkaline till 9.5.Use Hydrated lime.Use polyelectrolyte anionic in chemistry.
3. Primary settling tank to settle the settable solids.
4. Thickner and bench filter press to remove and dewater the sludge. Sludge can be treated again by making its pH neutral.
5. Overflow from PST to Bioreactor, here keep the floating aeration with Philadelphia make floating aerators.Maintain minimum 2.0 ppm D.O.
Keep Sludge volume index around 100 and sludge settling around 10.
Advantage-
Cost effective method
Troubleshooting is minimum.
Maintenance is very low.
Disadvantage-
Day to day rigorous monitoring is required with making sure BOD , pH to be maintained with stipulated biochemical load.
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