Study of Oxidation Ditch using Cascade Aerator for Dairy Waste Abstract: Mrs. ReenaNitinPantawane Assit.Prof.(Civil Engg.Dept) Jawaharlal Darda Institute Of Engineering And Technology Yavatmal, India. Water is the gifted boom to human beings but it should be like that when it is free from impurities. But natural water may contain so many impurities to overcome it from water the low cost treatment are preferred. Oxidation ditch is use to reduce the impurities present in the water and also waste water. The waste water coming from various industries is fully contaminated and need treatment in that case economic point of view oxidation ditch is used. The waste water from processing of milk product which entirely composed of organic material or colloidal suspended solid simpler and economical treatment is used. For the treatment of diary waste various biological treatments are carried out which are classified are as follows 1) Non mechanized method a) Anaerobic lagoon b) Oxidation pond 2) Mechanized method a) Aerated lagoon b) Oxidation ditch Since milk waste containsvery little suspended matter, preliminary settling for solid removal does not result in appreciable reduction in BOD in most cases the amount of sand and other floating in the waste is sufficient to warrant a small screen and grit removal chamber. Oxidation ditch which use to enhance DO concentration and COD removal efficiency of waste generated from diary wasteusingcascadeaeration along with oxidation ditch is used to enhance the COD removal efficiency of diary waste. A cascade is provided in addition to original setup of oxidation ditch. The sample of dairy is used for checking the COD removal efficiency. To study of aeration system three cases are to be taken in laboratory initially simple rotor is used for aeration for waste generated from diary. DO concentrations is calculated then only cascade aerator is used and DO concentration is calculated. Finally the combination of both cascade and rotor is used for which oxygen transfer coefficient was observed in the range 4.9 maximum value of oxygen transfer by aeration system was found to be 11.9 gm/hr then COD removal efficiency is determine. ISSN: 2231-5381 http://www.ijettjournal.org Page 485
The process has given upto 96%COD removal efficiency,while using cascade aerator withoxidation ditch. Treatment of Dairy Waste : Introduction: With increase in demand of milk products quality of milk products increased, Quantity of milk is being collected in an organized way and processed in the dairies. It is true that with recent methods of mechanized handling the quantity of milk lost to dairies is less but the organic matter from dairies is much higher than the waste water from communities. Though the waste from dairies are rich in inorganic matter.they are readily degradable like municipal waste water and more amenable to any biological treatment however due coincide aeration aspect this is mostly due to the no availability of suitable and economical methods and the design criteria under Indian condition for past few years consideration work has been done on this aspect oxidation ditch is proffered. Study of Oxidation Ditch : Types -1)Pasveer 2) Carrousel types The oxidation ditch was developed during 1950 at the research Institute for Public Health Engineering in Netherlands (1982) The 1 st oxidation ditch was placed in service in 1954 at Voorshopen,Holland.The plant was designed by Dr.Pasveer known as Pasveer Ditch. A study on comparison on Pasveer oxidation ditches are Pasveer Carrousel Types of aerator The rotor consists of a series of Vertical aerators of several Around the horizontal centre shaft. Rows of blades arranged types have been used. Depth of immersion Controlled by adjusting the level Controlled by a jacking screw of outer weir from the ditch. On the vertical shaft. Sitting of aerator The aerator may be seated at any The surface aerator must be Position along the ditch. Positioned above the deep Section of ditch. Construction Uniformly continuous channel Uniform channel usually 2m ISSN: 2231-5381 http://www.ijettjournal.org Page 486
Usually 1.0-0.8m deep. In depth with aerator porkers 3m Deep. Pasveer type ditch is used to perform the COD removal efficiency of dairy waste. Design criteria The National Environmental research Institute Nagpur given the following standards for oxidation ditch, Organic loading rate -0.15 kgbod/kg mlss Velocity of circulation -0.3 m/s Sludge recirculation -50 to 100 % average flow Excess sludge produced -2.5 to 7.5 gm per capita per day Sludge age (SRT) 30 day Sludge Volume Index -50 to 100 ISSN: 2231-5381 http://www.ijettjournal.org Page 487
Construction Material used masonry or earth work Oxygen requirement -1.5 to 2.0 kg O 2 Rotors:- Per kg BOD Applied 1) Speed of Rotation -70 to 75 rpm 2) Depth of immersion of rotor in mixed liquor 10 to 15 cm. 3) Power requirement 1.0 kw/m length of rotor per hour. Settling tank 1) Surface Loading -30-40 m 3 /m 2 /day 2) Detention time -1-2 hour 3) Shape of circular clarifiers for 1 large size. Experimental setup & operation 1) Preparation of model The oxidation ditch is used in practice have normally following dimensions depending upon design parameters. Depth -1.5 m Width -10 to 20m Length Depending on volume of waste to be treated. The oxidation ditch model was prepared with uniform thickness of 1.0 mm were used.bearings of 50mm diameter were provided for rotors. The experimental model was of fill and draw type and it was not possible to make arrangement of continuous feeding cascade aerator is attached for aeration following dimensions are adopted. Length of ditch -1000 mm Width of ditch -400 mm Depth -150 mm Total capacity -55 mm ISSN: 2231-5381 http://www.ijettjournal.org Page 488
Free board- 50 mm Method of operation After preparation of model and electrical connection DO test was conflicted for rotor performance only tap water was filled in the ditch and by adding calculated amount of Na 2 SO 3 DO of tap water at rotor speed 65rpm, DO concentration is calculated Dairy waste sample is collected from camp road area,amaravati. DO test was conducted and then sample is aerated upto 8hours to reduced the COD removal efficiency of dairy waste. Characteristics of dairy waste. 1. BOD-3070 Mg / l 2. COD-4510Mg / l 3. PH-8.1 4. Suspended solid-1810mg /l During one month 30 readings are taken the COD of influent are tabulated as below. Performance of oxidation ditch for various COD loadings. FOR 24 hours aeration S.N. Influent COD Effluent COD MLSS COD Removal Efficiency PH Room temp. 1 3600 250 2600 93% 8.1 29 2 4000 300 2650 93% 8.1 28.5 3 4500 350 2650 93% 8.1 29 4 5200 400 2650 93% 8.1 28 5 6800 500 2700 94% 8.1 29 These readings are taken for 24hours aerations but due to practical difficulties it is not possible to have aeration period 24hours only 5 reading are taken for which COD removal ISSN: 2231-5381 http://www.ijettjournal.org Page 489
Efficiency was found out upto 93% It is to be decided to take readings for 5hours aerations. S.N. Influent COD Effluent COD MLSS COD Removal Efficiency PH Room temp. 1 700 0 2600 100% 8.1 30.5 2 800 30 2600 96% 8.1 31.5 3 850 32 2650 96% 8.1 31.5 4 900 40 2650 96% 8.1 31.5 5 950 42 2600 96% 8.1 32.0 6 1000 50 2650 95% 8.1 32.0 7 1050 51 2650 95% 8.1 34.0 8 1100 53 2650 95% 8.1 34.5 9 1150 55 2600 95% 8.1 34.0 10 1250 60 2750 95% 8.1 34.5 11 1300 65 2750 95% 8.1 34.8 12 1400 68 2750 95% 8.1 34.9 13 1000 70 2800 95% 8.1 35.0 14 1550 72 2800 95% 8.1 34.0 15 1600 75 2800 95% 8.1 32.0 16 1700 78 2800 95% 8.1 34.0 17 1750 80 2800 95% 8.1 35.0 18 1800 82 2800 95% 8.1 37.0 19 1900 90 2800 95% 8.1 34.0 20 1950 95 2850 95% 8.1 35.2 21 2000 98 2850 95% 8.1 30.2 22 2050 100 2885 95% 8.1 28.9 23 2100 105 2890 95% 8.1 34.2 24 2150 108 2900 94% 8.1 34.9 25 2200 110 2900 95% 8.1 35.0 26 2250 110 2900 94% 8.1 35.0 27 2300 118 2900 94% 8.1 36.0 28 2350 120 2900 94% 8.1 36.8 29 2380 125 2900 94% 8.1 37.2 30 2400 130 2900 94% 8.1 37.0 ISSN: 2231-5381 http://www.ijettjournal.org Page 490
CONCLUSION & RESULT 1. For aeration period 2 hrs, COD of influent is 6800 mg/l and process has given 93% COD removal efficiency due to practical difficulties it was not possible to have 24 hours aeration it reduces to 8 hours 2. For 8 hours aeration process has given 100% COD removal efficiency for 700 influent COD. 3. Maximum COD of dairy waste was 2400 mg/l which was treated for 8 hours and given 94% COD removal efficiency. Referances: 1.Adema D: The Largest Oxidation Ditch for treatment of Industrial Waste 2. Eldrige E.F.: Industrial Waste Treatment Practice McGraw Hill Company (1980) 3.Garg S.K. Industrial and Waste Disposal Engineering 4.Govt.of Maharashtra Maintenance Manual For Dairy Machinery Dairy Development" 5.Siddiqi R.H.; Principles of Biological Treatment. Process design in Waste water. 6.Pasveer A.: Tertiary Treatment with Oxidation Ditch.10 th Symposium of low cost waste treatment Vol.2 Central Public Healh Engineering.Research Institute,Nagpur (1669) 7.Stepheson Roger v.et el: Performance of surface rotors in oxidation ditch Page-79-91 Journal of ASCU (1989) ISSN: 2231-5381 http://www.ijettjournal.org Page 491