ENVIRONMENTAL SCIENCE EXPERIMENT DETERMINATION OF BIOCHEMICAL OXYGEN DEMAND GROUP MEMBERS: MUHAMMAD AIZAT AHMAD AIZAT B SAMAD MUHAMMAD AIZAT B KATTNI MUHAMMAD RUZAIDI B ISMADI More free reports and articles @ docstoc ! Follow me @ Twitter ! TITLE DETERMINATION OF BIOCHEMICAL OXYGEN DEMAND OBJECTIVE • To determine DO and BOD in wastewater. METHODOLOGY Experiment Sample Wastewater Distilled water Apparatus • Pipette 25 mm • Test tube • Beaker • class A • wide bore • dropper • filter funnel • volumetric. Flask • syringe More free reports and articles @ docstoc ! Follow me @ Twitter ! • bulb • spectrophometer RESULT The value for DO and BOD before and after 5 days. Table 1: The DO and BOD value Initial (mg/L) Final (mg/L) BOD Sample 9.03 0.58 7.3 Blank 9.01 7.63 0.04 DISCUSSION Based on the result, it shown microorganisms activity happen in the wastewater. The dissolve oxygen decreased after 5 days. The low value of BOD contain in the wastewater show that the water is clean. The result is an increase in microbial populations, higher levels of BOD, and the increased oxygen demand from the photosynthetic organisms during the dark hours. This result in a reduction in dissolved oxygen concentrations, especially during the early morning hours. The difference in initial DO readings (prior in incubation) and final DO readings (after 5 days of incubation) is used to determine the initial BOD concentration of the sample. This is referred to as a BOD5 measurement. The dissolve oxygen contain in the bottle was measure by using the pH DO probe. The initial reading for the sample bottle is 9.03mg/L moving on towards the final reading is 0.58 mg/L. The reading of DO is decrease after 5 days of incubation. The blank bottle was duplicated in order to get the result, and the blank bottle for the initial reading is 9.01 mg/L, and the blank final reading is 7.63mg/L, which is also decrease. More free reports and articles @ docstoc ! Follow me @ Twitter ! CONCLUSION From the experiment, Biochemical oxygen demand (BOD) is usually defined as the amount of oxygen required by bacteria while stabilizing decomposable organic matter under aerobic conditions. The BOD test widely used to determine the pollution strength of domestic and industrial wastes in terms of oxygen that they will require if discharged into natural watercourses in which aerobic conditions exist. We also know how to conduct the experiment and understand the procedure on determining the DO and BOD. Terms “decomposable” may be interpreted as meaning that the organic matter can serve as food for the bacteria, and energy is derived from its oxidation. REFERENCES • Hammer, M.J., and Hammer, J.M.JR., ‘Water and Wastewater Technology’, 3rd edition, Prentice Hall International Editions, 1996. • Clesceri, L.S., Greeberg, A.E and Trussel, R.R.(1992) ’Standard Method for the Examination of Water and Wastewater ‘, 18th ed. American Public Health Association (APHA). • Metcalf & Eddy: Wastewater Engineering ; Treatment,Disposal Reuse, Mc Graw-Hill, 1979. More free reports and articles @ docstoc ! Follow me @ Twitter !
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