The best Side of BOD meaning
The best Side of BOD meaning
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Plant decomposition and leaf fall are common resources of organic and natural debris. Using the dissolved oxygen in the water, germs will decompose this organic things and type less sophisticated organic and natural molecules.
有機物の量：バクテリアが分解を終えた時、容器内の酸素が半分程度残されている必要があり、推測により希釈する
Sources of BOD consist of leaves and woody particles; useless plants and animals; animal manure; effluents from pulp and paper mills, wastewater cure vegetation, feedlots, and food stuff-processing plants; failing septic systems; and concrete stormwater runoff.
Calibration: Irrespective of technologies, it is usually recommended to only calibrate the instrument once daily just before readings are taken. Be certain there aren't any water droplets to the probe suggestion right before calibrating and that the probe is in a very a hundred% water-saturated air surroundings.
It's going to take some experimentation to find out the suitable dilution aspect for a certain sampling website. The final result is the main difference in dissolved oxygen among the initial measurement and the second just after multiplying the second result because of the dilution element. Far more facts are offered in the next portion.
DO concentrations fluctuate seasonally and about a 24-hour period. They range with water temperature and altitude. Cold water holds more oxygen than heat water (Desk 5.three) and water holds much less oxygen at higher altitudes. Thermal discharges, which include water utilized to interesting machinery inside of a manufacturing plant or an influence plant, increase the temperature of water and lower its oxygen written content.
Việc thử nghiệm chỉ số BOD là phép đo tốc độ hấp thụ hết oxy của vi sinh vật có trong mẫu nước thử ở nhiệt độ cố định (20 °C - mẫu thử nghiệm được đặt trong tủ ủ giống như tủ lạnh) và trong một khoảng thời gian chọn trước (thường là 5 ngày) trong bóng tối. Để đảm bảo mọi điều kiện là tương đương, một lượng rất nhỏ vi sinh vật mầm mống được thêm vào trong mỗi mẫu cần thử nghiệm cũng như trong một mẫu đối chứng chỉ chứa nước cất.
Make it possible for just as much time as is possible with the seed to "wake up" from its freeze-dried point out previous to use (but soon after hydration).
DO samples are collected utilizing a special BOD bottle: a glass bottle using a "turtleneck" in addition to a ground glass stopper. You can fill the bottle straight during the stream If your stream is wadable or boatable, or You should utilize a sampler which is dropped from a bridge or boat into water deep adequate to submerse the sampler.
試料の溶存酸素量や微生物の種類などによって測定値は影響を受けるため注意が必要である。
Each and every vial is mixed effectively and placed in to the reactor block for two hours. Immediately after two hours, the vials are faraway from the block to your cooling rack for about 15 minutes.
Bigger temperatures decrease the solubility of oxygen in water. Plant production raises DO in daylight hours but raises oxygen demand over the night time. Subsequent plant decomposition can deplete DO. Additionally, minimized turbulence from a lot less woody here particles may well minimize aeration.
Resources that Enhance the extent of Biological Oxygen Demand for water is both organic and anthropogenic. Air pollution is An important factor in the increase of BOD in water bodies.
A few varieties of titration apparatus may be used Along with the Winkler method: droppers, digital titrators, and burets. The dropper and digital titrator are fitted to field use. The buret is here a lot more conveniently Utilized in the lab (Fig.