Biochemical Oxygen Demand / Board of Directors

BOD Full Form in English, letter by letter

BOD is Biochemical Oxygen Demand, the oxygen microbes use to break down organic matter in water, and in business it means Board of Directors.

BOD Full Form in Indian Languages

BOD means Biochemical Oxygen Demand in water testing, and Board of Directors in company law. Most of this page covers the water-quality measure, with a short section on the business term. The name in six Indian languages follows.

What Biochemical Oxygen Demand measures

Biochemical Oxygen Demand is the amount of oxygen that bacteria and other aerobic microbes consume while breaking down organic matter in a water sample, reported in milligrams per litre.

The logic is straightforward: more organic waste means hungrier microbes and more oxygen used. That oxygen comes out of the dissolved oxygen in the water, which is exactly what fish and river life breathe.

So the number stands in for risk. It climbs when a town releases sewage or a mill discharges effluent, often before the water looks or smells foul.

How the five-day BOD test works

The routine test is called BOD5. A stoppered bottle of the sample is kept at 20°C in the dark for five days, and a dissolved oxygen meter reads the bottle before and after. The difference is the BOD.

Five days is a practical window. Most easily digestible organic matter is consumed by then, and the laboratory can report within the week. A longer test, up to 20 days, estimates the ultimate BOD but is rarely run.

Samples of heavily polluted water are diluted before testing, since the microbes would otherwise use up all the oxygen in the bottle. Typical readings frame the scale: clean river water is often 1 to 3 mg/L, treated sewage should be below the limit in its consent, and raw sewage commonly reads above 200 mg/L.

BOD and COD measure different things

COD, or Chemical Oxygen Demand, oxidises the sample with strong chemicals instead of microbes. It counts everything that can be oxidised, including matter bacteria cannot digest, so it reads higher than BOD and takes about two hours rather than five days.

Laboratories report both. The BOD to COD ratio is a quick guide to treatability. A ratio above roughly 0.5 means most of the waste is biodegradable and a biological treatment plant, such as an activated sludge plant, can usually handle it.

A much lower ratio, or a very high COD against a modest BOD, points to industrial effluent with chemicals that resist microbes and need pretreatment before the biological stage.

Where BOD limits apply in India

The Central Pollution Control Board and the Ministry of Environment notify effluent standards. The general limit for discharge into inland surface water is 30 mg/L of BOD for most categories of industry, and stricter limits apply in specific sectors and sensitive areas.

Sewage treatment plants in housing societies and commercial complexes are held to norms of 30 mg/L BOD and 100 mg/L suspended solids in the national notification, and some states and tribunals have ordered tighter limits for particular rivers and locations.

A state pollution control board grants or renews consent to operate against laboratory reports of BOD and COD. Repeated exceedances can bring show-cause notices, penalties or closure, so large plants test far more often than the minimum.

For river water, CPCB's designated best-use classes use BOD too: water fit for drinking after conventional treatment is expected to stay near 2 mg/L or below, and outdoor bathing water near 3 mg/L or below. Students meet BOD in environmental science and civil engineering papers and in questions on the Ganga and Yamuna.

BOD as Board of Directors

In business, BOD usually means Board of Directors, the group elected by shareholders to oversee a company. Under the Companies Act, 2013, a public company needs at least three directors and a private company at least two. A listed company must have independent directors, and certain classes of company must have at least one woman director.

At least one director must have stayed in India for 182 days or more in the year. The board appoints senior managers, approves accounts and decides policy, and its decisions are recorded in minutes. If a form or email says BOD resolution, it means a decision passed by the Board of Directors, and has no connection with water testing.

When you see BOD next to a river, a drain or a treatment plant, it means Biochemical Oxygen Demand, a five-day test of how much waste the water carries. Beside a company name, it means the Board of Directors.

BOD Full Form: Common Questions