How do you account for the BOD of seeded dilution water?

How do you account for the BOD of seeded dilution water?

#2 Seed BOD = (DO depletion x 300)/Seed dilution, mL The calculated seed BOD represents the BOD exerted by 300 mL of undiluted seed material. The ratio of the seed BOD to 300 mL will be used to calculate the seed correction for seeded samples.

What is seeding in BOD test?

What is seed, and how is it used in the BOD dilution method? Using seed in BOD analysis. The term “seed” refers to microorganisms that consume the biodegradable organic matter in samples for measurement of Biochemical Oxygen Demand (BOD).

What is dilution factor in bod?

Dilution is needed to prevent the depletion of entire oxygen present in in BOD bottle in less than incubation period of 5 days. For a valid BOD test APHA manual specifies some min DO of 1 mg/L to be present in the bottle after end of 5 days and DO consumed should be at least 2mg/L during incubation.

How is dilution factor calculated?

Dilution factor is defined as: total volume of solution per aliquot volume. Where total volume of solution is: 10.0 + 240.0 = 250.0 mL (volumetric flask.)

What is BOD formula?

Biochemical Oxygen Demand ???, ??/? = ?1 − ?2 ? When the dilution water is seeded ?????/?, = ?1 − ?2 − ?1 − ?2 ? ? Where: D1: Dissolved oxygen of diluted sample immediately after preparation, mg/L D2: Dissolved oxygen of diluted sample immediately after 5day incubation at 20⁰C, mg/L B1: Dissolved oxygen of seed control …/span>

What is a good BOD level?

1-2 ppm

What causes increase in BOD?

Laboratory experiments indicate that BOD is not influenced by water temperature at the time of sampling or by enrichment with nitrate or ammonia. Rather, enrichment with macrophyte leachate sharply increases BOD, and enrichment with phosphate produces a small but significant increase in BOD.

Does BOD increase with temperature?

The BOD removal rate in the bioreactor increased when the temperature increased from 20 degrees C to 30 degrees C, 40 degrees C, and 50 degrees C, but it decreased when the temperature increased from 50 degrees C to 60 degrees C. Higher temperature enhanced the endogenous respiration of microbes in the bioreactor.

Why is bod done for 5 days?

The standard oxidation (or incubation) test period for BOD is 5 days at 20 degrees Celsius (°C) (BOD5). The BOD5 value has been used and reported for many applications, most commonly to indicate the effects of sewage and other organic wastes on dissolved oxygen in surface waters (see TECHNICAL NOTE).

What causes high COD in wastewater?

However, soluble organic compounds are most likely to contribute to escalated COD concentrations. Residual food waste from bottles and cans, antifreeze, emulsified oils are all high in COD and are common sources of COD for industrial stormwater. A typical COD concentration for soda and beer is about 100,000 mg/L./span>

What is the relationship between BOD and DO?

(a) Are directly proportional. Hint: DO are dissolved oxygen and BOD are biochemical oxygen are certain parameters by which one can find out the degree of water pollution or the concentration of readily biodegradable organic matter in the water bodies. …

What is BOD and do in water?

Dissolved Oxygen (DO) is the amount of oxygen dissolved in the water system. Therefore it is important to monitor the amount of DO in the water and also the BOD so it will not deplete the oxygen levels to a low and cause the system to become unhealthy and unsupportable to sustain life.

What is the BOD of safe drinking water?

For drinking water BOD has to be less than 5 mg/L and for treated wastewater to be disposed of in the water bodies it is 30 mg/L, 100 mg/L if treated waste water is discharged into the sewerage system in India.

What is BOD and why is it important?

The decay of organic matter in water is measured as biochemical or chemical oxygen demand. Oxygen demand is a measure of the amount of oxidizable substances in a water sample that can lower DO concentrations. BOD is used, often in wastewater-treatment plants, as an index of the degree of organic pollution in water.

What is the value of BOD of good quality water?

Typical values Most pristine rivers will have a 5-day carbonaceous BOD below 1 mg/L. Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/L. Rivers may be considered severely polluted when BOD values exceed 8 mg/L.

What is COD in wastewater?

The chemical oxygen demand (COD) is a measure of water and wastewater quality. The COD test is often used to monitor water treatment plant efficiency. The COD is the amount of oxygen consumed to chemically oxidize organic water contaminants to inorganic end products.

How do you reduce COD in wastewater?

The most important way to get rid of the sludge is to use coagulants and flocculants. The principle is to bind the sludge to one another so that a larger clumps of sludge and then be deposited in a sedimentation tank. Some chemicals commonly used as a coagulant, among others; PAC, FeCl3 (Ferric Chloride) and Alum….

Is high COD good or bad?

COD is an indicative measurement of the amount of oxygen that can be consumed by reactions in a measured solution. COD detection can be used to easily quantify the amount of organics in water. The higher the COD value, the more serious the pollution of organic matter by water.

How do you test for BOD and COD in water?

The COD test uses a chemical (potassium dichromate in a 50% sulfuric acid solution) that “oxidizes” both organic (predominate) and inorganic substances in a wastewater sample, which results in a higher COD concentration than BOD concentration for the same wastewater sample since only organic compounds are consumed …

What are the interferences during COD test how this can be eliminated?

Total COD is run on undiluted samples. If the COD exceeds 1500 mg/L, the sample should be diluted to bring the results in range. Chloride is the primary interference. Vials with mercuric sulfate can be used to eliminate chloride interference up to 2000 mg/L Cl–.

What is dilution water?

1. n. [Drilling Fluids] Also called make-up water, which is water added to maintain or dilute a water-mud system. The added water may be fresh water, seawater or salt water, as appropriate for the mud.

Why do we measure BOD and COD?

BOD measures the amount of oxygen required by the aerobic organisms to decompose organic matter and COD measures the oxygen required to decompose organic and inorganic constituents present in the wastewater by chemical reaction. Hence, the value of COD is greater than BOD.

What does the ratio of BOD to COD indicate?

If the BOD/COD ratio for untreated wastewater is 0.5 or greater, the waste is considered to be easily treatable by biological means. If the ratio is below about 0.3, either the waste may have some toxic components or acclimated microoorganisms may be required in its stabilization.

How cod is calculated?

Chemical oxygen demand, or COD, is a test that measures the amount of organic compounds in water. Consider the formula for COD calculation: (a – b) X C X 8,000 / the volume of the sample in mL. Let “a” represent the titrant used for your sample expressed in mL….

How is ThOD calculated?

We can calculate by following steps:

1. Write balanced reaction for the carbonaceous oxygen demand. CH2(NH2)COOH + 1.5O2 → NH3 + 2CO2 + H2O.
2. Write balanced reactions for the nitrogenous oxygen demand. NH3 + 1.5O2 → HNO2 + H2O. HNO2 + 0.5O2 → HNO3
3. Determine the ThOD. ThOD = (1.5 + 2) mol O2/mol glycine.

What is carbonaceous bod?

Carbonaceous Biochemical Oxygen Demand (CBOD) Carbonaceous BOD is a subset of BOD. BOD results are based on DO depletion from both carbonaceous and nitrogenous actors in a wastewater sample. CBOD measures DO depletion from only carbonaceous sources.