Tanya Jawab Seputar COD n BOD: Tutorial Pengolahan Air Limbah

Summary

This video addresses common questions about BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) in wastewater treatment. It explains why these parameters are crucial for monitoring water quality, how they are measured, and the differences between BOD and COD. The video also covers the correlation between the two, the practical benefits of measuring COD, and how it helps assess treatment facility performance. Additionally, it explores how COD values are typically higher than BOD due to the chemical versus biological oxidation of organic matter. The video also touches on the potential impact of ASI water in reducing COD levels.

Takeaways

• 😀 BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) are essential for assessing the organic pollution load in wastewater.
• 😀 BOD measures the oxygen consumed by microorganisms to degrade organic matter in aerobic conditions, typically tested over 5 days at 20°C.
• 😀 COD measures the oxygen required to chemically oxidize organic and other substances using a strong oxidizing agent like K2Cr2O7.
• 😀 COD values are typically higher than BOD values because COD measures both biodegradable and non-biodegradable organic material.
• 😀 BOD and COD both measure oxygen demand but differ in the types of organic material they assess: BOD is biologically oxidizable, while COD is chemically oxidizable.
• 😀 The ratio of COD to BOD in untreated domestic wastewater is generally between 0.5 and 1.0.
• 😀 After biological treatment, the COD to BOD ratio in domestic wastewater reduces to around 0.1 to 0.3.
• 😀 COD is more practical for monitoring wastewater treatment performance since it provides quicker results through chemical oxidation, unlike BOD, which requires days to complete.
• 😀 The BOD value can be estimated from COD using prior knowledge of the COD to BOD ratio.
• 😀 ASI (possibly a water treatment substance) can help reduce COD by volatilizing organic compounds and increasing oxygen, which accelerates biological oxidation of organic matter.

Q & A

Why is it important to measure BOD and COD in wastewater?

Measuring BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) is crucial for assessing the organic pollution load in wastewater. These measurements help in designing effective wastewater treatment facilities and understanding the oxygen requirements for biological and chemical degradation of organic matter.

What is BOD and how is it measured?

BOD (Biochemical Oxygen Demand) is the amount of oxygen consumed by bacteria and microorganisms to decompose organic matter in water under aerobic conditions. It is measured by calculating the difference in oxygen concentration before and after a sample is incubated at 20°C for five days.

What is COD and how is it measured?

COD (Chemical Oxygen Demand) is the amount of oxygen required to oxidize organic materials in water using strong chemical oxidizers like potassium dichromate (K2Cr2O7). It is measured by determining the oxygen needed for the chemical oxidation process, turning organic material into CO2 and H2O.

Why is COD typically higher than BOD?

COD values are generally higher than BOD because the chemical oxidation process (COD) can break down both biodegradable and non-biodegradable organic materials. BOD, however, measures only the biodegradable organic matter that can be decomposed by microorganisms.

What is the relationship between COD and BOD?

COD and BOD both measure the oxygen required for the oxidation of organic matter in water, but COD measures both biodegradable and non-biodegradable organics, while BOD measures only biodegradable organics that can be decomposed biologically by microorganisms.

What is the typical BOD to COD ratio in untreated domestic wastewater?

In untreated domestic wastewater, the BOD to COD ratio typically ranges from 0.5 to 0.7.

What happens to the BOD to COD ratio after biological treatment of wastewater?

After biological treatment, the BOD to COD ratio typically decreases to a range of 0.1 to 0.3, indicating a reduction in biodegradable organic matter.

Why is COD measurement more practical than BOD measurement in monitoring wastewater treatment?

COD measurement is more practical because it can be done quickly using a chemical method, providing immediate results. In contrast, BOD measurement takes several days due to the need for incubation.

Can ASI (Air Sealing Index) help in reducing COD in wastewater?

Yes, ASI can help reduce COD in wastewater in two ways: first, by evaporating volatile organic compounds, and second, by adding oxygen to the water, which accelerates the biological oxidation of organic material by microorganisms.

How does COD testing provide quicker results than BOD testing?

COD testing uses chemical oxidizers, allowing for the immediate measurement of oxygen demand. BOD testing, on the other hand, requires several days of incubation to determine the oxygen consumed by microorganisms during biological decomposition.