How many hours after sample collection should a BOD analysis ideally begin if immediate analysis is not possible?

For Biochemical Oxygen Demand (BOD) analysis, it is crucial to initiate the analysis as soon as possible after sample collection to ensure accurate measurements of organic matter in wastewater. If immediate analysis cannot be performed, it is essential to minimize alterations in the sample that could lead to inaccurate results.

Ideally, BOD analysis should begin within 24 hours of sample collection. This timeframe is largely recommended because, after 24 hours, there is a risk that microbial activity and environmental conditions may alter the sample's characteristics, potentially leading to erroneous BOD readings.

The 24-hour window allows sufficient time for transport and any necessary laboratory preparations while ensuring the organic content of the sample can still be measured effectively. This is why this timeframe is considered the standard in practice, striking a balance between logistical considerations and the need for reliable data.