Ways to Overcome Anaerobic Odor Problem

Wastewater System based on anaerobic treatment option to breakdown raw bloodwater from slaughterhouse can generated quite an unpleasant odor. Although the system is capable of reducing BOD as high as 90%, provided that there is sufficient residence time (at least 30 days), the odor issue can still result in setback towards viability of the whole treatment plan especially if the anaerobic pond is close to residential area. Most of these ponds are uncovered due to cost saving matters, so with that, gas from the processes such as hydrogen sulphide, methane will disperse and contaminate the environment. Not only will this lead to complaints but also under current environmental protection regulations, this will empower and give authority to the controlling bodies to issue summonses and potentially shut down the factory operations.

cattle production slaughterhouseTrying to deal with the odor problem coming from anaerobic process can be quite a challenge. Quite a number of times, engineers have been looking at waste treatment options either to work on improving the current system or proposing to the management team to spend on system upgrading. This might sound practical because after all, it’s a direct approach to cope up with the demand but question is, are those the only options available? There are ideas and suggestions such as turning the plant into aerobic waste converter which might seem feasible but overall, there is no firm and conclusive evidence that doing this will greatly reduce the entire foul odor generation problem. To my opinion, it makes little difference whether by changing a surface aerator into a submerged type will help because eventually the gases have to find ways to escape. Furthermore, if the odor problem is not due to hydrogen sulphide which can be removed by ferric chloride but with some other organic acids (from the anaerobic breakdown processes), then, it might turn up to be even more complicated approach. There is some success towards the idea on introducing a specific strain of bacteria to improve the biological process but sometimes, sudden die-off due to excessive loading or change of temperature can have detrimental effect to the bacterial breakdown efficiency. Also to take into consideration, if the amount of methane generation is low, it would not be cost effective at all to build a system to harvest the gas.

On the other hand, some engineers would actually look towards improving the system by adding pre-treatment processes such as DAF unit or introduction of ferric chloride to be used as a coagulant to lump together the blood and then hoping to reduce BOD load. This requires time to do jar testing and then trying to find the best operating condition that will work to remove most of the solids that contribute to the BOD load. This approach will somehow help to reduce odor generation but what I think is that, it will just add up to operation cost as some of these chemicals can be quite costly especially those proprietary ones claimed by some sales rep saying that it would work magic. My advice is, do not buy into the idea. The question is, would anybody actually look into ways to contain the source, that is to control on the waste blood generation and thus reduce loading amount? When the thought was first put up, not many would seem interested because in people’s mindset, it is normal for production to keep on producing and generating waste products. What involves is basically to implement some form of controlled measures on the most common activities like floor washing to curb on the bloodwater generation without jeopardizing the productivity or slaughterhouse operations. This can be done by designing a separate waste collection stream. Further discussion on this topic can be found at Slaughterhouse Waste Treatment Options.

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