8 ways the UASB is better than the lagoon for biogas generation 

You may think that all anaerobic process for biogas generation is the same, but you could be wrong. For example, both the UASB and anaerobic lagoon can produce biogas. They look totally different and have different features.  Here, we present 8 ways the UASB process is better than lagoon process. 

Papop is the leading wastewater and biogas technology provider in Thailand for over 30 years. We have board experience on both processes. We can provide you with the insight on biogas production. 

1.Higher COD removal efficiency  

the UASB process has COD removal efficiency of around 90-95% depending on the type of wastewater due to the high concentration of bacteria mass in the granular sludge. While the lagoon process has the COD removal efficiency of around 60-70% maximum. Hence, the UASB process can produce more biogas than the lagoon process. More biogas means the better return of investment, so the UASB is more superior than the lagoon process. 

2. Higher methane concentration in the biogas 

Biogas with higher methane content is better for application in boiler and genset. In this regard, the UASB process is superior than the traditional lagoon process. It is possible to achieve methane content up to 65%-70% with the proper design in the UASB process. Conversely, methane content in the lagoon process cannot be controlled. Hence, methane content in the lagoon is maximum at around 50%-60%. 

 3. Smaller footprint 

The design loading rate of the UASB process is 5-10 times higher than the lagoon process. Therefore, the UASB has a much smaller footprint than the lagoon. Hence, you will have the remaining area for other purposes. Besides the UASB tank is usually constructed in concrete or steel, so the strength is much higher and more robust than the lagoon process. 

 4. Revenue from selling of granular sludge 

For those who have used the UASB process know really well that granular sludge is an important component for fast startup and stable operation. You may also realize that the same granular sludge can be sold to generate revenue to your factory. In Thailand, good size and composition of granular sludge can be sold at around 1,000 THB per cu.m. If operate well, the UASB plant can generate excess granular sludge each year which has to be removed. What is a better way to dispose of unused sludge by selling it and make money? On the other hand, lagoon process does not generate granular sludge, so you will not get revenue from it. 

5. Faster startup time 
 Startup time for the UASB process with sufficient and healthy granular sludge is only around 1 month. This means you could achieve 100% of biogas generation within 1 month which is very quick. In the lagoon process, we cannot control this process. It happens naturally and may take up to 3-6 month. We cannot rush it. Hence, why not go for the UASB process and save those months. 

6. More stable operation 

The UASB process can be operated stably by the moderate skill operator. He/she needs to understand the basic concept of microbiology and how it works. This is not too difficult, but again it is not as simple as operation of the lagoon process.  While the lagoon biogas generation tends to be fluctuated over time. The UASB process biogas generation is much more stable. This is why it is more suitable for application in boiler and biogas genset. 

 7. Less maintenance cost in a long term 

Many people say the UASB requires more sophisticated maintenance than the lagoon process on flushing the distribution pipes to prevent clogging. This is true, but it is no longer laborious. Latest version of Papop’s the UASB do not require operators to manually open and close distribution pipes every day. Instead, it is all done automatically with PLC and SCADA and automatically valves. Therefore, it saves time and maintenance cost in a long term. On the other hand, operators have to stop operation of the lagoon process every 5-6 years to replace the cover sheet and desludging the lagoon. This process may take up to 6 months to complete. This process can cause odor issue to disturb the nearby residents. Besides, it is a headache to dispose the sludge from the lagoon. It is costly to remove and costly to dispose of. This is a constant headache for the lagoon process owner and will create direct and indirect cost (loss of opportunity). 

 8. Safer operation 

The UASB tank is typically designed as a concrete or steel tank. It is very safe against wind and storm. While, the lagoon process is not. There is always a high risk of the cover sheet in the lagoon process to break away if not designed and constructed properly. There were several cases of fire incidents in tapioca factories in Thailand 10 years ago, due to the damage lagoon process.  It is recommended that the lagoon process shall be avoided in the area of high wind or frequent storm visits. Additionally, these processes shall be located far away from the factory, offices or residential areas to minimize risks of fire.

Papop is the leading green tech company in Thailand. If you are interested in cost saving, waste treatment or mitigating climate change through the use of renewable energy, please contact us at  l  LINE: @papop l Call: +66 2 570 5580.