6.4.1 Clogging

The clogging of blackwater inlet pipes in biogas plants was observed as one of the issues that can significantly impact biogas plants’ functioning. According to the assessment in 2019, visiting 24 biogas digesters, 62.5% of operators reported experiencing this problem. The main reason for these clogs was attributed to the disposal of solid waste, such as sanitary pads, along with other plastic and rubber materials. During the visits, it was also observed that misalignment of the piping system gradient and bends could exacerbate the issue. Additionally, the heavy and sealed manhole lids further amplify the problem, making frequent checking and cleaning a challenging and labour-intensive task.

To address these specific challenges and mitigate the clogging issue, the following measures can be implemented:

Awareness Raising: Conduct targeted educational campaigns to raise awareness among users about proper waste disposal practices. Emphasise the importance of not flushing sanitary pads, plastic, and rubber materials down the toilet, and promote the use of designated waste bins.

Screens: Installing screen chambers for the pipe system prevents non-biodegradable materials from entering the system and preventing them from causing blockages further downstream.

Regular Maintenance and Cleaning Schedule: Establishing a proactive maintenance and cleaning schedule for the biogas plants, ensuring regular inspection and cleaning of the blackwater inlet pipes. This will help prevent clogs and maintain the optimal functioning of the system. Prioritise these tasks to address potential issues before they escalate.

Manhole Lid Modifications: Consider modifying the manhole lids to make them lighter and easier to open. This will facilitate regular checking and cleaning of the system, reducing the maintenance challenges associated with heavy and sealed lids.

Piping System Redesign and Alignment: Assess the piping system to identify and troubleshoot any misalignment in gradients and bends. The proper gradient will ensure a smooth blackwater flow, reducing the likelihood of clogs.