A pork processing plant’s onsite wastewater treatment facility had an air leak in the manifold that distributes air to “stones,” which oxygenate the water in its aerobic treatment basin.

This style of treatment tank requires all repairs to be made while the plant remains in operation, without disrupting airflow. This technique avoids impacting the wastewater treatment process, which could potentially cause more problems than the original issue. However, not all repair services have the skills to navigate this situation, so Bulldog Diving LLC was called in.

The main factor in any aeration basin air leak repair is to make sure the work restores airflow to the rest of the aeration grid. Bulldog’s dive technicians located and inspected the problem area and found the air leak. Once they located the issue, they devised a solution most appropriate to the problem. Options included replacement of parts, repair to existing parts, or permanently capping/plugging a portion of the damaged equipment to isolate that section of the plant from the rest, so it wouldn’t create a damage cascade effect.

Besides the typical challenges of commercial diving, aeration tanks required the divers to deal with limited-to-zero visibility conditions; time and pressure issues; and — especially in aeration systems — heat. Working in these live/running conditions, with continuous airflow, creates strong currents that push and pull the diver around, making the repairs more difficult and time consuming.

After inspecting the damaged area, the lead diver determined that an O-ring was blown out on an aeration stone, making it necessary for its retaining ring to be properly retightened. The client had also mentioned concerns about a gate valve in the same basin, which had ceased to be operational. Upon inspection, the diver reported the valve stem hardware — which made the connection to the gate — was damaged and required replacement. The client had the replacement hardware on site, and Bulldog’s dive team were able to get the gate operational during the same visit.

The team replaced the stone’s missing O-ring and retightened its retaining ring to standard specifications, sealing off the air leak and restoring 100% airflow to the rest of the aeration grid. This brought the wastewater treatment process back to normal operating status and kept the plant’s treatment processes running without delay or loss of productivity. A separate repair call was avoided by the diver’s inspection and diagnosis of the faulty valve, saving the client time and money.

Source: Bulldog Diving LLC