Fibrous Wastewater Pumping | Tsurumi BN Series Case Study

Almost every week, the maintenance team faced the same job – strip a Yardmaster pump, clear out the hay and silage, then put it back together.

That material was meant to reach the screening plant. Instead, it was clogging the pumps upstream.

The client

Silver Fern Farms

The project

At Silver Fern Farms in Pareora, sheep were hosed down after arriving on site. The washdown water carried hay, silage, grass and animal waste into the collection pit.

The pit pumps moved wastewater from the pit to the screening plant where the solids were removed and the remaining water went on to irrigation.

The screening plant at Pareora – where solids were removed from the washdown wastewater

The challenge

The two Yardmaster pumps could move the water. What they couldn’t handle was the fibrous material travelling with it.

One pump covered the normal flow – while the other was kept on standby and brought in when flows increased. But hay and silage wrapped around both impellers, driving up motor amperage until the pump tripped. Switching pumps only shifted the same problem.

For about eight months, Silver Fern Farms had been working around the issue by pulling hay out before it reached the pumps. That meant more manual handling and another bottleneck before the wastewater even reached screening.

Bins of hay and silage removed from the washdown wastewater before it reached the pumps

The solution

The answer wasn’t more flow – it was a different way of handling the solids.

Prime selected a Tsurumi BN Series submersible cutter pump in place of the end suction setup. Its cutter function broke up the fibrous material so it could pass through to screening rather than wrap around the impeller.

The BN model pumped directly from the main collection pit, with new pipework carrying the wastewater straight to the screening plant. That took the Yardmasters out of normal duty yet kept both in place as backup.

The Tsurumi BN Series Cutter Pump in Action

See how the BN Series cutter pump breaks down fibrous material before it can bind around the impeller.

The outcome

The biggest change was what Silver Fern Farms no longer had to work around. Early results were:

• One pump on normal duty – the Tsurumi BN handled the washdown transfer on its own, simplifying the day-to-day pumping setup

• Reduced power demand – the new BN pump had a 7.5kW motor and drew around 5.7kW in operation, helping reduce energy use and operating cost
• Existing backup pumps kept in place – installing the BN in the main collection pit let Prime bypass the existing Yardmaster setup without removing it, so both pumps stayed in place as fallback if needed
• Less reactive pump maintenance – removing the weekly pump strip-down freed two maintenance staff to focus on planned work elsewhere on site.

Repeated blockages from fibrous waste are often a sign the pump isn’t matched to the solids it needs to handle. Talk to a Prime pump specialist about a setup that is.

Tsurumi BN Series cutter pump installed in the main washdown collection pit