Recent increases in flushed nondegradable items can mean serious problems, but using the right valves will help
Choosing the appropriate check valve for wastewater applications isn’t as simple as it used to be, as the amount and type of modern trash going through wastewater pipelines is steadily increasing and changing.
Today’s increased use of cleaning towels and wipes made from fabrics and plastic resins have treatment plant operators across the globe experiencing more and more difficulties and maintenance issues in pumps and piping systems. These pieces of fabric hang up and get caught on areas of restriction within a pipeline system, causing blockages as material builds up behind them. This is often referred to as roping, and it impedes system performance. The time and equipment needed to remove large clogs can be significant, resulting in high costs for repairs.
Avoiding roping in a system is best done by preventing material like nonflushable wipes or other no disintegrating materials from entering the system. However, controlling what the public flushes is an impossible task. What you can do is build your system to limit the potential snag points by using components that allow maximum flow with less system maintenance.
Check valves are a necessary part of any pumping system to prevent backflow and protect the pump and system from damaging surges and water hammer, but they can also be a common point of maintenance and restriction depending on the style. Swing check valves are commonly used in wastewater applications and can create a snag point due to their internal components that feature a hinged disc that swings off a seat to allow flow in one direction but blocks reverse flow by swinging back onto the valve seat when flow stops. When materials that don’t break down get caught on the internal components, not only can it create large clogs, it can prevent the valve from closing fully and functioning properly leading to water surges and hammering.
Instead of using high-maintenance, snag-prone swing check valves in wastewater applications where modern trash is anticipated, consider using ball check valves. Ball check valves like the ones designed and manufactured by Flomatic are anti-roping and self-cleaning valves with no sharp edges or snag points, which prevents clogging from nonflushable wipes and other trash. They have been proven in wastewater lift stations for decades with a simple and reliable design with the only moving part being a vulcanized metal ball.
When fluid is flowing through a pipeline, the ball is pushed out of the seat and stream into a separate chamber of the valve housing (Fig. 1). When the flow stops or reverses the ball rolls back by gravity into the seat, creating a fluid-tight seal (Fig. 2). The ball itself is buoyant, which greatly reduces friction and improves
The simple ball-in-seat design creates a smooth valve interior so particles and trash are able to flow through the valve without getting stuck. When under flow, the ball is constantly spinning which also contributes to keeping the valve free of debris, allowing it to work properly and stop reverse flow. The ball check valve has a self-cleaning seat as the vulcanized metal ball will seat on a new surface each time it operates pumping efficiency.