Sulzer ABS Piranha PIR-S21/2 Submersible Grinder Pump

The Sulzer ABS Piranha grinder pump PIR-S21/2 is a submersible sewage pump built for the effective and economical discharge of wastewater and effluent through small-diameter pressure discharge lines. Using the unique Piranha shredding cutter system, the pump macerates rags, wipes, sanitary items and other fibrous solids commonly found in municipal and commercial sewage before they can reach the impeller, preventing clogging and enabling reliable pumping through pipework as small as 32-40 mm in diameter.

Piranha Shredding Technology

At the heart of the S21/2 is the Piranha cutting system: a hardened cutting plate and rotating cutter positioned at the pump inlet that shred solids into a fine slurry before they enter the pump chamber. This grinding action is essential for pressure sewer systems, low-pressure effluent networks and applications where gravity drainage to a large-diameter main is not practical, allowing wastewater to be conveyed over longer distances and through smaller pipe runs than a conventional non-clog pump would permit.

Technical Specifications

Performance and Construction

The Piranha S21/2 delivers a flow rate of up to approximately 47 m³/h against a maximum discharge head of around 32 m, with a 2.1 kW motor and a discharge connection of G2 (2 inch). The pump weighs approximately 37 kg and is built in a rugged cast iron housing designed for continuous submerged operation in pump stations, wet wells and sewage lifting stations. Ex-rated (ATEX) variants of the S21/2 are available for installations in potentially explosive atmospheres, alongside standard non-hazardous-area models, and cable lengths and float switch configurations can be specified to match the installation.

Typical Applications

Sulzer ABS Piranha grinder pumps are widely used in municipal and communal sewage pumping stations, private and commercial wastewater lifting stations, campsites, marinas, restaurants and any installation where wastewater must be pumped through small-bore discharge pipework or over an extended distance. The shredding action also protects downstream pipework, valves and treatment equipment from blockages and damage caused by rags, wipes and other non-biodegradable solids that increasingly challenge conventional wastewater pumping systems.

Maintenance and Service Life

Because the cutting mechanism is a wearing component subject to continuous contact with abrasive and fibrous solids, the Piranha S21/2 is designed for accessible inspection and replacement of the cutter plate and rotating blade during scheduled maintenance. Mechanical shaft seals protect the motor from wastewater ingress, and routine monitoring of seal condition, cutter sharpness and bearing performance helps extend service intervals and avoid unplanned pump station downtime. Genuine Sulzer ABS spare parts and cutting kits are recommended to maintain rated shredding performance and hydraulic output over the life of the pump.

Handling Difficult Solids in Modern Wastewater

Municipal and commercial wastewater increasingly contains non-biodegradable wipes, sanitary products, plastics and textile fibers that were never designed to pass through conventional plumbing or pumping equipment. Standard non-clog and vortex pumps can struggle with this material, leading to rag balls forming around the impeller, reduced flow, higher energy consumption and frequent unclogging call-outs. The Piranha S21/2 addresses this directly by shredding solids at the inlet before they can reach the impeller, reducing unplanned maintenance visits and helping pump stations maintain rated capacity between service intervals.

Installation Configurations

The Piranha S21/2 can be installed as a portable, transportable unit for temporary dewatering and bypass pumping, or permanently mounted on a discharge connection (DS or D01 type coupling foot) within a wet well or pump station for automatic, unattended operation. Automatic level control is typically achieved using float switches or level sensors that start and stop the pump according to wet well level, and dual-pump duty/standby configurations are common in municipal lift stations to provide redundancy and to allow pumps to alternate duty cycles, extending overall service life.

Selecting the Right Model

The Piranha range spans multiple power ratings and performance points beyond the S21/2, including smaller and larger frame sizes to match a wide range of flow and head requirements. Selecting the correct model depends on the design flow rate, the static and friction head of the discharge pipework, the expected solids loading, and whether the installation requires ATEX certification for a hazardous area. Seven Star LLC can assist with pump sizing calculations and can cross-reference existing Sulzer ABS pump station installations to confirm the correct replacement or upgrade model.

Energy Efficiency and Reliability

Because the Piranha cutting system prevents solids from lodging in the impeller passage, the pump maintains its designed hydraulic efficiency for longer between cleanings than a comparable non-shredding pump exposed to the same solids loading. Sustained blockage-free operation translates directly into lower energy consumption per cubic meter pumped and fewer emergency maintenance dispatches, which is particularly valuable for remote or unmanned pump stations where a clogged pump can otherwise go undetected until an overflow or high-level alarm occurs.

Seven Star LLC also supplies compatible cutter kits and mechanical seal spares for the Piranha range, helping utilities and facility operators plan preventive maintenance rather than reacting to unplanned failures.

Why Choose Seven Star LLC

Seven Star LLC supplies genuine Sulzer ABS submersible pumps, including the Piranha grinder pump range, to municipal utilities, industrial facilities and contractors across Oman and the wider GCC region. Our team can help specify the correct Piranha model, motor rating, cable length and hazardous-area classification for your pumping station, and can support spare parts and cutter kit supply to keep existing installations running reliably.

Get a Quote

Contact Seven Star LLC for pricing, lead time and technical specifications on the Sulzer ABS Piranha PIR-S21/2 submersible grinder pump, or for other Sulzer ABS dewatering, sewage and mixing pump solutions for your wastewater infrastructure.

Browse the full Sulzer range or see more Pumps products supplied by Seven Star LLC in Oman and the GCC.

See also: Sulzer VMS Vertical Multistage Pump; Sulzer SES End-Suction EN 733 Centrifugal Pump.