01.04.2018
The solids content of sewage continues to increase. Diapers, rags, items of clothing, wet wipes - especially sewage from public restrooms - for example, in hospitals, shopping centres, hotels or train stations - often contains items that can sometimes pose serious problems for pumps, and may possibly even cause failure.
The solids content of sewage continues to increase. Diapers, rags, items of clothing, wet wipes - especially sewage from public restrooms - for example, in hospitals, shopping centres, hotels or train stations - often contains items that can sometimes pose serious problems for pumps, and may possibly even cause failure. The compact solids separation system Wilo EMUport CORE offers maximum operational reliability during sewage collection and transport.
Operational reliability due to solids separation
Compared to conventional pump systems, the solids separation system provides considerable advantages: “Wilo EMUport solids separation systems separate the sewage into solid material and pre-cleaned sewage”, explains Carsten Stremmel, Wilo Product Manager. “With this technology, larger solid material does not have to be conveyed by the pump hydraulics.” While the coarser particles are collected in the solids separation reservoirs, the pre-cleaned sewage flows back through the pump into a collection reservoir. Once this reservoir is filled, one of the two pumps starts, based on the liquid level, and pumps the pre-cleaned sewage out of the collection reservoir and through the solids separation reservoir: “In this way, the collection reservoir is emptied, the separation reservoir is flushed and the solid material with the pre-cleaned sewage is conveyed into the discharge pipeline”, Stremmel explains with regard to the operating principle. “Wilo EMUport solids separation systems always use two pumps that operate alternately. This measure ensures that sewage intake via the second pump continues in parallel with the drainage pumping sequence, thereby assuring continuous sewage intake.”
Reliable long-term operation
In the course of the continued development of its EMUport CORE solids separation system, Wilo, the Dortmund-based manufacturer of pumps and pump systems, incorporated the experience gained from the more than 1000 units sold. Additional details were modified, further increasing the operational reliability and simplifying maintenance work. Similar systems often have collection reservoirs and solids separation reservoirs made of stainless steel. When selecting its materials, Wilo decided in favour of polyethylene and polyurethane: “In contrast to stainless steel, which can corrode quickly in the event of poor passivation after welding, these materials are absolutely corrosion-free”, says Stremmel. “Moreover, polyethylene stands out with its extremely long service life, and compared to other materials is very light, which greatly simplifies onsite relocation of the system.” The intake box is made of polyurethane, which is also corrosion-free and extremely impact-resistant so that larger solid objects such as stones or pieces of wood cannot damage the intake box. To minimise the volume of water remaining in the collection reservoir, the reservoir geometry was tailored to requirements. The entire bottom of the reservoir is sloped, whereby the lowest points of the reservoir are located directly under the pumps. This design prevents the formation of deposits in the collection reservoir.
The pump is also vented automatically: This is accomplished by mounting the pump at a slight angle on the system, thereby preventing air becoming trapped in the hydraulics. For hygiene reasons, the pumps are kept dry, yet nevertheless satisfy the demanding requirements for the high IP 68 protection class (continuously immersible): “Based on experience, every pumping station will be flooded at least once in the course of its life cycle, which does not pose a problem for pumps with the protection class IP 68”, explained Mr. Stremmel. “Operational reliability is thus assured even in the event of temporary flooding of the system.” The entire system is designed for continuous duty (operating mode S1).
Minimal maintenance and a small footprint
The solids separation unit has proven itself a thousand times over, a special design that combines the functions of a rake and a valve. Solid material that could disrupt pump operation and ultimately cause a breakdown is not allowed to enter the pump. Residue-free cleaning of the solids separation unit and the solids separation reservoir takes places automatically in the course of the regular pumping cycle. Maintenance work can be carried out without labour-intensive and time-consuming disassembly of the pumps. The intake box is just as easy to service: “Thanks to a transparent cover, visual inspection during operation is possible without the use of tools”, points out the Product Manager.
With its compact construction, the Wilo EMUport CORE
solids separation system also fits in chambers with an inside diameter of only 1.5 metres: “This further reduces the installation costs”, explains Mr. Stremmel.