Installed in October 2006, the peristaltic hose pumps have delivered trouble-free operation since then, improving sludge consistency.
The wastewater treatment plant was earlier using timer-controlled automatic actuated valves for auto-desludging of the primary tanks at the site.
Engineers at Lavister, which serves a population of 5500 found the valve technology difficult to control with the additional problem of variable sludge consistency.
Dave Hughes working on behalf of Dwr Cymru - Welsh Water said that the valves caused too much water content at the primary sludge holding tank. On the other hand, insufficient desludging resulted in blanket carry over from the primary tanks.
They decided to replace the valves with two SPX50 hose pumps, one for each tank, each of which currently produces approximately 7m³ of sludge per day.
Since installation, the SPX50 pumps have required only minimal routine maintenance with desludging taking place at the specified rate without interruption to flow.
The hose pumps installed at Lavister handle primary sludge with 3-5% dry solids content at a transfer rate of 2500 litres/hour.
Each pump runs at 16 RPM and has a discharge pressure of less than 5 bar.
WIMES Efficiency1 1.5kW cast iron frame motors are fitted to the pumps with fixed speed gearboxes.
Automatic cut-out switches are also fitted to the pumps to protect against blockages in the suction or discharge lines and provide burst hose protection.
Suction and delivery lines are fitted with surge dampers.
Peristaltic pumps are effective on abrasive sewage sludge pumping and similar applications from a combination of the gentle peristaltic pumping action, low operating speeds and the abrasion-resistant characteristics of the hose itself.
Key features of SPX50 hose pumps:
- Designed to deliver continuous flow rates of up to 5,000 l/h and pressures up to 16 bar
- Suitable for auto-desludging applications
- Composite, braided nylon reinforced hose element designed to handle sewage sludge as well as viscous, fibrous and abrasive materials
- Hose incorporates a patented internal reinforcing element for enhanced mechanical strength
- Hose elasticity is maintained by passing it continually through a bath of lubricant
- Rapid hose changing possible
- Low maintenance design
- Offers overload protection and enhanced corrosion resistance
- Achieves and maintains accuracy to within +/-1%
- Can handle additives such as lime slurry and easily damaged filamentous flocculants