The latest issue off PII is out now!

Read here!
Fluids Handling

Reducing Total Cost of Ownership in Polymer Dosing during Wastewater Treatment

Listen to this article

Abrasive Slurry Transfer

Peristaltic pumps are well known for their ability to handle abrasive fluids. Operating at vastly reduced speeds when compared to other pump technologies, they are built to experience little wear and accommodate abrasive solid laden liquids, which was why when a customer contacted us with a unit suffering from frequent hose replacement, we knew something wasn’t quite right.

A unit had been specified by another supplier with frequent hose wear and repeated downtime and maintenance being experienced on a system which was often left unattended for long periods of time. The effectiveness of wastewater treatment was at risk of being compromised, and needed rectifying swiftly.

The customer was losing faith in peristaltic technology and wondered if another solution may reduce service intervals.

Iron Hydroxide for Water Treatment

The customer was transferring Iron Hydroxide (Fe(OH)3) into Pharmaceutical bioreactors. Ferric Hydroxide is one of many liquids used in wastewater treatment applications for the removal of unwanted contaminants such as heavy metals from process effluent. It is dosed at a variety of rates into bioreactors to reduce membrane fouling and increase biomass activity.

Handling Abrasive Fluids

Effluent Treatment with Flocculant

Used as a flocculant or flocking agent these cause suspended particles within wastewater to be grouped together forming a flock or clumps for easier removal. Flock consists of suspended waste particles and encouraging particles to accumulate enables higher recovery rates of suspended solids. Ferric Hydroxide is a positively charged flocculant causing negatively charged suspended particles to become attracted to it.

Solids can be removed from wastewater as particles are large enough to be captured by filtration equipment, rather than finely dispersed throughout the fluid. Ferric Hydroxide is just one example of a flocculant used within the water industry where many differing types are used.

The unit was operating at 18 cycles a day, with each cycle dosing up to 300L at each interval, with Ferric Hydroxide Slurry being injected into a bioreactor tank.

The Relationship between Pump Speed & Wear

On assessing the current pump operating speed, cycles and hours of operation we knew something was amiss.

The existing unit was operating up to 3 times faster than a design we would specify for such an application. This meant it was suffering from abrasive wear with the unit operating at close to 100rpm over a 24 hour period. As a comparison, for this duty we would not operate a pump above 55rpm, and for a continuous dosing application would reduce unit speed to below 30rpm.

As the pump was operating too fast, another issue became apparent in that the pipework was only 1” and if we were to reduce the speed, then the associated pipework would also need to be changed to a minimum of 1.5” – DN40. Had it been specified correctly from the outset then the corresponding pipework could also have been installed correctly, which now needed replacing to eliminate the issue.

Peristaltic pumps are well known for their simplicity in design, consisting of a single hose without valves, seals or O rings to wear, making them ideal for abrasive or dry products. In such applications it can quite often be the speed of operation which causes frequent spare part replacement and utilising a hose pump of roller design means units can operate from as little as 1rpm up to 30 for continuous operation, whilst other technologies operate north of 200rpm causing units to suffer greatly from wear. The absence of seals ensures one of the often weakest & most problematic areas of a pump is not prone to failure and it is effectively designed out of the process.

The customer did wonder if another pump technology may be more appropriate. Progressing Cavity Pumps are often used in wastewater applications, however when reviewing the total cost of ownership including speed of pump maintenance, cost of spare parts, training required and space available a peristaltic pump met this requirement.

The pumping process was further optimised by changing the existing internal shoe design of pump to one of roller design which in low pressure applications reduces wear further as there is virtually no friction between rollers and the hose, with power consumption reduced by 30%.

Although the correct pumping technology had been applied to the process it had been incorrectly specified. Peristaltic design provides many benefits within chemical dosing and metering applications which can be summarised as follows:

Wastewater Industry Process Overview

8 Reasons to use a Peristaltic Pump for Chemical Dosing & Metering:

  1. Self-Priming means there are no problems with high suction lifts.
  2. Gassing liquids do not cause valves to open.
  3. Non Slip design means additional accessories such as foot or injection valves are not required, removing clogging points.
  4. Higher accuracy in variable pressure applications.
  5. Low Shear pumping movement.
  6. High solid content capability.
  7. Abrasive Fluids are handled with ease.
  8. Low maintenance.

Our Low Maintenance Effluent Treatment Solution

We specified, supplied and delivered an FMP50 Roller Hose Pump which is fitted with oversized rollers, increasing hose lifespan and reducing energy consumption. The unit was fitted with ANSI flanges to ensure consistency with their onsite pipework specification.  

Although various options were offered the customer selected a unit operating at only 38rpm – close to a 1/3 of the existing unit to minimize the number of pipework changes on site. The customer is likely to see many years of problem free pumping with their new equipment.

When specifying a pump for flocculant dosing within a 24 hour process, it is important that Total Ownership Costs are reviewed prior to final pump selection. Having an incorrectly specified pump will not only lead to higher maintenance costs, and longer maintenance periods but potentially operational downtime and periods of non-compliance with the potential for liabilities to accrue.

As North Ridge Pumps are not tied to a single pump technology, we specify pumps which are best suited for your process for lowest lifetime cost and maximum process efficiency.

To view our range of pumps for Wastewater Treatment visit here 

North Ridge Pumps
Premium Package

North Ridge Pumps

north-ridge-pumps-about

About us

North Ridge Pumps are an independent manufacturer and distributor of pumps. Having been established since 1998, we have a vast array of experience having become accustomed to supplying pumps for most processes.

We work within a range of industries both UK and Internationally, specifying pumps for a wide variety of applications from the transfer of corrosive and aggressive chemicals, to dewatered sludge, viscous grease, resin, glues, food and Seawater.

Our pumps range from standard centrifugal and multistage pumps, to immersed and process overhung solid handling pumps. We also supply a wide range of positive displacement pumps including Vane, Piston, Progressing Cavity and Peristaltic enabling us to specify more than one solution for your application, but also ensuring the majority of applications remain within our reach.

We offer the following services:

Technical support – We know at times pump selection is difficult. Pump selections are made with confidence by technical sales engineers who understand your process, ensuring equipment is engineered beyond your needs.

To select the correct technical solution for your requirement, longevity of design is prioritised. If there are existing issues you need assistance with, we work with you to solve these which could be high maintenance costs, frequent service periods, repeated equipment breakdown leading to lost revenue, inconsistent flow rates, clogging or where pumped product is inconsistent.

Application experience – Due to our 20 years of application experience we work with you to ensure our pumps operate according to your desired application. Our experience means we have most likely provided a solution for a similar process previously. With proven results, we know how to achieve your outcome sooner.

As our pumps are completely configurable, we design pumps with materials according to your requirement, and to your required duty point. Pumps are engineered specifically for your process whether they be baseplate mounted, within a mobile frame or in kit form with couplings, hoses, and dispensing nozzle.

Industry knowledge – We have a thorough understanding of a range of industries through experience from supplying the offshore oil and gas market, to paper mills, chemical plants and food manufacturers to name a few.

We not only understand the importance of downtime but also what each process requires and how small design improvements specific to the nature of your industry and application can reduce downtime, facilitate maintenance and improve longevity.

If you have a process or application you require a pump for, or a process which requires improving, get in touch to see how we can help.

What we do in a nutshell

Pump Specification & Supply

Show More

    Would you like further information about this article?

    Add your details below and we'll be in touch ASAP!


    Input this code: captcha

    Leave a Reply

    Your email address will not be published. Required fields are marked *

    Back to top button

    Join 25,000 process industry specialists and subscribe to:

    PII has a global network of suppliers ready to help...