Festo is combining measurement, control and regulation technology with pneumatic actuators and valve terminal blocks, along with its Aquatronics training capability, to supply customised automation solutions for water and wastewater treatment. MechTech talks to Durban-based industry segment specialist for water & wastewater at Festo, Strini Perumal.

Festo SA water wastewater Strini Perumal“Globally we have been automating water treatment plants for many years, and for the past few years we have been growing our water offering in the southern and South African market,” begins Perumal. “A key focus for us is providing complete turnkey solutions for municipalities, water utilities and industrial treatment plants,” he adds.

“South Africa has many manual system, where operators need to open and closer valves using wheels and levers. Festo provides fully automated systems, which offer much better control of water or wastewater treatment processes and deliver better and more consistent water quality. Equally important, though, is maintenance and these systems have built-in diagnostics and are designed for easy plug-and-play maintenance,” he tells MechTech.

“In partnership with water infrastructure contractors, we provide turnkey installation packages for water service providers with all media valves, pneumatic actuators, controls and up to the SCADA and software for the main control room – and we are able to optimise an automation solution regardless of the plant’s size or location,” Perumal assures.

Festo water automated skidsDescribing the needs of a typical municipal treatment plant for potable water, he says that water is generally pumped into the plant from a river into a raw water reservoir. From there it is first chemically treated (pre-chlorination) to minimise algae growth, before being aerated for the removal of dissolved solids.

The water is then treated with clarifying agents or flocculants, which cause tiny dispersed particles called colloids to coagulate onto larger ones. “The treated water is then slowly mixed before being passed into a clarifier tank, where the heavier particles sink forming a sludge at the bottom of the tank, while the clear water is tapped off over a weir at the top.

The clear water then passes into filter beds, typically gravity-fed sand beds that remove the remaining fine solid particles. “Between cycles, though, these beds are cleaned, via a backwash process,” Perumal point out. The filtered water is again dosed to remove any remaining bacteria and then transferred to storage reservoirs as potable water.

“At every stage of this process, valves are used to control the process flow. Valve actuators open and close these valves. This used to be done manually, but we are now able to automate every part of the process, from level control to dosing management and back purging,” Perumal explains.

There are two technologies available for automating valve actuation, electrical or pneumatic actuation. “Based on extensive research by Festo, we have found pneumatic actuation to be far more economical than electrical. Pneumatic systems need a compressor, air driers and filtration units, which have to be piped through to the valves and actuators, while electrical systems only need power. But electrical systems are more expensive and they need specialised technicians to manage them. They also need more complicated programming, since they are continuously variable devices,” he says, adding that, “pneumatic valve actuators are much easier to manage. All they need is two air lines into each valve.”

Perumal argues that cost comparisons need to be evaluated over time. “While pneumatic actuation systems are often believed to use a lot of compressed air, this is not really the case. Once a valve has been opened, it stays open, without consuming additional air, so very little is actually consumed. We use compressed air storage tanks across the plant, and once these have reached system pressure, the supply compressor can shut down.

“But the air that is used needs to be properly cleaned and dried. In the past, we have found that operators haven’t been properly draining and cleaning out their filters. This causes condensation to accumulate in the airlines, which eventually damages the actuators,” he explains.

“In response, we have automated the draining of the filters on the compressors. This enables operators to realise even better long-term cost savings. Instead of having to send a technician to drain the filters, we have automatic dump valves on timers that will ensure that these filters are adequately drained,” he adds.

Festo has an agreement with compressor suppliers to incorporate these dryers as part of an integrated compressor solution. “Also, with these compressors, we offer maintenance contracts to service compressors during our warranty periods,” he says.

On a component level, Festo offers an extensive range of valves and actuators with unique features to improve product life. “On butterfly valves, for example, the rubber seats can leak. A traditional valve, which is often controlling the flow of dirty or chemically dosed water, fluid can leak though the valve stem and into the actuator itself, eventually causing damage and shortening the valve life.

“Festo has a safety relief system on its actuators to automatically purge any leakage, safeguarding the actuator and prolonging its life,” Perumal says, adding that these particular valves can operate for between 20 add 50 million cycles. “Festo also provides service kits for all of its actuators and service agreements can be also be adopted to further improve reliability.”

A cornerstone of lowering costs is the simplicity and maintainability of pneumatic systems over electrical equivalents. “We believe that pneumatics offers better solutions for South Africa in terms of long term operational and maintenance costs, largely due to the system’s simplicity.

“Conventionally, where a pneumatic valve was connected to an actuator, each valve would have its air supply and electrical power and control cabling routed back via a thick conduit though junction boxes to a centralised filter bank and back to the main control room. Now, we can use valve terminal block technology in decentralised Festo panels to significantly reduce the complexity and amount of piping and cabling,” Perumal says.

“From a decentralised panel, which includes its own filter unit, we can control a number of nearby valves. And between the panel and the valve actuators, we need only connect one pneumatic pipe and an electrical feedback cable.

“Communication between each distributed panel and the centralised SCADA control system is achieved via a Fieldbus connectivity such as Profibus, Ethernet or DeviceNet or any other single cable protocol. This system also enables self-diagnostics. If a coil, valve or actuator fails to reach the position required, this is immediately diagnosed and an alarm signal is sent to the main SCADA to direct the operator to the problem point. So faultfinding is easy and much more immediate, significantly reducing downtime,” he tells MechTech.

Valve terminal blocks consist of all the solenoids, pneumatic valves and input/output signal sensor – ultrasonic level sensors, temperatures probes, valve position sensors, etc. The sensors are all wired into the valve terminal block in the distributed panel, from where ‘intelligent signals’ are sent to the central controller. And the distributed panels are IP65 protects from dust, moisture and sunlight.

“Panels are easy to access. LEDs are used to detect problems and, to replace a single valve-slice of a terminal block, all you need to do is to isolate the main pressure into the panel, remove two screws on the faulty terminal and replace it with a new one,” says Perumal.

Festo is currently involved with a rural project that involves remote monitoring and control. “At a water treatment plant in northern KwaZulu-Natal, we are installing an automated plant and SCADA system that will allow the water treatment plant and the pump station to be managed from one central point. Using the CPX-MPA valve terminal block, which has its own built-in PLC and wireless communication system, operators have full control functionality and faultfinding capability from the remote control and monitoring office.

In addition, for small rural treatment plants using borehole water, for example, Festo has a solution for containerised water treatment. “These systems have all the required water treatment processes packaged into a transportable container. This removes the need for any civil construction onsite, making it an ideal rural solution, particularly if coupled with remote control and monitoring,” suggests Perumal.

“We are a complete solutions provider in the automatic water treatment space,” he concludes. “This is a differentiator for us. We even offer the operator training courses at several different level through the globally developed Aquatronics courses.”

Latest News

Numsa looks for 15% wage increase in coal sector

Published: 23 September 2017

Following the three-year wage agreement signed with employers in the metals and engineering sector, the National Union of Metalworkers of South Africa (Numsa) has announced it will be meeting with...

Read more

Study finds SA’s power grid can handle additional wind and solar power

Published: 22 September 2017

The recently released Assessing the impact of increasing shares of variable generation on system operations in South Africa – a flexibility study, has found that the South African power system...

Read more

RS Components celebrates 80th anniversary

Published: 21 September 2017

RS Components is celebrating its 80th year of operations. Founded as Radiospares in the UK 1937, the company started as a supplier of parts to the radio market, and has...

Read more

New Renttech MD pursues “business as usual – with a new focus”

Published: 20 September 2017

Renttech South Africa, a supplier of welding, power generation, lifting and rigging equipment for rental or purchase across Southern and sub-Saharan Africa, has appointed a new Managing Director. Duncan Whitehead...

Read more

AU launches campaign for infrastructure development

Published: 19 September 2017

The African Union’s (AU) 5% Agenda campaign has been launched. The 5% Agenda campaign is intended to facilitate public-private partnerships in infrastructure development.

Read more

The importance of quality cutting consumables

Published: 18 September 2017

The initial capital outlay often prevents manufacturers who use large equipment to shy away from purchasing top quality machines. However, Mike Cronin, Managing Director of Elquip Solutions, says this can often...

Read more

Corrosion protection in non-ventilating spaces

Published: 17 September 2017

Cortec Corporation has announced its latest advancement in environmentally safe corrosion protection. Called BioPouch, this new, revolutionary “green” Vapor phase Corrosion Inhibitor is aimed at the protection of metal parts...

Read more

SA cartels to come under fire

Published: 16 September 2017

Reports by Reuters indicate that the Competition Commission will be opening a case against wholesalers of liquefied petroleum gas (LPG) should they ignore recommendations to end long-term supply agreements by...

Read more

The importance of insulation

Published: 15 September 2017

Insulation generally refers to any material which provides resistance to heat flow, limiting the flow of heat between two bodies that are not at the same temperature. A critical component...

Read more

Solar PV incubator announced

Published: 14 September 2017

Aimed at identifying PV projects of potential in sub-Saharan Africa by providing access to funding, and commercial and technical knowledge, the programme invites PV developers to submit proposals for projects...

Read more

GE commences commercial operations at Kusile Unit One

Published: 13 September 2017

GE has announced that it has successfully commenced commercial operations of Unit One of Kusile’s coal power plant. GE’s scope in Kusile Unit One is the Engineering, Procurement and Construction...

Read more

N3 bridge collapse explained

Published: 12 September 2017

The reason for the collapse of the pedestrian bridge on the N3 highway in Germiston last month has been found to have been a truck hitting the supporting pier of...

Read more

Skills needed to develop shale gas industry in SA

Published: 11 September 2017

Accoding to Professor Cyril O'Connor, a senior researcher at the University of Cape Town who chaired the Academy of Science of South Africa (ASSAf) panel which undertook the study on...

Read more

Types of HVAC fans

Published: 10 September 2017

One of the most important elements in HVAC products are the fans. There are many different types of fans that are used, so it is important to understand the basic...

Read more

API award winners announced

Published: 09 September 2017

The Africa Property Investment (API) Award winners have been announced. The awards, which were held at the API Summit and Expo 2017, recognised innovation and outstanding achievement across the entire...

Read more

More awards for Coega

Published: 08 September 2017

The Coega Development Corporation (CDC) recently won two award certificates at the recently held Exporters awards in Port Elizabeth. The awards were for IDC job creation and the best provider...

Read more

Mall of Africa wins CESA award

Published: 07 September 2017

The largest retail development to be built in a single phase in Southern Africa, The Mall of Africa, has won recognition at the Consulting Engineers South Africa (CESA) Awards. This...

Read more

Master Builders Congress agenda announced

Published: 06 September 2017

The annual Master Builders South Africa (MBSA) Congress, to be held on 11-12 September at the Century City Conference Centre in Cape Town, will be themed “Building South Africa Together”...

Read more

Legal wrangling commences around PPA signing

Published: 05 September 2017

Energy Minister Mmamoloko Kubayi recently announced that Eskom will sign the Power Purchase Agreements (PPAs) with Independent Power Producers in October. The announcement comes on the completion of stakeholder engagement...

Read more

New law for transboundary infrastructure development proposed

Published: 04 September 2017

The Economic Commission for Africa (ECA) has outlined a model law on transboundary infrastructure development in Africa. The proposed law provides a means of mitigating and managing the perceived risks...

Read more

Priscillah Mabelane appointed BPSA chief executive

Published: 03 September 2017

BP Southern Africa (BPSA) has appointed Priscillah Mabelane as its new chief executive. A chartered accountant, Mabelane is the first woman in the history of South Africa’s oil industry to...

Read more

Sanral awards Wild Coast bridge tender

Published: 02 September 2017

The South African National Roads Agency SOC Ltd (Sanral) has announced that the tender for the Mtentu bridge, which forms part of the N2 Wild Coast road (N2WC) project, has...

Read more

Hundreds of jobs created by Coega Development Corporation

Published: 31 August 2017

As a result of the many construction projects currently taking place in the Coega Special Economic Zone (SEZ), the Coega Development Corporation (CDC) has created 452 jobs. The announcement by...

Read more

Engineering sector wage deal signed

Published: 30 August 2017

Wage negotiations in the engineering sector have finally been concluded, with unions announcing that a three-year deal has been agreed to. The deal makes provision for a 7% wage increase...

Read more

SA to get $1.5-billion for infrastructure

Published: 28 August 2017

The African Regional Centre of the New Development Bank (NDB), which was opened this week by President Jacob Zuma, marks the official start to $1.5-billion worth of infrastructure projects. The...

Read more

ArcelorMittal threatens retrenchments

Published: 27 August 2017

Steel producer ArcelorMittal South Africa (Amsa) has announced plans to retrench more than 50 employees as low demand, rising costs, a strong rand and South Africa’s sluggish economy necessitate further...

Read more

PWC Tower wins SAICE award for Arup

Published: 26 August 2017

Built environment specialist Arup has received a Highly Commended Award in the Structural Engineering Project Division at the recent South African Institution of Civil Engineering (SAICE) Most Outstanding Project Awards...

Read more

Leadership training essential for HVAC engineers

Published: 25 August 2017

Leadership ability is just as important as the technical background and work experience of HVAC engineers. According to Rubber World Industries (RWI), leadership skills should always be considered as a...

Read more

Energy storage a growing market

Published: 24 August 2017

Energy storage is predicted to see explosive growth in the next few years. According to the Energy Storage Association, the US market alone grew to 280 megawatts (MW) in 2016...

Read more

Minister of Trade and Industry: Development of infrastructure essential

Published: 23 August 2017

Addressing the first day of the recent Infrastructure Africa Business Forum, The Minister of Trade and Industry, Dr Rob Davies says the development of infrastructure is an essential and absolutely...

Read more


African Fusion

AfricanFusionAfrican Fusion, the official publication of the Southern African Institute of Welding (SAIW), aims to provide up-to-date insight into welding technology and the welding industry.

Capital Equipment News

Capital Equipment News is dedicated to the application of equipment and modes of transport that are used in the mining, construction, quarrying, and transport industries.

Construction World

ConstructionWorldConstruction World was first published in 1982 and has grown to become a leader in its field, offering a unique mix of editorial coverage to satisfy the diverse needs of its readers.

Electricity + Control

ElectricityandControlE + C publishes innovative, technical articles that provide solutions to engineering challenges in measurement, automation, control, and energy management.

Lighting in Design

LightingandDesignLighting in Design is a glossy, upmarket publication aimed at lighting professionals. It is the only B2B magazine in SA that is dedicated solely to the subject of lighting.

MechChem Africa

MechChemJanuary2017cover MechChem Africa supports African engineering and technical managers across the full spectrum of chemical and mechanical disciplines.

Modern Mining

ModernMiningEstablished in 2005, Modern Mining is one of SA's leading monthly mining magazines, noted for the quality and accuracy of its writing and the breadth of its coverage.

Modern Quarrying

ModernQuarryingModern Quarrying is firmly entrenched as a leading industry-specific magazine. It focuses on promoting the science and practice of quarrying and processing in southern Africa.

Sparks Electrical News

SparksElectricalNewsReadable and informative, Sparks Electrical News is the newspaper for those involved in installing and maintaining electrical supplies and equipment.

Contact Crown

Web Manager: Karen Smith
Email: admin(@)crown.co.za

Phone: +27 11 622 4770
Fax: +27 11 615 6108

Crown House
2 Theunis Street
Cnr Sovereign Street
Bedford Gardens
Bedfordview 2007
P.O. Box 140
Bedfordview 2008

linkedin facebook twitter google plus youtube tv rss

sign up newsletter

Full Name*
Invalid Input

Company Name*
Invalid Input

Your Email*
Invalid Input

Invalid Input

Postal Address 1*
Invalid Input

Postal Address 2*
Invalid Input

Postal Code*
Invalid Input

Street Address 1
Invalid Input

Street Address 2
Invalid Input

Postal Code
Invalid Input

Town / City*
Invalid Input

Invalid Input


Invalid Input

Invalid Input