Flowing with the Times

Scarcity fears, greater environmental awareness, and tighter legislation are some of the reasons behind the increasing sophitication of water and wastewater processes

Water has always been a basic human need. As knowledge of how impurities and contaminants in water affect human health grew, the need for treating the water before supply for consumption, assumed paramount importance. Industrial activity contributed to a rise in demand for public water supply. Over time, it became imperative to protect the environment and this added another component to the water cycle – wastewater treatment before disposal. Just as legislations governed the quality of the water supplied, laws were passed to ensure that the used water was treated to acceptable standards before disposal.

The standards have become more and more stringent, necessitating advancements in water and wastewater treatment made possible by technological developments. Networks have grown and metamorphosed over the years, improving all along. Automation tools have graced the sector in the recent past, making the management of the water-wastewater network assets simpler and effective.

Privatisation of the arms of the water-wastewater sector in many parts of the world, the subsequent inevitability of competition, and the need for efficiency improvements have bolstered the need for investing in upgrading the systems and investing more in obtaining state-of-the-art capital equipment, In Europe alone, thanks to the stringent EU legislations and the expansion of the EU community to eastern Europe, the market for automation in the water-wastewater sector was to the tune of US$540 million in 2006, and is likely to grow up to over US$780 million in 2013, according to a Frost and Sullivan report. It is only a matter of time before the burgeoning Asian market catches up.

Dissecting the network

The water-wastewater sector one refers to the public water supply and wastewater treatment systems serving small communities, mid-size towns or big cities. The water treatment plants, the pipeline networks, pumping stations and the wastewater treatment plants source their machinery, equipments, chemicals, etc, from suppliers in the manufacturing sector.

While it goes without saying that the manufacturing firms supplying pump-sets, equipments and chemicals for treatment, pipelines and pipeline accessories, have also been making the most of automation solutions to improve their productivity and the quality of their products, they fall beyond the scope of this article.

Wastewater treatment is certainly not just a function of the municipalities in a township or city, but some industries – such as pulp and paper – need to treat their effluent process water for the removal of some undesirable components before either directly discharging it into receiving water bodies or into the wastewater mains for further treatment downstream at wastewater treatment plants.

Also, the influent process water may be further treated within industrial complexes to meet the specific requirements of the processes in which it would be used – for example, treatment of boiler water in thermal power plants before it enters the heat transfer cycle.

This article however restricts itself to the public water-wastewater works which treat water and supply it to consumers in the domestic, commercial and industrial sectors and collect the effluent wastewater, treat it to certain specified standards before discharging it into inland or coastal water bodies.

Figure 1 depicts a typical water-wastewater cycle of a town/city/metropolis. It is seen that the network can be broadly categorised into five main components:

• Water treatment plant
• Pipeline network
• Wastewater treatment plant
• Pumping stations
• The consumers serviced

It should be borne in mind that most networks have multiple water and wastewater treatment units (of different capacities and types of treatment) to share the water-wastewater loads, and that water-wastewater treatment typically involves several different processes.

Treatment time

Water and wastewater treatment involves several processes and thereby a plethora of equipments and chemicals. While supply water needs to be treated to be made fit for consumption, wastewater is treated to meet environmental standards of discharge into receiving water bodies. Some of the wastewater may even be re-treated for reuse, especially in countries grappling with problems of water scarcity and dependence on imported water to fulfil their citizens’ needs.

Table 1 lists the typical treatment processes. It should be noted that there are some processes common to both water and wastewater treatment, and some which are unique to one or the other. Process control to optimise the use of materials and energy while attaining the desired treatment goals, is of utmost importance, while continuous measurement of the output water/treated wastewater quality via SCADA (data acquisition) systems is also necessary.

In both water and wastewater treatment plants, it is necessary to maintain a constant flow rate into the chain of treatment processes. The fluctuations in influent flow are handled by using equalization basins in conjunction with automated sensor actuator flow control devices. Blowers/compressors supplying air (oxygen) for aeration/air-stripping/ flotation used to run at the same speed all round, consuming energy all the while, even when most of the oxygen pumped into the wastewater would escape into the air – being in excess of what could dissolve in the water at a given point of time. Super-efficient motors (running on energy produced from in-plant waste heat or from captive wind power plants for that matter) and good quality blowers in this case are fine indeed, but that is not all.

Process control is also very important to make the most of the benefits. For aeration in biological treatment units in wastewater plants, monitoring the oxygen concentration in the wastewater in the tank using oxygen-sensing probes, and controlling the speed of the motor suitably through variable speed drives, to deliver air only when required, can save a lot of energy for wastewater treatment plants around the world.

After all, delivering efficiently when no deliveries are required in the first place is meaningless. It makes sense to supply efficiently only when there is a demand. In the flocculating units where paddles accomplish gentle mixing of the water/wastewater being treated to enable the coagulant chemicals to flocculate the suspended impurities, variable speed drives controlled by sensors monitoring temperature, flow rate and water quality, enable streamlining of power supply to the shafts driving the paddles to the actual demand from the process.

Just like measuring the dissolved oxygen content in biological treatment (aerobic treatment), pH control is also of utmost importance in order to maintain the efficiency of biological treatment, coagulation and mass transfer in wastewater treatment plants.

The performance of micro-organisms in general deteriorates when the pH decreases below six or increases above eight. Alkaline waters also reduce the effectiveness of the commonly-used coagulant chemicals ferric sulphate and alum. Automated pH control entails coupling the acid/base buffer-feeders to a pH meter and dosing just the right amount only when required.

If oxygen sensors can save energy, pH sensors bring down chemicals use. On-line sensors for organic carbon, nitrogen and phosphorus in wastewater are still not very common. Some modern sequencing batch reactor wastewater treatment plants however do employ state-of-the-art SCADA systems with powerful programmable logic and control, which can support complex, realtime control of the said parameters.

By incorporating dynamic real-time control, it becomes possible to reduce the organic carbon, nitrogen and phosphorus loads in the effluent, in order to reduce the expenditure which accrues in the form of emission taxes in some countries. This is an instance of policy-making and legislations triggering growth in the market for water-wastewater sector automation.

Reportedly, the costs of the sensors have decreased over the years (however, the labour costs of instrumentation/control/automation specialists have risen to about 1500 Euros per day in the western world). Table 2 lists the costs (2005) of some of the sensors/probes used in water-wastewater treatment plants.

Pump it up

Pumping water and wastewater consumes a good deal of energy, and it is thus imperative given the current energy cost climate to rein in consumption. Energenecs, a water-wastewater systems integrator in the US, believes that pumping systems in general account for nearly 20 percent of the global energy consumption. The company’s SCADAPack controller monitoring pumping stations implemented in water-wastewater networks have enabled utilities to cut down their electricity bills.

By enabling intelligent pump switching, peak demand period avoidance and varying the speed of the motor driving the pumps in response to demand, an automated control system goes a long way in making the operation of pumping water and wastewater less energy-intensive.

Utilities have become increasingly aware of the fact that steps ranging from installing watt-meters and energy meters – which was not common and is still not in many pumping stations around the world – to keep a tab on the power drawn by the pump-sets, to replacing old motors with high-efficiency ones with variable speed drives, to installing automated control and monitoring systems, can go a long way towards reducing energy consumption. However, there is still a lot to be desired as far as the water-wastewater networks in Asia are concerned; and paucity of funds and lax legislations are the barriers to be countered.

Gian Francesco Imperiali, Head of ABB’s Water Industry Global Initiative, tells CE Asia that the company’s portfolio includes advanced drives, high efficiency motors and automation solutions that rein in expenditures for the utilities. The Bangkok Metropolitan Water Authority is one of the utilities which have benefited from ABB’s “energy-efficient” technologies.

Down the line

Pipelines are made of concrete, stone/brick, plastics (PVC, PE, PPP) or ferrous materials (grey cast iron, ductile iron and mild steel). They come in different lengths, diameters and thicknesses and serve as the veins and arteries of the network, carrying water or wastewater around from node to node.

The pipelines need to be inspected, repaired and rehabilitated during the use phase. They are monitored for chemical and mechanical corrosion detection, inhibition of flow, detection of pipe misalignment, leakages and cracks; and periodically cleaned. At end-of-life, pipelines generally are left buried beneath the ground – disconnected from the network and left sub terra.

Until a few years ago, sensors to detect damages in the wetted portion of the inner circumference of pipelines were not available. The Emscher river project in western Germany, known to be one of the largest European Environmental Projects (4.4 billion Euros invested over 25 years), will be overcoming this obstacle by resorting to the deployment of ultrasound and laser scanners in damage detection and survey devices for large sewers which will divert wastewater away from the river and lead it to wastewater treatment plants.

With the dual option of being moved along the sewer pipeline on wheels or swimming forward on the water surface, the survey and detection devices are capable of identifying corrosion (to an accuracy of +/- 4 mm), cracks (to an accuracy of +/- 2 mm), spalls, deposits and incrustations both in the water and the “gas” spaces inside the pipeline, misalignment of the sewer pipeline and widening of the gap between the couplings. The updates relayed on a continuous basis will enable remote monitoring and decision making to avert damage.

While pipeline manufacturing is highly automated in order to cater to demands on quality and longevity from the utilities, as Prof Sveinung Sægrov, pipeline expert and research manager at SINTEF, Norway, tells CE Asia, CCTV inspections are gradually gaining ground not just in the West but also in the developing countries. And with water and the environment becoming increasingly key points on the agendas of governments, sewer inspection is often a component of international aid to the Third World. Prof Sægrov says he may himself be cooperating with researchers in India on an EU-funded project on water and wastewater networks.

Turning on the tap

As they say, “as the subjects, so is the King”. In order to help or coerce the elected authorities in government to legislate responsibly, the governed citizens (electorate/ consumers) need to exhibit their keenness in optimising water use. This would encourage producers of devices like sensor-controlled taps and faucets to enter the market and the government to support such producers with subsidies and tax benefits.

One sees these wonderful water conservation arrangements in public places like airports, but the culture has to seep further into homes and industries and offices. Automating conservation at the consumers’ end will have a virtuous cascade effect, all the way upstream and downstream reducing loads on pumping and treatment and bringing down energy and materials consumption. Taps and faucets apart, white goods drawing water within households are also increasingly being automated with controls which ensure “more out of less” – the less being with respect to energy and water consumption.

There are published reports of reduction in water consumption in wash rooms in the industrial sector. One such is the Indian Tobacco Company’s factory in Saharanpur in North India, which, by installing sensor-controlled taps in its complex, achieved a substantial reduction in water consumption. Of course, the attractiveness of investing in installing such taps depends on how pricey water is, in the first place, and the maintenance expenses incurred on the upkeep of the electronics within the taps. The return of investment would thus be different from one case to another.

Auto Taps (UK), one of the few companies in the world specialising in the design and manufacturing of infrared sensor-controlled taps, has been instrumental in saving several gallons of water over the years for its customers in the UK and beyond.

What next?

In the years to come, as water-wastewater networks attempt to scale up their operations and enhance the element of automation in them, industrial mobile communications, M2M communication, adaptive and multivariate controllers, and artificial intelligence, which have been embraced by the manufacturing and process sector, are likely to foray into water and wastewater treatment plants.

Dave Gorman of Veolia Water Solutions and Technologies (Singapore) says, “Given water scarcity, environmental concerns due to industrial pollution, and the rise in demand from a growing population, it is becoming increasingly important for the Southeast Asian countries to implement appropriate water management strategies, water reuse and recycling.” ABB’s Gian Imperiali thinks likewise (about the Asian water-wastewater sector) and points out that Singapore is becoming an international hub for water-related investments.

The Singapore International Water Week (www.siww.com.sg) in the last week of June 2008 promises to be a platform for knowledge sharing, technology transfers and business deals in the water-wastewater sector, and automation solutions providers may well have a “field week”. Certainly, ABB’s Imperiali hopes to meet potential business partners at the event.

Later in the year, in September, the World Water Congress and Exhibition (www. iwa2008vienna.org) will be held in Vienna – sponsored by Siemens Water Technologies, Veolia Water, Suez Environment, ITT Fluid Business, and the Best Water Technology Group.

Water, from which life originated on earth, stakes its claim on man’s attention more than ever before. Drinking water supply is no longer as banal and boring and taken-for-granted as it was a few years ago. And wastewater treatment – a set of low end operations till not very long ago - has increasingly become more and more sophisticated thanks to innovative technologies and automation solutions that have graced it.

========================================================================

‘Energy efficiency is a key driver for automation’

Gian Francesco Imperiali, Head of ABB’s Water Industry Global Initiative, talks to CE Asia about what prospects the water-wastewater sector in Asia and the world as a whole hold for the automation major.

Q: How extensive is ABB’s scope of supply to the water-wastewater sector?

A: The ABB portfolio for the water sector includes products and systems covering automation and instrumentation plants and networks. A diverse portfolio and specific know-how enables us to deliver integrated solutions for several applications like turnkey pumping stations, SCADA systems for distribution networks, engineered packages for desalination plants (an emerging source of water supply), and industrial wastewater treatment projects.

Our current annual turnover in this business is approximately US$500 million, and in order to make good use of the opportunities in the ever-growing market, ABB recently launched a global initiative to focus and coordinate efforts and develop solutions for the water-wastewater sector around the world.

Q: Your thoughts on the Asian market with respect to the overall global picture?

A: The Asian market, needless to say, is already one of the most important ones for ABB group (not just in the water wastewater sector for that matter), and we are gearing up to tap the potential in the years to come. India and China are attracting foreign and domestic investments in water infrastructures, while Singapore is becoming an international hub for water-related investments. In this backdrop, Asia will play a key role in both the demand and supply-side activities for our group.

Q: Can you describe some specific projects for the sector?

A: We have many examples of fruitful co-operation between ABB and Asian water utilities and EPCs. In Singapore, we have served the Public Utilities Board (PUB) in several projects like the Deep Tunnel Sewerage System (DTSS) and the Marina Barrage.

In Thailand, we helped the Bangkok Metropolitan Waterwork Authority in managing the metropolis’ wide and complex water distribution network, delivering an advanced SCADA System with a Water Leakage Management application to monitor performance, and constructing and revamping many pumping stations.

And in India – on the consumer side - we delivered complete engineered electromechanical packages for some large irrigation lift schemes like the Kalwakurthy Project in the State of Andhra Pradesh in the south.

Q: How about prospects for energy savings through implementing automation?

A: The need for energy efficiency is one of the key drivers in this sector, especially in developed countries where ageing assets are characterized by high energy consumption. Our portfolio includes advanced drives, high-efficiency motors and automation solutions that rein in expenditures for the utilities. Due to the significant savings and other benefits in any applications, the tangible short-term return on the investment in this field is expediting the application of “energy-efficient” technologies.

Q: Could you comment on the expected business deals at the Singapore International Water Week (SIWW) this year?

A: To date, Singapore is one of the recognized international hubs for the water business, a reference marketplace, and a place from where many companies are setting up bases to serve the regional market. During this important event, SIWW, we expect to meet customers and potential partners to explain our value proposition to this market and to demonstrate our capabilities on the strength of our global experience.

========================================================================

Monitoring the Pipeline

Prof Sveinung Sægrov is Research Manager at SINTEF, Trondheim, Norway, and Adjunct Professor at the Department of Hydraulic and Environmental Engineering at the Norwegian University of Science and Technology. As an expert in sanitation engineering and water and wastewater pipelines, he tells CE Asia how technology is facilitating operation and maintenance in the pipeline network.

Q: Is closed-circuit television (CCTV) inspection and monitoring of water and wastewater pipelines becoming more common in developing countries?

A: CCTV inspections normally are carried out on wastewater pipelines and not drinking water ones. I am not totally certain about the current status in the developing countries, but assume that this technology may already be in vogue in quite a few Asian cities. The first users of this technology have proven that this is extremely efficient and hence, when utilities in the developing countries decide to prioritise the maintenance of sanitary systems and are willing and able to invest in upgrading the inspection and repair operations, CCTV inspection will become the norm.

Sewer inspection, in my opinion, will be on the agenda of international aid programmes to the developing world. Thus, funds will cease to be a deterrent in the coming years for utilities handling water supply and wastewater treatment.

Q:. Are there moves towards automating the monitoring of the condition of the pipelines by having software interpret the CCTV images?

A: Videofilms of the CCTV inspections are stored by the utilities and recourse there to can be had at a later date when rehabilitation programmes are drawn up, for instance, based on assessment of pipeline damages and failures. To have a quantitative report – expressing the videofilms in terms of degree of damage and probabilities of failure – engineering expertise is mandatory.

Digitised images, of course, give a direct quantitative measure of defects, for instance - bursts, displacements etc. Development of damages is mapped by comparing new images with previous ones. The use of digitised images to assess the condition of pipelines is becoming common, though it may take more time for it to become well-entrenched, even in the Western world.

Q: Is it a common practice to install sensors to sense such variables in the flowing water and pipeline as pressure, temperature, etc, and relay this information continuously to monitoring stations or to equipment which could take preventive action if needed? For example, anticipating the buildup of deposits and blockages?

A: It is a common practise to install water flow and pressure meters in drinking water networks to measure these parameters remotely and continuously. The network is normally divided into leakage zones, and flow and pressure measurements are made at the borders between the zones – to determine leakages and losses. In wastewater networks, continuous flow monitoring is done at pumping stations and combined sewer overflows.

Q: Your comments on automation in the pipeline manufacturing sector?

A: Pipeline production is highly automated, and this certainly has contributed to improvements in quality over time. Manufacturers have large research divisions, which keep suggesting process improvements in order to enhance the production efficiency, product quality and longevity in the use phase.

The physical lifetimes of pipelines have conspicuously increased over the years, and automated manufacturing facilities have
contributed to this improvement. The main drivers for investments are surely the demands from utilities (municipalities) for better quality pipelines, and also privatisation in the water-wastewater sector which has introduced the element of competition and subsequently the need for efficiency improvement to augment shareholder value.

========================================================================

‘Technology has changed the face of water and wastewater treatment’

Veolia Water Solutions & Technologies (VWS) is a global player in the water treatment sector, providing dedicated solutions to municipal and industrial customers. Dave Gorman, Controls, Instrumentation and Electrical Manager for the Southeast Asia division, which is based in Singapore, talks to CE Asia.

Q: Which are the likely growing market areas for Veolia in Asia – water supply or wastewater treatment?

A: For over two decades in Southeast Asia, VWS has developed local capabilities to serve industries such as oil & gas, semiconductors, pharmaceuticals, food & beverage, power, pulp & paper. During this period, VWS has designed and built over 100 ultra-pure water plants and water reclamation plants. As far as the wastewater sector goes, its growth in this part of the world is a new opportunity for our company to provide high-end technology solutions.

Given water scarcity and environmental concerns due to industrial pollution, it is becoming increasingly important for the Southeast Asian countries to implement appropriate water management strategies, water reuse and recycling. The key drivers are government regulations.

Q: Does Veolia resort to state-of-the-art automation of processes in all the treatment plants it builds, irrespective of location or capacity?

A: There have been dramatic changes in three major areas of automation over the years – the electricals, instrumentation and controls. We have seen advances in electrical system design to allow for both improvements in function and power management. Instrumentation has adapted to the requirements of improved accuracy, demands on environment/location and interface with control systems. VWS has followed these developments over the years, and has been applying them wherever required in its water/wastewater projects.

However, plant management extends much beyond just designing and construction. Maintaining equipment in the treatment plant and facilitating unhindered operation is also very necessary. It goes without saying that the operations and maintenance costs in the water/wastewater sector have been causes for concern, and with the advances in automation, it is now possible to directly retrieve data to provide reports and statistical information for fine-tuning the entire range of operations.

Developments in variable frequency drives and soft starters have permitted improvements in control, operational information and diagnostics. Control systems have undergone dramatic changes over the years, evolving from simple hard-wired logic circuits to true processor-based controllers with much greater processing power and memory, better functionality in program design and superior inbuilt diagnostics. Along with these changes, the overall design has improved reliability and given rise to a variety of options to allow the system to be tailored to best suit the overall design.

Q: Are utilities around the world keen on investing in upgrading their setups?

A: Technology has changed the face of water and wastewater treatment over the last two decades. Earlier, systems were much simpler. Nowadays, systems embrace the entire spectrum of process management, and most certainly utilities around the world are very keen on changing and evolving. The driving forces, as indicated earlier, are mainly the regulations enforced by the governments.