Environmental Stewardship

Leon Awerbuch

Chairman of the IDRA Energy and Environment Committee

The desalination industry is serious in its commitment to environmental responsibility and, in fact, it has already done much to mitigate potential environmental impacts. While the demand for desalinated water is growing at a pace of 15% per year, care of the environment, sustainability considerations and energy efficiency are playing an increasing role in the type, configuration, siting and energy source for desalination plants. Modern seawater desalination has a 60-year history and demonstrated ability to provide new clean water for continuous development of communities around the world.

Protection of Marine Life

Protection of marine life is also a key consideration. Advanced seawater intake designs reduce the threat of entrainment or impingement of marine species. Improved outfall designs efficiently discharge and diffuse the concentrate, and the desalination industry has also developed new methods for backwash solids handling and disposal.

Seawater intake options include offshore intakes, sub-seabed intakes, co-located intakes, and passive intakes. Habitat restoration – the process of restoring an area equivalent to that impacted by an intake or outfall – is another alternative that has been proposed at some locations.

Improved Concentrate Disposal Strategies

There are several options that can be employed to reduce the impact of concentrate, or brine discharge that results from the desalting process, and new technologies offer the promise of further reductions. These options include multi-port diffusers, co-location with facilities to blended discharges with cooling water and treated wastewater effluent; deep well injection; evaporation and salt/mineral recovery; and many new technologies for green solutions minimizing or eliminating chemical use, reaching high recovery allowing Minimum Liquid Discharge (MLD) or Zero Liquid Discharge (ZLD).

Monitoring

An important aspect of any desalination plant operation is the ongoing monitoring of the environment surrounding the facility. Improved monitoring technologies and practices allow for more accurate observation of potential impacts and enable the facility operator to change operating conditions to respond to environmental responses.

Public Outreach

It is important to include early public outreach in any planned desalination project, to educate stakeholders regarding the facility and its relationship with the environment. This practice will de-stigmatize desalination and any potential concerns regarding the facility and the environment can be addressed and mitigation measures put in place early-on the project development.

As the need for desalination continues to grow around the world, it is critical that desalination plants be constructed and operated in an environmentally-friendly manner. Facilities around the world have proven this can be achieved.

Mr. Devesh Sharma

Co-chair of EEC

In your opinion, what are the most pressing issues and opportunities regarding environmental stewardship in the field of advanced water treatment as it relates to meeting growing industrial water needs?

The pressing issues for industry include managing the cost of discharge, addressing reliability as feed water quality sources worsen, and balancing the costs of environmental stewardship while ensuring continued economic viability and profitable operations.

Where industrial end-users once simply discharged their waste water, the opportunities to continue this practice are dwindling. This is either because of more stringent regulation, increased costs to discharge, or in most cases, both. To compound this, the accessibility to abundant and fresh water sources for operations is constantly thinning.

This evolving landscape provides some unique opportunities to apply advanced water treatment technology…. specifically, increased recycle and reuse. The improvement of various membrane technologies has made the complete recycling of any industrial effluent possible. This water can be used for virtually any application, from cooling tower make up to ultrapure water. A great example of this is Kuwait, where the waste reject from one of the largest sewage recycle facilities in the world is being treated and recycled into very high purity water for oil field development.

Recycling industrial waste water is not new, but doing so and improving overall economics is. This is the inflection point that will catapult the water reuse industry. There is a lot of ongoing development work to reduce energy consumption, reduce chemical consumption, and make membranes and consumables last longer. All of this is directly linked to environmental sustainability improvement. The next horizon will be converting waste to valuable resources, for example, recovering valuable minerals from the concentrated brine streams generated from water reuse.

This just the tip of the iceberg for industrial water management. The biggest opportunity is applying the ongoing developments in advanced water technology to be an enabler for an industrial end user’s core operations. Purer water can lead to better production yields and thus, more profits.

The intersection of water scarcity and increasing environmental regulations is increasing water risk for industry but tackled head on can be a great opportunity to reduce environmental discharge and fresh water usage costs, improve production yields with higher quality water, and exhibit world class environmental stewardship all at the same time.

Dr. Ahmed Al-Arifi

How has Saudi Arabia monitored environmental impact issues related to desalination, especially with the spectacular expansion of the use of desalination in your country? What lessons can you share with the global community?

With over 30 desalination plants in operation producing more than 5.6 million m3/day of drinking water, SWCC has strong commitment to secure a reliable water supply for millions of our customers while preserving and safeguarding the marine environment along the Red Sea and Gulf shores. SWCC desalination experts address potential environmental impacts during all phases of project development and implementation – from planning and design, to construction, commissioning and operation.

All desalination plants of SWCC have in-house environmental specialists who continuously track plant compliance with the strict regulations and discharge water quality standards set by the government of KSA. The Desalination Technology and Research Institute of SWCC (DTRI) has a multifaceted group of environmental scientists, marine biologists and desalination technology experts that conduct frequent near- and offshore surveys of the marine ecosystems near the plant discharges to monitor and sustain their vitality and biodiversity.

Mr. Borja Blanco

As a global consultant, could you provide some examples where desalination has been implemented with the highest respect for the environment?

In today’s world, respect for the environment is a very high priority for everyone designing, building and operating desalination plants.  One particular example of good practices is Australia, a country that has built large scale desalination facilities in every major city.

Australia began construction of its first desalination plant in 2005 for the city of Perth, followed by Gold Coast, Sydney, Melbourne, Adelaide and a second large-scale plant for Perth.  They call them the “Big 6.”  These plants were implemented with the Australian “triple-bottom-line” (economic, social and environmental) mentality, and quickly demonstrated their sustainability with regard to energy consumption and environmental impact.  Australia engaged independent members of academia and universities to monitor the main areas of environmental concern consisting of dilution of the brine discharge, toxicity of the brine, a perceived threat to dissolved oxygen levels in some areas, waste products, and energy consumption.

Energy consumption was minimized using optimized designs and the latest advances in energy recovery technology, and often the carbon footprint was neutralized by sustainable energy sources such as wind farms.

With regards to environmental impact, multi-year studies published in Water Research magazine found that brine discharge from water desalination plants into the ocean does not have a toxic impact on marine life.  The use of well-designed diffusers that return the high-concentrate salt water to the ocean at high velocity are so effective at diluting the brine that salinity was almost at background levels within a short distance from the outfall.

Dr. Mike Dixon

Does brine disposal from desalination facilities cause Harmful Algae Blooms?

Brine disposal from desalination plants won’t cause harmful algae blooms (HABs). HABs are generated when nutrient (such as nitrogen and phosphorus) in seawater is elevated and are mostly associated with a rise in seawater temperature. Saline concentrate from desalination plants contain low levels of nitrogen and phosphorus. Additionally, state of the art outfalls are designed to maximize rapid mixing with surrounding seawater, so any affects are localized to within a 100m radius (or less) in best practice scenarios. The extremely large HABs commonly found in place such as the Gulf or immediately outside the Straight or Hormuz are due to either naturally occurring high nutrient concentrations or in some cases agricultural run-off. A far greater threat to causing HABs is climate change as overall seawater temperatures are rising at increasing rates.

Dr. Masaru Kurihara

What are some of the most important R&D programs now taking place that if successful, will have the greatest positive impact from an environmental perspective in relation to the use of desalination technologies? 

One of the most important R&D programs now taking place is the reduction of marine pollution by facilities and less chemical cleaning of the plant through optimization of chemical usage by implementing biofouling monitoring technology of the “Mega-ton Water System” project for green desalination．

Sustainable seawater reverse osmosis desalination in the 21^st century requires: (1) reduction of energy resources, (2) high efficiency seawater RO system, and (3) desalination drainage to reduce marine pollution. The goals of the “Mega-ton Water System” project were: (1) energy saving (20%), (2) low environmental impact (no chlorine & no sodium bisulfite (SBS) dosing, (3) low water production cost, and (4) reliable plant operation. Goals (2) and (4) are directly related to environmental impact.

The “Mega-ton Water System” project envisions that sustainable desalination and reclamation.
Seawater Reverse Osmosis (SWRO) operation lacks reliability due to heavy biofouling and large amounts of brine discharge contaminated with chemicals. For reliable desalination, systems with lower environmental impact, membrane-processing technology including biotechnology (such as marine bacteria) were examined as national research* in Japan in the “Mega-ton Water System” project.

We examined the influence of chlorination on marine bacteria using the fluorescence microscopic observation method and found that the effect of chlorination is limited. Another finding is that chlorination sterilization triggers biofouling, and SBS dosing as a de-chlorinating agent also triggers biofouling. So, a process with no chlorine and no SBS dosing would reduce biofouling. As polyamide SWRO membranes have low chlorine resistivity, such a process would enable longer membrane life in real plants.

We used a biofouling monitoring technology to evaluate the biofouling possibility of RO feed seawater by the Membrane Biofilm Formation Rate (mBFR).  The mBFR value is very important to design the pretreatment system of the plant system and predict the number of chemical cleanings. A lower number of chemical cleanings also contributes greatly to reducing the chemical consumption of the plants and the reduction of pollution.

* Japan’s national research Funding Program for World-Leading Innovative Research & Development on Science and Technology (FIRST Program) promoted in-depth research of water treatment core technologies, the “Mega-ton Water System”, and included research on basic and system technologies.

This biofouling monitoring technology using mBFR with no chlorine and no SBS doing was verified in a pilot test, at first in Japan, then the technologies were also verified at the Desalination Technology Research Institute (DTRI) of SWCC, Al-Jubail (Arabian Gulf), Saudi Arabia during one year.

The next step of the Mega-ton project is the verification of this technology at a full-scale plant in Ummluji (Red Sea), Saudi Arabia.

Prof. John H. Lienhard V

How is academia helping to advance environmental stewardship in desalination, now and for the next generation?  Especially on the issue of brine disposal and Environmental Impact Assessments?

Academic researchers are keenly aware of the importance of understanding and limiting the environmental impact of desalination. These efforts are multifaceted and wide-spread, including university researchers all around the world, often working in multi-national teams.  Major government research centers are contributing as well, in the US, the EU, the Middle East and beyond.

Energy efficiency has been a major theme of academic research for many years, with rapidly rising interest in the past decade. These efforts have encompassed new system configurations and hybrids, as well as the integration of renewable energy sources — especially solar energy and wind power.

Brine management has seen rising interest as well, including work to increase water recovery and to capture valuable by-products from brines. The latter include ideas such as salts-recovery, valuable metal harvesting, and the production of industrial chemicals such as sodium hydroxide.

Finally, academic researchers have conducted direct field studies of the impact of desalination plants on local marine life and of the effectiveness of brine diffusers.  On the latter point, ocean engineers have developed a deep understanding of the buoyancy, transport, and dispersion of brine plumes, leading to methods of safely returning ocean salts to the ocean.

The work of universities in this area focuses around creating and vetting new ideas. Ideally, these ideas will reach a sufficient level of development and economic analysis that industry can comfortably take them forward into deployed products and practices. But we must not overlook the other very important mission — the central mission — of universities: to help young engineers and scientists learn about these challenges and develop the skills and knowledge that will make them our future leaders in the area.

Mr. Juan Miguel Pinto

Besides renewables, what is being done to enhance energy efficiency and reduce the carbon footprint of desalination?

First, we need to define carbon footprint and energy efficiency. A carbon footprint is defined as the total amount of greenhouse gases produced to, directly and indirectly, support human activities, usually expressed in equivalent tons of carbon dioxide (CO₂).  Energy efficiency is the goal to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature.

With regards to reducing carbon footprint in the desalination industry, the most common solutions are using renewable energies, optimizing operational processes, designing desalination plants to minimize carbon footprint, or looking at emerging technologies.

Optimization of the operational process

A desalination O&M company needs to operate the plant to minimize the carbon footprint generated by the day to day operation; optimization of chemical dosing; optimizing plant operation to reduce osmotic pressure.

Design desalination plants to minimize carbon footprint:

The EPC and end-user need to design the SWRO systems and building to minimize environmental impact. For example: insulate the building, VFDs for the pumps, select pumps with high efficiency, isobaric energy recovery devices, select the location of the SWRO plant as close as possible to the seawater, new membrane technology to reduce osmotic pressure, pretreatment solution to reduce osmotic pressure, and other options

Emerging technologies:

• New RO membrane technology – new materials
• New high-efficiency pumps – Positive displacement pumps with higher flow capacity
• New chemicals – To optimize SWRO plant operation
• Others

The most energy efficient systems designs are not necessarily the most cost-effective design.  Designing systems to minimize carbon footprint is a challenge for EPCs.  However, future advances in technology will continue to drive down the energy consumption of the SWRO systems.

Mr. Miguel Angel Sanz

Can you share with us the philosophy of Suez toward environmental impact in the use of desalination and water reuse technologies?

Respecting the environment and safety is a “must” and the first priority in our company. It has always been in the “DNA” of Suez, not only in the design phase but also during construction and long-term operation.

Plants like Perth and Melbourne in Australia; Mirfa and Barka 4 in Middle East; Barcelona in Spain; and West Basin in USA are the best examples to demonstrate how we have treated the subjects to minimize any potential environmental impact. Some of them are environmental flagships in the desalination or water reuse industry, being frequently mentioned in best practices documents.

The first step is to follow the environmental regulations of the local authorities and project environmental impact assessment recommendations for on-shore and off-shore works and activities – and also to considerer any air impact.

DB and O&M HAZOPs are usual tools to improve analysis and implement solutions. We take special care in the design of water intakes and in the brine discharge to avoid any impact in sea life (vegetal or animal) and we use the most advanced models and specialized companies in the design and operation of discharge diffusion and follow up. Reduction of chemicals and treatment of any byproduct, as sludge, is present in all of our plants.

Since energy is the main driver in water cost and sustainability, we invest important resources in minimizing energy consumption and reducing carbon footprint of the plants. We were pioneers in the use of renewable energies in this field.

To finish this point, I’d to underline that environment, energy and carbon footprint are the main drivers to develop new products and solutions for the future in Suez Innovation Centers.

Mr. Nikolay Voutchkov

Regarding brine disposal – what is the status of current approaches to environmental impact for both seawater and brackish water desalination?

Today, desalination industry and regulators have comprehensive systems to predict, monitor and control the potential environmental impacts during all phases of project development and implementation – from planning to design, construction and operation. Safeguarding aquatic environment and ecosystems in the vicinity of desalination plant discharges is an essential component of good operation practices of the desalination industry. The desalination plants in operation worldwide continuously monitor and comply with the strict environment regulations and discharge water quality standards set by the country’s governmental bodies in charge of protecting aquatic environment.