ENERGY EFFICIENCY FOR THE SUSTAINABLE CONTROL OF THE WATER TREATMENT COSTS

Transcription

1 ENERGY EFFICIENCY FOR THE SUSTAINABLE CONTROL OF THE WATER TREATMENT COSTS Committed together to water, a source of life

2 [ The stakes ] Energy efficiency,... Due to the economic development of countries, a 50 to 300% increase in consumption is expected by Energy is mainly produced from fossil (oil, gas, coal) and fissile (nuclear) energies which have limited reserves. Some 10 billion toe (tonnes of oil equivalent) are produced each year. Implementing energy efficiency entails reducing and optimising the energy consumption of a process while maintaining its efficiency. This approach has financial and environmental benefits. The possibility of producing green energy and using it to power facilities directly or supplying energy to grids reduces the greenhouse gas emissions of plants, cuts their energy bill and their dependence on energy prices. 20 % of a community s expenditure for the water cycle is used to cover energy costs. 95 % of energy self-sufficiency is achievable for a wastewater treatment plant. 90 GWh of green electricity was produced by Degrémont s facilities in

3 ...a means of controlling the long-term cost of water treatment Drinking water production The treatment needed to produce drinking water consumes relatively little energy. Upstream and downstream pumping are the largest energy consumers in the process; they can be optimised by the choice of the local setting up (by preferring for example a gravity flow, particularly in a mountainous area) and equipment. Concerning the treatment itself, energy needs can range from Wh/m 3, for conventional treatments, to 200 Wh/m 3 for membrane ultrafiltration treatment. Energy savings can thus also be achieved through improved process management. Seawater desalination Two desalination processes are primarily used on an industrial scale to produce fresh water from seawater: thermal processes (distillation) and membrane processes (reverse osmosis). Distillation processes require a substantial amount of thermal energy. They need to be coupled with other heat-producing applications which must be physically close. The energy expenditure specific to reverse osmosis represents more than 50% of the operating costs and 20% of the price of the treated water. But in 40 years, the energy requirement for the seawater desalination by reverse osmosis has decreased considerably thanks to improvements in pump yield, the implementation of energy recovery systems and the development of new membranes. Wastewater treatment and reuse The energy consumption of a wastewater treatment plant depends on the required quality level of the discharge. Ongoing optimisation work is performed on all of the processes in order to reduce their energy impact due to the improvement in treatment performance. The split in electricity consumption highlights the substantial proportion of biological treatment in the overall consumption: energy optimisation of aeration and the stirring of tanks are essential. Treatment of sludge from wastewater treatment plants The potential energy of sludge represents more than twice the electricity consumption of a wastewater treatment plant. More than a waste, sludge is a recoverable resource: digestion and incineration will be a source of savings and green energy production. 3

4 [ Know-how ] Engineering Operation & Maintenance Electricity network IGN DES NT ME L UIP WA EQ ENE R Cogeneration E NC NA TE IN MA PRO CES S SE LEC TION S S ES N OC TIO PR MIZA TI OP Energy efficiency: the asset that sets the offer of the SUEZ ENVIRONNEMENT s water treatment specialists apart Digesters Gas network Biofuel Heat pump Degrémont, at the forefront of energy efficiency, has developed a full range of solutions to improve the energy efficiency of all processes associated with water treatment. Its energy optimisation policy aims to enhance the best practices of its areas of activity: the working out of its processes in R&D and the design phase of its plants, the management and operations of the plants for which it is responsible, and the provision of equipment. The water treatment specialists of SUEZ ENVIRONNEMENT satisfy the energy and environmental concerns of their municipal and industrial customers, while complying with the framework of regulations that impose increased health safety in the production of drinking water and more thorough treatments in the purification of wastewater and sludge treatment. They incorporate renewable energy sources into their projects whenever possible. Expertise Engineering and Process engineering Choosing the least energy-intensive treatment systems Choosing energy efficient processes and optimisation Design of the plant: - hydraulic gradient; - adjusting the number of works; - choosing the most efficient equipment by taking into account the total cost of the life cycle; - endogenous energy recovery (hydraulic, biogas, recovery of heat produced by the process, cogeneration); - use of green energy sources (solar, wind energy); - optimisation of the thermal performance of buildings and the methods for heating premises (e.g. heat pumps). 4 Wind turbines Solar panels Dedicated action plan Operation & Maintenance Training in energy efficiency Energy audit tool developed by Degrémont; Creation of energy efficiency indicators under Aquacalc (energy management software to optimise and report on the energy performance of facilities); Calculating the environmental footprint thanks to the Life Carbon Tool TM; Installing control, frequency converter and energy meter systems at critical system points; Preventive checking and calibration of sensors; Improvement in cycles and scrapping of peak hours through selective loadshedding of targeted equipment; Replacing electromechanical equipment (blowers, air diffusers, motors, pumps). R ecommendations and choosing the best systems and processes; Running workshops; Maintaining equipment; Replacing equipment; Energy efficiency management; A dvice on implementing the ISO standard; Degrémont has implemented a three-year energy efficiency action plan. By the end of 2016, for at least 95% of treatment plants it operates, the managers of facilities supported by their energy efficiency manager will have: conducted an energy efficiency audit; implemented an energy management system; obtained an ISO certification of their energy management system, or will have scheduled it with a projected certification date. 5

5 [ Know-how ] Engineering Operation & Maintenance Electricity network IGN DES NT ME L UIP WA EQ ENE R Cogeneration E NC NA TE IN MA PRO CES S SE LEC TION S S ES N OC TIO PR MIZA TI OP Energy efficiency: the asset that sets the offer of the SUEZ ENVIRONNEMENT s water treatment specialists apart Digesters Gas network Biofuel Heat pump Degrémont, at the forefront of energy efficiency, has developed a full range of solutions to improve the energy efficiency of all processes associated with water treatment. Its energy optimisation policy aims to enhance the best practices of its areas of activity: the working out of its processes in R&D and the design phase of its plants, the management and operations of the plants for which it is responsible, and the provision of equipment. The water treatment specialists of SUEZ ENVIRONNEMENT satisfy the energy and environmental concerns of their municipal and industrial customers, while complying with the framework of regulations that impose increased health safety in the production of drinking water and more thorough treatments in the purification of wastewater and sludge treatment. They incorporate renewable energy sources into their projects whenever possible. Expertise Engineering and Process engineering Choosing the least energy-intensive treatment systems Choosing energy efficient processes and optimisation Design of the plant: - hydraulic gradient; - adjusting the number of works; - choosing the most efficient equipment by taking into account the total cost of the life cycle; - endogenous energy recovery (hydraulic, biogas, recovery of heat produced by the process, cogeneration); - use of green energy sources (solar, wind energy); - optimisation of the thermal performance of buildings and the methods for heating premises (e.g. heat pumps). 4 Wind turbines Solar panels Dedicated action plan Operation & Maintenance Training in energy efficiency Energy audit tool developed by Degrémont; Creation of energy efficiency indicators under Aquacalc (energy management software to optimise and report on the energy performance of facilities); Calculating the environmental footprint thanks to the Life Carbon Tool TM; Installing control, frequency converter and energy meter systems at critical system points; Preventive checking and calibration of sensors; Improvement in cycles and scrapping of peak hours through selective loadshedding of targeted equipment; Replacing electromechanical equipment (blowers, air diffusers, motors, pumps). R ecommendations and choosing the best systems and processes; Running workshops; Maintaining equipment; Replacing equipment; Energy efficiency management; A dvice on implementing the ISO standard; Degrémont has implemented a three-year energy efficiency action plan. By the end of 2016, for at least 95% of treatment plants it operates, the managers of facilities supported by their energy efficiency manager will have: conducted an energy efficiency audit; implemented an energy management system; obtained an ISO certification of their energy management system, or will have scheduled it with a projected certification date. 5

6 [ Solutions ] Degrémont, the SUEZ ENVIRONNEMENT s water treatment specialist, designs, builds, operates, develops services, implements technologies and equips its facilities by combining technical and energy performance Drinking water production The hydraulic gradient Degrémont has developed its own tool for calculating the best hydraulic gradient to optimise energy consumption related to pumping. Pumping Through a close collaboration with the major pump suppliers, Degrémont has developed a decision-making support tool for selecting pumps whose best efficiency point corresponds to the needs of the project and compares them according to their purchase price, their energy cost and their maintenance cost based on the overall life cycle. Filtration Degrémont s open filters (Aquazur, Carbazur, Mediazur ) can be equipped with the Regulazur III energy management system for filtration and backwashing. Disinfection The energy efficiency of Aquaray H2O and Aquaray 3X low-pressure UV lamps is three times greater than a medium-pressure lamp (30% versus 10%). Desalination by reverse osmosis Pumping The installation of high performance pumps, variable speed drives and high motor yields substantially optimises the energy consumption of plants. Pretreatment Degrémont s know-how and expertise in pretreatment processes allow it to increase the performance of reverse osmosis systems and as such to decrease their energy requirements. Reverse osmosis With support from its partners, Degrémont has contributed and continues to contribute to the control of energy efficiency, such as in the areas of high pressure pumping and low consumption membranes. These increasingly permeable membranes consume less energy for a higher conversion rate. Energy recovery Degrémont also provides its input in the area of pressure exchangers between the concentrate and the pretreated water which can achieve yields in excess of 95%. Green energy In its offers, Degrémont includes the use of alternative energy (e.g. wind power) when local conditions allow it. Next contributions of the SUEZ ENVIRONNEMENT s water treatment specialists for improving energy efficiency in desalination field will relate to: the decrease in water losses during pretreatment; improved performance in the first stage of reverse osmosis (via new membranes and advances in membrane engineering); the development of innovative energy-efficient sea water desalination technologies supplied by renewable energy sources (e.g. pilot desalination unit for Masdar Abu Dhabi); alternative processes for boron removal. 6

7 Wastewater treatment Pumping In addition to the tool for calculating the best hydraulic gradient, with a view to optimising energy consumption associated with pumping, Degrémont has developed an evolutionary tool that gathers information about the submersible pumps of major suppliers. For given capacity, total head and operating conditions, the tool selects the pumps whose optimum yield point corresponds to the specified point of operation. Aeration In order to obtain reliable and efficient air production and distribution, all options must be taken into account, from the design of aeration tanks to the choice of air production machines, the type of diffuser used and the aeration control system. Design of the tanks A good design for tanks leads to efficient mixing within them and less air need (e.g. Combigreen which combines an annular aeration channel -with air insufflation- with a very high clarifier: removal of under-speed areas that are a source of additional energy expenditure for air requirements and stirring). Regulating aeration Degrémont has developed an original control system called Greenbass which simultaneously uses N-NH + 4 and N-NO - 3 concentrations to adjust the nitrification/denitrification process with greater precision and thus as well the aeration. Greenbass reduces energy consumption by up to 15%. Choice of equipment The choice of air production machines, if they are chosen correctly, can lead to save up to 30% of the energy consumed by aeration. Degrémont has developed a selection tool for air production machines, based on a calculation of the life cycle cost (energy represents between 80% and 95% of the overall life cycle cost over ten years). 7

8 [ Solutions ] Air treatment In a wastewater treatment plant, odour control accounts for approximately 10% of the plant s overall energy consumption. Degrémont focuses on three challenges to maximise the efficiency of ventilation systems: - correct sizing of the air supply circuit; - limiting the quantity of polluted air to be treated by preventive (limiting polluting emissions) or curative actions; - reducing the quantity of energy needed to treat a given volume of air, by the selection of the fan and the motor. Treatment of sludge from wastewater treatment plants The sludge treatment steps DIGESTION THICKENING SETTLING DRYING DEWATERING RECOVERY / REUSE FLOTATION COMPOSTING INCINERATION 8

9 The four biogas recovering solutions HEAT RECOVERY Thanks to a biogas boiler: heating digesters and premises; supplying the dryers with heat energy. COGENERATION It allows the simultaneous production of electricity and heat: electricity used on site or reinjected into the network; heat recovered on site. 1 kg of VS 1 Nm 3 of biogas 6.3 kwh Cogeneration Electricity 2.2 kwh Heat 1.8 kwh INJECTION INTO THE NATURAL GAS NETWORK The closeness of a natural gas network offers the possibility of directly recovering the biogas produced after prior treatment (transformation into biomethane). PRODUCTION OF BIOFUELS The biogas transformed into biomethane allows also to produce biofuels. fuel for long-distance transport vehicles; fuel for urban transport vehicles. BIOMETHANE BIO NGV BIO LNG Urban environment Long-distance La digestion The principal advantage of digestion in terms of energy efficiency is the production of green energy through the biogas generated. The result of a partnership with CAMBI, Digelis Turbo is a Degrémont technology for boosting digestion and increasing the production of biogas. Advanced dewatering Dehydris TM Twist implements a process that Degrémont adapted from a technology developed by BUCHER. The process is totally automated and uses less energy than modern dewatering systems. The greater dryness obtained results in a lower volume of dewatered sludge, so less fuel is consumed in sludge drying and incineration. Low consumption drying Evaporis LE is a high-temperature and low consumption dryer which has the lowest energy input on the market. The process is based on the combination of direct drying and indirect drying, recovering heat between the two stages. Compared to traditional drying, this technology reduces energy consumption by 30%. Evaporis LT is a low-temperature drying process which reduces primary consumption by recovering unavoidable thermal energy. Fuel requirements are limited, and the benefits are both environmental (limiting the need in fossil fuels and limiting greenhouse gas emissions) and economical. Green incineration A significant quantity of heat is available in the flue gas from sludge incineration. The possibility of producing energy through the recovery of heat from flue gas makes it possible to envisage zero consumption of fossil fuels. Thermylis 2S is a process based on the preliminary drying of sludge using the heat in the flue gas from incineration before traditional incineration. It has a very low environmental impact and doesn t require any fuel to be added. Thermylis 2R uses the ORC (Organic Rankine Cycle) technology patented by Degrémont. The available heat source is used to evaporate the organic fluid. The advantages include highly efficient electricity production and reusable thermal power. 9

10 [ References ] Flagship realisations... As Samra (Jordan) Type of plant Urban wastewater treatment 365,000 m 3 per day. Recovered energy sources Biogas (Digelis TM ) + Hydraulic turbines Energy and environmental performances production by cogeneration of 10,000 kw (10 groups of 1,000 kw); Hydraulic energy recovery (3,835 kw) by 5 turbines (two of 850 kw, two of 810 kw and one of 515 kw); 95% of electric needs are covered by the biogas cogeneration units and the turbines; production of 78 GWh of electricity per year from renewable sources. La Feyssine (France) Type of plant Urban wastewater treatment 300,000 PE Recovered energy sources Biogas (Digelis TM 4,187 Nm 3 /day) + Solar (220 m² of photovoltaic panels) Energy and environmental performances biogas source: heat production = 1,400 kw; solar source: electricity production = 22 MWh/year; use of heat for digestion and sludge drying (77% of the dryer s needs); natural gas savings of approximately 950,000 Nm 3 /year. 10

11 Tournus (France) Type of plant Urban wastewater treatment 10,500 PE Saved energy sources Choosing processes and Design: - Combigreen TM = optimised hydraulic aeration channel (annular shape with optimum geometry); - Greenbass TM = smart control of the activated sludge aeration. Energy and environmental performances 15% in energy savings; CO 2 emissions reduced by 4.5 tonnes per year. Mapocho - El Trebal (Chile) Type of plant Urban wastewater treatment 3,500,000 PE Recovered energy sources Biogas (Digelis TM Turbo) Energy and environmental performances production by cogeneration of 8,100 kw (3 groups of 2,700 kw); recovery of heat from flue gases to meet the steam needs of the Digelis TM Turbo. The heat needs for digestion are covered; up to 60% of electricity needs covered by biogas cogeneration units; CO 2 emissions reduced by 4,600 tonnes per year. 11

12 [ References ] Flagship realisations... Melbourne (Australia) Type of plant Seawater desalination by reverse osmosis 450,000 m 3 per day Recovered energy Pressure from concentrates from the first pass through pressure exchangers (486 ERI PX260 energy recovery systems) Energy and environmental performances 48% of the energy required for reverse osmosis of the first pass is produced by the energy recovery systems; all the plant s energy needs are covered by renewable electricity supplied by two wind farms. Nice (France) Type of plant Urban wastewater treatment 650,000 PE Establishing an energy efficiency programme objective of the programme: to achieve a 15% saving in the plant s total energy consumption; optimisation and replacement of equipment. Energy and environmental performances changing air blowers = saving of 0.7 GWh/year; replacing the aeration system (piping and distribution) = saving of 1.4 GWh/year; installation of variable speed drives on motors = saving of 0.7 GWh/year. 12

13 ISO certification Spain Degrémont has obtained ISO certification for its energy management system set up at the wastewater treatment plants in Santander, Adeje and Arriandi and at its offices in Bilbao. France Within the context of the operation of the Valenton Seine-Amont wastewater treatment plant on behalf of SIAAP, the energy management system installed by Degrémont enabled it to obtain ISO certification. This wastewater treatment plant is the first one in France with a capacity of over 100,000 PE to receive this certification. Grenoble (France) Type of plant Urban wastewater treatment 400,000 PE Recovered energy source Biogas Energy and environmental performances Production of biomethane = 280 Nm 3 /h 13

14 [ Commitments ] A partnership strategy and a proximity commitment TO CONSOLIDATE AND ENHANCE THE ADDED VALUE OF ITS PRODUCTS AND SERVICES, Degrémont, within SUEZ ENVIRONNEMENT, is committed to genuine partnerships and maintains constant dialogue with customers. Technological cooperation creates value and differentiation With their expertise in water treatment and experience acquired at numerous plants, the SUEZ ENVIRONNEMENT s water treatment specialists team up with appropriate equipment manufacturers to develop and optimise new treatment solutions, new energy recovery systems and new sources of alternative energy. In addition, by calling on partners to contribute know-how outside their own areas of expertise, they have extended their scope and competitiveness. Being competitive is not just a question of price. It also means acting on a whole set of parameters such as energy consumption to obtain the best global and health quality-operation cost ratio. Programmes with local authorities and industry Degrémont develops partnerships with some of its major customers, especially through research programmes and in the field of social and environmental responsibility. This approach helps Degrémont to understand the challenges they face. Customised associations Within SUEZ ENVIRONNEMENT, Degrémont is committed to Alliance contracts with some of its customers, especially for the joint management of water and wastewater services, with the aim of optimising costs and delivering environmentally friendly performances, in particular energy performance. Constantly listening to customers Understanding their stakes, anticipating their needs, innovating and controlling costs by being always in tune with their customers, the SUEZ ENVIRONNEMENT s water treatment specialists can propose technological differentiating solutions which match their objectives and address the challenges that water represents for them. In this way: local authorities can provide drinking water to the population and treat the wastewater in accordance with local health, safety and environmental standards; industry can increase their competitiveness thanks to reliable process water and effective purification of their effluent, while reducing environmental impact and continuously complying with the ever so stringent regulatory standards. 14

15 A culture of innovation and industrial excellence WITHIN SUEZ ENVIRONNEMENT, DEGRÉMONT CREATES THE BEST TECHNOLOGICAL, COMMERCIAL, LOGISTICAL, FINANCIAL AND CONTRACTUAL SOLUTIONS to address its customers requirements. Customers are the source of anticipation and innovation SUEZ ENVIRONNEMENT and Degrémont s global reach enables them to anticipate and detect early indications of major changes, such as consideration of energy efficiency, that will affect everyone with an interest in water treatment. For the SUEZ ENVIRONNEMENT s water treatment specialists, innovating means putting customers and their needs at the heart of the process. They are perfectly positioned to analyse evolving requirements, devise tomorrow s solutions and adapt to local conditions. This approach is conducive to generating original solutions not only from a technological, but also a financial, contractual and logistical standpoint that best respond to global or local needs. Dedicated specialist teams Having experts in design, build, equipment and operation, within SUEZ ENVIRONNEMENT, Degrémont is able to draw on the particular skills of its employees for each project to create a response that meets the specific needs of its customers. The commitment and motivation of its teams enable Degrémont to deliver efficient, reliable and energyefficient plants to its customers, within short timescales and at an optimal capital and operating cost, and to guarantee the quality of water they require whether for consumption, industry or agriculture. Responsible involvement at all stages of the project For example, by signing a BOT (Build, Operate and Transfer) contract, within SUEZ ENVIRONNEMENT, Degrémont is committed: over the long term, from design, during operation and through to transferring the plant; to integrating responsibility for raising the necessary finance; to establishing the legal framework for the project; to securing completion of the project by involving selected partners to contribute added technical or financial value, specific know-how and local knowledge. A BOT contract involves Degrémont in long-term commitment and service to the customer, guaranteeing the performance of the plant in terms of volume and quality of the treated water. GoodCorporation TM Degrémont is the first company in the sector to obtain GoodCorporation TM certification. First obtained in 2009, this certification was renewed in 2011, 2012 and It is a label certifying responsible practice based on an audit of an organisation s management with regard to its stakeholders (customers, suppliers, employees, etc.), protection of the environment and its contribution to the community. 15

16 DEGREMONT Infographie : Olivier Aubert Photos : D. Marlan, P. Weymouth, L. Francini, J.-I. Haga, M. Martinez Boulanin 2014 Réf. M-ENER-002-EN-1408