Lesson 7: Green Technology for Energy and Water Efficiency PDF

UEPM 103 – GREEN AND ECOLOGICAL TECHNOLOGIES IN URBAN PLANNING FINALS – LECTURE- LESSON 1 PREPARED BY: DESIEREE A. DE ARO LESSON 7: GREEN TECHNOLOGY FOR ENERGY AND WATER EFFICIENCY I. GREEN TECHNOLOGIES FOR WATER EFFICIENCY The sustainable water management approach is t...

UEPM 103 – GREEN AND ECOLOGICAL TECHNOLOGIES IN URBAN PLANNING FINALS – LECTURE- LESSON 1 PREPARED BY: DESIEREE A. DE ARO LESSON 7: GREEN TECHNOLOGY FOR ENERGY AND WATER EFFICIENCY I. GREEN TECHNOLOGIES FOR WATER EFFICIENCY The sustainable water management approach is to view all water systems as a whole, including drinking water, wastewater, rainwater, and stormwater drainage as a collective system that should be managed together to be truly efficient and sustainable, namely, integrated water management. Advantages of Sustainable Water Management 1. Solving Problems – some water-related problems such as drought, flooding, groundwater over- extraction, water-borne diseases, land and water degradation, insufficient wastewater treatment, ongoing damage to ecosystems, and escalating water conflicts in rural areas that might be intractable to conventional, single-sector approaches can be addressed by sustainable water management approaches. As such, issues could be identified holistically and solved effectively from multiple sectors without creating other troubles and complications. 2. Avoiding poor investments and expensive mistakes - sustainable water management promotes the consideration of economic implications of infrastructure maintenance, water services potential for cost recovery, and both short and long-term environmental impacts. This can avoid losses and high costs associated with unsustainable development and irreparable harm. 3. Getting the most value from investments in infrastructure – ensure maximum returns of investments from infrastructure planning, design, and management both socially and economically. It facilitates the different investments working synergistically and producing greater returns than possible through a single sector. 4. Allocating water strategically – provide strong links among allocation decisions, national development, and economic planning processes, using tools such as water pricing and tariffs, appropriate incentives and subsidies, and the removal of ill-considered incentives and subsidies both inside and outside the water sector. Water Efficient Technologies In this connection to sustainable water management in urban planning, the context of water efficiency is needed. This refers to the decrease in the usage of water as well as the decrease in the wastage of water. Wastage of water or its extra usage leads to the drawing out of more water from freshwater resources, resulting in depletion. Thus, water-efficient technologies have been developed to conserve potable as well as non- potable water and to save the already limited freshwater resources. 1. Rainwater Harvesting - it is the collection and distribution of rainwater for use in daily life, rather than allowing it to run off. Rainwater is generally accumulated from rooftops. Then it is deposited in a a reservoir with percolation. It is used for gardening, cultivation, and domestic use. The harvested water can also be used as groundwater recharge. 2. Graywater recycling and reuse – refers to the domestic wastewater that is drained out excluding the wastewater from kitchen sinks and the water closed as they have high concentrations of organic matter. Disclaimer: This handout is solely for educational purposes and is a reference to be used by the students enrolled in this subject only. Uploading or distribution of e-copies of this material without the consent of the author is prohibited. UEPM 103 – GREEN AND ECOLOGICAL TECHNOLOGIES IN URBAN PLANNING FINALS – LECTURE- LESSON 1 PREPARED BY: DESIEREE A. DE ARO Some advanced green Water Efficiency Technologies 1. Bioreactors – a device containing bacteria and microorganisms placed or immobilized in/on: a moving bed biofilm reactor, deposited on a packed or fibrous bed, or attached to a membrane to form a biofilm. Bioreactors are usually equipped with separators linked to sequential tanks and a mechanical separator aimed to accelerate the split of liquid water from the biosolids. In addition, they also contain aerators for oxygen supply aimed to speed up the biochemical reactions undertaken by living microorganisms. The contact between the Image source: springerlink.com wastewater and bacteria/microorganisms present in the bioreactor’s platform induces biochemical reactions, which in the end lead to a transformation of contaminant/ pollutant to other less or non-toxic forms. In the case of metal- containing wastewater, bioreactors inoculated with sulfate-reducing bacteria produce hydrogen sulfide which precipitates the dissolved metals as insoluble metal sulfide that are recovered as valuable by- products. 2. Biofiltration – some selected species of bacteria and microorganisms are grown on a biofilter to form a biofilm. The wastewater is then passed through the biofilm either upflow or downflow and in a continuous or discontinuous manner. During this process, the immobilized living microorganisms speed up the degradation of organic matter and pollutants present in the wastewater. Parameters like the activity of the microorganisms, age of the biofilm, oxygen levels, temperature, and water composition play key roles in the performance of the biofilm, and thus the quality of the resulting treated wastewater. Although commonly used for Image source: sciencedirect.com treatment as domestic wastewater, this type of advanced green technology is also finding application for the removal of heavy metals from industrial wastewater. 3. Bioremediation - a process that employs living microorganisms to remove and neutralize pollutants and hazardous species from contaminated Disclaimer: This handout is solely for educational purposes and is a reference to be used by the students enrolled in this subject only. Uploading or distribution of e-copies of this material without the consent of the author is prohibited. Image source: weebly.com UEPM 103 – GREEN AND ECOLOGICAL TECHNOLOGIES IN URBAN PLANNING FINALS – LECTURE- LESSON 1 PREPARED BY: DESIEREE A. DE ARO wastewater sites to yield less toxic and non-toxic materials. The process can either be performed in situ or ex situ. Living microorganisms are directly added to contaminated sites during in-situ remediation processes, and contaminated sites are treated elsewhere during ex-situ remediation. In general, when it comes to the treatment of contaminants and hazardous species, living microorganisms, however, have their limitation as not all contaminants are cleaned through bioremediation or biofiltration. Examples are heavy metals like copper, nickel, cadmium, lead, and mercury. 4. Electrotwinning – in this process, a current is passed between two electrodes (cathode and anode) immersed in an electrolyte solution. Metals are then electroextracted from their oxidized forms (dissolved cations) to deposit on the cathode. Thus, heavy metals including copper, nickel, silver, gold, cadmium, bismuth, cobalt, and others can be recovered from wastewater through electrowinning. Image source: sciencedirectcom 5. Electrocoagulation – it uses an electric current to remove contaminants from wastewater. Cations are generated at the sacrificial anode set off physical and chemical reactions that can be divided 3 successive stages: a. By applying an electric current, hydrated cations are produced at the sacrificial iron or aluminum anode; b. The released cations neutralize the charges of pollutant particles which become unstable forming micro-flocculants; c. These destabilized particles begin to coagulate as microscopic flocs that can be easily separated from the water. - The overall mechanism is a combination of ionization, electrolysis, hydrolysis and free-radical formation which modifies not only the physical but also chemical properties of the wastewater resulting in a net removal of pollutant species and production of a clear treated water suitable for discharge. Disclaimer: This handout is solely for educational purposes and is a reference to be used by the students enrolled in this subject only. Uploading or distribution of e-copies of this material without the consent of the author is prohibited. UEPM 103 – GREEN AND ECOLOGICAL TECHNOLOGIES IN URBAN PLANNING FINALS – LECTURE- LESSON 1 PREPARED BY: DESIEREE A. DE ARO Image source: sciencedirect.com 6. Desalination 7. Decentralized graywater recycling – the system takes water from showers, washing machines and air conditioning units and treats it on the spot. The recycled water is used for flushing toilets, laundry, irrigation, and other non-potable uses. Depending upon user behavior, the system can reduce water consumption in a house by up to 45%. 8. Reverse osmosis of seawater – reverse osmosis is the most common desalination technology. During the osmosis process, water with different concentrations of salts for example is separated by a semi- permeable membrane. As these different concentrations come into contact through the membrane, water with a lower concentration naturally crosses over to water with a higher concentration until equilibrium is reached. In reserve osmosis, pressure is added to highly concentrated water, forcing it through the membrane to obtain clean, and salt-free water. 9. Multi-stage Flash Desalination (MSF) – is a thermal desalination technology. It uses heat to evaporate and condense water to purify it. In the MSF desalination system, incoming seawater is first heated in a heat exchanger. The water then enters different flash chambers, where pressure is continually reduced and the water exposed to a series of explosive evaporation (flashing). The purified vapor is then condensed to leave behind salty brine. Meanwhile, the heated water helps preheat incoming seawater thereby reducing energy use. As heat transfer and evaporation are separated, the risk of scaling (caused by the salt) is reduced. B. GREEN TECHNOLOGIES FOR ENERGY EFFICIENCY /RENEWABLE ENERGY TECHNOLOGIES Renewable Energy Technologies or Renewable Energy Sources – is an umbrella term that stands for energy production using renewable energy sources like solar, wind, water (hydro and tidal), biomass (biofuels and wastes), and geothermal heat. Renewable energy system – the actual power plant that converts the renewable energy carrier or source into electrical, mechanical, or thermal energy for use by the consumer. 1. Biomass - when gas is produced, it can be stored and used at a later stage. The common types of biomass plants are Biomass fermentation plants and biomass thermal power plants which produce electric energy or gas. - These fuels have to be actively produced all year long; biomass plants need to include storage facilities or be designed to process a wide range of biomass fuels. - Biomass plants need to include storage facilities or be designed to process a wide range of biomass fuels. Disclaimer: This handout is solely for educational purposes and is a reference to be used by the students enrolled in this subject only. Uploading or distribution of e-copies of this material without the consent of the author is prohibited. UEPM 103 – GREEN AND ECOLOGICAL TECHNOLOGIES IN URBAN PLANNING FINALS – LECTURE- LESSON 1 PREPARED BY: DESIEREE A. DE ARO - Sustainability of the biomass production and whether this production is competing with production. 2. Water - Water energy used to produce electricity is generally created by damming and directing water through turbines that are connected to generators which produce electric energy. This principle is found in all hydroelectric power plants, although there are some differentiations in design, size, and operating techniques. - Water use in tidal systems is differentiated as tidal wave, sea current, and wave vertical movement power plant, which operate in saltwater conditions and are thus extremely prone to corrosion. 3. Solar - In solar energy production three principal systems prevail: a. Photovoltaic (VP) - solar energy is turned into electric direct current; only functions as long as sunlight is available b. Solar thermal energy (ST)- a fluid like water is directly heated for immediate use; only functions as long as sunlight is available c. Concentrated solar power (CSP) – a process fluid is heated by means of mirror arrays to produce electric energy; it can provide baseload power, as the hot and inert fluid can be processed over a duration of several hours 4. Wind - Wind turbine generators convert wind energy from mechanical into electrical energy. 5. Geothermal energy - Makes use of the temperature of the Earth. The application of resources is in principle twofold: either directly for heating and cooling, primarily in domestic applications, or indirectly in electric power plants (called binary systems). - Geothermal energy can also be used to supply the heating systems in domestic housing. Depending on the ground conditions, a pipe system is installed either inside a hole that is only a few meters underground. These pipes are made of stainless steel or plastic tubes and are part of a heat exchanger system. System fluids are circulated through these pipes in order to extract heat from Earth. Reference: Barshai, A. (2017). Advanced green technology for wastewater treatment. URL://blog.emew.com. Accessed on October 20, 2024 Zepf, V. (2020). The dependency of renewable energy technologies on critical resources. The Material Basis of Energy Transition, 49-70. Doi:10:106/b978-0-12-819534.00004-0. Disclaimer: This handout is solely for educational purposes and is a reference to be used by the students enrolled in this subject only. Uploading or distribution of e-copies of this material without the consent of the author is prohibited.