Life cycle energy and greenhouse gas emissions of an integrated water management system, City of Clearwater, FL

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1 Life cycle energy and greenhouse gas emissions of an integrated water management system, City of Clearwater, FL Behnaz H. Zaribaf a, Qiong Zhang a, Nan Bennett b a Department of Civil and Environmental Engineering, University of South Florida b City of Clearwater, Public Utilities Abstract Providing quality water is an energy intensive process. The amounts of energy used and the greenhouse gas (GHG) emitted largely depend on the water source, quality of raw water, the treatment process employed and the local electricity mix. Groundwater is the primary source for potable water supply at city of Clearwater. Since the local groundwater has elevated total dissolved solids (TDS) from shallow wells and salinity of water extracted from deep wells (called brackish water) is high, alternative water treatment processes such as reverse osmosis (RO) for brackish water treatment and alternate water sources such as reclaimed water, for nonpotable purposes, are considered. In City of Clearwater, the water systems are managed in an integrated approach, called integrated water management system (IWM), as water treatment and water reclamation facilities (wastewater treatment plants) are managed and controlled under the same agency. The goal of this study is to conduct a life cycle assessment (LCA) to evaluate the life cycle energy and GHG emissions of the whole integrated water system. In this study, the energy intensity of an advanced treatment process, RO, employed for brackish water treatment was compared to the conventional groundwater treatment, and the benefits of resource recovery in terms of the amount of energy recovered and the GHG emissions avoided were determined. Current resource recovery practices at City of Clearwater system include water reclamation, methane production for heating the sludge and sludge land application. Life cycle inventory data was collected from each plant including the types and amounts of chemicals used as well as the electricity consumed at the plant. Water-Energy Sustainability Tool (WEST) tool was used as an analytical software. The results show that wastewater treatment process has the highest GHG emissions and life cycle energy consumption followed by water treatment process. The main contributor to life cycle energy and GHG emissions at wastewater treatment process is electricity consumption followed by chemical consumption. For the water treatment process, electricity consumption is the dominant contributor for GHG emissions but chemical consumption is the main contributor for life cycle energy consumption. The results for water treatment plants show that the life cycle energy and GHG emissions of the RO plant are higher than those of other two water treatment plants while the results of water reclamation facilities show that all three plants are having similar energy consumption and GHG emissions rates. Resource recovery practices, such as water reclamation, methane generation at anaerobic digesters, and dewatered sludge land application, could save noticeable amount of energy and GHG emissions. Future studies will focus on the evaluation of disinfection methods beyond chlorination from energy, cost and environmental impacts perspectives. 1

2 1. Introduction Raw water resources are the finite vulnerable sources that need to be extracted, treated and used wisely. Unfortunately, depletion of freshwater sources and deterioration of raw water quality caused serious issues in providing potable water in communities (Al-Kharabsheh 1999; Tularam and A. 2009). Moreover, an intensive amount of energy is needed to extract raw water, treat it to the required level and then deliver to the customers. Those processes, consequently, have adverse environmental impacts including Greenhouse Gas (GHG) emissions. Therefore, in order to meet future water demand, water systems should be managed in a way that not only meet local water demand but also minimize the associated environmental impacts and preserve their natural resources. Integrated Water Management (IWM) is one of the approaches that can help managers and planners to manage water and other resources in a holistic way. This approach brings together all stages of water supply, water treatment and sewage management to achieve the maximum benefit of water reuse and recycling (Fahmy 2004; Clifton and Purohit 2011). Futuristic plans on water reuse such as recharging aquifers and providing alternative non-potable water sources to prevent groundwater overdrawing can be planned and employed in an IWM system. There are several studies focused on integrated water systems in Europe, China and Middle East (Lazarova et al. 2001; Sharda 2010; Zhang et al. 2010). Lazarova et al. (2001) focused on wastewater reuse as one the important strategies of the integrated water management and reviewed the economic, financial and technical factors that help to have successful water reuse projects in different regions of Northern and Western Europe and also in Mediterranean areas. Sharda (2010) presented a computer-based system, called Digital Ecosystem, to monitor and control a system integrating the use of freshwater, rainwater and grey water. Zhang et al. (2010) presented a legal framework and policies related to the implementation of integrated water management in China focusing on the role of human health and ecological functions. The main focus of previous studies, however, was on the application of IWM approach and its related issues. The benefits of having an integrated water system were not evaluated from energy and environmental aspects. Therefore, there is a need to evaluate the environmental impact associated with the whole water cycle in an IWM system and quantify the energy saved and environmental impact avoided compared to the traditional management systems. The current study used Life Cycle Assessment (LCA) method to estimate the life cycle energy and Greenhouse Gas (GHG) emissions of an IWM system. City of Clearwater utility, as an example of integrated water management systems, was evaluated in this study. The data used in the study is for the fiscal year of 2011 (FY 2011), from October 1, 2010 to September 30, System description City of Clearwater is located in Pinellas County, Florida, nearly due west of Tampa and northwest of St. Petersburg. As of 2011 census, the city had a permanent population of 107,000, before counting for tourists and seasonal residents (US census, 2012). This study divided the city s water management system into four sections: 1. water/wastewater infrastructure, 2. water treatment, 3. water reclamaition, 4. resource recovery practices. 2

3 2.1. Water/Wastewater : Water/Wastewater infrastructure is comprised of raw water uptake, potable water distribution, wastewater collection, and reclaimed water distribution. Raw water is pumped out of the local wells and delivered to three water treatment plants (WTPs) through 19 miles of pipes composed of polyvinyl chloride (PVC), ductile iron (DI), and concrete. After raw water is treated at the WTPs, potable water is delivered to the customers through 592 miles of pipes, mainly made of PVC and DI. After water is used, wastewater is collected at the lift stations (LS), before being delivered and treated at water reclamation facilities (WRFs). Wastewater is collected and delivered to WRFs through 400 miles pipes made of vitrified clay pipe (VCP), PVC and cast iron (CI). Finally, the reclaimed water distribution system delivers reclaimed water to the customers through 76 miles of primary PVC pipes Water Treatment: City of Clearwater treats raw water at three water treatment plants, WTP No.1 (WTP1), WTP No.2 (WTP2) and WTP No.3 (WTP3). WTP1 has an average production of 3 million gallon per day (MGD) of potable water in FY WTP1 employs reverse osmosis (RO) technology to treat brackish water (TDS ranges from 800 to 1000 mg/l), which comes from the local wells. WTP 2 and WTP3 have the average production of 2.73 MGD and 5.95 MGD in FY 2011, respectively. The treatment process employed at WPT2 and WTP3 is limited to the chemical treatment, which includes Sodium Hypochlorite, Aqua Ammonia and Polyphosphate, due to the high quality of raw water from the wells. In additional to the local ground water treated at WTP2 and WTP3, water is purchased from the regional water supply, which is blended with local raw water, and the combined water is chemically treated as necessary to city standards. The annual average purchased water varied depending on the demand. In FY 2011, the average purchased water were 1.7 MGD and 3.6 MGD for WTP2 and WTP3, respectively Water Reclamation Facilities: City of Clearwater has three water reclamation facilities (WRFs): Northeast (NE) WRF, with the average flowrate of 6.09 MGD, Marshall Street (Marshall) WRF with the average flowrate of 5.9 MGD, and East WRF with the average flowrate of 2.14 MGD in FY The treatment processes employed at all three plants include primary treatment (bar screen, grit removal, primary clarifier), secondary treatment (activated sludge), and tertiary treatment (biological nutrient removal, BNR). The final effluent, as reclaimed water, meets the standards for irrigation water. The average annual reclaimed water production is 4.25 MGD at NE plant, 2.92 MGD at Marshall plant, and 0.35 MGD at East plant. On an average annual basis in FY 2011, more than 50% (53% of the wastewater entering the water reclamation facilities is converted to reclaimed water for beneficial use. General characteristics of the influent wastewater entering the water reclamation facilities are shown in Table 1. 3

4 Table 1. Average characteristics of the influent wastewater for three WRFs Components Value TN 29 mg/l BOD mg/l TP 5.1 mg/l TSS 201 mg/l Temperature 28 C PH 7.03 Chlorides 249 mg/l 2.4. Energy and resource recovery practices City of Clearwater employs several citywide resource recovery practices to preserve groundwater sources, generate new energy and material sources and also mitigate the environmental impacts associated with the urban water cycle. These recourse recovery practices are described in this section. I. Reclaimed water production Reclaimed water is produced at three WRFs using the advanced wastewater treatment process. Reclaimed water is used in the city as a replacement of potable water for irrigation applications that high quality water is not required. Therefore, potable water is considered as an avoided product when reclaimed water is used. II. Energy production in the form of biogas Biogas is produced from the anaerobic digestion (AD) process at Marshall and NE WRFs. It should be noted that the sludge produced at East WRF is trucked to the NE WRF where it is combined and treated with the biosolids from NE plant at the anaerobic digester to the Class B sludge for land application. The quantity of biogas produced by the anaerobic digesters is estimated at the operations reports for Marshall and NE plants. Currently, the biogas produced through anaerobic digestion is used as a fuel in a boiler that heat the sludge, however, construction of a co-generator to produce electricity from the biogas is underway. This will lead to the decrease in the net energy required at WRFs. III. Dewatered sludge land application After sludge is stabilized at the anaerobic digesters, sludge will be dewatered and trucked to land application sites. Dewatered sludge is used for the land application that will avoid or decrease the amount of artificial fertilizers used. The amounts of sludge produced and the fertilizers avoided are taken from 2011 Annual Biosolids Report for both Marshall and NE WRFs. 3. Methodology Life Cycle Assessment (LCA) is used in this study which is an assessment framework used to quantify the environmental impacts of a product or a process within a specific system boundary (Bauman and Tillman 2004). The Water-Energy Sustainability Tool (WEST) ( developed at University of California at Berkeley (Stokes and 4

5 Horvath 2009) was used to calculate the life cycle energy and GHG emissions associated with Integrated Water Management (IWM) system at City of Clearwater. A LCA consists of four main steps: 1) goal and scope definition, 2) inventory analysis, 3) impact assessment, and 4) interpretation Goal and Scope The goal of this study is to assess the life cycle energy and GHG emissions associated with the integrated water management system, City of Clearwater. This study considered both construction and operation phases of the systems and collect the inventory data on the material, chemical and electricity consumption at each phase. Functional unit and system boundary are two important components of a LCA study that need to be defined carefully. The functional unit considered in this study is one cubic meter of water/wastewater delivered, collected or treated in the system. Figure 1 shows the system boundary considered in this study. The system boundary includes raw water uptake and delivery, water treatment, potable water distribution, wastewater collection, wastewater treatment, and reclaimed water distributed to customers and for/or groundwater recharge or discharge to Surface waters. Reclaimed Water Use Groundwater recharge to wells Reclaimed Water Distribution Raw Water Uptake Raw Water Delivery Discharge to Bay Water Reclamation Facilities (WRFs) Water Cycle Water Treatment Pants (WTPs) Wastewater collection Potable Water Distribution Water Use Figure 1.Steps included in the urban water cycle at City of Clearwater. The broken line shows the system boundary considered in this study. 5

6 3.2. Life cycle inventory In this step, all the energy and materials used as an input in either construction or operation phase are determined based on the functional unit defined earlier and equipment The construction phase includes the production of the material used and also the electricity and fuels consumed in the construction of structures and equipment the building. WEST web tool uses the dollar value as the input. The cost (in $2002) of the structures and infrastructure was used in the water/wastewater treatment process to calculate the associated life cycle energy and GHG emissions. Data for the costs of constructions phase was taken from the capital cost report titled CIP Cost provided by the finance department, City of Clearwater. Then, Consumer Price Index (CPI) was used to convert those values to $2002 (Bureau of Labor Statistics 2012). The size and materials of the pipes as well as the type and number of other infrastructure equipment (such as meters, valves, etc.) in each system were taken from the GIS database and the schematic design of each plan, provided by the engineering department, City of Clearwater. The values of the equipment used are obtained from the invoices and contracts from different vendors Chemical and Electricity consumption The data for the chemical consumption was collected from the operation reports maintained by each water/wastewater plant manager at City of Clearwater. The electricity consumption rate was obtained from the electric energy utility bills. The annual average of chemicals and electricity consumption at treatment facilities in FY 2011 is shown in Table 2 and 3, respectively. Table 2. Average FY 2011 chemical consumption rates at water/ wastewater treatment facilities Chemicals Average consumption (lb/1000 gal water) Average consumption (kg/m 3 water) Water treatment plants Sodium Hypochlorite Ferric Chloride Sodium Bisulfite Antiscalant Sodium Hydroxide Ammonia Polyphosphate Wastewater treatment plants Sodium Hypochlorite Alum Calcium Hypochlorite Sodium Bisulfite Polymer Magnesium hydroxide Micro CG

7 Table 3. FY 2011 Electricity consumption at each phase of water cycle Phase Average consumption Average consumption (KWh/m 3 (KWh/1000 gal water) water) Raw water uptake Potable water distribution Wastewater collection (including lift stations) Reclaimed water distribution Water treatment WTP1 (RO) WTP WTP Wastewater treatment East WRF plant NE WRF plant Marshall WRF Direct emissions (CO 2, CH 4 and N 2 O) Equations 1 and 2 are adopted from the study by RTI (2011) to estimate the direct carbon dioxide (CO 2 ) and methane (CH 4 ) emissions at each wastewater treatment plant. Equation 3 adopted from Chandran (2011) was used to quantify N 2 O emission. Eq.1 Eq.2 (RTI 2010) CO 2 = CO 2 emissions rate (metric ton/hr) CH 4 = CH 4 emission rate (metric ton/hr) 10-6 = Units conversion (Metric ton/g) Q ww = Wastewater influent flow (m 3 /hr) OD= Oxygen demand (mg/l= g/m 3 ) Eff OD =Oxygen demand removal efficiency CF CO2 = Conversion factor for maximum CO 2 generation per unit of Oxygen demand (1.375 g CO 2 /g Oxygen demand) CF CH4 = Conversion factor for maximum CH 4 generation per unit of Oxygen demand (0.5 g CO 2 /g Oxygen demand) MCF WW = methane correction factor for wastewater treatment unit, indicating the fraction of the influent oxygen demand that is converted anaerobically in the wastewater treatment unit (0.3) BG CH4 = Fraction of carbon as CH 4 in generated biogas (default is 0.65) λ = Biomass yield (g C converted to biomass/g C consumed in the wastewater treatment process= 0.45). Eq. 3 (Chandran 2010) N 2 O= N 2 O emission generated from wastewater treatment process (metric ton of N 2 O/ hr) 7

8 Q= Wastewater influent flow rate (m 3 /hr) TKN= Amount of TKN in influent (mg/l) EF= N 2 O emission factor ( g N emitted as N 2 O/g TKN) 44/28= Molecular weight conversion, g N 2 O/g N emitted 10-6 = Unit conversion factor (metric ton/g) 3.3. Impact assessment and interpretation The WEST web tool used in this study is based on a process-based input-output analysis for the environmental impact assessment of water/wastewater systems. The process-based LCA is a method defined by the Society of Environmental Toxicology and Chemistry (SETAC), Environmental Protection Agency (EPA) and the International Organization for Standardization (ISO) series standards. It consists of four stages of goal and scope definition, inventory analysis, impact categories considered in the tool, and improvement analysis (SETAC 1993; Vigon 1993; ISO 1997, ISO 1998). Economic input-output analysis-based LCA (EIOLCA) method used the economy value of products to estimate the corresponding resource consumption and environmental emissions (CMU Green Design Institute 2008). This study chose energy and GHG emission as the representative indicators of the environmental impacts. GHG emission is expressed in the unit of Kg CO 2 eq. 4. Results and discussions The life cycle energy and GHG emissions associated with each stage of the water cycle is shown in Figure 2. As expected, the wastewater treatment has the highest life cycle energy and GHG emissions, followed by the water treatment process. This is mainly due to the high rate of electricity consumption at wastewater treatment process. Moreover, it was observed that the life cycle energy and GHG emissions for infrastructures (water uptake, potable water distribution, wastewater collection and reclaimed water distribution) are relatively lower than those in water/wastewater treatment plants due to their lower electricity consumption. This is inline with the results of previous studies that showed a lower contribution of infrastructure phase compared to the treatment phase (Lassuax et al. 2007; Stokes and Horvath 2009). In the following sections, the results for each stage of the water cycle would be presented and discussed in details. 8

9 Life cycle energy (MJ/ m 3 ) Water uptake infrastrure Water treatment Potable Wastewater Wastewater Reclaimed water distribution collection treatment water distribution Figure 2. Life cycle energy and GHG emissions of each section in the whole water cycle 4.1. Water/Wastewater The comparison of life cycle energy and GHG emission from both construction and operation phase at four components of water/wastewater infrastructure is shown in Figure 3. The construction phase includes the energy used to manufacture the pumps, pipes and other equipment and associated GHG emissions while the operation phase includes the electricity and chemical used to deliver water/wastewater from one place to another GHG emissions (Kg CO 2 /m 3 ) GHG emissions Life cycle energy It was observed that the majority of life cycle energy and GHG emissions is due to the operation phase rather than the construction phase, except for water uptake infrastructure. As the electricity consumption rate at the water uptake phase is low, it is close to that used in the infrastructure section. Comparing different infrastructure sections revealed that potable water distribution has the highest life cycle energy and GHG emissions, followed by wastewater collection. This is mainly due to the large amount of electricity consumed to deliver the finished water at the required pressure to the customers. As it can be seen in Table 3, potable water distribution has the highest electricity consumption among the infrastructure systems. The high rate of energy consumption at wastewater collection is mostly due to the electricity consumed at lift stations to move wastewater from one place to another, usually from a lower elevation to a higher one. The high electricity consumption at the lift stations is due to the geographic location of the area. Unlike most of the places that wastewater is mainly collected and transported to the lowest point by gravity (EPA 1994; Nielsen 2006, Ghneim 2010), Clearwater is located in a relatively flat area that energy is required to collect and transport wastewater from the users to the treatment plants. 9

10 The life cycle energy and the GHG emission associated with reclaimed water distribution section are mainly due to electricity consumed to deliver reclaimed water to the irrigation customers all around the city. Finally, water uptake infrastructure has the lowest energy consumption and GHG emissions as water treatment plants are built relatively close to the wells. kg CO 2 / m 3 or MJ/ m Constrcution GHG emission Life cycle energy GHG emission Life cycle energy GHG emission Life cycle energy GHG emission Life cycle energy Water uptake Potable water Wastewater Reclaimed infrastrure distribution collection water Figure 3. Life cycle energy and GHG emissions at each section of distribution water infrastructure 4.2. Water treatment section Figures 4 and 5 show the GHG emissions, life cycle energy and relative contribution from different components at each WTP. In all three WTPs, the life cycle energy and GHG emission of the operation phase is much higher than the one of the construction phase. Comparison of three plants, RO has the highest GHG emissions and life cycle energy rate at both infrastructure and operations phases. The higher rate for the infrastructure phase is because of more numbers of equipment employed at the plant. For operation phase, WTP1 (RO plant) also has the highest GHG emissions and life cycle energy. This is mainly because of the higher rate of electricity, chemical, and material (cartridge filter change) consumption. The large amount of electricity is used at WTP1 in RO pumps to overcome the osmosis pressure of brackish water and push the water through the membranes. The high chemical consumption rate at RO plant is due to the antifouling chemicals used and also the high dose of chlorination used for both oxidation and disinfection purposes. The main contributor to the GHG emissions is chemical consumption for WTP3 and electricity consumption for WTP2. The high chemical consumption rate at WTP3 is due to the large amount of sodium hypochlorite used. WTP2 has a relatively lower chemical consumption rate due to the higher quality of raw water compared with other two treatment plants. 10

11 Kg CO 2 / m Electrcity consumption Equipment Cartridge filter change Chemical consumption RO WTP2 WTP3 Figure 4. GHG emission contributed by each section at water treatment plants (WTPs) MJ/ m Electrcity consumption Cartridge filter change Equipment Chemical Consumption RO WTP2 WTP3 Figure 5. Life cycle energy contributed by each section at water treatment plants (WTPs) 4.3. Water reclamation (Wastewater treatment) section Figures 6 and 7 show the GHG emissions and life cycle energy and relative contribution from different components of each WRF, respectively. It was observed that at all three WRFs, the GHG emissions and the life cycle energy of the operation phase are much higher than the construction phase. The construction section includes the manufacturing of the equipment used at the plant and also construction of the structure. Comparison of construction section at three WRFs, it was observed that the contribution of construction phase to GHG emissions and life cycle energy is higher for East and NE plant than the Marshall plant. This can be due to the minor difference in the types equipment used at those plants. Additionally, it can be seen that the dominant contributor to the GHG emissions and life cycle energy of construction phase is manufacturing of equipment rather than the construction of the structures. 11

12 Figure 6 shows that the GHG emissions rates of all three plants are almost the same and the main contributor is electricity consumption followed by chemical consumption. Figure 7 shows that the life cycle energy consumption of Marshall and East WRFs are similar but higher than the NE WRF. This similarity could be due to the fact that all three plants are using the same treatment technology and the characteristics of the wastewater enter the plants are similar. The lower rate of life cycle energy consumption at NE plant is due to the higher efficiency and also lower amounts of chemicals used. 1 GHG emission (Kg CO 2 / m 3 ) Electrcity consumption Equipment Direct emission Chemical Consumption Marshall WRF NE WRF East WRF Figure 6. GHG emissions from different sections at each wastewater treatment plant Life cycl energy(mj/m 3 ) Electrcity consumption Equipment Chemical Consumption Marshall WRF NE WRF East WRF Figure 7. Life cycle energy of from different sections at each wastewater treatment plant 12

13 4.4. Life cycle energy and GHG emissions of resource recovery practices As described earlier, there are several resource recovery practices at WRFs including reclaimed water production, dewatered sludge land application and methane production. Figure 8 describes the portion of GHG emissions and life cycle energy that can be offset by resource recovery practices. It can be seen that using reclaimed water can save 62% of the GHG emissions and 50% of the life cycle energy. The land application of dewatered sludge and methane production could offset 1-3% of the GHG emissions and 3-7% of the energy consumed. 34%, GHG emissions left 40%, Reclaimed Water 3%, Sludge land application 1%, Methane 62%, Reclaimed Water 50%, Not Recovered Energy 3%, Methane 7%, Sludge Figure 8. Left: Percentages of GHG emission saved by energy recovery practices Right: Percentages of energy offset by resource recovery practices at water reclamation facilities. Figure 9 shows the life cycle energy and GHG emissions of each WRF with and without resource recovery practices. It can be seen that the life cycle energy and GHG emissions at each WRF is significantly decreased with having an IWM system, except for East plant that the decrease is not that much significant. The lower change for the East plant is because of the lower amount of reclaimed water produced at this plant and also because there is no anaerobic digestion on site. Although, the sludge produced at the East plant is delivered to the NE plant to be stabilized and methane is produced but there is also some environmental impacts associated with the transportation process. Finally, we can conclude resource recovery practices can save significant amounts of GHG emission and energy consumption. 13

14 GHG Life cycle GHG Life cycle GHG Life cycle emissions energy emissions energy emissions energy Marshall St. WRF NE WRF East WRF Figure 9. Comparison of life cycle energy and GHG emissions at each WRF with and without having resource recovery practices 5. Conclusions This study estimated the life cycle energy and GHG emissions of the integrated water management system including water/wastewater infrastructure (raw water uptake, potable water distribution, wastewater collection, and reclaimed water distribution), water treatment, wastewater treatment and resource recovery at City of Clearwater. In the entire water cycle, the wastewater treatment has the highest life cycle energy and GHG emissions, followed by the water treatment process. Among different water/wastewater infrastructure, potable water distribution has the highest GHG emissions and life cycle energy due to the high electricity consumption. For City of Clearwater, wastewater collection system also has high life cycle energy due to the large amount of electricity consumed at lift stations used to collect and transport wastewater. In terms of water treatment, WTP1 has the highest life cycle energy and GHG emissions because it employs RO process to treat brackish water. Electricity consumption and chemical consumption are major contributors to the environmental impacts of water treatment. Three water reclamation facilities, Marshall, NE and East plants have similar life cycle energy and GHG emissions and electricity consumption is the main contributor to environmental impacts. Finally, it was observed that resource recovery practices (reclaimed water production, 14

15 sludge land application and methane production) could offset the 50% of the life cycle energy and 66% of the GHG emissions of water reclamation facilities. References: Al-Kharabsheh, A. (1999). "Influence of Long-term Overpumping on Groundwater Quality at Dhuleil Basin, Jordan " Journal of the Dept. of Hydrogeology and Environment, University of Würzburg 18: Bauman, H. and A. M. Tillman (2004). The Hitchhiker's Guide to LCA. Lund, Sweden, Studentlitteratur AB. Bureau of Labor Statistics (2012). Clearwater (city), Florida. Carnegie Mellon University Green Design Institute. (2008) Economic Input-Output Life Cycle Assessment (EIO-LCA), US 1997 Industry Benchmark model [Internet], Available from:< Accessed June, Chandran, K. (2010). Greenhouse nitrogen emission from wastewater treatment operations. INTERIM REPORT. Water Environment Research Foundation, Columbia University. ISO (1997): Environmental Management Life Cycle Assessment General Principles and Framework. International Organization forstandardization ISO (1998): Environmental Management Life Cycle Assessment Goal and Scope Definition Inventory Analysis. International Organization for Standardization ISO (2006) Environmental management Life cycle assessment Principles and framework, International Organisation for Standardisation (ISO). Geneve. Lassaux, S., Renzoni, R., Germain, A. (2007) Life Cycle Assessment of Water: From the pumping station to the wastewater treatment plant. The International Journal of Life Cycle Assessment, 12 (2), Lazarova, V., Levine, B., Sack, J., Cirelli, G., Jeffrey, P., Muntau, H., and Brissaud, F. (2001). Role of water reuse for enhancing integrated water management in Europe and Mediterranean countries. Water Science & Technology, 43(10). SETAC (1993): Guidelines for Life Cycle Assessment: A Code of Practice. Society of Environmental Toxicology and Chemistry, Sesimbra,Portugal. Sharda, N. (2010) Integrated water management: models for integrating rainwater, greywater and freshwater use in Australian homes with digital ecosystems. Ozwater 2010, March 2010, Brisbane, Australia. Stokes, J. R. and A. Horvath (2009). Energy and Air Emission Effects of Water Supply. Environmental Science & Technology 43(8): Tularam, G. A. and K. A. (2009). "Long term consequences of groundwater pumping in Australia: A review of impacts around the globe." Applied Sciences in Environmental Sanitation, 4(2): US Census (2012) State & County Quick Facts, Clearwater (city), Florida. Available at Accessed Feb Vigon, B.W. (1993): Life Cycle Assessment: Inventory Guidelines and Principles. US Environmental Protection Agency, Cincinnati, Ohio. Zhang, Z., Chang, X., Jiano, J. (2010) The Practice of Integrated Water Resource Management in China. International Conference on Future Information Technology and Management Engineering, Changzhou, China. 15