Life cycle assessment of drinking water: comparing conventional water treatment, reverse osmosis and mineral water in glass and plastic bottles

This study evaluated the environmental impacts caused by drinking water consumption in Barcelona (Spain) using the Life Cycle Assessment (LCA) methodology. Five different scenarios were compared: 1) tap water from conventional drinking water treatment; 2) tap water from conventional drinking water treatment with reverse osmosis at the water treatment plant; 3) tap water from conventional drinking water treatment with domestic reverse osmosis; 4) mineral water in plastic bottles, and 5) mineral water in glass bottles. The functional unit was 1 m3 of water. The water treatment plant considered in scenarios 1, 2 and 3, treats around 5 m3 s-1 of surface water. The water bottling plants considered in scenarios 4 and 5 have a production capacity of 200 m3 of bottled water per day. The LCA was performed with the software SimaPro®, using the CML 2 baseline method. The results showed how tap water consumption was the most favourable alternative, while bottled water presented the worst results due to the higher raw materials and energy inputs required for bottles manufacturing, especially in the case of glass bottles. The impacts generated by domestic reverse osmosis were between 10 and 24% higher than tap water alternative depending on the impact category. It was due to the higher electricity consumption. Reverse osmosis at the water treatment plant showed impacts nearly twice as high as domestic reverse osmosis systems scenario, mainly because of the higher energy inputs. Water treated by domestic reverse osmosis equipment was the most environmentally friendly solution for the improvement of tap water organoleptic characteristics. An economic analysis showed that this solution was between 8 and 19 times cheaper than bottled water.Peer ReviewedPostprint (author's final draft

A new type of pump turbine system specially developed for reverse osmosis application

A n ew type of pump has been developed specially suitable for reverse osmosis applications. The hydrodynamic theory of the pumps is given as well as some mechanical calculations typical of these p u m p s. Finally, the experimental performances of a number of working models arq - shown. A very short comment is also included on the feasibility of - utilizing a combined turbo-pump group of this type for energy recovery in reverse osmosis desalination plant

Reducing Cognitive Overheads in a Web Warehouse using Reverse-Osmosis

This paper provides a quantitative analysis of reducing cognitive overheads in a Web warehouse using an important class of operation called reverse osmosis. The analysis is used to examine two different cognitive overheads of locating relevant nodes or information and display time of a Web table. A reverse-osmosis operation enables us to eliminate in relevant information from a collection of Web documents stored in the form of a Web table. We call such an operation reverse-osmosis because it is analogous to the reverse osmosis process in the field of water purification. We discuss a formal algorithm of the reverse-osmosis operatio

On the potential of forward osmosis to energetically outperform reverse osmosis desalination

We provide a comparison of the theoretical and actual energy requirements of forward osmosis and reverse osmosis seawater desalination. We argue that reverse osmosis is significantly more energy efficient and that forward osmosis research efforts would best be fully oriented towards alternate applications. The underlying reason for the inefficiency of forward osmosis is the draw-dilution step, which increases the theoretical and actual energy requirements for draw regeneration. As a consequence, for a forward osmosis technology to compete with reverse osmosis, the regeneration process must be significantly more efficient than reverse osmosis. However, even considering the optimisation of the draw solution and the benefits of reduced fouling during regeneration, the efficiency of an optimal draw regeneration process and of reverse osmosis are unlikely to differ significantly, meaning the energy efficiency of direct desalination with reverse osmosis is likely to be superior

Effects of Activated Carbon and Cationic Exchange Resin Pretreatments on Groundwater Defluoridation by Reverse Osmosis Process

The objective of this research was to study the effects of a pretreatment using activated carbon and cationic exchange resin on groundwater defluoridation by a reverse osmosis membrane. Actual groundwater containing a high fluoride concentration was collected and examined. Experiments were operated under controlled conditions: a transmembrane pressure of 0.6 MPa and temperature of 25 °C. The reverse osmosis system with activated carbon and cationic exchange resin pretreatments had higher fluoride removal than the one without the pretreatments, 97% compared to 95%, respectively. Additionally, the reverse osmosis system with the pretreatments also produced a higher permeate flux, 1.1 × 10-5 compared 9.6 × 10-6 m3/m2•s without the pretreatment. When the reverse osmosis systems with and without pretreatments were fouled, they showed a decrease in fluoride rejection, as well as a permeate flux decline. After the fouled reverse osmosis membranes were chemically cleaned, the permeate flux recovery and the fluoride rejection of the osmosis system with the pretreatments improved. It could be concluded that the activated carbon and cationic exchange resin played an important role in improving the reverse osmosis system as they contributed to high fluoride rejection and high permeate flux.The objective of this research was to study the effects of a pretreatment using activated carbon and cationic exchange resin on groundwater defluoridation by a reverse osmosis membrane. Actual groundwater containing a high fluoride concentration was collected and examined. Experiments were operated under controlled conditions: a transmembrane pressure of 0.6 MPa and temperature of 25°C. The reverse osmosis system with activated carbon and cationic exchange resin pretreatments had higher fluoride removal than the one without the pretreatments, 97% compared to 95%, respectively. Additionally, the reverse osmosis system with the pretreatments also produced a higher permeate flux, 1.1 x 10-5 compared 9.6 x10-6 m3/m2·s without the pretreatment. When the reverse osmosis systems with and without pretreatments were fouled, they showed a decrease in fluoride rejection, as well as a permeate flux decline. After the fouled reverse osmosis membranes were chemically cleaned, the permeate flux recovery and the fluoride rejection of the osmosis system with the pretreatments improved.  It could be concluded that the activated carbon and cationic exchange resin played an important role in improving the reverse osmosis system as they contributed to high fluoride rejection and high permeate flux

Reverse-osmosis membranes by plasma polymerization

Thin allyl amine polymer films were developed using plasma polymerization. Resulting dry composite membranes effectively reject sodium chloride during reverse osmosis. Films are 98% sodium chloride rejective, and 46% urea rejective

Reverse Osmosis in the Treatment of Drinking Water

An extensive review of the literature was conducted and results were evaluated for the use of the reverse osmosis process in the treatment of drinking water supplies. All aspects of reverse osmosis technology, including pretreatment requirements; membrane type and configuration; membrane cleaning and maintenance; and reverse osmosis removal of organics, inorganics, and microbial contaminants were incorporated inot the literature evaluation. A survey (Appendix E) of existing full scale reverse osmosis installations was also carried out and results of the survey are discussed. In light of data presented in the literature and results of the survey conducted, the following recommendations were made to prevent catastrophic membrane fouling occurrences and costly plant shutdowns in the future. 1) Conduct a comprehensive raw water quality evaluation. 2) Maintain continuous feed and product water quality monitoring. 3) Incororate process automation and system upset warning provisions in future installations. 4) Provide greatly improved training for reverse osmosis installation operators. The reverse osmosis system is particularly well suited for the treatment of water supplies which contain a number of contaminants that would otherwise require a combination of treatment processes for their removal, due to the ability of the reverse osmosis process to remove salts, organics, and a number of microbial contaminants. Effective pretreatment and routine backwashing, membrane cleaning, and disinfection must be carried out; however, if adequate system operation is to be assured

Recovery of Water and Salt from Hyper-Saline Mine Water using Freeze Crystallization

The Freezerbacks researched, designed, and economically evaluated a full-scale freeze crystallization process as well as two alternative full-scale processes: 5 stage multiple effect evaporation and reverse osmosis. All three processes were designed to treat hyper-saline mine water that was sent into evaporation pond systems. These systems were designed for Freeport-McMoRan’s mines that need to treat impacted water. The Freeport-McMoRan copper mine in Miami, Arizona was visited in order to gain insight about the problem. The mine is no longer actively mining copper and is in the process of reclaiming land used. An essential part of restoring the land is treating impacted water that is currently being recirculated throughout the process before discharging. Current methods, evaporation ponds, are neither time nor cost effective. Ultimately, the water needs to be purified to the EPA standard of the maximum concentration level of sulfates (250 mg/L). After the feed has been processed, a waste stream will be disposed of via existing evaporation ponds. The deciding factor between the processes is the economics and total recovery. Multiple effect evaporation can be modified to recover more than 50% of water therefore reducing the footprint for the evaporation ponds. Although the heat of vaporization for water is about six times greater (40.65 kJ/mol) than the heat of fusion for water (6.02 kJ/mol), the capital cost for freeze crystallization is greater, and the process is unused on an industrial scale. Reverse osmosis will purify 50% of the water with a simpler system and cheaper overall cost. All processes are being presented as viable, with preference for the reverse osmosis. A batch bench scale system was constructed to model freeze crystallization. It was designed to process one gallon of salt solution in a single vessel. The bench scale process overall recovered 72% of the water with a final salt composition that ranges from 1.44 wt.% to 5.10 wt.%. For full-scale design purposes, 2.5 wt.% recovery was assumed. Reverse osmosis further purified the melted ice to EPA standards. A thorough evaluation was conducted by generating a full-scale economic analysis for each process, taking into consideration the advantages and disadvantages of each. Important factors taken into consideration were capital and operating costs, complexity, total recovery of water, and concentration of sulfates in the water recovered. In the freeze crystallization process, impacted water is pumped through two units in a semi-batch process where ice is formed on concentric plate coils in vessels. A total of 75% water is first recovered by crystallization and then the recovered water is passed through a reverse osmosis membrane (RO) to recover 50% of the initial brine water at environmental specifications. The net present value (NPV) after 10 years of operation is $(21.4 million) with a 50$(9.44 million). The reverse osmosis process will require two stages and a total of 21 elements. Reverse osmosis proved to be the most economical with an NPV of $(2.96 million) and a 50% purified water recovery compared to the other two processes

Reverse osmosis water purification system

A reverse osmosis water purification system, which uses a programmable controller (PC) as the control system, was designed and built to maintain the cleanliness and level of water for various systems of a 64-m antenna. The installation operates with other equipment of the antenna at the Goldstone Deep Space Communication Complex. The reverse osmosis system was designed to be fully automatic; with the PC, many complex sequential and timed logic networks were easily implemented and are modified. The PC monitors water levels, pressures, flows, control panel requests, and set points on analog meters; with this information various processes are initiated, monitored, modified, halted, or eliminated as required by the equipment being supplied pure water

Removal of Coolant from Effluent Water by Combined Demulsification and Reverse Osmosis

The purpose of this project is to separate coolant from effluent water by combined demulsification and reverse osmosis. There are several methods in removing oil from wastewater such as ultrafiltration, anaerobic thermophilic fluidized bed reactor (afbr), dissolve air floatation and reverse osmosis. The selected method is chosen in order to prevent fouling of reverse osmosis membrane and to prevent coolant oil from accumulated at the membrane surface. Firstly, a demulsification process is conducted as a pre-step before reverse osmosis by using IMEC Meczym 579 demulsifier. The effect of time, heating temperature and demulsifier dosage was conducted. It can be summarized that the demulsification process is effective by using 30mg/l of demulsifier at temperature of 27°C and six hours time. The coolant oil accumulated after the demulsification process is removedfrom the effluent water. Later, the effluent water that has been separated from coolant oil is sent to reverse osmosis process. The process is done at pressure of 3.7 MPa and temperature of 27.8 °C. After that, total organic carbon, chemical oxygen demand and turbidity tests were conducted to samples of effluent water before demulsification, after demulsification and reverse osmosis. The value obtained from the three tests show that the selected method is a promising method in removing coolant from effluent wate