A comparative life cycle assessment of process water treatment technologies at the Secunda industrial complex, South Africa

Objectives : This article provides a comparative analysis of boron removal for brackish water reverse osmosis (BWRO), boron selective ion exchange (IX), or capacitive deionization (CDI) processes. Permeate of 1st-Pass RO process has to be post-treated for additional boron removal. Hence, we experimentally analyzed the performance of boron removal and specific energy consumption (SEC) of three aforementioned processes and investigated whether the processes are suitable for 2nd pass process of RO desalination.Methods : Raw feed water was prepared using NaCl and B(OH)3. Semi-pilot scale RO and IX systems (over 1 m3/hr capacity) and bench scale CDI system (over 2.5 L/min) were tested for performance comparison. Boron concentration was measured using Azomethine-H method for feed and product water. Energy consumption was monitored by using power quality analyzer.Results and Discussion : Each process has its own operating conditions. The RO process required high pH of feed water for high boron removal rate, the IX process was operated below breakthrough point considering adsorption capacity of boron selective resin, and the CDI process didn’t remove boron because chloride ion has higher ion selectivity for carbon electrode than boron. In terms of SEC, the pressure-driven RO process showed the highest SEC among three processes. The CDI process based on electrical adsorption of carbon electrode showed a considerable energy consumption as well. On the other hand, the IX process was operated at low energy consumption because its removal is just based on adsorption-desorption mechanism.Conclusions : The RO and CDI processes have received a lot of attention as leading and emerging technology while the IX process was regarded as a stubborn process because of regeneration of resin and its several segmentalized steps. However, we found that the IX process has a better performance for boron removal and energy consumption.

Nanofiltration (NF), reverse osmosis (RO), electrodialysis (ED), and electrocoagulation (EC), were all tested at the bench scale for removing selenium (Se) from mine water. All of these technologies reduced the concentration of total Se from 216 µg/L (i.e. 120.1 µg/L of selenate; 59.1 µg/L of selenite, and 0.6 µg/L methyl-selenic acid) in the raw mine water to about 2 µg/L or less in the treated water, equivalent to more than 99% removal. Electrodialysis was found to be the most effective, removing more than 99.5% of the Se. The untreated mine water was toxic to algae. In contrast, RO and NF reduced the toxicity of the mine water, allowing algae to grow between 15,000 to 25,000 cells/mL, while ED and EC did not allow algal growth, likely due to complete removal of essential minerals (ED) or the presence of other contaminants (EC), such as copper. The Se speciation did not change as a result of membrane filtration; however, selenite in the effluent was almost fully transformed to selenate in the brines from the ED and EC treatment processes. The effluent treated by NF and EC generated seleno-cyanate at 0.37 and 1.01 µg/L, respectively. Further testing is recommended at the pilot-scale with the same mine water as well as different mine water.

Nitrate removal with reverse osmosis in a rural area in South Africa

<p>Water is the most important substance. Drinking water in the industry comes from raw water and is treated through a heating process. The results of laboratory tests on raw water used for drinking water are 41 MPN/100ml, so it is necessary to process raw water into drinking water using Reverse Osmosis (RO) membrane technology. The purpose of this study is to determine the difference in the decrease in the total amount of Coliform in drinking water based on variations in water pressure on the Reverse Osmosis membrane in the canteen of X Industry. This type of research is an experiment with the design used is pre-test post-test without control, the sampling technique used is grab sampling, and the total sample is 36 samples with a volume of 3600 ml. The decrease in the total number of Coliforms was analyzed using univariate and bivariate tests. The results of total Coliform in drinking water after treatment with Reverse Osmosis membranes are the average results for a pressure of 1 bar is 0 MPN/100 ml, a pressure of 1.5 bar is 2.81 MPN/100 ml, and a pressure of 2 bar is 5.3 MPN/100 ml. This study concludes that there is a difference between the pressure of 1 bar, 1.5 bar, and 2 bar on the decrease in the total Coliform content in the canteen of X Industry with a p-value of 0.001, and the most effective pressure to reduce total coliform in drinking water in the canteen of X Industry is a pressure of 1 bar with a 100% percentage. Suggestions for further research to carry out the saturated condition of the Reverse Osmosis membrane.</p>

Life cycle assessment of advanced wastewater treatment processes: Involving 126 pharmaceuticals and personal care products in life cycle inventory

Assessing the sustainability of acid mine drainage (AMD) treatment in South Africa

Graphene oxide (GO)-enhanced membranes are being developed to solve major limitations in both reverse osmosis (RO) and membrane distillation (MD) technologies, which include high electricity and thermal energy consumption. This study performed, for the first time, a life cycle assessment to determine the effects of using GO-enhanced membranes on the environmental impacts of seawater desalination via RO and MD. Four scenarios were evaluated and eighteen environmental impacts were quantified according to the ReCiPe impact assessment method. The average impacts for the RO-GO scenarios were lower than those of RO by 3–7 %. The reduction in the climate change impact was 3–8 %, which could avoid the release of 380–850 kt CO2 eq. per year globally if these membranes were used in current seawater RO systems. The MD-GO scenarios had, on average, 27–34 % lower impacts than the MD scenarios. Overall, the RO-GO systems were the most favourable, with lower impacts than MD-GO for most categories. However, using solar-thermal energy instead of natural gas in MD desalination would lead to 43–93 % lower impacts in nine categories than RO powered predominantly by fossil fuels. This includes climate change, which would be 64 % lower; however, freshwater ecotoxicity would be more than four-times higher. The results of this work indicate the potential environmental benefits of GO-enhanced membranes and discuss the future developments needed to improve the performance of RO and MD.

For inland brackish water desalination by reverse osmosis or RO, concentrate or reject disposal poses a major challenge. However, enhanced recovery and consequent reduction in the reject volume using RO processes is limited by the solubility of ions present in the feedwater. One of the most common and stubborn precipitate formed during desalination is calcium sulfate. Reducing or eliminating the presence of sulfate would allow the process to operate at higher recoveries without threat to membrane scaling. In this research, this goal is accomplished by using an appropriate mixture of self-regenerating anion exchange resins that selectively remove and replace sulfate by chloride prior to the RO unit. Most importantly, the mixed bed of anion exchange resins is self-regenerated with the reject brine from the RO process, thus requiring no addition of external chemicals. The current work demonstrates the reversibility of the hybrid ion exchange and RO (HIX-RO) process with 80% recovery for a brackish water composition representative of groundwater in San Joaquin Valley in California containing approximately 5200 mg/L of total dissolved solids or TDS. Consequently, the reject volume can be reduced by 50% without the threat of sulfate scaling and use of antiscaling chemicals can be eliminated altogether. By appropriately designing or tuning the mixed bed of anion exchange resins, the process can be extended to nearly any composition of brackish water for enhanced recovery and consequent reduction in the reject volume.

The bacterial and chemical contamination of dialysate fluids are important problems in haemodialysis therapy and may be caused by the water used for dialysate preparation. We performed a survey of the microbiological and chemical quality of the water used in seven dialysis wards. Special attention was paid to the effects of each water treatment step, for example ion exchange, reverse osmosis and UV disinfection, on the number of bacteria (measured as colony forming units, CFU), the amount of endotoxin (endotoxin units, EU) and various chemical parameters, the main focus being on calcium, magnesium, sulphate, aluminium and heavy metals. CFU values exceeding the European Pharmacopeia value, determined at an incubation temperature of 22 degrees C, were found in the samples of raw water (20.0%, n=25), after ion exchange (66.7%, n=12), after reverse osmosis (33.3%, n=18) and also in samples of the dialysis water taken at the inlets (12.5%, n=40) and outlets (50.0%, n=18) of the machines. Whereas all raw water samples from the wards showed high mean values for endotoxin (0.56-9.10 EU/ml) and the endotoxin levels were often enhanced after ion exchange (0.13- >9.49 EU/ml), treatment by reverse osmosis led to a satisfactory decrease in endotoxin in all samples (<0.03 EU/ml). Sufficient reductions in calcium, magnesium and sulphate could only be achieved by the combined application of ion exchange and reverse osmosis. Mercury contamination was observed in the samples after ion exchange at three treatment plants, this was possibly caused by polluted regenerants. Increased amounts of aluminium, copper and zinc were found in water samples from different sites in the treatment systems and were caused by materials in contact with the water. A sufficient chemical water purification treatment system should consist of ion exchange and reverse osmosis. Attention has to be paid to the suitability of materials in contact with the water and of the chemicals used, for example regenerants or corrosion inhibitors. From the microbiological point of view, a safety UV disinfection step in the water-treatment system is favourable. To avoid bacterial recontamination periodic cleaning and disinfecting of the water-treatment and distribution systems, as well as the dialysis machine are essential. There is the need for complete guidelines regarding dialysis water that include all relevant chemical and microbiological parameters. Based on this standard, periodic examination of the water after each treatment step has to be performed.

The helplessness of coastal communities in processing salt and brackish water into drinking water is a great irony of modern society, in the midst of technological advances and the industrial era 4.0. The problem in the coastal areas of Sungai Kakap subdistrict, Kubu Raya district, is the lack of availability of clean water and the absence of clean water infrastructure. Peat groundwater in coastal deltas cannot support the use of groundwater sources due to high levels of acid and organic substances. This can trigger problems of poor community sanitation and cause the community's inability to optimize the potential of villages that have abundant natural resources. This activity aims to empower and increase community participation in designing and processing brackish/salt water into drinking water using Reverse Osmosis (RO) technology to meet the need for hygienic ready-to-drink water. Small scale water treatment system design using ultrafiltration (UF) and reverse osmosis (RO) membranes. The raw water used comes from river surface water in coastal areas. The small-scale water treatment design consists of two FRP tubes containing filter media, three filter cartridges, and UF and RO membranes. Two thrust pumps, with a minimum pressure specification of 40 m, are used to provide pressure that exceeds osmosis pressure so that raw water can be filtered through the RO membrane. The results of the activity show that the implementation of the RO system has succeeded in increasing the availability of clean water in Sungai Itik Village, which previously experienced challenges in providing adequate water supply. In addition, the integration of local business startups with RO technology opens up new opportunities for local residents to participate in the local economy and increase family income. Key factors supporting the success of this economic empowerment strategy were identified, including active community involvement in planning and implementation, collaboration between local government and local stakeholders, and adoption of new technologies and skills by local communities. This activity provides an important contribution in understanding the role of clean water technology innovation as a catalyst for local economic transformation in coastal areas. The practical implications of these findings can help decision makers in designing sustainable and effective policies to improve the welfare of coastal communities through sustainable economic empowerment. The use of this technology can help increase the availability of clean water in areas that previously experienced difficulties in this regard.

Although emerging desalination technologies such as hybrid technologies are required to tackle water scarcity, the impacts of their application on the environment, resources, and human health, as prominent pillars of sustainability, should be evaluated in parallel. In the present study, the environmental footprint of five desalination plants, including multi-stage flash (MSF), hybrid reverse osmosis (RO)–MSF, hybrid nanofiltration (NF)–MSF, RO, and hybrid NF–RO, in the Persian Gulf region, have been analyzed using life cycle assessment (LCA) as an effective tool for policy making and opting sustainable technologies. The comparison was based on the impacts on climate change, ozone depletion, fossil depletion, human toxicity, and marine eutrophication. The LCA results revealed the superiority of the hybrid NF–RO plant in having the lowest environmental impact, although the RO process produces more desalinated water at the same feed and input flow rates. The hybrid NF–RO system achieves 1.74 kg CO2 equivalent, 1.24 × 10−7 kg CFC-11 equivalent, 1.28 × 10−4 kg nitrogenous compounds, 0.16 kg 1,4-DB equivalent, and 0.56 kg oil equivalent in the mentioned impact indicators, which are 7.9 to 22.2% lower than the single-pass RO case. Furthermore, the sensitivity analysis showed the reliability of the results, which helps to provide an insight into the life cycle impacts of the desalination plants.

The use of reverse osmosis as a 35,600m 3/day concentrator in the waste water management scheme at 4640 MW Bayswater/Liddell Power Station complex - Australia

In the context of South Africa’s water scarcity, desalination has emerged as a possible solution for coastal areas. However, the quality of the intake water for desalination is often problematic, prompting the need for pre-treatment. The aim of this study was to conduct a comparative environmental life cycle assessment (LCA) on 4 seawater filtration systems intended for the pre-treatment of a reverse osmosis desalination project. These systems were implemented in a pilot trial and are based on modern water treatment technologies, namely, granular filtration (pressure driven and gravity driven), dissolved air flotation (DAF), and ultrafiltration (UF). For all 4 systems, data were collected for both the construction and operation phases, and LCAs were performed, resulting in environmental scores that allow for comparison based on the pre-treatment of 1 kL of seawater of the same quality. The SimaPro LCA tool and the ReCiPe midpoint method were used and environmental scores were calculated for 18 impact categories, including climate change, acidification, toxicity, eutrophication, resource depletion, etc. This methodology also allowed the identification of the highest environmental burdens/scores within each system. The most significant finding is that local electricity consumption is responsible for the greatest proportion of environmental impacts. Thus, the systems consuming more energy for operating equipment such as blowers, pumps, and mixers were found to have the highest environmental burdens. Hence, the DAF system has the highest environmental scores for most impacts, followed by the single-phase gravity filtration system, then the two-phase partial pressure filtration system and finally the UF system. Therefore, focus should shift towards energy optimisation of process units, especially the rotary ones, as well as energy mitigation and recovery strategies. The use of renewable energy for pre-treatment should also be considered locally.

Alternative technologies to granular activated carbon (GAC) are of interest to improve the sustainability and reduce the cost of munitions wastewater treatment. Research efforts have highlighted GAC alternatives, yet few reports of environmental and economic impacts associated with these technologies are available. Herein, a life cycle assessment (LCA) aids in assessment of environmental impacts associated with six munitions wastewater treatment configurations—specifically GAC, compared to five configurations that include combinations of ion exchange (IX), reverse osmosis (RO), aerobic granular reactors (AGR), UV/H2O2, and ozone technologies. The LCA compares environmental impacts generated by treating 1 m3 of munitions wastewater, impacts by life cycle stage, and effects of IX, RO, and GAC replacement frequency. Results show that IX resin pairs with AGR (for flow‐through treatment) and ozone (for IX regenerant treatment) generated 22 ± 18% less impact than GAC in nine of ten environmental impact categories during production, transportation, and disposal. Treatment trains with ozone or AGR produce 35% less environmental impact than those with UV/H2O2. Production and use stages generate more environmental impacts than transportation and disposal stages for most treatment technologies. This LCA provides insights into the sustainability of six munition wastewater treatment technologies and identifies areas where treatment sustainability can be improved.

In this paper, a comprehensive life-cycle assessment (LCA) is carried out in order to evaluate the multiple environmental-health impacts of the biological wastewater treatment of the fish-processing industry throughout its life cycle. To this aim, the life-cycle impact assessment method based on endpoint modeling (LIME) was considered as the main LCA model. The proposed methodology is based on an endpoint modeling framework that uses the conjoint analysis to calculate damage factors for human health, social assets, biodiversity, and primary production, based on Indonesia’s local data inventory. A quantitative microbial risk assessment (QMRA) is integrated with the LIME modeling framework to evaluate the damage on human health caused by five major biological treatment technologies, including chemical-enhanced primary clarification (CEPC), aerobic-activated sludge (AS), up-flow anaerobic sludge blanket (UASB), ultrafiltration (UF) and reverse osmosis (RO) in this industry. Finally, a life-cycle costing (LCC) is carried out, considering all the costs incurred during the lifetime. The LCA results revealed that air pollution and gaseous emissions from electricity consumption have the most significant environmental impacts in all scenarios and all categories. The combined utilization of the UF and RO technologies in the secondary and tertiary treatment processes reduces the health damage caused by microbial diseases, which contributes significantly to reducing overall environmental damage.