Water Resources and Industry最新文献

Released cesium-137 poses a serious threat to living organisms and the environment. As a radioactive substance, it can only be disposed by the greatest possible concentration and safe storage. In our work, a highly efficient sorbent @CuHCF/P (q_max = 143.6 ± 3.2 mg/g) composed of pectin (P) and modified copper hexacyanoferrate (@CuHCF) was prepared for the removal of cesium from aqueous solutions. Suitable modification of CuHCF generated a homogeneous and highly packed sorbent with active substances (up to 50%). The as-prepared sorbent exhibited a suitable bead shape (round, 2–4 mm diameter, wet form) for application in dynamic systems and allowed easy separation from the purified solution. @CuHCF/P sorbent showed high sorption capacity in seawater (q = 104.6 ± 3.5 mg/g) and stability over a wide range of pH (4-10) and temperatures (12 °C, 22 °C and 32 °C). In addition, @CuHCF was dust-free, and occupied little volume when dry. Therefore proposed sorbent can be successfully used to trap cesium ions.

The European Union's Environmental Technology Verification (ETV) program aims to foster innovative environmental technologies to reach the market and reassure potential users. This paper presents an investigation of using ETV for three technologies, being developed within the EU Zero Brine research and innovation project. The technologies were designed to recover high quality water, salts and minerals from brine solutions. The technologies in focus are the forward feed MED evaporator, the Multi Feed – Plug Flow Reactor Crystalliser and Eutectic Freeze Crystallization. The study sought to understand the challenges of the ETV process, the readiness and eligibility of technologies, and possible preparations within the project lifetime. Challenges identified included: understanding what sufficient market readiness is, and achieving this within the duration of a project (also linked to funding allocation for the ETV process); and developing suitable performance claims, supported with sufficient levels of test data. A simple framework is presented to aid the integration of ETV into the development process. It promotes the use of life cycle assessment to understand the environmental added value of the technology and aid the development of performance claims.

Coal-mine effluent treatment has the potential to both reduce the environmental impact of the effluent and provide economic opportunities by recovering valuable minerals and clean water. In this study, we modeled a novel treatment process, which includes nanofiltration (NF), two-step crystallization, reverse osmosis (RO), electrodialysis (ED), multi-effect distillation (MED), and a NaCl crystallizer, and performed a techno-economic analysis of its full-scale implementation, using a circular economy approach. We estimated the thermal and electrical energy consumption to be 745.5 kWh_th/ton_NaCl and 565.1 kWh_el/ton_NaCl (or 13.6 kWh_th and 10.3 kWh_el per m³ of feed effluent), respectively. The levelized cost of the NaCl salt that accounts for the revenue from the plant's co-products (Mg(OH)₂, CaSO₄ and, pure water) was estimated to be 203 USD/ton_NaCl. The economic viability of the treatment chain can be improved by using renewable electricity sources, reducing the total expenditure on NF and RO, and integrating alternate technologies into the treatment plant.

Traditionally, industrial processes produce wastes that, even though often containing useful materials, are discarded, contributing to environmental pollution and depletion of natural resources. An example of such wastes are brines, flows of concentrated salts, produced in water treatment processes, which are now routinely discharged into receiving water bodies. Brines however can also be considered as flows of reusable materials which should be recovered, and the Zero Brine cooperation project aims to develop processes for that purpose. For a demineralized water production plant in the port of Rotterdam (the Netherlands), a closed water processing cycle was proposed to treat the large volume of spent Ion Exchange (IEX) regenerant brine which, apart from recovering demineralized water, is also intended to produce magnesium (Mg²⁺) and calcium (Ca²⁺) salts, with the highest purity possible, from the otherwise discharged brine. The process scheme includes nanofiltration (NF) for separating mono- and multivalent ions, followed by sequential chemical precipitation of Mg²⁺ and Ca²⁺ ions from the NF concentrate, and production of demineralized water by evaporation of the NF permeate. The concentrate of monovalent ions produced in the evaporator, essentially a concentrated sodium chloride solution, in its turn might be reused for IEX regeneration. Part of the supernatant of the sequential precipitation may be fed to the evaporator as well, but bleeding the other part of this supernatant is essential in order to maintain process stability, avoid accumulation of minor pollutants, and reduce scaling. In this study, various scenarios to operate the process were modeled, using PHREEQC and Excel. According to the simulation results, recovery of ≈97% of Mg²⁺ and Ca²⁺ is possible, the latter with a higher purity than the former. The main factors affecting the results are the concentration of carbonate present in the spent IEX regenerant, as well as characteristics of the NF membrane and the dosing of sodium hydroxide in the sequential precipitation steps. The results of the simulations were used for the design and operation of a pilot plant, comprising all mentioned process steps.

It is critical that the development of new technologies to solve environmental problems do not shift the burdens (impacts) to other mediums. Therefore, to ensure the optimum environmental design of water treatment and recovery systems, it is pertinent to apply life cycle assessment (LCA) at an early stage of development. Using LCA at an early developmental stage is known as prospective LCA and is particularly challenging due to the low data availability or quality. The aim of this study is to highlight the opportunities and challenges of using prospective LCA in the development of water treatment and recovery technologies. To do this we utilise two case studies from the EU Zero Brine project and apply LCA at two developmental stages. The treatment systems are specifically tailored for each case to treat the individual brine compositions and selectively recover its constituents. The first stage LCAs are based on laboratory experiments and engineering-based calculations, whilst the second stage assessments use improved input data from pilot plants and simulation. The paper compares the analyses of both stages, identifies key differences and discusses these disparities. In addition, it provides insights on the challenges of applying LCA for the design and development of wastewater treatment and recovery systems.