Disposal Criteria Research Articles

A survey of cell processing practices for hematopoietic cell transplantation.

There is considerable heterogeneity in cell handling practices for hematopoietic stem cell transplantation in cell processing centers in Spain. The European Directorate for the Quality of Medicines and international standards are not intended to establish best practices or to include all procedures; therefore, each cell processing laboratory must define its own practices and procedures. A survey was conducted to better understand the differences among cell processing laboratories in Spain in terms of type of facilities and equipment available, service portfolio, staff, informatics systems, product handling, environmental and product quality control tests, batch release criteria, storage and shipping conditions, and criteria for product disposal or recall, to identify areas for harmonization. In this study, 31 authorized centers responded to the survey. Fifteen centers do not usually wash cryopreserved grafts, in contrast to others that perform washing systematically (n = 5) or when the product contains >1 g/kg/dimethyl sulfoxide or recipient body weight is <25 kg (n = 11). We observed high variability in terms of handling of thawed samples, such as in protocols used to enumerate CD34+ cells, compensation solution, temperature and time delay between thawing and CD34+ enumeration. Storage time for cell therapy products varied between 5 and 30 years. Additionally, 12 centers do not reduce plasma before cryopreservation to save space. Overall, this survey demonstrates variability in activity, logistics and staff among cell processing laboratories in Spain. Some issues remain ongoing and further efforts should be undertaken to harmonize practices in these facilities, such as indications and procedures for washing cryopreserved stem cells and handling of cryovials to enumerate viable CD34+ cells after thawing. Efforts are needed to regulate product storage to optimize space utilization and reduce associated costs.

Wastewater Management as a Part of Solution for Water Resources Problem in Erbil City

In Erbil City, municipal wastewater (MWW) is disposed directly without any treatment processes in the natural environment water body and in some places used for irrigation purposes. Untreated MWW causes problems for the environment, and people's health. Water quantity and quality variation produce complications for water sources in Erbil City, Kurdistan Region-Iraq. There is a lack of performing MWW management fundamentals in the area as well. This research aimed to study the MWW management in Erbil City, presenting water resource difficulties and bringing about suitable solutions for the water resource problems, and also to highlight the risk for the poor Management. MWW Data on Erbil municipal (EMWW) water quality parameters were collected and analyzed for the study period (four months), beginning in October 2022 and ending in March 2023. Twelve EMWW quality parameters were captured and tested in the Laboratory, arranged, and compared with MWW disposal criteria and local standards. The following MWW parameters include pH, electrical conductivity (EC), total dissolved salts (TDS), chloride (CL), total solids (TS), total alkalinity, total acidity, chemical oxygen demand (COD), and colour. The results showed that Erbil's MWW characteristics in terms of temperatures ranged between 11-23 °C and in turn, affected biological species activities. Maximum PH value was 7.7. Total alkalinity found in the range from 140 to 178 mg/l. Chloride concentration results showed for October was 62 mg/l and the maximum value was 80 mg/l in November due to the increment in temperature and evaporation. The range of the COD values of sewage water for five months was 246 -773 mg. Erbil's MWW's moderate to medium strength may be treated and utilized for landscaping, fountains, and irrigation, minimizing the need for fresh water from resources like wells and surface water in the Greater Zab River.

Asset Management in the Implementation of Public Sector Regional Property Disposal Systems

Abstract: This research aims to understand the procedures and challenges involved in the disposal of regional property at the Financial and Revenue Management Agency of Hulu Sungai Selatan Regency, following the Standard Operating Procedures (SOP). Effective management of regional property is essential as it supports the primary revenue of a region. The study employs a qualitative research method with a descriptive approach, focusing on illustrating the research object, organizational structure, main tasks and functions, and the detailed system of regional property disposal. The research findings reveal that the SOP for regional property disposal issued by the Hulu Sungai Selatan Regency Government has been well-implemented and aligns with the prescribed standards. The SOP serves as an effective guideline for property disposal, although challenges persist during the disposal process, including issues related to the property itself and the accompanying documentation. Despite these challenges, the disposal procedures at the Financial and Revenue Management Agency have adhered to the established SOP. The main obstacles encountered include insufficient documentation and properties not meeting the disposal criteria. In conclusion, the study highlights the critical role of strategic asset management in the public sector, particularly in the disposal of regional property. The recommendations provided aim to address the existing challenges and improve the efficiency and effectiveness of the property disposal process, ensuring better resource utilization and enhanced financial performance. This research contributes valuable insights for policymakers and public administrators seeking to optimize asset management practices. Keywords: Implementation of Regional Property Disposal System, Regional Asset Disposal System, Standard Operating Procedures

Advances in ultrasonic treatment of oily sludge: mechanisms, industrial applications, and integration with combined treatment technologies.

In the petroleum sector, the generation of oily sludge is an unavoidable byproduct, necessitating the development of efficient treatment strategies for both economic gain and the mitigation of negative environmental impacts. The intricate composition of oily sludge poses a formidable challenge, as existing treatment methodologies frequently fall short of achieving baseline disposal criteria. The processes of demulsification and dehydration are integral to diminishing the oil content and reclaiming valuable crude oil, thereby playing a critical role in the management of oily sludge. Among the myriad of treatment solutions, ultrasonic technology has emerged as a particularly effective physical method, celebrated for its diverse applications and lack of resultant secondary pollution. This comprehensive review delves into the underlying mechanisms and recent progress in the ultrasonic treatment of oily sludge, with a specific focus on its industrial implementations within China. Both isolated ultrasonic treatment and its combination with other technological approaches have proven successful in addressing oily sludge challenges. The adoption of industrial-scale systems that amalgamate ultrasound with multi-technological processes has shown marked enhancements in treatment efficacy. The fusion of ultrasonic technology with other cutting-edge methods holds considerable potential across a spectrum of applications. To fulfill the goals of resource recovery, reduction, and neutralization in oily sludge management, the industrial adoption and adept application of a variety of treatment technologies are imperative.

Navigating Produced Water Sustainability in the Oil and Gas Sector: A Critical Review of Reuse Challenges, Treatment Technologies, and Prospects Ahead

The petroleum industry produces a large amount of wastewater, known as produced water (PW), during oil production and processing. This PW contains hazardous organic and inorganic components that can harm the environment. Conventional treatment methods have been used to purify PW, but they do not meet environmental regulations, especially when the goal is to reuse the water. Therefore, further research is needed to find an effective technology for managing PW. This review focuses on the characteristics and management of PW originating from oil and gas fields. Firstly, we provide a detailed overview of PW production scenarios worldwide and in the US with detailed quantities and chemical compositions of organic, inorganic, and physicochemical characteristics. Secondly, challenges and environmental concerns associated with treating PW are discussed. Thirdly, all relevant treatment technologies for PW are systematically explored. In addition, this review highlights the management of PW and suggests treatment options and best practices for the industry, and finally, future research needs and opportunities for sustainable water treatment and effective reuse technologies are addressed. Because PW contains a variety of severe contaminants, single methods have not been effective in converting it to a reusable form or fulfilling disposal criteria. As a result, integrated technologies may provide a potential approach that not only meets regulatory standards but also provides chances to employ PW as a non-conventional water supply. Advances in PW management are critical and demand a defined framework and risk-based approach to determine and build the most efficient plan.

О вариантах технических решений по обращению с радиоактивными отходами класса 1 при создании и эксплуатации ПГЗРО

The article focuses on design options proposed for radioactive waste Class 1 (RW-1) transportation and horizontal disposal in DGR using corrosion-resistant overpacks or packages. Since canisters with RW-1 are going to be shipped from the PA Mayak site in TUK-108/r, the article suggests that a special Pick Up and Packaging Station can be arranged to provide RW-1 packaging in accordance with the DGR waste acceptance criteria for disposal. It also considers the proposals on the fabrication of non-returnable packages and their transportation from the Pick Up and Packaging Station to the horizontal RW disposal compartment. The article presents the proposed compartment layout. It provides preliminary estimates regarding possible RW-1 and RW-2 disposal volumes assuming the concept of horizontal RW-1 disposal in the DGR.

Реализация единства измерений характеристик РАО при передаче на захоронение

The paper discusses the comprehensive measures implemented to ensure the uniformity of measurements as regards the RW characteristics demonstrating their compliance with waste acceptance criteria for disposal. Under this framework, the following regulations have been developed by JSC VNIINM: the Unified Industry Guidelines for the Measurements of Radiation Waste Characteristics, standard measurement and test procedures, as well as the standard of the State Corporation Rosatom for monitoring physical and chemical property indicators and characteristics of the RW form.

Calculation of the Absorbed Dose by a Borosilicate Glass Matrix and its Simulated Irradiation

The state of liquid radioactive wastes (LRW) management at Ukrainian Nuclear Power Plants (NPPs) is characterized by the lack of a completed technological cycle from processing to obtaining the final product suitable for further long-term storage or disposal. As a result, the storage tanks for bottoms residue (BR) are 65-75% full (Zaporozhye and South-Ukrainian NPPs), and the resource for placing molten salt at Zaporizhzhya NPP (92.7%) is close to exhaustion [1]. Therefore, the development of technologies and materials for NPP LRW solidification is an urgent need and aims to ensure the processing of LRW to a solid state that will meet the acceptance criteria for disposal in centralized storage facilities. One of the effective methods of LRW solidification is their vitrification. The main advantage of vitrification is that during the vitrification process the volume of waste is reduced by several times and this saves expensive storage space [2, 3]. The purpose of this work is to calculate the absorbed dose that borosilicate glass matrices with included bottoms residue will accumulate over 300 years of storage, and to study the effect of simulated X-ray irradiation on their physical and mechanical properties.

Negatively charged hollow crosslinked aromatic polymer fiber membrane for high-efficiency removal of cationic dyes in wastewater

• Negatively charged hollow crosslinked polymer fiber membranes were fabricated. • The membrane exhibited high adsorption capacity and rate for cationic dyes. • The membrane indicated high flux of 530 L·m −2 ·h −1 without external driven pressure. • The rejection ratio of 100% and 20 L pure water per gram of membrane were achieved. • The membrane showed absolute superiority to the reported carboxylated cellulose fabrics membrane. The complete, high-efficiency removal of cationic dyes in industrial wastewater before discharge becomes particularly urgent due to their biological toxicity. The membranes have emerged for removal of dyes benefiting from free separation, cheap component and easy operation, and thus aroused increasing research interest. Herein, the negatively charged hollow crosslinked aromatic polystyrene (PS) fiber (HPF-C) membrane has been successfully synthesized by a rapid room-temperature crosslinking of linear PS in HPF membrane, followed by deep sulfonation. The sulfonated HPF-C (HPF-C-S) membrane showed high experimental equilibrium adsorption capacity of 443.6 mg·g −1 for basic red 46 (BR46) with initial concentration of 50 mg·L -1 . Its maximum adsorption capacity (346.0 mg·g −1 ) of methylene blue (MB) calculated by Langmuir model was about 5 times that of carboxylated cellulose fabrics (CCFs) membrane and higher than that of the most reported or commercially available nanofiber/nanoparticle adsorbents. Without external driven pressure, a flow rate of cationic dye solution through HPF-C-S membrane was up to 530 L·m −2 ·h −1 which was about 90 times that (6 L·m −2 ·h −1 ) of the CCFs membrane. The solution concentration through the HPF-C-S membrane always remained 0 mg L -1 (lower than the LODs of UV) before the permeation volume reached 4000 mL for 2 mg L -1 BR46 solution (In other words, 20 L of clean water could be obtained through per gram of membrane) and 1500 mL for 2 mg L -1 MB solution, respectively. The rejection ratio of 100% fully met the environmental criterion for wastewater disposal, indicating absolute superiority to the reported CCFs membrane that could not completely purify dyes. Moreover, the HPF-C-S membranes indicated excellent sustainability and stability. Besides, the kinetics, thermodynamics and mechanism behind these phenomena were studied.

A short review on landfill leachate treatment technologies

The solid waste disposal problem is a well-known global environmental issue, wherein landfilling and open dumping are the most widely followed practices. The production of toxic liquid, leachate, is a significant issue with landfilling practices. This leachate needs to be treated carefully before its disposal in the environment. Landfill leachate is characterized by very high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) consisting of unappealing constituents like toxic organic and inorganic pollutants. In general, leachate parameters such as landfill age, COD/BOD ratio, and COD are the decisive factors in the selection of appropriate treatment methods. The various adopted technologies for leachate treatment are assessed and summarized under heads like biological, physicochemical, and hybrid methods. The purpose of this research is to look at the technological improvements used for landfill leachate treatment, taking into account the lessons learnt over time and the solutions that have been implemented. It was observed that, when the treatment techniques are employed in standalone mode, they are unable to meet the acceptable water quality criteria, nevertheless when the treatment techniques are used in combination, then it meets the stringent criteria for disposal. The integrated biological and physicochemical treatment methods are viewed as critical for adhering to sustainable release limits and ensuring environmental protection by achieving satisfactory COD, BOD, and ammonia nitrogen removal efficiencies. The evaluation includes state-of-the-art research outputs as well as potential combined applications of various treatment strategies covered in previous works.

Impact of diatomite addition on lead immobilization in air pollution control residues from a municipal solid waste incinerator

Air pollution control (APC) residues, which are known to be the byproducts of incineration treatment, exhibit a high leaching potential of toxic metals. Calcium silicate hydrate (C-S–H), which is a major hydration product of hardened cement and immobilizes toxic metal, can be formed by the reaction of Ca with pozzolanic Si in a highly alkaline environment. Toxic metals might be immobilized by the addition of pozzolanic material to APC residues (instead of using cement), which is a Ca source and provides an alkaline condition. In this study, diatomite, which mainly comprises amorphous silica (SiO2·nH2O), was investigated as a pozzolanic material for Pb immobilization in APC residues obtained from a municipal solid waste incinerator. APC residues were cured with and without the addition of diatomite at different temperatures. When diatomite was added to APC residues, pozzolanic phases such as C-S–H gel were formed via the consumption of Ca(OH)2 and CaClOH. Compared to APC residues cured without diatomite, the leaching of Pb decreased by 99% for APC residues cured for 14 days with 10% diatomite at 70 °C. The results of sequential chemical extraction showed that water-soluble Pb in APC residues was reduced from 10.3% to nearly zero by the pozzolanic reaction. Consequently, the leaching amount of Pb dropped below 0.3 mg/L (Japanese criteria for landfill disposal). Overall, these experiments provide promising results regarding the possibility of using diatomite for pretreating APC residues.

Characterization of milk production systems in the county of Alegrete, RS, Brazil, based on productive indexes

This study aimed to characterize dairy production systems in Alegrete, RS, Brazil, based on productive indices, management practices, and technification. The present study was conducted on 43 farms distributed in 22 localities of the county. The collection of data on milk production systems was carried out through visits to the properties, using a semi-structured guide questionnaire. The data obtained with the questionnaires were tabulated in Excel and with the aid of the IBM SPSS Statistics 20.0 software, through multivariate statistics, data were submitted to main component analysis (MCA) and hierarchical clusters analysis (HCA), allowing the division of 43 production units into homogeneous groups. The studied variables were summarized through the MCA in two main components (1 and 2), which clarified 71.53% of the explained variance. The alpha-Cronbach values observed for the two main components totaled 0.977, a result that confirms the reliability of the questionnaire used and reveals the high correlation between the answers obtained. From the hierarchical classification analysis, the dataset of the 43-farm studied was reduced to six groups (G1, G2, G3, G4, G5, and G6). The quadrants obtained from the insertion of the axes of the main components 1 and 2 allowed the interpretation of the groups of systems, according to the characteristics related to milk production. G2 presented the highest number of farms of the six systems formed, representing 41.86% of the establishments studied. These are characterized by being a more productive farm, an average 881-1 L day, with greater technological adoption of production and greater area destined to milk production, corresponding to the average of 78 hectares. The productive aspects that define the characteristics of milk production systems in the county were related to the structure of the herd, pasture area, daily production, disposal criteria, and milking management. The main differences found in the different groups are related to the productive indexes, suggesting that the technical assistance and rural extension actions in the dairy production systems in the county of Alegrete should be directed according to the individual need of each group formed.

Prototyping of co-composting as a cost-effective treatment option for full-scale on-site remediation at a decommissioned refinery

The costs for managing process wastes and their environmental and social impacts is contributing to the poor economics of petroleum hydrocarbon refining. The hypothesis tested was that oily sludge co-composted at a pilot scale would enable a proof of concept (prototype) for remediation at commercial field scale. The aims of the study were to translate pilot-scale outcomes to commercial terms for full scale treatment, as well as studying leachability of the contaminants, and biodegradation of the petroleum fractions. A co-composting experiment, based on a relatively simple windrow design with readily available organic amendments, demonstrated the potential to cost effectively remediate oil-contaminated soil and sludge on-site at a petroleum refinery. An initial mesophilic - thermophilic phase, characterised by high windrow temperatures (up to 60–65 °C), incorporating weekly windrow turning, resulted in fast rates of removal of total petroleum hydrocarbons (TPH) (>3000 mg kg−1. day−1) and polycyclic aromatic hydrocarbons (PAHs) (9 mg kg−1. day−1) over the first month. The remaining period of the biphasic degradation process was passive i.e. without windrow turning. At the end of the experiment, TPH in the composted windrows of organic amended sludge were decreased from 62% (w/w) (in air dried sludge), the highest reported in the oil composting literature, to 1% in the final mix, meeting the targeted solid waste disposal criteria of 1% TPH. PAHs were reduced by 96% to below relevant solid waste and contaminated soil health investigation levels (HILs) to considerably less than 100 mg kg−1. The major conclusion was that the study enabled costings for commercial scale-up to be developed indicating on-site treatment could be achieved at approximately $AUD 150 compared to off-site treatment at $AUD 1250 per tonne.

Thermal plasma technology for radioactive waste treatment: a review

In this paper, a review of radioactive wastes treatment using thermal plasma technology is presented as a treatment method for radioactive waste management. Virtually all waste streams can be treated by the thermal plasma technologies, resulting in a conditioned product, free from organics and liquids, definitely meeting the acceptance criteria for safe storage and disposal. The application of the thermal plasma system in the nuclear area is still one of the current research topics due to the theoretical and practical complexity of the treatment. This paper discusses the performance of the thermal plasma systems, addressing the advantages and limitations of the method.

Analysis of Safety Aspects of Disused Sealed Radiation Source Disposal

Sealed radiation sources (SRS) are extensively used worldwide in agriculture, industry, medicine and different research areas.&#x0D; If further use of SRS is not envisaged, and the decision is made on declaration of these disused SRSs (DSRS) as radioactive waste (RW), then legislative and regulatory requirements for RW management are fully applicable from that point.&#x0D; Since DSRSs have essential distinctions from other types of RW, in particular, high specific activity, it is critically important to ensure safe management of DSRS, declared as RW, at all stages of their management including disposal. DSRS disposal as RW is the final phase of SRS lifecycle and final stage of their safe and reliable management.&#x0D; In this paper, there are considered safety issues for management of DSRS, declared as RW. Approaches to DSRS disposal recommended by IAEA, advantages and drawbacks of different disposal options for DSRS are analyzed.&#x0D; DSRS disposal needs shall be considered taking into account safety requirements for RW disposal. First, DSRS shall be attributed to specific RW class to address respective disposal needs. This is a challenging issue because the approaches for categorization of SRS and classification of RW are essentially different.&#x0D; DSRS declared as RW may be disposed of either together with other RW in the existing or planned RW disposal facilities, or in the disposal facilities designed and constructed specially for DSRS.&#x0D; Current situation with DSRS management in Ukraine is analyzed. DSRS management strategy in Ukraine envisages their long-term storage in the centralized facility for 50 years with subsequent transfer for disposal. At that, there are neither specified disposal facilities where DSRS will be disposed of, nor established generic waste acceptance criteria for DSRS disposal. Recommendations on further steps for solving challenging issues related to safe disposal of DSRS in Ukraine are provided.&#x0D; Solution of a set of challenging issues related to DSRS management revealed in the paper will promote implementation of comprehensive approach to safe disposal of DSRS in Ukraine.

Plasma Technology to Recondition Radioactive Waste: Tests with Simulated Bitumen and Concrete in a Plasma Test Facility

The operation and maintenance of nuclear power plants, the non-nuclear fuel cycle, etc generate low-level radioactive waste which, along with the historical radioactive waste from past nuclear activities, needs to be treated and stored, awaiting final disposal. Plasma technology offers a very effective way of treating this waste with a high-volume reduction factor (VRF), free from organics, liquids and moisture, and meets without a doubt the acceptance criteria for safe storage and disposal. By means of a plasma beam of approximately 5000°C, the inorganic materials are melted into a glassy slag, containing most of the radioactive isotopes while the organic material is gasified, oxidized and purified in an off-gas cleaning system. First the paper describes the new full-scale Plasma Melting Facility (PMF) at the Kozloduy Nuclear Power Plant in Bulgaria which was taken into nuclear operation in May 2018. The plant has a capacity of 250 tons per year and the maximum contact dose rates of the incoming waste is 2mSv/h. Different mixtures of radioactive waste packed in 200l drums were successfully treated resulting in a glassy slag free from liquids and organic material with an important volume reduction factor (VRF). The Project was co-financed through a grant by Kozloduy International Decommissiong fund (KIDSF) administated by the EBRD through Bulgarian national funding. Plasma is a suitable technology for treatment of problematic waste or even reconditioning waste so Belgoprocess was contracted to do plasma tests with simulated conditioned waste types. One can do tests on a laboratory scale on smaller samples and torch capacities of e.g. 50kW but Belgoprocess wanted to do more realistic and reliable tests. So Belgoprocess contracted Phoenix Solutions Co who has a full-scope test facility equipped with a 1200kW plasma torch for full-scope treatment of simulated conditioned waste. For a first confidential contract simulated 2001 (55 gallon) bitumen drums were treated. The drums contained different pucks of compacted waste such as rags, used filters, granulates, etc. The pucks were stacked in the 2001 drums and subsequently embedded with bitumen. A total of 6 drums were treated in the plasma facility. For a second contract simulated homogeneous 2001 (55 gallon) concrete drums with on the one hand concentrates and on the other hand spent resins were selected. A total of 6 drums with concrete and spent resins were treated and melted in the plasma testing facility. The paper describes the test facility, volume reduction factor (VRF) of different waste streams and most important parameters.

Treatment of spent ion exchange resins: Comparison between hydrothermal and acid leaching processes

Ion exchange resins (IERs) are used to treat radioactive liquid effluents from nuclear industry. Today, the management of spent IERs as nuclear waste is an issue. We propose here the use of hydrothermal and leaching treatments to transfer radioactivity from organic solid phase to aqueous phase, in order to connect to existing outlet systems. Co, Cs, Sr and Eu were chosen as α and βγ radionuclide surrogates. The efficiency of the treatment was assessed in terms of extraction yields and contaminant concentrations in wastewaters. The highest extraction efficiencies of 90–100 % were obtained in supercritical water in batch and semi-dynamic mode in the presence of oxidant. In subcritical conditions, yields adequate are lower but suitable with the disposal criteria for the residual solid waste. Complete extraction was also achieved by leaching with ethylenediaminetetraacetic acid solutions. The optimal choice between all these processes is therefore discussed with regards to the requirements of effluent treatment plant including post-treatment steps such as coprecipitation and advanced oxidation.

Direct reuse at industrial level of ion-exchange resin regeneration wastewater in MDF manufacturing

Industrial wastewater is currently a big challenge for authorities due to its environmental issues when disposed to the ecosystem. From an economic perspective and long treatment time, it is yet more reasonable to recover and reuse wastewater in industries. In this work, the wastewater from an ion exchange resin regeneration process was directly and without any further treatment reused in the wood industry for manufacturing medium density fiberboards (MDF). Comparing with the disposal criteria of international standards, the reused wastewater exhibited much higher electrical conductivity, turbidity, total dissolved solid, total suspension solid, and inorganic salt content than the permissible limits; therefore, it is categorized as hazardous material. The highly saline wastewater was added during and after synthesizing of the urea–formaldehyde (UF) resin but before mixing with the wood fibers. The Fourier transform infrared spectroscopy and differential scanning calorimetry analyses of the UF resin samples, respectively, demonstrated the high stability of the chemical structure and higher strength against decomposition for the UF resins after being treated with the wastewater. The physico–mechanical properties of MDFs prepared by reused wastewater were significantly improved whilst the formaldehyde emission of the boards was noticeably reduced (~ 17%) to the benefit of the environment.

Дослідження процесів озонолізу органічних компонентів модельних розчинів рідких радіоактивних відходів реакторів ВВЕР

The article highlights the problem of reprocessing of liquid radioactive waste (LRW) from the Ukrainian nuclear power plants with VVER reactors. The main method of these LRW treatment is distillation (evaporation) and ion exchange sorption. The final products of LRW processing by distillation are distillation residues, spent sorbents and sludges, and salt melt with significant radioactivity accumulated in large volumes, which do not meet the long-term storage and disposal criteria. So, it is necessary to develop a new, more efficient LRW treatment scheme that can solve the problems of large volumes of LRW and transfer waste to a state suitable for long-term storage and disposal. One of the important and challenging problems of LRW treatment is the presence of organic components (ethylenediaminetetraacetic acid (EDTA), oxalic acid, synthetic surfactants (SPAR) in the waste, since these substances complicate removal of radionuclides from the LRW. The results of investigation of ozonolysis conditions of LRW organic components are presented on the example of a model solution with imitated solutions of disodium salt of ethylenediaminetetraacetic acid and ethane diacid. It was established, that ozonation of organic components of LRW results in decreasing of pH value, which causes reduction of their destruction efficiency. Control of the pH values at the initial level (11−12 units) by permanent alkalifying can increase the ozonolysis efficiency of LRW organic components in 30%. EDTA is better destructed by ozone than ethane diacid. Destruction of LRW organic components progresses in two stages: the first is fast and second is low. The maximum of EDTA destruction degree, in the experimental conditions, was 86%; destruction degree of ethane diacid — 51%; maximum of LRW model solution organic components (EDTA, ethane diacid, synthetic surface-active reagent) destruction degree was 67%. Due to co-precipitation and adsorption during the solution ozonizing, decrease in Mn concentration in LRW model solution reaches 94.3%, 137Cs activity decreases by 26%, and 90Sr — 15.7%, concentration of Co decreases only by 6%.

Highly efficient and sustainable carboxylated cellulose filters for removal of cationic dyes/heavy metals ions

Treatment of textile wastewater containing highly toxic dyes and heavy metal ions raises serious health concerns that need to be addressed urgently. Carboxylated cellulose fabric filters were fabricated by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation and employed to remove heavy metal ions and dyes efficiently by adsorption from simulated wastewater. A series of characterizations including ATR, TGA, and SEM measurements were employed to investigate their structure and morphologies. The carboxylated cellulose fabrics exhibited excellent mechanical properties evidenced by tensile experiments and comparisons with other non-woven counterparts. Lead ion (Pb (II)) and methylene blue (MB) were introduced to investigate the filtration performance of carboxylated cellulose filters; high flux, high rejection ratio, and low pressure drop were achieved due to the internal micro-nanoscaled structure of the cellulose fabrics as revealed by XPS and elemental mapping characterizations. The maximum adsorption capacities for Pb (II) and MB were 81.30 and 76.92 mg/g, respectively, while the pressure drop for dynamic adsorption was as low as 0.07 kPa, indicating that the filtration performance was drivable by gravity. A spiral wound cartridge of cellulose fabrics was fabricated and a long-term filtration performance against multicomponent wastewater containing 2.0 mg/L Pb (II) and 2.0 mg/L MB, simultaneously, was demonstrated. The wastewater treatment capacities of 3.6 g of the filter were up to 21.7 L and 36.1 L, respectively, which was 10-times higher than that of the original cellulose fabrics; and the rejection ratios against MB and Pb (II) were 98.7% and 98.2%, respectively, which met the environmental criteria for wastewater disposal. The recycling and reusability of the filters were also demonstrated, indicating that the carboxylated cellulose fabrics can be considered as sustainable filters for wastewater treatment.