[en] The treatment of wastewater presents the dual challenge of protecting public health and the environment. The presence of increasing amounts of chemical contaminants such as pharmaceuticals, petrochemicals, pesticides and dyes resulting from agricultural, industrial or municipal activities has potential negative impacts on ecosystems. Radiation technologies have been studied for many years for treating different organic pollutants, and their reliability and effectiveness have been demonstrated. This publication provides new insights into the radiation treatment methodologies, particularly the evaluation of toxicity of waste water after radiation treatment, techno-economic aspects of such treatment and its integration with the existing conventional technologies.

[en] Electron beam irradiation has been applied for three pharmaceuticals in water solution and in mixtures, as follow: Fluoxetine Hydrochloride (Prozac), Propranolol, Voltaren (sodium diclofenac), Fluoxetione Hydrochloride + Propranolol; Fluoxetione Hydrochloride + Voltaren and Fluoxetione Hydrochloride + raw sewage. Radiation benefits through toxicity removal were measured with D. similis and V. fischeri, although other living organisms were exposed to Prozac. From 5% up to 88% of toxicity removals were obtained for pharmaceutical and their mixtures when treated at 5 kGy, however the efficacy was very dependent on the biological specie. Higher than 90% of Fluoxetione was decomposed by 0.5 kGy but relatively low TOC removal was obtained even at 20 kGy. (author)

[en] Effects of coagulation/flocculation, coagulation/flocculation + EB, Fenton, EB + Fenton on COD and colour indices removals were investigated for the advanced treatment of industrial textile wastewater. The results demonstrated that COD and colour indices were removed by coagulation/flocculation, EB irradiation as well as Fenton reaction. However, the combination of EB and Fenton can significantly decrease COD and colour indices to below 50 mg/L and 10 times, respectively. A following pilot-scale demonstration study on EB irradiation of industrial textile wastewater also confirmed the lab-scale experiments. (author)

[en] High-energy electron beam (eBeam) irradiation is an effective disinfection technology for wastewater treatment plants. Depending on the eBeam dose, significant reductions of all target organisms is achievable. The conventional view that municipal wastes be treated primarily to prevent the transmission of diseases and prevent environmental impacts is rapidly changing. Sewage sludges are significant pools of water, energy substrates, and nutrients. Water availability is a major challenge facing regions around the world and especially cities and states in the US. Thus, wastewater treatment plants should be viewed as “Sustainable Resource Recovery Facilities” where high value resource recovery operations are performed rather than just locations for the treatment and disposal of municipal wastes. This project focused primarily on the economic analysis associated with eBeam technology adoption in the wastewater industry (sewage sludge and effluent). Major outcomes of this project included engagement with different stakeholders to obtain a clear understanding of the technology and regulatory challenges associated with commercial adoption of this technology by the wastewater industry. (author)

[en] The decomposition of monuron was investigated in dilute aqueous solutions. Pulse radiolysis was used to identify the intermediates and γ-radiolysis to analyse final products. The main reaction takes place between monuron and the hydroxyl radicals yielding hydroxycyclohexadienyl type radicals with a second order rate constant of (7.4±0.2) x 10⁹ mol⁻¹ dm³ s^-1. In •OH reactions, the aminyl and phenoxyl radicals may also form. Dechlorination was observed in both hydroxyl radical and hydrated electron reactions. The •OH induced dechlorination reactions are suggested to occur through OH substitution or phenoxyl radical formation. The rate of oxidation is very high in the presence of dissolved oxygen. (author)

[en] Gamma irradiation-induced degradation of a chlorinated organic compound, 3-chloro-4- hydroxybenzoic acid (CHBA) in treated effluent was studied and its performance was compared to that in pure water. Results showed that CHBA was degraded effectively using gamma irradiation and the removal of CHBA followed the pseudo first-order kinetic reaction. The rate constant in the treated effluent was 1.7-3.5 times lower than that in pure water. The radiolytic yield, G values of CHBA decreased with increasing the absorbed dose and it was lower in the treated effluent. The CHBA degradation is favoured at acidic condition and decreased at neutral and alkaline pH. Both of Fe²⁺ and H₂O₂ additives exhibited an obvious synergetic effect on the degradation of CHBA in the treated effluent following gamma irradiation and the removal efficiencies of CHBA and TOC increased by 11-12% and 4-10%, respectively. The degradation mechanism of CHBA using gamma irradiation was ascribed to the oxidation by ·OH and reduction by e_aq- and H· radicals. As exposed to gamma irradiation, dechlorination takes place rapidly and combines with the oxidation and cleavage of the aromatic ring, producing chloride ions, small carboxylic acids and acetaldehyde into the solution. (author)

[en] The radiolytic degradation of antibiotic compounds including lincomycin (LMC), sulfamethoxazole (SMX), and tetracycline (TCN), and the change of biodegradability of the radiation-treated target compounds were evaluated. As a result, the degradation of target antibiotics by hydrolysis, biodegradation, and gamma irradiation showed a compound dependent manner. However, the biodegradability of all target compounds was enhanced by the gamma irradiation. The enhanced biodegradability after gamma irradiation (2 kGy) followed the trend of LMC (18.89%) < SMX (28.33%) < TCN (36.62%), indicating that gamma irradiation might transform non-biodegradable compounds into biodegradable. Consequently, the effective degradation of non-biodegradable antibiotics can be accomplished by ionizing radiation followed by biodegradation. This result indicated that ionizing radiation technology would be useful to enhance biodegradability of the recalcitrant pollutants and can facilitate further degradation of residuals or intermediates in the effluent when discharged into surface water. (author)

[en] The technology for the decomposition of trace amounts of halogenated pharmaceuticals/antibiotics was developed in wastewater by use of the combination method of zeolite adsorbent and ionizing radiation. Toxicity test was conducted using a luminescence bacterium on the irradiation of aqueous solution of 2-chlorophenol (2-ClPh) as a simple model of halogenated pharmaceuticals/antibiotics. Toxicity of 2-ClPh solution increased with the increase in γ-ray dose. The toxicity after γ-ray irradiation originates only in neither 2-ClPh nor primary products, but it is thought that it is based on a synergistic effect including organic acid or aldehyde. HMOR, a hydrophobic high-silica mordenite-type zeolite, was employed to concentrate 2-ClPh on it. HMOR adsorbed above 99% of 2-ClPh from dilute aqueous solutions. The yield of Cl⁻ production in HMOR mixture corresponded to the aqueous solution containing 10 fold higher concentration of dissolved 2-ClPh. Clofibrate and triclosan, one of chlorinated pharmaceuticals/antibiotics, in real wastewater were treated by use of the combination method of HMOR and ionizing radiation. Production yield of Cl^- by use of the adsorbent was about twice higher than that in aqueous solution, and HMOR was contributed for effective reduction of chlorinated pharmaceuticals/antibiotics in real wastewater. (author)

[en] Mechanism of sedimentation process of nonorganic pollutants initiated by ionizing radiation was confirmed experimentally. It was found that irradiation considerably affects wastewater filterability, bound-water content, and the enhancement of agglomeration of suspended particles. Evaluation from technical and economical point of view of this specific radiation technology was performed towards feasibility study preparation for industrial wastewater facility. Particularly electron accelerators performances were investigated to evaluate their disadvantages and advantages to make characteristic a final decision regarding accelerator selection. The optimization beam utilization coefficient was performed by computer simulation based on Monte Carlo method to increase the facility throughput. Cost analysis of industrial wastewater effluents treatment by radiation was performed to establish basic parameters and facility cost-effectiveness assumptions on the base of accelerator performances, required dose and established electron beam utilization coefficient. Accelerator (electron energy 1MeV, beam power 400 kW) cost including spare parts, installation and training and the cost related to the building construction, irradiation chamber and other spending were taking into account. The total investment cost was estimated as 4.2 M$. The exploitation cost was evaluated taking into account variable and fixed costs. When bank credit is adopted (8% for 20 years) and electricity cost 0.05 $/kWh is applied the annual exploitation cost amounts 1.1 M$. Estimated costs for wastewater electron beam treatment process in above conditions was obtained as 0.40 $/m3. To justify process implementation the dose rate should be properly decreased by process parameters optimization (temperature, additives) and value of by-product should be taken into economic evaluation. (author)

[en] The work done over the last years has shown that ionizing radiation can induced an increase in antioxidant activity in cork cooking water. To confirm this statement, antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. The overall antioxidant activity was found to increase with ionizing radiation confirming the previous results. Toxicity tests were performed to access the added value of these wastewaters after irradiation and/or potential minimization of the environmental impact of treated water discharge in the environment. Two different methods for toxicity evaluation were performed in order to predict behaviour of different cells (bacterial and eukaryotic). The gamma radiation treatment seems to not affect the toxicity of cork compounds for Pseudomonas fluorescens growth inhibition test. On the other hand, the same radiation treatment of cork wastewater indicated to decrease the viability of Raw 264.7 and A549 cells, which could be related to a cytotoxicity effect of radiolytic products of cork compounds. These results could give two important outcomes: a) gamma radiation treatment does not affect the ecotoxicity of cork industry effluent which could reduce the environmental pollution problematics; b) cork wastewater cytotoxicity increases with gamma radiation treatment. Consequently, the applicability of the added-value cork wastewater by-products needs to be carefully studied to evaluate both the antioxidant potential as well as the cytotoxicity. (author)