Evaluating the photodegradation of Carbamazepine in a sequential batch photoreactor system: Impacts of effluent organic matter and inorganic ions (original) (raw)
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Bioresource Technology, 2011
This paper aims to demonstrate that integrating biological process and photocatalytic oxidation in a system operated in recycling mode can be a promising technology to treat pharmaceutical wastewater characterized by simultaneous presence of biodegradable and refractory/inhibitory compounds. A lab-scale system integrating a membrane bioreactor (MBR) and a TiO 2 slurry photoreactor was fed on simulated wastewater containing 10 mg/L of the refractory drug Carbamazepine (CBZ). Majority of chemical oxygen demand (COD) was removed by the MBR, while the photocatalytic oxidation was capable to degrade CBZ. CBZ degradation kinetics and its impacts on the biological process were studied. The adoption of a recycling ratio of 4:1 resulted in removal of up to 95% of CBZ. Effluent COD reduction, sludge yield increase and respirometric tests suggested that the oxidation products were mostly biodegradable and not inhibiting the microbial activity. These results evidenced the advantages of the proposed approach for treating pharmaceutical wastewater and similar industrial effluents.
Journal of Environmental Chemical Engineering, 2014
The initial biodegradability of the organic matter present in the linear alkyl benzene (LAB) production wastewater estimated as the BOD 5 /COD was low 0.12. To decrease the time and operational cost necessary for the mineralization of LAB wastewater, an optimum operation condition of the integrated photocatalysis and biological treatment was investigated. An immobilized TiO 2 photocatalytic reactor under UVA (365 nm) irradiation and a continuous feeding intermittent discharge (CFID) bioreactor were employed in this study. The effects of initial COD concentration, reaction time and initial pH on COD removal efficiency and BOD 5 /COD ratio were studied in photocatalytic reactor. The maximum COD removal efficiency and BOD 5 /COD ratio for the photocatalytic reaction alone were found 37% and 0.45, respectively at initial COD 400 mg/l and pH of 3 after 240 min. The remaining COD concentration after the photocatalytic reaction (after 120 min) was about 280 mg/l with BOD 5 /COD = 0.4 which was used as feed for the CFID bioreactor. The bioreactor was operated at hydraulic retention time (HRT) 12 h and mixed liquor volatile suspended solid (MLVSS) 5000 mg/l a corresponding to organic loading rate (OLR) and food to microorganism (F/M) ratio of 0.74 g COD/l d and 0.148 d À1 , respectively. The integrated system showed a good performance with about 80% total COD removal efficiency. It is concluded that this combination (PCR-CFID) was a good strategy to achieve a high COD removal efficiency in a short period of time and lower cost for such a low biodegradable wastewater.
Integrated System for Recycling and Treatment of Hazardous Pharmaceutical Wastewater
2021
This study aimed to investigate an integrated system that can deal with different pharmaceutical wastewater. Pharmaceutical wastewater was subjected to biological, chemical, and advanced oxidation according to its pollutant’s nature. Wastewater with high Total Suspended Solids (TSS 480 mg/l) was subjected to a conventional chemical treatment process utilizing different coagulants. The best results obtained by using Calcium Oxide and Alum aided with Calcium Oxide where, the removal efficiency of COD was 46.8% and 51 %. Highly loaded pharmaceutical wastewater (COD 9700 mg/l, BOD/COD 0.16) had been subjected to Fenton oxidation, removal of COD reached 80.4%, and the ratio of BOD/COD is enhanced to 0.6. Photocatalysis by using different nanomaterials was applied to pharmaceutical wastewater containing 10 mg/l of phenols. Phenol is completely removed by using Mesoporous TiO2 after 90 min irradiation and after 120 min in the case of TiO2/P25 and TiO2/UV 100 nanocomposites while it is remo...
Journal of Chemical Technology & Biotechnology, 2020
BACKGROUND: Occurrence of pharmaceutical compounds in wastewater has become a major concern 3 for human health and the environment. Therefore, it is challenging to improve the conventional 4 wastewater treatment to remove these compounds. Coupling a biological treatment with an advanced oxidation technology has been widely studied in the literature, but only sequential associations of the 6 two processes have been used. This study proposes an innovative concept based on a real integration of 7 the photocatalytic oxidation process in a continuous recycling loop on a membrane bioreactor. The role 8 of the oxidation is not here to completely degrade pharmaceuticals, but to oxidize them moderately to 9 increase their biodegradability so that they can be eliminated by the biological process. 10 RESULTS: Preliminary experiments on oxidation process indicated that a flux density of 5 W.m-2 was 11 sufficient to increase biodegradability and decrease toxicity of a cocktail of 3 pharmaceuticals. Then 12 performances of a 20-L continuous membrane bioreactor treating wastewater with 7 pharmaceuticals, 13 without and with pre-oxidation at 5 W.m-2 were compared. Pre-oxidation has increased the global 14 removal for some recalcitrant pharmaceuticals (from 3 to 47 % for diclofenac and for 1 to 44 % for 15 furosemide) without affecting neither the removal of carbon, nitrogen and phosphorous by activated 16 sludge neither the removal of already highly removed pharmaceuticals. 17 CONCLUSION: This work proves the feasibility and interest of the innovative concept of a continuous 18 hybrid process coupling a photocatalytic oxidation process and a membrane bioreactor for the treatment 19 of pharmaceuticals in wastewater, with a low cost and size.
Stability and removal of anti-inflammatory dexamethasone sodium phosphate (DSP), anti-anxiety drug diazepam (valium) and spironolactone (SP) from wastewater produced at Al-Quds University Campus were investigated. Kinetic studies in both pure water (abiotic degradation) and in sludge (biodegradability) at room temperature were investigated. They demonstrated that DSP underwent degradation to its hydrolytic derivative, simply named dexamethasone, in both media. The first order hydrolysis rate of DSP in activated sludge at 25°C (3.80×10-6 s-1) was about 12-fold greater than in pure water (3.25×10-7 s-1). Diazepam showed high chemical stability toward degradation in pure water, and underwent faster biodegradation in sludge providing two main degradation products. The degradation reactions in sludge and pure water showed first order kinetics with rate constant values of 2.6 × 10-7 s-1 and 9.08 × 10-8 s-1 , respectively. The potassium-sparing diuretic (water pill) SP underwent degradation to its hydrolytic derivative, canrenone, in both media. The first order hydrolysis rate of SP in activated sludge at 25°C (3.80×10-5 s-1) was about 49-fold greater than in pure water (7.4×10-7 s-1). The overall performance of WWTP was also assessed showing that 90% of spiked DSP and SP were removed together with its newly identified metabolites. WWTP also showed that UF and RO were relatively sufficient in removing spiked diazepam to a safe level. In order to check for different tools to be used instead of ultra-filtration membranes, the effectiveness of adsorption and filtration by micelle-clay preparation for removing DSP was ascertained in comparison with activated charcoal. Batch adsorption in aqueous suspensions of the micelle-clay composite and activated carbon was well described by Langmuir isotherms showing the best results for micelle-clay material. Besides, filtration of DSP, DZ and SP aqueous solutions by columns filled in with a mixture of sand and micelle-clay complex showed complete removal of each drug at concentration higher than sand/activated-charcoal filled filters at flow rates of 2 mL min-1 .
One of the major threats to water quality is chemical pollution from heavy metals, solvents, dyes, pesticides, etc. Chemicals enter the aquatic medium in several different ways, either dumped directly, such as industrial effluents, or from wastewater treatment plants (WWTP) that do not fulfil their obligations. They may also enter the water indirectly through the use of plant health products, such as biocides and fertilizers, in agriculture. In general, very water-soluble substances can be transported and distributed more easily in the water cycle. Discharge resulting from lax enforcement of the rules, illegal use and inappropriate application of substances may be considerable. In the past, the focus was on detecting the severe, direct effects of individual pollutants and the short-term negative impact on ecosystems. But as scientific understanding has advanced, and the more concentrated emissions have been lowered, environmental evaluation reveals a considerable number of chronic effects that can usually only be detected after a long period of time. Furthermore, larger and larger quantities of persistent substances are being found at long distances from their sources of discharge (Meyer and Wania, 2007). Evaluation also used to concentrate mostly on the effect of individual substances, whereas we are now beginning to study and understand interactions in mixtures of these substances (Hernando et al., 2005; Hildebrant et al., 2006). The main routes for destroying toxic compounds in natural water are biodegradation and photodegradation. Photodegradation may be by direct or indirect photolysis. In indirect photolysis, a photosensitizer (as nitrate or humic acids) absorbs the light and transfers the energy to the pollutants, which otherwise would not react, since they do not absorb light in the wavelength interval of the solar photons that arrive on the Earth's surface (i.e. .300 nm). Biological degradation of a chemical refers to the elimination of the pollutant by the metabolic activity of living organisms, usually microorganisms and in particular bacteria and fungi that live in natural water and soil. In this context, conventional biological processes do not always provide satisfactory results, especially for industrial wastewater treatment, since many of the organic substances produced by the chemical industry are toxic or resistant to. Conventional methods of water decontamination can address many of these problems. However, these treatment methods are often chemically, energetically and operationally intensive, focused on large systems, and thus require considerable infusion of capital, engineering expertise and infrastructure, all of which precludes their use in much of the world. Furthermore, intensive chemical treatments (such as those involving ammonia, chlorine compounds, hydrochloric acid, sodium hydroxide, permanganate, alum and ferric salts, coagulation and filtration aids, anti-scalants, corrosion control chemicals, and ion exchange resins and regenerants) and residuals resulting from treatment (sludge, brines, toxic waste) can add to the problems of contamination and salting of freshwater sources. Air stripping and adsorption, merely transferring toxic materials from one medium to another, is not a long-term solution. Incineration is
Environmental Technology Reviews
To reduce demand and discharge, instead of industrial wastewater being poorly treated and disposed of, it can be recycled, reused, or recovered if it is properly managed, thus having a substantial decrease in the water requirement and environmental impacts. The challenge is to select the appropriate process or combination of processes to achieve this based on the wastewater quality. Consequently, the objective of this investigation is to review every technology from conventional through advanced, for reliable and sustainable wastewater treatment and derived sludges, focusing on advantages, disadvantages, and technical gaps for development. Even though there is a wide range of possible technologies, it was evinced that there is huge potential to exploit and make them economically and sustainably viable for waste processing and circular economy, even in the mature massively implemented wastewater treatment technologies in the industry. Overall, we identify that independently from the technology to be studied, the future investigations on every unit, especially on those not vastly implemented, should be focused on: (1) The capacity in removing selected pollutants and decreasing impurities, (2) energy e ciency, (3) environmental safety, (4) economic viability, (5) hybrid processes, and (6) sustainability by waste processing. Previously, industrial wastewater treatment plants (WWTP) mainly involved settling and ltration (Screening, Coarse media ltration to a lesser extent rapid ltration) combine with a biological process (Ranade & Bhandari, 2014b). Nowadays, these are still extensively used in industry because of their large-scale experience and simple operation. Other technologies as otation or chemical precipitation are common methods for IWW treatment, especially when the goal is to recover metal from it, being used the precipitation for high content of metals and otation for low content. These have the bene ts of simple process, low investment, mature technology, extensive large-scale experience, and a high degree of automation (Kyzas, 2018; J. Wang, 2018). In addition to these treatment units, Adsorption is an effective treatment process for recalcitrant impurities which are hard to remove by biological alternatives in IWW (Mai et al., 2018). It can be considered that this process, in the same way as those already mentioned, has securely established itself in terms of commercial use and are also technologically mature, indicating their wide acceptability in the industry and remained to be one of the most promising recovery options owing to its facile implementation, low cost, high availability and high removal e ciencies even at low target metal concentrations (Dawn &
Removal of organic Pollutants from wastewater using different treatment technologies
International Case Studies Journal
Abstract: Stability and removal of anti-inflammatory dexamethasone sodium phosphate (DSP), anti-anxiety drug diazepam (valium) and spironolactone (SP) from wastewater produced at Al-Quds University Campus were investigated. Kinetic studies in both pure water (abiotic degradation) and in sludge (biodegradability) at room temperature were investigated. They demonstrated that DSP underwent degradation to its hydrolytic derivative, simply named dexamethasone, in both media. The first order hydrolysis rate of DSP in activated sludge at 25°C (3.80×10-6 s-1) was about 12-fold greater than in pure water (3.25×10-7 s-1). Diazepam showed high chemical stability toward degradation in pure water, and underwent faster biodegradation in sludge providing two main degradation products. The degradation reactions in sludge and pure water showed first order kinetics with rate constant values of 2.6 × 10-7 s-1 and 9.08 × 10-8 s-1, respectively. The potassium-sparing diuretic (water pill) SP underwent d...
Waste Water Treatment in Chemical Industries: The Concept and Current Technologies
The world’s chemical industries face formidable environmental regulatory challenges in treating their wastewater effluents. The present work aims at highlighting the various industrial wastewater treatment technologies currently available including physico-chemical and biological processes as well as constructed wetland and conventional or advanced oxidation processes. Activated carbon prepared from low cost material, Agricultural by-product materials or modified natural polymers, which is considerably efficient for removal of direct dyes from wastewater, is also discussed. Combinations of anaerobic and aerobic treatment processes are found to be efficient in the removal of soluble biodegradable organic pollutants. The use of membrane in final stage of industrial wastewater treatments is increasing. The chemical oxidation techniques to treat wastewater, classical chemical treatment and advanced oxidation processes, is discussed.