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A variety of advanced oxidation processes (AOPs; O3/OH-, H2O2/UV, Fe2+/H2O2, Fe3+/H2O2, Fe2+/H2O2/UV and Fe3+/H2O2/UV) have been applied for the oxidative pre-treatment of real penicillin formulation effluent (average COD0 = 1395 mg/L; TOC0 = 920 mg/L; BOD(5,0) approximately 0 mg/L). For the ozonation process the primary involvement of free radical species such as OH* in the oxidative reaction could be demonstrated via inspection of ozone absorption rates. Alkaline ozonation and the photo-Fenton's reagents both appeared to be the most promising AOPs in terms of COD (49-66%) and TOC (42-52%) abatement rates, whereas the BOD5 of the originally non-biodegradable effluent could only be improved to a value of 100 mg/L with O3/pH = 3] treatment (BOD5/COD, f = 0.08). Evaluation on COD and TOC removal rates per applied active oxidant (AOx) and oxidant (Ox) on a molar basis revealed that alkaline ozonation and particularly the UV-light assisted Fenton processes enabling good oxidation yields (1-2 mol COD and TOC removal per AOx and Ox) by far outweighed the other studied AOPs. Separate experimental studies conducted with the penicillin active substance amoxicillin trihydrate indicated that the aqueous antibiotic substance can be completely eliminated after 40 min advanced oxidation applying photo-Fenton's reagent (pH = 3; Fe(2+):H2O2 molar ratio = 1:20) and alkaline ozonation (at pH = 11.5), respectively.
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PMID:Pre-treatment of penicillin formulation effluent by advanced oxidation processes. 1522 36

In TFT-LCD industry, water plays a variety of roles as a cleaning agent and reaction solvent. As good quality water is increasingly a scarce resource and wastewater treatment costs rises, the once-through use of industrial water is becoming uneconomical and environmentally unacceptable. Instead, recycling of TFT-LCD industrial wastewater is become more attractive from both an economic and environmental perspective. This research is mainly to explore the capacity of TFT-LCD industrial wastewater recycling by the process combined with membrane bioreactor and reverse osmosis processes. Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 97.3%. For TOC and BOD5 items, the average removal efficiencies were 97.8 and 99.4% respectively. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of the UF membrane device incorporated with biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After treatment of RO, excellent water quality of permeate were under 5 mg/l, 2.5 mg/l and 150 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled for the cooling tower make-up water or other purposes.
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PMID:Combined membrane bioreactor (MBR) and reverse osmosis (RO) system for thin-film transistor-liquid crystal display TFT-LCD, industrial wastewater recycling. 1534 79

This study focuses on the practical application of high concentration powdered activated carbon coupled membrane bio-reactor to domestic wastewater reclamation. The study was conducted in three parts, such as analysis of secondary domestic wastewater effluent, design and operation parameter evaluation and reclaimed water quality estimation for stream restoration. The organic concentration was 25.2-80.2 mgCOD(Cr)/L for the effluent of three domestic wastewater treatment plants. Around 50-75% of the COD was low molecular substances less than 1,000 which were quite biodegradable. The sawdust PAC was estimated to be proper adsorbent for the organics in the secondary effluents. Its Freundlich constant, K value was 5.847 and 1/n, 0.36. Using a system consists of single reactor with high concentration PAC (80 g/L) and submerged hollow fiber MF membrane module with nominal pore size of 0.1 microm, design and operation parameters were obtained, such as HRT of the bioreactor (2.5 hr), PAC concentration (80 g/L), the initial flux (less than 0.5 m/day) and intermittent suction cycle (12 min. suction and 3 min. idling). Organic removal by the system was high enough to produce reclaimed water for urban stream restoration The effluent organic concentration was at the level of 2 mg/L in terms of TOC (around 5 mg/L as COD(Cr)). Substances with molecular weight cut off < 1,000 were removed mostly by adsorption and biodegradation. Those above 1,000 were rejected at PAC cake layer on the membrane and gradually degraded by microorganisms during extended contact.
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PMID:Domestic wastewater reclamation by submerged membrane bioreactor with high concentration powdered activated carbon for stream restoration. 1534 88

Untreated wastewater from the dye industry and dyehouses cannot be directly discharged into the environment due to the high content of organic matter and intensive colouration, even with low concentrations of dye. In this paper, the application of a high voltage pulsed electrical discharge in the aqueous phase has been assessed for the dye degradation. Experiments were conducted in a batch reactor using model wastewater of the commercial water-soluble monoazo dye C.I. Direct Orange 39 (DO39). The effects of zeolite and ferrous sulphate in combination with the corona discharge were examined. Experiments were conducted for a range of process parameters including pH, conductivity, type and amount of zeolite, and ferrous sulphate concentration. A mathematical model to describe the kinetics of DO39 degradation in the corona reactor was developed. Aqueous phase pulsed streamer corona discharge as a method for coloured wastewater treatment showed very high effectiveness in the case of iron salt addition (Fenton's reaction). Low pH enhanced dye removal by corona in the absence of zeolite, thus implying that the acid properties of zeolites are important in dye degradation. Ecological parameters such as COD, TC, IC, TOC and IC50 measured before and after corona treatment showed that the treated wastewater can be discharged into the environment or reused as process water.
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PMID:The removal of Direct Orange 39 by pulsed corona discharge from model wastewater. 1534 60

This paper presents the results of the treatment of phenolic compounds containing wastewater generated from phenol-formaldehyde resin manufacturing, oil refinery and bulk drug manufacturing industries by electrochemical method. Experiments were conducted at a fixed current density of 5.4 A/dm2 using Ti/TiO2-RuO2-IrO2 electrode and an undivided reactor. During the various stages of electrolysis, parameters such as COD and TOC concentrations were determined in order to know the feasibility of electrochemical treatment. Adsorbable organic halogens (AOX) were detected at high concentrations during the electrolytic treatment of the effluents. However, it was observed that increasing the electrolysis time bring down the AOX concentration to lower levels. Energy consumption and current efficiency during the electrolysis were calculated and presented. The present study proves the effectiveness of electrochemical treatment for highly concentrated bio-refractory organic pollutants present in the industrial wastewater.
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PMID:Electrochemical treatment of industrial wastewater. 1536 21

Two types of practical electrochemical treatment systems (treatment capacities of 4 and 0.5 m3/h) were constructed. These systems generate radical species for effective oxidation of organic pollutants in wastewater, providing a novel treatment system for treating various kinds of wastewater. A series of experiments was performed using effluents from an anaerobic digester (EAD) of cattle wastewater, supernatants from primary sedimentation in a sewage plant (SPS), and domestic wastewater to evaluate the systems' treatment abilities. As a result, for both EAD and SPS, the 4 m3/h system was found to remove 87-91% of T-P, 74-96% of T-N, 70-94% of NH4-N, 88-91% of TOC, 75-87% of COD. Similarly, for wastewater, the 0.5 m3/h system was able to remove 62-90% of T-P, 83-92% of T-N, 90-100% of NH4-N, 75-83% of TOC, 80-100% of COD. It was further demonstrated that the high-voltage pulses and ultrasonic treatment effectively decomposed NH4-N and TOC due to the formation of radical species such as hydroxyl radicals and hypochlorite, T-P was removed by the electrocoagulation.
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PMID:Performance of two new electrochemical treatment systems for wastewaters. 1547 42

Sanitary landfills are the major method used today for the disposal and management of municipal solid waste. Decomposition of waste and rainfall generate leachate at the bottom of landfills, causing groundwater contamination. In this study, leachate from a municipal landfill site was treated by electrochemical oxidation in a pilot scale flow reactor, using oxide-coated titanium anode. The experiments were conducted under a constant flow rate of 2000 lh(-1) and the effect of current density on chemical oxygen demand, total organic carbon, color and ammonium removal was investigated. At a current density of 116.0 mA cm(-2) and 180 min of processing, the removal rates achieved were 73% for COD, 57% for TOC, 86% for color and 49% for ammonium. The process proved effective in degrading leachate, despite this effluent's usual refractoriness to treatment.
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PMID:Electrodegradation of landfill leachate in a flow electrochemical reactor. 1552 31

In the present study, oxidative pre-treatment of pharmaceutical wastewater originating from the formulation of the penicillin Sultamycillin Tosylate Diydrate via ozonation at varying pH and ozone feed rates was investigated. Biological treatability studies were performed with a synthetic wastewater alone and supplemented with raw and ozonated penicillin formulation effluents. The highest COD (34%) and TOC (24%) removal efficiencies were obtained at pH 11.0, whereas the BOD5 value increased from 16 mg l(-1) to 128 mg l(-1) after 40 min of ozonation, corresponding to an applied ozone dose of 1670 mg l(-1) and 33% relative ozone absorption. The studies showed that no degradation of raw penicillin fraction (30% of total COD) occurred, and degradation of the synthetic wastewater being completely treatable without penicillin addition, was inhibited by 7%. Upon 40 min ozonation, the synthetic wastewater could be completely oxidized and at the same time 35% of ozonated penicillin wastewater removal was obtained. Respirometric studies were conducted in parallel and produced results indicating a 22% decrease in the total oxygen consumption rate established for raw penicillin formulation effluent compared to the results obtained from the aerobic batch reactor. No inhibition of the synthetic fraction was observed for the 40 min-ozonated penicillin formulation effluent, biodegradability of the 60 min-ozonated penicillin effluent decreased possibly due to recalcitrant oxidation product accumulation. The modeling study provided experimental support and information on inhibition kinetics in activated sludge model no. 3 (ASM3) by means of respirometric tests for the first time.
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PMID:Biological treatability of raw and ozonated penicillin formulation effluent. 1556 74

In this study, the effects of preozonation on the biodegradability of mixed 2-chlorophenol/4-cresol solution were investigated using a new gas-inducing reactor, which can provide high ozone utilization efficiency. The decomposition rate of phenolic mixture, COD removal and TOC removal increases with increasing pH. A half-order overall kinetic model can correctly describe the decomposition of phenolic mixture. The BOD(5)/COD ratio of the preozonized solutions increases with increasing preozonation time, indicating that preozonation can enhance the biodegradability. Based on high ozone utilization rate, it is concluded that the best characteristic time can be chosen at the rapid increase of ozone gas outlet concentration. Since the ozone gas outlet concentration can be easily monitored, it is a useful real-time control parameter in preozonation.
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PMID:The effects of preozonation on the biodegradability of mixed phenolic solution using a new gas-inducing reactor. 1585 39

The objective of this study was to explore the extent of mineralization, reduction in color and reduction of COD of gallic acid, tannin and lignin by ozonation and a combination of aerobic biodegradation and ozonation. Ozonation of pure aliquots (phase I experiments) resulted in the decline in TOC, COD, COD/TOC ratio, UV absorbance at 280 nm and color of the three model compounds investigated, with COD removals of greater than 80% and high removals (>90%) of UV absorbance at 280 nm and color observed in all cases at an ozone dose of 6 mg ozone/mg initial TOC or higher. Aerobic biodegradation of pure gallic acid, tannin and lignin aliquots resulted in COD decline of approximately 36-38%. Subsequent ozonation (phase II experiments) resulted in further decline in TOC, COD, COD/TOC ratio, and increase in UV absorbance at 280 nm and color removals. COD and TOC removals comparable to phase I experiments were obtained with 30-40% lower ozone absorption in phase II experiments. The biodegradation step was quite effective in removing specific UV absorbance at 280 nm, with up to 75% removal observed. Subsequent ozonation increased overall specific UV absorbance at 280 nm to greater than 90%.
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PMID:Mineralization of some natural refractory organic compounds by biodegradation and ozonation. 1589 91


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