Papers by Keyword: Chemical Oxygen Demand (COD)

Abstract: The need for less harmful remedies to olden day inorganic coagulants like alum regarding with health and environment is for a long time pushing for research towards more sustainable options. This has embarked on by researching the capability of pomegranate seeds as an integral component which is environmentally friendly when it comes to treatment process of waste materials. The impacts of pomegranate seed extract at different concentrations were analyzed to find out their abilities in reducing preference ratio, color, and chemical oxygen demand (COD). It’s only at an optimum dose level set at 500 mg/l that a significant decrease in pollutants’ content was achieved such as this case; 78.3% removal efficiency rate was recorded on turbidity followed by 93.5% of TSS removal rate 91.5% color removal efficiency and finally 17.7% COD removal percentage. These findings indicate that pomegranate seed might be considered as an appropriate alternative to traditional coagulants during water treatment processes.

Abstract: Recent advancement on biological wastewater treatment is via granular sludge technology. It is widely known that, aerobic granular sludge has been developed in a batch operation since its discovery. Yet, most of the wastewater treatment plant (WWTP) is operated in continuous mode. Now, the real challenge is how to adopt the granular technology while maintaining present operation mode of WWTP. Thus, this study attempts to evaluate the feasibility of developing aerobic granular sludge in continuous airlift reactors feed with two different substrates, namely glucose and acetate. Two identical airlift reactors (6 L) were employed and operated at room temperature (30°C). Prior to the substrate feeding, both reactors were inoculated with seed sludge obtained from a palm oil mill anaerobic pond. One of the reactors was fed with 2000 mg COD L^-1 of glucose (ALR1) and the other reactor with 2000 mg COD L^-1 of acetate (ALR2). The hydraulic retention time (HRT) and organic loading rate (OLR) for both reactors were maintained at 4 days and between 0.2 to 0.5 kg m^-3day^-1 respectively. Dissolved oxygen was maintained between 5.0 and 6.0 mg O₂L^-1 and supplied by air compressor. The reactor performance was monitored based on COD removal. Aerobic granules developed throughout the study period was evaluated based on granules size and morphology, sludge volumetric index (SVI₃₀) and SVI₅/SVI₃₀ ratio analysis. Results showed that ALR1 demonstrated the formation of filamentous-type aerobic granules with most of the SVI₃₀ average at 100 to 190 mL g^-1. Ratio SVI₅/SVI₃₀ analysis was evaluated at 0.2 and 0.5. The largest granules size obtained during the experiment was about 600 μm on day-136 and average granules size obtained at 200 to 400 μm. ALR1 able to achieve 95% COD removal. For ALR2, round shaped aerobic granules were developed with average SVI₃₀ from 100 to 1000 mLg^-1. SVI₅/SVI₃₀ analysis indicated an average ratio between 0.7 and 0.9. The average granules size was between 30 to 50 μm and the largest was 78 μm on day-60. 90% of COD removal efficiency was obtained in ALR2. In conclusion, ALR fed with acetate had indicated better aerobic granules characteristics as compared to glucose fed reactor. Furthermore, the study demonstrated that to develop aerobic granules in continuous reactors is feasible.

Abstract: An improved method for the determination of chemical oxygen demand (COD) is presented. This method is based on the standard method but using silver sulfate as a masking agent for the chloride and using the microwave for the digestion. The method gives tiny errors when the chloride of the samples increases from 606.6 mg/L to more than 30,000 mg/L. The method applies to the samples containing macromolecules and give better results when the sample is prehydrolysed.

Abstract: The main theme of this paper is to assure the importance of natural material like peat to remove oil from water. Elimination of oil from the water is not a simple task. It requires some particular processes to separate oil from water. Oil in water is not only harmful for sea life but also the few manufacturing processes like dyeing and finishing of textiles cannot be carried out efficiently because of low absorbency. That is why it is very much important to remove oil from water. It is known that peat has outstanding absorbency qualities, since in its natural state is has absorbed approximately 90% water, however, that on drying peat to approximately 5-10% moisture content in the manner , such peat can absorb other liquid materials, like oil. This paper will explore the ability of peat to take in oil from oil polluted water. The absorption of oil measured by designed experiment.

Abstract: Based on the problem of industrial wastewater of 4-Toluene Sulfonic Acid (4-TSA) with characteristics of high concentration and high toxicity, also low treatment efficiency by common biological treatment , this study was used aerobic biological fluidized bed (ABFB) to analyze the impact of 4-TSA treatment by changing water load chemical oxygen demand (COD), aeration amount, and pH value of input water, and so on technological parameters. The result showed that the average degradation rate of 4-TSA in wastewater can researched to 96.9% under condition of reactor steadily running, HRT=9 h, temperature 25°C, pH=8.0, ORP-141~-93 mV,DO 3.5~8.72 mg/L, the inflow water 4-TSA concentration 600 mg/L, aerobic amount 210 L/h. Therefore, the best aerobic amount to treat wastewater contained 4-TSA is 210 L/h in aerobic biological fluidized bed. The degradation rate of 4-TSA is decreased as the increasing of water load. The scanning electronic microscope (SEM) indicated that the bacillus is the mainly part on the biological carrier, suspended sludge is composed by aurous and bacillus.

Abstract: This paper presents a comparative study of the performance of ferrate (VI) towards wastewater treatment. The ferrate was produced by microwave irradiation-assisted hypochlorite-oxidation method. And the concentration of the prepared ferrate was determined by UV-Vis spectrum. Domestic wastewater collected from Longting lake of Kaifeng city was treated with ferrate (VI). Samples were analyzed for COD and ammonia-nitrogen removal. Results demonstrated that low addition of ferrate (VI) leads to good removal of COD and ammonia nitrogen. So ferrate (VI) is an effective reagent for wastewater treatment.

Abstract: The paper uses the research means of numerical simulation for marine pollution problem of the ocean dumps from offshore industries, which is concerned by the coastal countries; it adopts ECOM Water Quality Model. It has carried out the simulation research on those projects influence on the environment of sea area. By taking COD of wastewater as the research object, the paper confirmed the influence range of COD emission on marine ecological environment.

Abstract: The removal effect of raw wastewater treatment by anaerobicSBR was investigated, and the removal effects of wastewater COD, ammonia and orthophosphate were studied. Then the raw wastewater decolonization was implemented. The results showed that influent COD, ammonia and orthophosphate was at about 2000 mg/L, 80.7 mg/L and 7.1 mg/L, the removal efficiency of COD, ammonia and orthophosphate was at 96.5%, 95.3% and 97.2% respectively. When the raw wastewater color is about 200 times with PAC adding dosage 10~40 mg and activated carbon adding dosage 1.5~3.0 g, the effluent color can decrease lower than 50 times.

Abstract: Chemical Oxygen Demand (COD) is an much important key water quality parameter . In view of the technical defects of existing detection methods and monitoring instruments for measuring COD, a new detection method based on ultrasonic assisted sample digestion and spectrum analysis was put forward in this paper, and the automatic monitoring system prototype based on such detection method had been developped. Aiming at environmental water samples, the spot experiment had been carried out to contrast prototype with Chinas national standard analysis method for measuring COD, and the results showed that the automatic monitoring instrument prototype had good repeatability (10%) and high accuracy (±10%), which met the technical qualifications of Chinas envirormental protection industry standards.

Abstract: Simulative wastewater was treated by a biofilm with soft filling and biological filter processing, the removal rate of COD /TN/NH₄⁺-N and TP were discussed at different C/N ratio. The combined processing of biofilm and biological filter was studied. The results showed that the removal rate of COD is 80%. Biofilm had highly treatment efficiency and biological filter processing needed lower energy at low organic loading. The combined processing showed that the removal rate of COD and NH₄⁺-N is more than 80% and 65% respectively. It will help for further study of domestic sewage treatment.