جستجوی مقالات مرتبط با کلیدواژه « bod » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

A lab based hybrid constructed wetland system (1.645 m2) consisting of sludge drying bed (0.135 m2), vertical sub-surface flow bed (0.58 m2), and horizontal sub-surface flow bed (0.93 m2) was operated for the treatment of septage. All the beds were filled with gravels of varied sizes (5-40 mm), sand (0.25 mm) and planted with Canna indica L. Average concentration in influent and effluent was observed as; BOD5 (2395.6±1196.4 and 41.87±8.9 mg/L), COD (7442± 7342.6 and 29.6±7.6 mg/L), TSS (4965.9±801.69 and 336.1±152.9 mg/L), TN (1774.8±693.5 and 55.7±13.7 mg/L), and Total P (849.3±237.7 and 7.05±3.5mg/L) during study period. Hybrid System was operated with high influent loads of BOD5 (175.2± 87.5 g m-2 d-1), COD (544.5±537 g m-2 d-1), TSS (363.3±58.6 g m-2 d-1), Total N (129.8±50.7 g m-2 d-1), NH4-N (7.8±1.1 g m-2 d-1), and Total P (62.1±17.4 g m-2 d-1), throughout the study period. Hybrid-CW has showed significant removal of BOD5 (99.1±0.3%), COD (99.7±0.3%), TS (98.2±6.8%), TSS (96.9±4.9%), Total N (98.4±0.4 %), NH4-N (94.8±0.1%), and Total P (99.6±0.1%) from the septage. Finally treated septage met effluent discharge standards for all parameters except BOD5.

TiO2 photocatalyst was used to degrade Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) from petrochemical wastewater. The photocatalytic performance of the TiO2 was studied with variations of treatment parameters such as temperature, pH, contact time, and catalyst dosage. Design of Experiment (DOE) utilizing the Taguchi method was used to find and optimize the process model. Results for photocatalytic degradation of COD and BOD indicated the proper performance of TiO2 as the photocatalyst. The best result was achieved at pH 5 after 90 min with 73% COD conversion. COD degradation of petrochemical waste was optimized according to the experimental results, while process optimization indicated best process conditions are pH ≈ 5.2, temperature ≈ 42.8 °C, catalyst dosage = 0.75, and contact time of 88 min.

Three vertical sub-surface flow (VSSF) constructed wetland (CW) systems (CW-1, CW-2 and CW-3) filled with different filter media, each 4 m2 in area, planted with Arundo donax was operated for 4 years for treating dairy farm wastewater. The vertical CW systems received high fluctuations in influent concentration and loads i.e. BOD (26 to 619 mg L-1 and 1.5 to 34 g m-2 d-1), TSS (165 to 643 mg L-1 and 9.1 to 24 g m-2 d-1), TP (16 to 49.9 mg L-1 and 1.2 to 2.7 g m-2 d-1) and NH4-N (24.5 to 76.2 mg L-1 and 1.3 to 4.2 g m-2 d-1) during the assessment period. Average annual removal rates showed fluctuations in removal of BOD (70.5 to 92.9%), TSS (82.5 to 97.5%), TP (51.1 to 91.9%) and NH4-N (34.6 to 69%). This shows that the removal of BOD is very sensitive to inlet load fluctuations in CWs. High inlet loads may confine good nitrification that affects ammonium-nitrogen removal while TP removal rate reduced when inlet TP loads reduced. The average concentration of the pollutants (BOD, TSS, TP and NH4-N) in the treated effluent showed noticeable decrease: 43.4 to 16.1 mg L-1 for BOD; 43.3 to 11.7 mg L-1 for TSS; 17.9 to 3.1 mg L-1 for TP and 33.2 to 22.7 mg L-1 for NH4-N. Thus from the outcomes of the current study, it can be concluded that the VSSF CW system may provide promising outcomes despite there is fluctuations in the influent loads.