Impact of ozonation in removing organic micro-pollutants in primary and secondary municipal wastewater: effect of process parameters

The study investigates the influence of process parameters on the effectiveness of ozonation in the removal of organic micro-pollutants from wastewater. Primary and secondary municipal wastewater containing phenol was treated. The effect of operating parameters such as initial pH, ozone dosage, and initial contaminant concentration was studied. An increase in contaminant decomposition with pH (3–11) was observed. The contaminant removal efficiencies increased with an increase in ozone dose rate (5.5–36.17 mg L−1 min−1). Furthermore, the ultraviolet absorbance (UV 254 nm) of the wastewater decreased during ozonation indicating the breakdown of complex organic compounds into low molecular weight organics. Along the reaction, the pH of wastewater decreased from 11 to around 8.5 due to the formation of intermediate acidic species. Moreover, the biodegradability of wastewaters, measured as biological and chemical oxygen demand (BOD5/COD), increased from 0.22 to 0.53. High ozone utilization efficiencies of up to 95% were attained thereby increasing the process efficiency; and they were dependent on the ozone dosage and pH of solution. Ozonation of secondary wastewater attained the South African water standards in terms of COD required for wastewater discharge and dissolved organic carbon in drinking water and increased significantly the biodegradability of primary wastewater.

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Assessing the potential of a UV-based AOP for treating high-salinity municipal wastewater reverse osmosis concentrate

Water Science & Technology ◽

10.2166/wst.2013.417 ◽

2013 ◽

Vol 68 (9) ◽

pp. 1994-1999 ◽

Cited By ~ 14

Author(s):

Muhammad Umar ◽

Felicity Roddick ◽

Linhua Fan

Keyword(s):

Reverse Osmosis ◽

Municipal Wastewater ◽

High Salinity ◽

Oxygen Demand ◽

Process Efficiency ◽

Secondary Effluent ◽

Biological Processes ◽

Fluorescence Excitation ◽

H2o2 Treatment ◽

Humic Compounds

The UVC/H2O2 process was studied at laboratory scale for the treatment of one moderate (conductivity ∼8 mS/cm) and two high salinity (∼23 mS/cm) municipal wastewater reverse osmosis concentrate (ROC) samples with varying organic and inorganic characteristics. The process efficiency was characterized in terms of reduction of dissolved organic carbon (DOC), chemical oxygen demand (COD), colour and absorbance at 254 nm (A254), and the improvement of biodegradability. The reduction of colour and A254 was significantly greater than for DOC and COD for all samples due to the greater breakdown of humic compounds, as confirmed by fluorescence excitation-emission matrix spectra. Fairly small differences in the reduction of DOC (26–38%) and COD (25–37%) were observed for all samples, suggesting that the salinity of the ROC did not have a significant impact on the UVC/H2O2 treatment under the test conditions. The biodegradability of the treated ROC samples improved markedly (approximately 2-fold) after 60 min UVC/H2O2 treatment. This study indicates the potential of UVC/H2O2 treatment followed by biological processes for treating high-salinity concentrate, and the robustness of the process where the characteristics of the secondary effluent (influent to RO) and thus resultant ROC vary significantly.

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Removal of COD and BOD from biologically treated municipal wastewater by electrochemical treatment

Journal of Applied and Natural Science ◽

10.31018/jans.v5i2.356 ◽

2013 ◽

Vol 5 (2) ◽

pp. 475-481 ◽

Cited By ~ 2

Author(s):

Arun Kumar Sharma ◽

A. K. Chopra

Keyword(s):

Municipal Wastewater ◽

Operating Cost ◽

Operating Time ◽

Sewage Treatment Plant ◽

Oxygen Demand ◽

Operating Conditions ◽

Optimum Operating ◽

Initial Ph ◽

Treated Municipal Wastewater ◽

Maximum Removal

The present investigation observed the effect of current density (CD), operating time (OT), inter electrode distance (IED), electrode area (EA), initial pH and settling time (ST) using Fe-Fe electrode combination on the removal of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) from biologically treated municipal wastewater (BTMW) of Sewage Treatment Plant (STP). The maximum removal of COD (92.35%) from BTMW was found with the optimum operating conditions of CD (2.82 A/m2), OT (40 mins.), IED (0.5 cm), EA (160 cm2), initial pH (7.5) and ST (60 min.), while the maximum removal of BOD (84.88%) was found with the ST (30 min.) at the same operating conditions. There was no need of pH adjustment of the BTMW during ET as the optimal removal efficiency was close to the pH of 7.5. Under optimal operating conditions, the operating cost was found to be 54.29 Rs./m3 / 1.08 US$/m3 in terms of the electrode consumption (78.48 x 10-5 kg Al/m3 ) and energy consumption (108.48 Kwh/m3).

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Influence of Process Parameters on the Process Efficiency in Laser Metal Deposition Welding

Physics Procedia ◽

10.1016/j.phpro.2016.08.068 ◽

2016 ◽

Vol 83 ◽

pp. 657-666 ◽

Cited By ~ 5

Author(s):

Michael Güpner ◽

Andreas Patschger ◽

Jens Bliedtner

Keyword(s):

Process Parameters ◽

Metal Deposition ◽

Process Efficiency ◽

Laser Metal Deposition ◽

Influence Of Process Parameters

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Removal of a mixture of pharmaceuticals sulfamethoxazole and diclofenac from water streams by a polyamide nanofiltration membrane

Water Science & Technology ◽

10.2166/wst.2020.166 ◽

2020 ◽

Vol 81 (4) ◽

pp. 732-743

Author(s):

Daniela Gomes ◽

Mafalda Cardoso ◽

Rui C. Martins ◽

Rosa M. Quinta-Ferreira ◽

Lícinio M. Gando-Ferreira

Keyword(s):

Wastewater Treatment ◽

Municipal Wastewater ◽

Vibrio Fischeri ◽

Applied Pressure ◽

Treatment Plant ◽

Oxygen Demand ◽

Operating Conditions ◽

Process Efficiency ◽

Secondary Effluent ◽

Municipal Wastewater Treatment

Abstract Wastewater treatment plants are not specially designed to remove pharmaceutically active compounds (PhACs), since these substances are toxic and bio-refractory. This paper aims to investigate and optimize the performance of the Trisep TS80 nanofiltration (NF) membrane for the removal of a mixture of two of the most detected PhACs in municipal wastewaters worldwide, sulfamethoxazole and diclofenac. Several NF tests were carried out to study the rejections of these contaminants both spiked in demineralized water, filtrated water taken from Mondego River and secondary effluent coming from a municipal wastewater treatment plant. Among the several studied operating variables, pH was the one that most affected the contaminant rejection and membrane permeability. In the case of synthetic effluent, an applied pressure of 10 bar and pH 7 were determined as the best operating conditions, which allowed almost total chemical oxygen demand retention and a global contaminant rejection of 96.3% to be achieved. The application of different water matrices (river water and secondary municipal effluent) had no relevant impact on process efficiency. Vibrio fischeri luminescence inhibition tests revealed that treatment by nanofiltration reduced acute toxicity of all studied effluents.

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