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

2013 ◽  
Vol 68 (9) ◽  
pp. 1994-1999 ◽  
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.

Potential of UV/H2O2 oxidation for enhancing the biodegradability of municipal reverse osmosis concentrates

2011 ◽  
Vol 63 (11) ◽  
pp. 2605-2611 ◽  
Author(s):  
K. Liu ◽  
F. A. Roddick ◽  
L. Fan
Keyword(s):  
Reverse Osmosis ◽  
Oxygen Demand ◽  
Complex Compounds ◽  
Secondary Effluent ◽  
Pseudo First Order Reaction ◽  
Fluorescence Excitation ◽  
Oxidation Performance ◽  
H2o2 Oxidation ◽  
Reverse Osmosis Concentrates ◽  
Biological Treatment Process

UVC/H2O2 and VUV/H2O2 oxidation processes were evaluated for the degradation of organic pollutants in reverse osmosis concentrate (ROC) produced from a municipal secondary effluent. It was found that the oxidation by UVC/H2O2 and VUV/H2O2 processes could be described as a pseudo first-order reaction. For UVC increased oxidation occurred with increasing H2O2 dosage up to 2 mM above which improvement in oxidation performance decreased. At the same H2O2 dosage, VUV irradiation gave better overall oxidation performance. Compared with UVC/6 mM H2O2, VUV/2 mM H2O2 gave a greater rate of reduction of chemical oxygen demand, but a lower rate for reduction of dissolved organic carbon, suggesting that oxidation of organics by the two methods followed different pathways. The change of absorbance at 254 nm and fluorescence excitation emission matrix spectra of irradiated samples indicated that the large and complex compounds were fragmented rapidly by the •OH, resulting in rapid decolourisation. The biodegradability of the organics in the ROC was increased from 11% to 35% after 1 h treatment by UVC/3 mM H2O2, whereas a greater increase (41%) was obtained with VUV/2 mM H2O2. This increase in biodegradability indicates the potential for employing a subsequent biological treatment process.

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

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.

Preliminary study on novel backwash cleaning for reverse osmosis fouling control in water reuse

2010 ◽  
Vol 10 (3) ◽  
pp. 296-301
Author(s):  
Jian-Jun Qin ◽  
Maung Htun Oo ◽  
Kiran A. Kekre
Keyword(s):  
Product Quality ◽  
Reverse Osmosis ◽  
Water Reuse ◽  
High Salinity ◽  
Full Scale ◽  
Elapse Time ◽  
Secondary Effluent ◽  
Fouling Control ◽  
Membrane Flux ◽  
Preliminary Study

We have demonstrated a novel backwash cleaning technique of direct osmosis (DO)-high salinity (HS) for reverse osmosis (RO) fouling control in water reuse. An UF-RO pilot system was continuously (24-h) operated on site with the secondary effluent as the feed over 4 months. The RO plant was run at 75% recovery and at the membrane flux of 17 l m−2 h−1 (LMH) to simulate the full scale NEWater production when DO-HS treatment was conducted once per day and five times per week during the last two months. Permeability of RO membranes as a function of elapse time of the pilot operation was monitored and compared over different durations. Impact of DO-HS treatment on RO product quality in terms of TOC and conductivity was investigated. It was concluded that the DO-HS treatment preliminarily demonstrated a benefit to low RO fouling rate by 2.5–4 times in 30–60 days without interruption on RO operation and impact on RO product quality.

scholarly journals Advanced nitrogen removal from municipal wastewater treatment plant secondary effluent using a deep bed denitrification filter

2018 ◽  
Vol 77 (11) ◽  
pp. 2723-2732 ◽  
Author(s):  
Xiaowei Zheng ◽  
Shenyao Zhang ◽  
Jibiao Zhang ◽  
Deying Huang ◽  
Zheng Zheng
Keyword(s):  
Wastewater Treatment ◽  
Quartz Sand ◽  
High Throughput Sequencing ◽  
Municipal Wastewater ◽  
Nitrate Nitrogen ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Microbial Distribution

Abstract With the improvement of wastewater discharge standards, wastewater treatment plants (WWTPs) are continually undergoing technological improvements to meet the evolving standards. In this study, a quartz sand deep bed denitrification filter (DBDF) was used to purify WWTP secondary effluent, utilizing high nitrate nitrogen concentrations and a low C/N ratio. Results show that more than 90% of nitrate nitrogen (NO3-N) and 75% of chemical oxygen demand (COD) could be removed by the 20th day of filtration. When the filter layer depth was set to 1,600 mm and the additional carbon source CH3OH was maintained at 30 mg L−1 COD (20 mg L−1 methanol), the total nitrogen (TN) and COD concentrations of DBDF effluent were stabilized below 5 and 30 mg L−1, respectively. Analysis of fluorescence revealed that DBDF had a stronger effect on the removal of dissolved organic matter (DOM), especially of aromatic protein-like substances. High throughput sequencing and qPCR results indicate a distinctly stratified microbial distribution for the main functional species in DBDF, with quartz sand providing a good environment for microbes. The phyla Proteobacteria, Bacteroidetes, and Chloroflexi were found to be the dominant species in DBDF.

scholarly journals Isolation of high-salinity-tolerant bacterial strains, Enterobacter sp., Serratia sp., Yersinia sp., for nitrification and aerobic denitrification under cyanogenic conditions

2016 ◽  
Vol 73 (9) ◽  
pp. 2168-2175 ◽  
Author(s):  
N. Mpongwana ◽  
S. K. O. Ntwampe ◽  
L. Mekuto ◽  
E. A. Akinpelu ◽  
S. Dyantyi ◽  
...  
Keyword(s):  
High Salinity ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Correlation Coefficients ◽  
Aerobic Denitrification ◽  
Biological Processes ◽  
Bacterial Isolates ◽  
Bacterial Strains ◽  
Treatment Processes ◽  
Metabolic Functions

Cyanides (CN−) and soluble salts could potentially inhibit biological processes in wastewater treatment plants (WWTPs), such as nitrification and denitrification. Cyanide in wastewater can alter metabolic functions of microbial populations in WWTPs, thus significantly inhibiting nitrifier and denitrifier metabolic processes, rendering the water treatment processes ineffective. In this study, bacterial isolates that are tolerant to high salinity conditions, which are capable of nitrification and aerobic denitrification under cyanogenic conditions, were isolated from a poultry slaughterhouse effluent. Three of the bacterial isolates were found to be able to oxidise NH4-N in the presence of 65.91 mg/L of free cyanide (CN−) under saline conditions, i.e. 4.5% (w/v) NaCl. The isolates I, H and G, were identified as Enterobacter sp., Yersinia sp. and Serratia sp., respectively. Results showed that 81% (I), 71% (G) and 75% (H) of 400 mg/L NH4-N was biodegraded (nitrification) within 72 h, with the rates of biodegradation being suitably described by first order reactions, with rate constants being: 4.19 h−1 (I), 4.21 h−1 (H) and 3.79 h−1 (G), respectively, with correlation coefficients ranging between 0.82 and 0.89. Chemical oxygen demand (COD) removal rates were 38% (I), 42% (H) and 48% (G), over a period of 168 h with COD reduction being highest at near neutral pH.

scholarly journals Municipal Wastewater Reclamation and Water Reuse for Irrigation by Membrane Processes

2019 ◽  
Vol 33 (3) ◽  
pp. 417-425 ◽  
Author(s):  
Davor Dolar ◽  
Marko Racar ◽  
Krešimir Košutić
Keyword(s):  
Reverse Osmosis ◽  
Water Reuse ◽  
Municipal Wastewater ◽  
Produced Water ◽  
Oxygen Demand ◽  
Agricultural Irrigation ◽  
Moderate Degree ◽  
Wastewater Reclamation ◽  
Membrane Conductivity ◽  
Severe Degree

Municipal wastewater was treated by membrane bioreactor (MBR), and the obtained<br /> MBR effluent was then treated by reverse osmosis (RO), and nanofiltration (NF). The MBR effluent was additionally treated by reverse osmosis (XLE) and nanofiltration (NF90 and NF270) membranes. RO and NF permeate output streams were assessed for their utilization in agricultural irrigation. The MBR used a hollow fiber ZeeWeed 1 ultrafiltration<br /> membrane. Conductivity, turbidity, total suspended solids, chemical oxygen demand, and dissolved organic carbon were rejected by MBR with average values of 10 %, 100 %, 99.8 %, 96 %, and 88 %, respectively. Further treatment with RO/NF membranes showed additional reduction in all measured parameters. According to results, MBR effluent belongs to the ‘slight to moderate’ degree of restriction on use due to conductivity, chloride, and sodium concentrations. RO/NF permeate, based on all parameters, belongs<br /> to the ‘none’ degree of restriction on use, except on sodium adsorption ratio (SAR), where it belongs to the ‘severe’ degree of restriction on use. Based on conductivity and SAR parameters, assessment of produced water quality obtained by blending of two effluents<br /> (50 % of MBR and 50 % of NF270 permeate) resulted in an output stream appropriate for irrigation, proving that the blending of output streams in this ratio is a good strategy for agricultural irrigation.

Limiting the emissions of micro-pollutants: what efficiency can we expect from wastewater treatment plants?

2011 ◽  
Vol 63 (1) ◽  
pp. 57-65 ◽  
Author(s):  
J. M. Choubert ◽  
S. Martin Ruel ◽  
M. Esperanza ◽  
H. Budzinski ◽  
C. Miège ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Reverse Osmosis ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biological Processes ◽  
Municipal Wastewater Treatment ◽  
Different Types ◽  
Removal Efficiencies ◽  
Micro Pollutants

The next challenge of wastewater treatment is to reliably remove micro-pollutants at the microgram per litre range in order to meet the environmental quality standards set by new regulations like the Water Framework Directive. The present work assessed the efficiency of different types of primary, secondary and tertiary processes for the removal of more than 100 priority substances and other relevant emerging pollutants through on-site mass balances over 19 municipal wastewater treatment lines. Secondary biological processes proved to be in average 30% more efficient than primary settling processes. The activated sludge (AS) process led to a significant reduction of pollution loads (more than 50% removal for 70% of the substances detected). Biofilm processes led to equivalent removal efficiencies compared to AS, except for some pharmaceuticals. The membrane bioreactor (MBR) process allowed to upgrade removal efficiencies of some substances only partially degraded during conventional AS processes. Preliminary tertiary processes like tertiary settling and sand filtration could achieve significant removal for adsorbable substances. Advanced tertiary processes, like ozonation, activated carbon and reverse osmosis were all very efficient (close to 100%) to complete the removal of polar pesticides and pharmaceuticals; less polar substances being better retained by reverse osmosis.

Using a membrane bioreactor/reverse osmosis system for indirect potable reuse

2001 ◽  
Vol 1 (5-6) ◽  
pp. 303-313 ◽  
Author(s):  
J. Lozier ◽  
A. Fernandez
Keyword(s):  
Drinking Water ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Secondary Effluent ◽  
Potable Reuse ◽  
High Calcium ◽  
Indirect Potable Reuse ◽  
The City

The City of McAllen, Texas, with the assistance of CH2M HILL, has pilot tested an integrated membrane bioreactor (MBR)/reverse osmosis (RO) treatment train to reclaim municipal wastewater to a quality suitable for use as a new drinking water supply in the process called indirect potable reuse. Previous testing by the City (Phase 1) demonstrated the applicability and cost of microfiltration (Memcor and ZeeWeed systems) to enhance the quality of secondary effluent for subsequent treatment by RO and the feasibility of a membrane bioreactor system (ZenoGem) to produce RO feedwater directly from minimally processed sewage. Phase 2 testing, reported on in this paper, is designed to demonstrate reliable operation of MBR/RO treatment for processing screened, degritted sewage and that the effluent from such a train can meet all federal primary and State secondary drinking water regulations and comply with anticipated State requirements for indirect potable reuse. Results show the ZenoGem process to be reliable, require minimal operator attention and maintenance, produce an effluent that can be processed by RO with little fouling and that easily exceeds the City's current effluent discharge requirements relative to BOD, TSS and ammonia. The ZenoGem permeate quality exceeds RO feedwater criteria for turbidity and silt density index and RO system performance confirms minimal membrane fouling by particles. However, the high calcium hardness and phosphate levels in the City's wastewater (and ZenoGem permeate) caused mineral precipitation within the RO system when operated at higher recoveries. Precipitation can be controlled, however, by increased acidification of the RO feedwater.

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

2016 ◽  
Vol 74 (3) ◽  
pp. 756-765 ◽  
Author(s):  
Achisa C. Mecha ◽  
Maurice S. Onyango ◽  
Aoyi Ochieng ◽  
Maggy N. B. Momba
Keyword(s):  
South African ◽  
Process Parameters ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Contaminant Removal ◽  
Influence Of Process Parameters ◽  
Initial Ph ◽  
Complex Organic ◽  
Micro Pollutants

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.

scholarly journals Feasibility of on-site grey-water reuse for toilet flushing in China

2016 ◽  
Vol 8 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Jie Zhu ◽  
Martin Wagner ◽  
Peter Cornel ◽  
Hongbin Chen ◽  
Xiaohu Dai
Keyword(s):  
Water Reuse ◽  
Municipal Wastewater ◽  
Reclaimed Water ◽  
Oxygen Demand ◽  
Biological Processes ◽  
High Concentration ◽  
Domestic Water ◽  
Grey Water ◽  
Toilet Flushing ◽  
Grey Water Reuse

Abstract Although the total reuse rate of municipal wastewater was 8.8% in China in 2012, water crisis is forcing China to increasingly develop water reuse. Urban reuse is comparatively poor and has significant potential to be promoted in China. It is a sensitive matter whether to include kitchen wastewater in grey-water reuse in water-deficient areas when kitchen wastewater accounts for a large proportion of total domestic water consumption. Concentrations of chemical oxygen demand, BOD5 (biochemical oxygen demand), and total organic carbon in kitchen wastewater are comparatively lower in China than in other countries, but a high concentration of nitrogen from washing tableware and rice makes it difficult to meet nitrogen requirements in Chinese guidelines. Whether kitchen wastewater should be included in grey-water reuse in China needs further study. Aerobic biological processes combined with physical filtration and/or disinfection is preferred in grey-water treatment, and how to balance the investment and treatment costs with reuse criteria still needs to be researched further. The promotion of reclaimed water for toilet flushing faces resistance in China. The necessity and effectiveness of existing restrictions in water reuse guidelines for toilet flushing in China are in doubt and need further discussion.

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