scholarly journals Degradation of 17 Benzodiazepines by the UV/H2O2 Treatment

2021 ◽  
Vol 9 ◽  
Author(s):  
Wen-Dan You ◽  
Pu Ye ◽  
Bin Yang ◽  
Xin Luo ◽  
Jie Fang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Phosphate Buffer ◽  
Degradation Products ◽  
Reaction Pathway ◽  
Treatment Plant ◽  
Main Reaction ◽  
Psychoactive Drugs ◽  
Solution Ph ◽  
H2o2 Treatment ◽  
Buffer Solutions

Benzodiazepines are one group of psychoactive drugs widely detected in water environments, and their persistence during conventional wastewater treatment has raised great concerns. Here we investigated the degradation of 17 benzodiazepines in water by UV/H2O2 treatment. The results showed that the UV/H2O2 treatment significantly increased the degradation of 17 benzodiazepines in phosphate buffer solutions at pH 7.0. This can be attributed to the high reactivity of hydroxyl radicals (·OH) towards benzodiazepines with second-order rate constants of 3.48 × 109 M−1 s−1–2.44 × 1010 M−1 s−1. The degradation of alprazolam, a typical benzodiazepine, during the UV/H2O2 treatment was increased with the increasing H2O2 dosage. The solution pH influenced the alprazolam degradation significantly, with the highest degradation at pH 7.0. Water matrix, such as anions (Cl−, HCO3−, NO3−) and humic acid, decreased the degradation of alprazolam by UV/H2O2 treatment. Based on the degradation products identified using quadrupole time-of-flight mass spectrometer, the degradation mechanisms of alprazolam by UV/H2O2 treatment were proposed, and hydroxylation induced by ·OH was the main reaction pathway. The degradation of 17 benzodiazepines by UV/H2O2 treatment in wastewater treatment plant effluent and river water was lower than that in phosphate buffer solutions. The results showed that the benzodiazepine psychoactive drugs in natural water can be effectively removed by the UV/H2O2 treatment.

Nutrient removal (nitrogen and phosphorous) in secondary effluent from a wastewater treatment plant by microalgae

2014 ◽  
Vol 41 (2) ◽  
pp. 118-124 ◽  
Author(s):  
Alison Chan ◽  
Hamidreza Salsali ◽  
Ed McBean
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Ammonia Removal ◽  
Secondary Effluent ◽  
Solution Ph ◽  
Removal Rates ◽  
Total Phosphorous

Microalgae as a feasible option to remove nutrients (phosphorous and nitrogen) from domestic wastewater treatment plant discharge is demonstrated. Laboratory-scale experiments are described, characterizing nutrient removal of total phosphorous and ammonia by three cultured microalgae strains: Chlorella vulgaris, Spirulina maxima, and mixed cultures of naturally growing algae found in wastewater from the Collingwood Wastewater Treatment Plant in Ontario, Canada containing Synechocystis sp. (dominant), Chlorella sp. (common), and a few cells of Scenedesmus sp. Removal of phosphates strongly positively relates to solution pH. Volatilization of ammonia due to increase in pH is not a dominant contributor to overall removal efficiency. Total phosphorous removal rates reached 95.8% and 90.4% for untreated and autoclaved secondary effluent, respectively. Ammonia removal rates reached 94.6% and 86.2% for untreated and autoclaved secondary effluent, respectively. These results demonstrate that use of microalgae represents a sustainable approach to improve removal efficiencies of nutrients in wastewater treatment.

Analysis and balance of phosphorous removal from wastewater at urban wastewater treatment plant

2020 ◽  
Vol 15 (2) ◽  
pp. 142-151
Author(s):  
Peter Lukac ◽  
Lubos Jurik
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Phosphorus Recovery ◽  
Anaerobic Sludge ◽  
Biological Phosphorus Removal ◽  
The Mean

Abstract:Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.

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