Comparing geometric parameters of a hydrodynamic cavitation process treating pesticide effluent

Abstract

Paper focuses on comparison between two different orifice plate configurations (plate number 1 and plate number 2) used as cavitating device in the hydrodynamic cavitation reactor for improving pollutant removal efficiencies. Effect of four different parameters such as hydraulic characteristics (in terms of range of flow rates, orifice velocities, cavitation number at different inlet pressures); cavitation number (in range of 5.76-0.35 for plate number 1 and 1.20-0.35 for plate number 2); inlet pressure (2-8 bars) and reaction time (0 to 60 min) in terms of chemical oxygen demand (COD) removal and chlorpyrifos degradation has been studied and compared. Optimum inlet pressure of 5 bars exists for degradation of pollutants for both the plates. It is found that geometry of orifice plate plays important role in removal efficiencies of pollutant. Results obtained confirmed that orifice plate 1 with configuration of 1.5 mm 17 holes; cavitational number of 1.54 performed better with around 60% COD and 98% chlorpyrifos removal as compared to orifice plate 2 having configuration of 2 mm single hole; cavitational number of 0.53 with 40% COD and 96% chlorpyrifos in 2 h duration time.

A Transport-Phenomena Approach to Model Hydrodynamic Cavitation of Organic Pollutants

“…Pin (100 kPa) According to the literature, the most trivial reason for this is that, as the pressure increases, the flow rate in the main line increases so the liquid can go through the cavitating device several times and undergoes the AOP for a longer time. After reaching the maximum degradation rate at an optimal pressure, higher P in values may produce the onset of super cavitation (i.e., indiscriminate growth of bubbles downstream of the constriction resulting in splashing and vaporization of the flow and in the formation of cavity cloud) having a negative effect on the HC process because of coalescence and reduced activity [20,29,[34][35][36][37][38][39][40]. The modeling results in the next session will give more quantitative details.…”

“…The liquid sampling and the measurement of pollutant/oxidative species' concentration occurs in the tank. Different analytical methods have been reported in the literature for the detection of pollutants including spectrophotometry, gas-liquid chromatography, and high-performance liquid chromatography (HPLC) [36][37][38][39][40][41][42]. Some works include the identification of byproducts generated by the cavitation treatment and depict possible degradation pathways [39].…”

“…The former works dealt with the HC effectiveness in pollutant degradation the investigation of the effect of process parameters such as orifice-to-pipe ratio (β), inlet fluid pressure (P in ), and cavitation number (C v ) [32][33][34]. The most important parameter is P in , directly linked to the velocity at the orifice throat, the bubble growth and collapse intensity, as well as the pollutant concentration in the oxidative region [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. Commonly, the degradation rate increases with an increase of the inlet pressure P in reaching to the maximum value at a specific "optimal" pressure and then decreases.…”

“…Commonly, the degradation rate increases with an increase of the inlet pressure P in reaching to the maximum value at a specific "optimal" pressure and then decreases. Other parameters affecting the process efficiency are the physicochemical properties of the solutes and the solvent (surface tension of water, hydrophobic character and volatility of the solute, pH of the solutions); these may influence the collapse intensity, the initial size of the nuclei [1,2,7,8], as well as the actual location of the solute with respect to the hot spots [10][11][12][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40].…”

Inventory: The pesticides application and its risk assessment in the irrigated perimeter of Tadla-Morocco

“…It started with the emergence of the first scientific studies on the use of chemicals for crop protection and the fight against pest and disease. Some products are extracted from plants for long time ago, as the antiparasitic, that was discovered in china almost 2000 years ago (Randhavane 2019); as well as the nicotine, which is used to control aphids since the beginning of the 19th century (Abdellaoui et al 2018;Lee et al 2019). Among the mineral products, the copper acetoarseniate (Paris green) is used against mosquito larvae since the beginning of the century.…”