Hydraulics and water resource Engineering

The basic function of project cost control is to monitor the deviations of the actual project execution from its plan, and then to take corrective actions and/or to revise the original plan. There are two types of control patterns, one is "real-time" control, and the other is "trend control". 2 the other is "trend control".

The basic function of project cost control is to monitor the deviations of the actual project execution from its plan, and then to take corrective actions and/or to revise the original plan. There are two types of control patterns, one is "real-time" control, and the other is "trend control". 2 the other is "trend control".

The practicability of direct contact membrane distillation (DCMD) process for the removal of fluoride was investigated under different feed water, operational and membrane characteristics. Commercially available hydrophobic 0.22 mm porous polytetrafluoroethylene (PTFE) and polyvinylidenefluoride (PVDF) membrane applied on fluoridated ultrapure water exhibit over 99% rejection of fluoride, yielding fluxes of up to 39.3 and 26.4 kg/m 2 h at 60°C, respectively. The dusty gas mathematical model and energy balance equations were employed to study the mass and heat transfer mechanisms. In addition to the good agreement between the theoretical and experimental comparison, the overall mass transfer analysis revealed that Knudsen–molecular–Poiseuille transition diffusion and Knudsen–Poiseuille diffusion are the dominant mass transfer mechanisms across the 0.22 mm flat sheet PVDF and PTFE membranes, respectively. The effects of different parameters, such as temperature, initial fluoride concentration, feed flow rate, and membrane properties, on the flux and removal efficiencies were also evaluated, and feed temperature was found to be the most important operating parameter since higher temperatures induce the lowest temperature polarization coefficient (TPC) and a higher thermal efficiency (TE). Moreover, a wetting rate analysis in actual industrial wastewater sample indicated that a solution with higher organic matter, an membrane distillation (MD) system with PTFE membrane , and a sample with bigger initial fluoride concentration induce bigger wetting rate. Therefore, the DCMD process can be applied on fluoride affected water sources toward producing high-quality water suitable for a potable water supply. Exploiting renewable source potentials or industrial waste (free) energy will bring better economic advantage on the application.

P-chlorophenol (P-CP) is a recalcitrant toxicant in wastewater. Recently, the use of composite materials and environmentally friendly technology in the degradation of pollutants in wastewater has attracted widespread attention. For the first time, the nano zerovalent iron nano zerovalent iron (NZVI)-loaded muscovite (NZVI@ muscovite), a novel composite material, was synthesized by liquid-phase reduction. The different physicochemical properties of NZVI@muscovite indicated that the muscovite could support NZVI of 40-50 nm sizes. The NZVI@muscovite had a low agglomeration degree, good dispersibility, and improved catalytic activity. In addition, the optimization experiments of P-CP degradation demonstrated that NZVI@muscovite actively degraded P-CP at a pollutant:catalyst ratio of 714 mg:1 g. This ratio was higher than that of the other composite materials under optimal operating conditions. Adsorption and degradation by Fenton-like reaction were the main mechanisms underlying P-CP degradation. This study extended the use of NZVI@muscovite as an efficient composite material for the degradation of P-CP in an aqueous environment.

Bisphenol A (BPA) is a toxic environmental pollutant commonly found in wastewater. Using non-toxic materials and eco-friendly technology to remove this pollutant from wastewater presents multiple advantages. Treatment of wastewater with clay minerals has received growing interest because of the environment friendliness of these materials. Bentonite is a 2:1 layered phyllosilicate clay mineral that can support nano-metal catalysts. It can prevent the agglomeration of nano-metal catalysts and improve their activity. In this article, a green catalytic nano zero-valent iron/bentonite composite material (NZVI@bentonite) was synthesized via liquid-phase reduction. The average size of NZVI was approximately 40-50 nm. Good dispersion and low aggregation were observed when NZVI was loaded on the surface or embedded into the nanosheets of bentonite. Degradation of BPA, a harmful contaminant widely found in wastewater at relatively high levels, by NZVI@bentonite was then investigated and compared with that by pristine NZVI through batch Fenton-like reaction experiments. Compared with pristine NZVI and bentonite alone, the NZVI@bentonite showed a higher BPA degradation ratio and offered highly effective BPA degradation up to 450 mg/g in wastewater under optimum operating conditions. Adsorption coupled with the Fenton-like reaction was responsible for BPA degradation by NZVI@bentonite. This work extends the application of NZVI@bentonite as an effective green catalyst for BPA degradation in aqueous environments.

Clay minerals, as abundant natural resources, are among the most suitable supporting materials for nano metal. In this manuscript, new Fe 3 O 4 nanoparticle/rectorite (Fe 3 O 4 /rectorite) catalysts are developed via in-situ precipitation oxidation reaction. Various physicochemical characterizations of Fe 3 O 4 /rectorite show that Fe 3 O 4 nanoparticles (nano-Fe 3 O 4) with an average particle diameter of approximately 10-20 nm are effectively loaded on the surface of acid leached rectorite (Al-rectorite) and have low coaggregation and improved dispersion. Moreover, the catalytic activity of Fe 3 O 4 /rectorite on degradation of P-chlorophenol by heterogeneous Fenton method is studied. Results of degradation experiments show that Fe 3 O 4 /rectorite has higher degradation efficiency of P-chlorophenol than bare nano-Fe 3 O 4. Regeneration studies also show that Fe 3 O 4 /rectorite maintains 100% of its maximum P-chlorophenol degradation capacity after seven consecutive cycles. Fe 3 O 4 /rectorite can be easily separated by magnetic separation, and thus has good stability and reusability. The degradation mechanism of Fe 3 O 4 /rectorite is adsorption coupled with a Fenton-like reaction, which accounts for P-chlorophenol degradation of up to 625 mg/g. This work demonstrates a new composite material for the effective remediation of refractory organic compounds from wastewater. Recently, Fenton technology, as an advanced oxidation process, has been widely used to treat a variety of organic pollutants from wastewater, especially non-biodegradable and persistent pollutants (Kurian and Nair, 2015; Huang et al., 2017). The Fenton reaction involves the reaction of hydrogen peroxide (H 2 O 2) with a metal catalyst to form a hydroxyl radical (%OH) that non-selectively attacks the organic pollutants for mineralization (Li et al., 2016). Traditional homogeneous Fenton catalysts had many shortcomings, such as the production of iron sludge and narrow pH requirement (Ezzatahmadi et al., 2017). To

A zero-valent iron/rectorite nanocomposite (NZVI/rectorite) was developed as a heterogeneous H 2 O 2 catalyst for P-chlorophenol degradation. The physicochemical properties of NZVI/ rectorite were characterized by various techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analysis. Results showed that NZVI sphere nanoparticles were successfully loaded on the rectorite surface with less aggregation and good dispersion. Moreover, compared with acid-leached rectorite (30.91 m 2 /g), the NZVI/rectorite appeared to have larger surface area (50.75 m 2 /g). In addition, the effects of pH, reaction time, initial P-chlorophenol concentration, catalyst amount, and H 2 O 2 dosage on the P-chlorophenol degradation were systematically investigated. Results showed that NZVI/rectorite presents better properties for the degradation and mineralization of P-chlorophenol compared with pristine NZVI due to the large surface area, low aggregation, and

Several defluoridation techniques for reducing high initial fluoride concentration (IFC) in wastewater have been tested, but only a few of them have achieved the permissible standards. This study examined the hybrid crystallization-reverse osmosis technique (HRO) in light of flux, fluoride removal efficiency, fouling tendency, mineral recovery, complying zero liquid discharge (ZLD), and effluent discharge standard (EDS). Simulated wastewater with an IFC of 6,600 mg/L was utilized and the final HRO performance was compared with those of the low-pressure (30 bar) standalone reverse osmosis (SRO), nanofiltration (SNF), and membrane distillation (SMD) processes. Accordingly, the study on SRO and SNF revealed that pressure, feed pH, membrane type, and IFC were the major factors affecting performance, and SRO was unable to sufficiently defluoridate wastewater with IFC > 614 mg/L, needing pretreatment. Subsequently, the HRO process was selected and it was seen that the optimum calcium dose

The practicability of direct contact membrane distillation (DCMD) process for the removal of fluoride was investigated under different feed water, operational and membrane characteristics. Commercially available hydrophobic 0.22 mm porous polytetrafluoroethylene (PTFE) and polyvinylidenefluoride (PVDF) membrane applied on fluoridated ultrapure water exhibit over 99% rejection of fluoride, yielding fluxes of up to 39.3 and 26.4 kg/m 2 h at 60°C, respectively. The dusty gas mathematical model and energy balance equations were employed to study the mass and heat transfer mechanisms. In addition to the good agreement between the theoretical and experimental comparison, the overall mass transfer analysis revealed that Knudsen-molecular-Poiseuille transition diffusion and Knudsen-Poiseuille diffusion are the dominant mass transfer mechanisms across the 0.22 mm flat sheet PVDF and PTFE membranes, respectively. The effects of different parameters, such as temperature, initial fluoride concentration, feed flow rate, and membrane properties, on the flux and removal efficiencies were also evaluated, and feed temperature was found to be the most important operating parameter since higher temperatures induce the lowest temperature polarization coefficient (TPC) and a higher thermal efficiency (TE). Moreover, a wetting rate analysis in actual industrial wastewater sample indicated that a solution with higher organic matter, an membrane distillation (MD) system with PTFE membrane, and a sample with bigger initial fluoride concentration induce bigger wetting rate. Therefore, the DCMD process can be applied on fluoride affected water sources toward producing high-quality water suitable for a potable water supply. Exploiting renewable source potentials or industrial waste (free) energy will bring better economic advantage on the application.

Substantial amounts of trace hazardous elements have been detected in industrial wastewater (e.g fluoride > 900 mg/L). Feed water characteristics, operational parameters, and membrane properties are major factors affecting flux and rejection of the MD process. Membrane parameters such as membrane material type and pore size have been investigated. Fluoride ion rejection was selected to setup amethodology to remove trace elements from wastewater by adjusting the membrane parameters in DCMD. Study of the fouling thickness of the MD membrane using pH and feed water composition revealed that a PVDF membrane with a smooth surface holds a thicker fouling layer, which enhances fluoride rejection while reducing the permeate flux. On the other hand, PTFE and PP membranes showed higher mass transfer and higher wetting performance, respectively. Therefore,a PVDF membrane with low organic feed water at higher alkaline pH can be utilized to obtain high-quality permeate, while PTFE can provide the highest flux with acceptable permeate water quality. Therefore, this methodology can be applied toidentify the optimum membrane to fit the required

The production of the existing nitrogen fertilizer is costly and less environmental-friendly. Various green technologies are currently emerging toward providing alternative options. In this study, a liquid/liquid hydrophobic hollow-fiber membrane contactor was employed at ambient temperature and natural urine pH ~ 9.7 to recover ammonium fertilizers from human urine. Results showed that permeate side chemistry was one of the major factors affecting the ammonia mass transfer. The study on the ammonia capturing performance of diluted sulfuric acid, phosphoric acid, nitric acid, and DI water confirmed that acid type, acid concentration, and permeate side operating pH were the most important parameters affecting the ammonia capturing tendency. Sulfuric acid was slightly better in capturing more ammonia than other acid types. The study also identified increasing acid concentration didn't necessarily increase ammonia mining tendency because there was always one optimum concentration value at which maximum ammonia extraction was possible. The best permeate side operating pH to extract ammonia for fertilizer purposes was selected based on the dissociation equilibrium of different types of acids. Accordingly, the analysis showed that the membrane process has to be operated at pH > 3 for sulfuric acid, between 3.5 to 11.5 for phosphoric acid, and above 0.5 for nitric acid so as to produce their respective high-quality liquid ammonium sulfate, ammonium monophosphate/diphosphate, and ammonium nitrate fertilizer. Therefore, permeate side acid concentration, pH, and acid type has to always be critically optimized before starting the ammonia mining experiment.

In this study, autoclaved aerated concrete particles (AACPs) from construction waste were used to simultaneously remove phosphorus and nitrogen in biological aerated filters (BAFs). The effects of air/water (A/W) ratio on the removal performance of phosphorus (PO4 3−), total organic carbon, total nitrogen (TN), and ammonia nitrogen were investigated. Results showed that AACP BAF was more efficient than commercially available ceramsite (CAC) BAF. For example, the removal rates of TN with AACP and CAC were 45.96% and 15.64%, respectively, and those of PO4 3− with AACP and CAC were 72.45% and 33.97%, respectively, at the A/W ratio of 3:1. Different characterization methods were utilized to evaluate the surface shape, elemental compostion, and internal and surface structure of AACP. The interconnectivity and uniformity of pores and the rough surface of AACP were found to be suitable for the growth of microbial biofilm. In addition, the growth of internal pores in AACP promoted the removal of phosphorus and nitrogen. The surface of used AACP contained a small amount of irregular crystals and was covered with a layer of aggregates, which were characterized as hydroxyapatite [HAP, Ca5(OH)(PO4)3]. The formation of HAP as a final byproduct confirmed the successful removal of phosphorus. Therefore, construction wastes, such as AACPs, could be recycled and utilized as a promising biofilter media for excellent wastewater treatment. Keywords: autoclaved aerated concrete; hydroxyapatite; simultaneous removal of nitrogen and phosphorus; construction waste Highlights by rubber casting experiment to determine the environmental microorganisms in ACCP. 4. AACP biological aerated filter (BAF) had relatively higher removal rate than commercially available ceramsite BAF for total organic carbon, total nitrogen, phosphorus (PO4 3−), and ammonia nitrogen at the air/water ratio of 3:1 and the hydraulic retention time of 7 h.