Industrial Water Treatment Research Articles

Knowledge Reuse in a Small Company in the Water Treatment Industry: A Case Study

AbstractThis paper presents a case study that explores how a small company in the water treatment industry can facilitate knowledge reuse. Small companies often find themselves focusing resources on operational activities and fire‐fighting, preventing them from properly utilizing previously acquired knowledge in new similar projects.We conducted in‐depth interviews with company employees to establish a set of requirements for the new knowledge system. We then gathered theory through a literature review and developed the system iteratively with frequent feedback from employees at the company. The paper includes a case study on an ongoing wastewater treatment plant project in the company.The new knowledge management system is built up of interconnected A3s that provide the user with both a system overview and detailed information. We validated the results through a survey. The survey displayed that employees were positive towards implementing and using the new knowledge management system. We observed that employees were curious during the development process and willingly contributed when required. This paper also presents different barriers and benefits related to knowledge management initiatives in a small company.

A novel modification method for polystyrene microspheres with dithizone and the adsorption properties for Pb2+

Dithizone is known to be very effective for heavy metal ions retention and widely used as developer in detection methods. To explore a novel surface modified polymer microspheres, this paper prepared a novel modified polystyrene (PS-g-D) microspheres by grafting dithizone as the complexing agent and developer on the surface of PS microspheres. The structure of PS-g-D was analyzed by FT-IR, and the formation of dithizone grafted PS microspheres was proved. The thermal stability and surface morphology of PS and modified PS were studied by TGA and SEM. PS-g-D had a uniform diameter of about 1 μm and exhibited a good thermal stability. The Pb2+ removal increased and reached up to 99% with the decrease of initial Pb2+ concentrations. The study of the isotherms model showed that the adsorption between PS-g-D and Pb2+ is consistent with the Langmuir and Temkin adsorption isotherm models. The adsorption kinetics of PS-g-D is described well by the pseudo-second-order model. It can be seen that the modified PS microspheres exhibit a good adsorption property, and has real potential as a novel adsorbent for water treatment industry due to the introduction of dithizone as complexing agent and developer.

Water use, reuse and treatment in the food industry: A theorical study

This paper aims to analyze the scientific literature produced on water use, reuse, and treatment, in the food industry during the period between 2008 and 2018. The study considered articles indexed in the Scopus and Web of Science databases, as well as Brazilian theses and dissertations. The research used content analysis to explore the corpus, which was formed by the publications’ abstracts, and the software Iramuteq was used to support the analysis. The content was separated into two lexical blocks: a) “water management,” explained by the classes “water consumption indicators,” “rational use of water,” and “environmental management;” and (b) “wastewater management,” explained by the classes “fluent management” and “measurement and monitoring.” The study pointed to four emergent research opportunities on the theme: “water conservation;” “water reuse;” “new productive standards,” and “empirical studies.” The results show a high interest of Chinese, Indian, and European researchers in water management in all cycles of use, and scarce studies in highly industrialized countries with a strong projection of water stress, such as the USA, Japan, and Russia. Also, it is possible to observe that there is a growing interest in this subject due to the projection of water stress in the near future.

Catalytic degradation of malachite green using a crosslinked colloidal polymeric system loaded with silver nanoparticles

ABSTRACT Aim of this work is to investigate the catalytic efficiency of silver nanoparticles loaded poly(N-isopropylacrylamide-co-acrylic acid)[Ag-P(NAA)] microgel system towards degradation of an organic dye (malachite green (MG)) in aqueous medium. Ag-P(NAA) system was synthesised by free-radical precipitation polymerisation followed by in-situ reduction of silver nitrate in the presence of reducing agent. Fourier transform infrared, UV-Visible Spectroscopy and transmission electron microscopy were employed for characterisation of synthesised catalytic system. Measurement of surface Plasmonic property of the silver nanoparticles was used to study the stability of the hybrid system as a function of time of storage and pH of the medium. Catalytic potential of Ag-P(NAA) towards reductive degradation of MG in aqueous medium was investigated. The experiments were performed at various concentrations of reducing agent, dye and catalyst for the evaluation of a kinetic parameter called apparent rate constant (kapp ) using pseudo first-order kinetic model. The results revealed that hybrid microgels can degrade dye completely in few minutes. Values of kapp under different reaction conditions suggested that the catalytic process takes place through Langmuir–Hinshelwood mechanism. Ag-P(NAA) system is highly useful for the treatment of industrial waste water containing organic dyes.

Flow field in fouling spiral wound reverse osmosis membrane modules using MRI velocimetry

Magnetic Resonance Imaging (MRI) velocimetry was applied to study non-invasively the water flow field inside a spiral-wound desalination membrane module (diameter: 2.5 in.; length: 18.5 in.), located in a pressure vessel, at typical practice operational conditions as a function of alginate fouling, simulating extracellular polymeric substances (EPS). Cross-sectional velocity images were acquired at an in-plane spatial resolution of 0.137 mm at multiple locations along the length of the reverse osmosis module and were acquired as a function of alginate concentration. At a total system alginate concentration of 3.25 mg/l, significant changes in the cross-sectional velocity map were observed near the module inlet due to alginate fouling, with limited changes observed in the middle and outlet regions of the module. When the total system alginate concentration was increased to 75 mg/l, it caused the module brine seal to fail resulting in significant local water flow by-passing the membrane module. This was clearly discernible in this opaque membrane system using MRI and resulting in dramatic changes in fluid velocity distribution through the membrane module. These observations of significant flow field heterogeneity as fouling develops are consistent with ‘irreversible’ fouling effects noted frequently in practice by the water treatment industry.

Highly reusable Cu2O/PP fibrous membranes for oil/water separation

ABSTRACT In this work, we reported a cuprous oxide/polypropylene (Cu2O/PP) fibrous membrane with superhydrophobic (WCA = 151.8°±2.1°) and superlipophilic (OCA = 0°) for highly efficient oil/water separation through melt-electrospinning and magnetron sputtering, respectively. The surface morphology, microstructure, and wettability of the modified membrane were characterized by atomic force microscopy, scanning electron microscopy and contact angle goniometer, respectively. It was demonstrated that the Cu2O/PP fibrous membranes showed superhydrophobic and superlipophilic, attributing to its higher roughness and lower surface energy after the deposition of Cu2O nanoparticles. For separation of oil/water emulsion, the Cu2O/PP fibrous membranes exhibited high separation efficiency (above 92% for various oil/water emulsion; 94.14% for n-hexane/water mixture), good stability and remarkable recyclability (92.52% for n-hexane/water mixture after 30 cycles), attributing to an outstanding adhesion of Cu2O nanoparticles to fibrous membrane. This work could provide a simple and efficient method to fabricate highly efficient fibrous membranes in industrial oil-contaminated water treatment and marine spilt-oil cleanup.

Ni0.5Zn0.5Fe2O4/ polypyrrole nanocomposite: A novel magnetic photocatalyst for degradation of organic dyes

Ni0.5Zn0.5Fe2O4(NZ)/polypyrrole(PPy) nanocomposites, were prepared via in-situ oxidative self-polymerization method in presence of different weight percentage of NZ, synthesized via sol-gel auto combustion method. Structural, compositional, spectral and optical properties of the samples were thoroughly investigated. Samples were also characterized by SQUID magnetometer to determine room temperature saturation magnetization (Ms) of the samples. Among all of the prepared samples, 50 wt% of NZ/PPy nano hybrid (NZ50/PPy) showed best photo catalytic degradation of Methylene blue (MB) and Rhodamine B (RhB) dyes under visible light illumination even after five cycles of repeated use. To compare the efficiency of the organic-inorganic photo catalysts for both of the dyes, first order rate constants of the photo degradation process were calculated. Scavenger test was also carried out to detect the active species. Facilitation of charge separation due to formation of organic-inorganic nano hybrid as well as enhanced electron-hole pair generation may be attributed to the excellent photo degradation of dyes. Moreover, the sample, NZ50/PPy showed reasonable amount of Ms, which makes it suitable as a potential magnetically separable photo catalyst useful in industrial waste water treatment.

Membrane Distillation for Strategic Water Treatment Applications: Opportunities, Challenges, and Current Status

Membrane distillation (MD) has been known as a promising water treatment process for many years. However, despite its advantages, MD has never been able to compete with other processes for industrial water treatment and supply. Instead, it has been orientated towards several unique strategic water treatment applications. This review aims to uncover the opportunities and technical challenges pertinent to the MD process and the current status of its strategic water treatment applications most notably including decentralised small-scale desalination for fresh water provision in remote areas, hybridisation with forward osmosis (FO) for treatment of challenging polluted waters, regeneration of liquid desiccant solutions for air conditioning, and treatment of acid effluents for beneficial reuse. Pilot and small-scale MD systems have been demonstrated for decentralised desalination using various renewable energy sources to supply fresh water in remote, rural areas and on ships where other desalination processes are inefficient or unfeasible. For this strategic desalination application, MD is technically viable, but more works on configuration modification and process optimisation are required to reduce the process energy consumption and water production costs. For the three other strategic applications, the technical viability of the MD process has been proved by extensive lab-scale researches, but its economic feasibility is still questionable due to the lack of large-scale evaluation and the uncertain costs of MD systems. The orientation of MD towards strategic water treatment applications is clear. However, huge efforts are required to facilitate these applications at commercial and full scale.

Performance of Treated Sludge as a Replacement of Fine Aggregate in Construction Application

Large quantities of sludge are produced during the conventional processes of coagulation, flocculation and sedimentation in water treatment plants. The volume of sludge generated during water treatment process can be as high as 2% of the total volume of water treated. The cost of treatment and the disposal of the sludge plays a significant part of a water treatment plant. As the disposal of sludge produced from water treatment plants is highly expensive and difficult, valuable reuse options have been proposed to remove the sludge. In India, there are numerous emanating treatment plants bringing about mounting of sludge. It is very difficult and expensive to transfer the sludge from treatment plant. The more waste generated by the plants creates environmental problems of toxic threat. The treated waste sludge materials can be used as a replacement of fine aggregate to minimize the landfills is one of a cost-effective solution to this problem. There is a lack of conventional construction materials such as cement, fine aggregate and coarse aggregate due to the rapid increase in construction activities. To find replacement materials in construction many research have been conducted. The usage of treated sludge as a fine aggregate in construction material is an environmentally friendly option for the disposal sludge generated by water treatment industry.

Removal of Cadmium(II) and Lead(II) from Water by Chemically Treated Citrullus lanatus Peels as Biosorbent in Cost Effective Way

This study presents the use of Citrullus lanatus peels for the removal of Cd(II) and Pb(II) using batch mode. Their chemically modified acid and base treated forms were utilized for biosorption studies by optimizing all parameters. Results indicated that base modified Citrullus lanatus peels were more effective for removal of these metal ions. Removal efficiency for cadmium and lead was found to be 92.32-94.1 % and 91.94-92.58 %, respectively. Isothermal and thermodynamic investigations were carried out to find sorption mechanism and their suitability to use on bulk scale. Promising sorption capacity values for Cd(II) 19.310 mg/g and Pb(II) 25.775 mg/g, along with pseudo-second order mode and exothermic thermodynamic nature; all these favour their use for industrial scale water treatment.

Chromium (III) Removal from Synthetic Wastewater Using Biochar Produced from Vegetable Tanned Leather Shaving Dust

In recent years, the rapid industrialization leads to increase industrial discharges without any appropriate treatment. The present study deals with the removal of Cr (III) ions from aqueous solutions by ZnCl2 treated biochar produced from vegetable tanned leather shaving dust. Effect of various process parameters like solution pH, adsorbent dose, adsorbent type, initial Cr (III) concentration and temperature have been studied in batch system. The thermal resistivity and scanning electron microscopy (SEM) analysis were engaged to perceive the surface morphologies of chemically treated and untreated biochar adsorbent. The experimental data was fitted well to the Langmuir adsorption isotherm model and the adsorption efficiency of chromium (III) was found to be maximum (70%) at low values of pH (around 3) for 0.75 g/50 mL dose of ZnCl2 treated biochar adsorbent. The model matrix of 24 full factorial design approach has been applied at a 95% confidence level to find the impact of different variables on removal Cr(III) ions from waste water. This study revealed that three main factors: Adsorbent type (p < 0.0001; 66.39%), pH (p < 0.001; 16.01%) and adsorbent dose (p = 0.032; 12.15%) have significant impact on Cr (III) ions removal efficiency. For using ZnCl2 biochar, Cr(III) ions removal efficiency was increased 66.39% compared to using untreated biochar. Subsequently, two interaction factors: pH-time and adsorbent type-time (α = 0.05, p < 0.05) have shown statistically significant on Cr(III) ions removal efficiency. The ZnCl2 treated biochar adsorbent prepared from vegetable tanned leather shaving dust is efficient and it is proposed that it can be conveniently employed as a low cost alternative in the treatment of industrial waste water.

Model-based risk assessment for cyber physical systems security

Traditional techniques for Cyber-Physical Systems (CPS) security design either treat the cyber and physical systems independently, or do not address the specific vulnerabilities of real time embedded controllers and networks used to monitor and control physical processes. In this work, we develop and test an integrated model-based approach for CPS security risk assessment utilizing a CPS testbed with real-world industrial controllers and communication protocols. The testbed monitors and controls an exothermic Continuous Stirred Tank Reactor (CSTR) simulated in real-time. CSTR is a fundamental process unit in many industries, including Oil & Gas, Petrochemicals, Water treatment, and nuclear industry. In addition, the process is rich in terms of hazardous scenarios that could be triggered by cyber attacks due to the lack of possible mechanical protection. The paper presents an integrated approach to analyze and design the cyber security system for a given CPS where the physical threats are identified first to guide the risk assessment process. A mathematical model is derived for the physical system using a hybrid automaton to enumerate potential hazardous states of the system. The cyber system is then analyzed using network and data flow models to develop the attack scenarios that may lead to the identified hazards. Finally, the attack scenarios are performed on the testbed and observations are obtained on the possible ways to prevent and mitigate the attacks. The insights gained from the experiments result in several key findings, including the expressive power of hybrid automaton in security risk assessment, the hazard development time and its impact on cyber security design, and the tight coupling between the physical and the cyber systems for CPS that requires an integrated design approach to achieve cost-effective and secure designs.

Water Treatment with New Nanomaterials

The studies introduced in this special issue aim to provide a state-of-the-art vision for nanomaterials-based technology that could profit the water treatment industry. Given the expanding crisis of water shortages across the world, this perspective is invaluable and of paramount importance. No doubt, as the environmental challenges are going to be more complicated and to extend to as-yet unconsidered areas, we need to upgrade our facilities and knowledge to address them properly. Nanomaterials are indeed promising building blocks for such advanced technologies that enable them to purify water streams from complex pollutants in an energy, cost and time-effective manner. The focus of the (review and original research) articles collected in this issue is on various kinds of nanomaterials made of carbon, polymer, metal, and metal oxides (magnetic and photocatalyst), that are employed for adsorption and photodegradation of heavy metals and organic pollutants, respectively. Here, I briefly review the insights given in these precious studies and suggest new directions for future research in this field.

Optimization of Coil Width and Magnetic Field Switching Speed for Non-Contacted Electromagnetic Flowmeter

Electromagnetic flowmeter (EMF) is a widely used flow measurement instrument in the 20th century. It is based on the Faraday's law and developed rapidly in recent decades. It plays an important role in our daily life such as water treatment, food production and chemical industry. An improved excitation structure with E-type frame made by permeable material added in the traditional Helmholtz coil is proposed in this paper to simulate the distribution of the magnetic field. The optimal coil width is obtained which can ensure the uniformity of magnetic field with minimum physical size. A compensate method is discussed to improve the switch speed of the magnetic field so that the EMF can be used to measure fast flow.

Evaluation of chemistry and key reactor parameters for industrial water treatment applications of the UV/O3 process

In this study, the main influence factors of combined UV/O3 process in practical industrial application were explored through laboratory trials and industrial pilot tests. Dimethyl phthalate (DMP) was analyzed as the research subject through different experiments in laboratory. The degradation effect of organic compounds by O3 and UV/O3 processes in different air distribution methods was compared independently, and the mechanism of free radical generation by the two processes was analyzed. This study found that the combined UV/O3 process for organic matter mineralization is clearly better than that of independent effect of O3 process as mixed gas-liquid distribution method was superior to the bubble aeration method. The experimental conditions included inlet O3 concentration between 70 and 75 mg/L, reactor internal relative pressure at 0.3 MPa, contact reaction time of 12 min, DMP mineralization efficiency reaching 63.07%. The calculated dosing ratio of O3 in the dynamic experiment was around 0.74 mg CODCr/mg O3. The results showed that the best effect in wastewater treatment was achieved when the conditions of ultraviolet lamp irradiation intensity and the O3 dosage reached 822.88 W/m2 15 mg/L and utilized in conjunction with biochemical reactions. The resulting CODCr concentration of effluent reached 39.8 mg/L. Finally, it is determined that the main influence factors affecting the economically efficient operation of UV/O3 process were the efficient O3 distribution mode, control of the relative pressure within the reactor, proportion of ozone addition and light source configuration.

Experimental investigation of a solar-heated direct contact membrane distillation system using evacuated tube collectors

Solar-powered membrane distillation (SP-MD) is examined as a promising renewable solution in the desalination and water treatment industry. In this study, an innovative direct contact membrane distillation (DCMD) module to directly utilize solar thermal energy is proposed. While previous studies focused more on utilizing solar energy indirectly (i.e. to heat the feed water outside the MD module), the proposed system integrates hollow fiber membranes inside evacuated tube solar collectors in order to achieve a more compact system. The performance of the direct SP-MD module is measured first indoors in a bench-scale experiment, and then tested outdoors under sunlight. Results show that applying radiation directly can enhance the efficiency and permeate flux up to 17% compared to the same process when radiation is not applied under the same operating conditions. The daily operation of a stand-alone, directly heated SP-MD unit equipped with 0.035 m2 membrane area achieved a permeate flux of 2.2 to 6.5 kg·m−2·h−1 depending on solar intensity.

Ion Exchange: The Most Important Chemical Reaction on Earth after Photosynthesis

Ion exchange is the interchange of equivalent amount of ions from the solution with ions which are swarming in a boundary of charged surface in equilibrium. It is developed due to the presence of charge in the soil colloids or layer lattice clay minerals. The source of charge developed in the colloidal surface site of soil is mainly from two processes viz. isomorphous substitution and pH dependent charge. The charge can be positive or negative due to the exchange reaction in the layer lattice. The ion exchange capacity is the sum of cation exchange capacity (CEC) and anion exchange capacity (AEC). It depends on the types of soil and the amount of charge present in the layer lattice colloidal structure. With high negative charge in the lattice surface the CEC increases and with positive charge the AEC. Ions with higher charge have larger affinity to adsorbed more strongly than lower. Ion exchange capacity in soil has the ability to retained more nutrients in the form of cations or anions making available to plant for a long time which improved the fertility of soil. Leaching loss of different nutrients from the soil is reduced by holding different ions. Ion exchange processes have been widely used for heavy metal removal for waste water treatment and water purification because of its high remedial capacity, high removal efficiency and fast kinetic. Due to its applications in agriculture, environmental management, industries, waste water treatment in mining industries, laboratory, nanotechnology, geotechnical and other soil reclamation processes it is considered as the second most important reaction in the globe after photosynthesis.

Study on Influencing Factos of Wet Oxidation Technology

For refractory organic wastewater treatment, this water treatment industry is difficult, wet oxidation technology can effectively play a role. The effect of chemical reaction is closely related to the process conditions of operation (that is the influencing factors). The influencing factors of wet oxidation technology include nine aspects: reaction temperature, reaction pressure, reaction time, stirring strength, influent pH value, influent concentration, salt effect of influent, nature of influent, reaction heat of wastewater and amount of air needed. Among these factors, the reaction temperature is an important influence factor, and the relationship between the chemical reaction velocity constant and temperature follows the arenius formula.

A critical review on arsenic removal from water using biochar-based sorbents: The significance of modification and redox reactions

Biochar is considered to be the cost-effective, environmentally-friendly and sustainable sorbent that has an extraordinary potential to efficiently remove toxic elements, including arsenic (As) from water. Until now, no review has focused to understand various important and intriguing aspects on biochar use as a sorbent for As removal from water, either pristine or modified. This review discusses various factors governing As removal potential of biochars (e.g., pH, biochar dose and physico-chemical properties of biochar), sequestration mechanisms, fate of sorbed As on biochar and the redox-mediated interactions between biochar and As. The significance of biochar-derived materials for the treatment of As-contaminated drinking water/wastewater and their potential regeneration ability is also critically discussed, which has not been previously elaborated. This comprehensive review article could be greatly valuable for scientists, policymakers, water treatment industries, environmentalists and graduate students, who are involved in biochar-As research. The review covers some new overarching and key scientific opportunities for the remediation of As-contaminated water using biochar-based materials, which is a potential health risk to millions of people worldwide.

Effect of barium and strontium ions on the morphology and polymorphism of CaCO3

Industrial internal water treatment programs provide a robust solution for many water related problems such as scale inhibition, corrosion control, microbial growth etc. in heat transfer equipment. In order to design a good program it is essential to study the individual effect of each constituent in the program and how it affect the parameters for which it is added. Ethylenediaminetetraacetic acid (EDTA) is one such constituent widely used in internal treatment for scale inhibition. Calcium carbonate (CaCO3) is one of the major constituents in scale. Polymorphism and morphology of the crystallites have significant effect on the nature of scale. In this work, we report the effect of EDTA on the morphology and polymorphic composition of CaCO3 in the presence of barium and strontium ions and their effect on the scale inhibition.