Flocculation, precipitation, sedimentation and flotation for use as pretreatment stages for brackish water and seawater in desalination plants

Ion exchange (IEX) processes are a promising alternative to remove and recover nutrients from municipal wastewater. To assess the feasibility and viability of IEX processes for full-scale application, this study aimed at providing an evaluation of performance and economics on upscaling these processes for two different configurations in a 10,000 population equivalent wastewater treatment plant (WWTP) and compared them with a traditional biological nutrient removal (BNR) plant. The IEX processes were designed based on existing pilot-scale data, and after aerobic or anaerobic carbon removal stages. The nutrients were recovered from spent regenerants in the form of (NH4)2SO4 and hydroxyapatite Ca5(PO4)3(OH), allowing regenerant reuse. The 40-year whole life cost (WLC) of IEX coupled with traditional activated sludge processes was estimated to be ~£7.4 M, and WLC of IEX coupled with anaerobic membrane process was estimated to be £6.1 M, which was, respectively, 17% and 27% less than the traditional BNR based WWTP. Furthermore, ~98 tonnes of (NH4)2SO4 and 3.4 tonnes of Ca3(PO4)2 could be recovered annually. The benefits of lower costs, reduction in greenhouse gas emissions and nutrient recovery aligned with circular economy, illustrated that IEX processes are attractive for nutrient removal and recovery from municipal wastewater.

Hybrid systems in seawater desalination-practical design aspects, status and development perspectives

The rapid industrialization and urbanization as well as rising global transportation have induced numerous challenges regarding energy security, environmental protection, waste management, and greenhouse gas emissions across the world. Addressing these current issues is crucial to guarantee the sustainable development, green environment, and circular economy. The implementation of advanced chemical technology in industrial production, worldwide transportation, and environmental treatment could contribute to efficiently solve these global challenges. This special issue of Chemical Engineering & Technology highlights the recent research trends in chemical technology towards sustainable development such as advanced material synthesis from various waste sources, biological and thermochemical processes for alternative biofuels and chemicals production. In particular, the synthesis of polysulfide from waste cooking palm oil and the production of hybrid films reinforced with cellulose nanofibers used as packaging materials are thoroughly discussed. Additionally, a comprehensive review regarding waste biomasses transformation to value-added biofuels and biochemicals via thermochemical processes, namely, liquefaction, gasification, torrefaction, and pyrolysis, is presented in this special issue. The environmental benefits associated with these approaches are also underlined. Computer-aided methods including simulation, modeling, and optimization of different chemical engineering processes for energy and environmental applications are offered as well. The contribution from authors across the world to this thematic issue is highly appreciated. The guest editors also acknowledge the valuable effort and constructive comments from reviewers for manuscript assessment. Lastly, we would like to appreciate the Editor in Chief Dr. Barbara Böck and the entire editorial office for their valuable support and guidance during the completion of this topical issue. Dr. Dai-Viet N. Vo, Institute of Applied Technology and Sustainable Development, Nguyen Tat Thanh University, Vietnam Dr. Sumaiya Zainal Abidin, Department of Chemical Engineering, College of Engineering, Universiti Malaysia Pahang, Malaysia Dr. P. Senthil Kumar, Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, India Dr. Muthusamy Govarthanan, Department of Environmental Engineering, Kyungpook National University, South Korea Dai-Viet N. Vo Sumaiya Zainal Abidin P. Senthil Kumar Muthusamy Govarthanan

Measuring sedimentation rates may provide useful information on the habitat preferences of marine organisms. To understand the effect of flow rates and meteorological conditions on sedimentation in the absence of other confounding factors, sedimentation of organic (OM) and inorganic (IOM) matters was measured at 6 sites in Lough Hyne Marine Reserve (a semienclosed marine lake) over the course of 13 months. During winter, both OM and IOM were imported to the Lough, peaking in December at Whirlpool, the site nearest to the Lough entrance, likely as a result of extreme weather conditions causing resuspension of matter outside the Lough. Highest inorganic matter (IOM) sedimentation occurred in December (47.36 gm−2d−1at Whirlpool Cliff) and was related to November wind speeds (, ). Decreasing current speed also caused a decline in IOM sedimentation. Highest OM sedimentation occurred in December at Whirlpool (5.59 gm−2d−1), but was not related to meteorological conditions. No single environmental factor strongly influenced organic matter (OM) sedimentation. One-way ANOVAs on OM and log-transformed IOM data showed that sedimentation differed significantly amongst the six sites within the Lough. Increased plankton production in the Lough during summer led to increased OM sedimentation in areas of low current speed away from the entrance of the Lough.

The properties of NOM particles removed from water in ultrafiltration, ion exchange and integrated processes

Electrochemical Direct Partial Oxidation of Methane to Methanol

An overview of the behaviour of biomass during combustion: Part I. Phase-mineral transformations of organic and inorganic matter

Accurate and reliable dating of paleosols, animal remains, and artifacts is of crucial importance in reconstructing environmental change and understanding the interrelationship between human activities and natural environments. Dating different materials in the same sample can help resolve problems such as soil carbon sources and carbon storage state. Conventional radiocarbon dating of soil (inorganic and organic matter) and accelerator mass spectrometry (AMS) dating of animal remains (fossil bones and teeth) result in different ages for materials from the same sample position in a typical loess section at Xinglong Mountain, Yuzhong County, Gansu Province in NW China. Inorganic matter is ∼3400 yr older than organic matter, 4175 ± 175 cal BP to 3808 ± 90 cal BP. A 1610-yr difference between the 14C ages of fossils (animal bones and teeth) and soil organic matter suggests that a depositional hiatus exists in the studied profile. The varying 14C ages of fossils and soil organic and inorganic matter have important implications for paleoclimate reconstructions from loess sections. It is critical to consider the meaning of the variable 14C ages from different material components from the same sample position in terms of soil organic and inorganic carbon storage, vegetation history reconstruction, archaeology, and the study of ancient civilizations.

Persistence of tidal wetlands under conditions of sea level rise depends on vertical accretion of organic and inorganic matter, which vary in their relative abundance across estuarine gradients. We examined the relative contribution of organic and inorganic matter to vertical soil accretion using lead-210 (210Pb) dating of soil cores collected in tidal wetlands spanning a tidal freshwater to brackish gradient across a Chesapeake Bay subestuary. Only 8 out of the 15 subsites had accretion rates higher than relative sea level rise for the area, with the lowest rates of accretion found in oligohaline marshes in the middle of the subestuary. The mass accumulation of organic and inorganic matter was similar and related (R2 = 0.37). However, owing to its lower density, organic matter contributed 1.5–3 times more toward vertical accretion than inorganic matter. Furthermore, water/porespace associated with organic matter accounted for 82%–94% of the total vertical accretion. These findings demonstrate the key role of organic matter in the persistence of coastal wetlands with low mineral sediment supply, particularly mid-estuary oligohaline marshes.

Each of the two major mineral components found in shale samples—organic matter (OM) and inorganic matter (iOM)—has a distinct pore system revealed by scanning electron microscope images, low-pressure nitrogen adsorption, and high-pressure mercury injection tests. Although a vast amount of research has been conducted to detect and measure pore sizes in OM and iOM separately, the connectivity of the pores in these two components remains unclear. In permeability models, pore connectivity between OM and iOM components plays an important role in studying and predicting fluid flow. We studied pore connectivity between OM and iOM by developing pore-network models to mimic the composite nature of distributed OM patches in shale. Input parameters to generate network models were porosity, pore- and throat-size distribution, and total organic content. Mercury injection and capillary-pressure curves were then simulated through generated network models using percolation theory. To study the effects of pore connectivity between OM and iOM, we changed the size and locale of OM patches in the generated network models. Simulation results showed that the locale of OM affects mercury saturation (location and numbers of invaded pores) at given applied pressures. To study the effect of pore-size overlap between OM and iOM pores, we simulated mercury injection for two groups of constructed pore networks: non-overlapping and overlapping. In non-overlapping cases, first all iOM pores were invaded with mercury; then, only OM pores at very high pressure were invaded. In overlapping cases, OM and iOM pores can be invaded simultaneously because some of the pores have similar sizes in both components. The simulated capillary-pressure curves show distinct behavior in the non-overlapping and overlapping cases. Non-overlapping capillary-pressure curves show a sudden increase when OM pores are invaded, whereas overlapping capillary-pressure curves are smoother. Results of this work increase understanding of the connectivity of pores from measured capillary-pressure curves for further implementation in permeability-predictive models.

The occurrence and treatment of antibiotics in a micro-polluted lake which serves as a drinking water source in East China was surveyed. A pilot plant with conventional and O3-BAC (biological activated carbon) processes was set up to investigate its effectiveness in dealing with the contaminants. Solid phase extraction (SPE) coupled with electro-spray ionization-tandem mass spectrometry (LC-ESI-MS-MS) was applied to detect various antibiotics simultaneously. Three groups of antibiotics, i.e. sulfonamides, fluoroquinolones and tetracyclines, were detected in the source water. The gross concentrations of them in the lake are up to 471, 23.4 and 1,039 ng/L, respectively. The conventional and O3-BAC processes could remove 78.9, 62.4 and 70.2% of them, respectively. Among the antibiotics, tetracyclines could be effectively removed by ozonation, while fluoroquinolones could be removed by the coagulation–sedimentation process. BAC could not degrade fluoroquinolones but enabled the reduction of the other two antibiotics. In addition, O3-BAC was an effective technology for the removal of bulk organic matter. The concentrations of chemical oxygen demand (CODMn), UV254 and dissolved organic carbon (DOC) in the effluent of the up-flow BAC process were 2.31 mg/L, 0.034 cm−1 and 1.76 mg/L, respectively, with the corresponding removal rates of 45.1, 67.3 and 65.1%, respectively. In all, the combined conventional and O3-BAC process was the best available technology to remove organic matter as well as antibiotics.

Electrodialysis for water desalination: A critical assessment of recent developments on process fundamentals, models and applications

This review investigates antifouling agents used in the process of membrane separation (MS), in reverse osmosis (RO), ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), membrane distillation (MD), and membrane bioreactors (MBR), and clarifies the fouling mechanism. Membrane fouling is an incomplete substance formed on the membrane surface, which will quickly reduce the permeation flux and damage the membrane. Foulant is colloidal matter: organic matter (humic acid, protein, carbohydrate, nano/microplastics), inorganic matter (clay such as potassium montmorillonite, silica salt, metal oxide, etc.), and biological matter (viruses, bacteria and microorganisms adhering to the surface of the membrane in the case of nutrients) The stability and performance of the tested nanometric membranes, as well as the mitigation of pollution assisted by electricity and the cleaning and repair of membranes, are reported. Physical, chemical, physico-chemical, and biological methods for cleaning membranes. Biologically induced biofilm dispersion effectively controls fouling. Dynamic changes in membrane foulants during long-term operation are critical to the development and implementation of fouling control methods. Membrane fouling control strategies show that improving membrane performance is not only the end goal, but new ideas and new technologies for membrane cleaning and repair need to be explored and developed in order to develop future applications.

Organic and inorganic matter in Louisiana coastal waters: Vermilion, Atchafalaya, Terrebonne, Barataria, and Mississippi regions

Electromembrane Processes: Basic Aspects and Applications