Water Treatment Operations Research Articles

Brief Communication: Analysis of the Fatalities and Socio-Economic Impacts Caused by Hurricane Florence

Florence made landfall on the southeastern coast of North Carolina (NC) generating torrential rainfall and severe flooding that led to 53 fatalities in three states (NC, SC, and VA) and $16–$40 billion in damage. Seventy-seven percent (77%) of the fatalities occurred in the rural flood plains of NC with Duplin county reporting a high of eight deaths. Approximately 50% of the total number of hurricane-related fatalities across the three states were vehicle-related. The predominant demographic at risk were males over the age of 50 years. The type of property damage was in line with other major hurricanes and predominantly affected residential structures (93% of the total number of damaged buildings). Florence is among the top 10 costliest hurricanes in U.S. history with approximately 50% of the damage projected as uninsured losses due to residential flooding. The cumulative 5-day rainfall resulted in major flooding along the Cape Fear, Lumberton, and Neuse rivers where many industrial waste sites (hog manure lagoons and coal ash pits) are located. Several of these waste sites located in the flood plain were breached and have likely cross-contaminated the waterways and water treatment operations. The observed extent of the flooding, environmental contamination, and impact to public health caused by Florence will add to the long-term disaster related mortality and morbidity rates and suggests an expansion of the 100-yr flood hazard zone to communicate the expanded risk to the public.

Removal of Hazardous Indigo Carmine Dye from Waste Water Using Treated Red Mud

Abstract The present work aims at developing an effective technologies in treating such effluents from Indigo Carmine (IC) dye industry through the use of the industrial wastes such as red mud. Red mud, hazardous aluminium industry waste in its activated form using hydrazine sulphate is employed in the removal of the IC dye by batch adsorption operation. The adsorbent is characterized by FESEM, EDX and FTIR methods and found to be potent enough in up-taking the IC dye. However, sensitivity analysis is carried out in identifying the optimum operating conditions at which the ultimate the adsorption capacity of the red mud is found to be 62.6 mg/g with 94.0% overall removal of the IC dye. The adsorption mechanism is analysed by various adsorption isotherm models and the kinetics of the adsorption process is examined. Further, the thermodynamic investigation projected the operation to be spontaneous and endothermic. Regeneration studies indicated the recyclability of the developed adsorbent with % removals not falling below 85.0% even after five regenerations cycles. However, the adsorbent is tested for its reliability by applying it to the water effluents gathered from commercial IC dye polluting industry and found effective enough in its use as a potential adsorbent in water treatment operations.

The Technology Horizon for Photocatalytic Water Treatment: Sunrise or Sunset?

Advanced oxidation processes via semiconductor photocatalysis for water treatment have been the subject of extensive research over the past three decades, producing many scientific reports focused on elucidating mechanisms and enhancing kinetics for the treatment of contaminants in water. Many of these reports imply that the ultimate goal of the research is to apply photocatalysis in municipal water treatment operations. However, this ignores immense technology transfer problems, perpetuating a widening gap between academic advocation and industrial application. In this Feature, we undertake a critical examination of the trajectory of photocatalytic water treatment research, assessing the viability of proposed applications and identifying those with the most promising future. Several strategies are proposed for scientists and engineers who aim to support research efforts to bring industrially relevant photocatalytic water treatment processes to fruition. Although the reassessed potential may not live up to initial academic hype, an unfavorable assessment in some areas does not preclude the transfer of photocatalysis for water treatment to other niche applications as the technology retains substantive and unique benefits.

Comparative analysis on floc growth behaviors during ballasted flocculation by using aluminum sulphate (AS) and polyaluminum chloride (PACl) as coagulants

For enhancing the understanding of ballasted flocculation (BF) mechanisms, a series of BF tests were performed to explore the coagulant dosage and mixing intensity effects on floc growth behaviors and corresponding particle settling by using coagulants of aluminum sulphate (AS) or polyaluminum chloride (PACl). As expected, different coagulant dosages brought about distinct surface charge characteristics of micro-floc aggregates after either Al-based coagulant addition, thereby affecting the development of ballasted floc size. More specifically, the higher the coagulant dosage was, the more the cationic hydrolyzed-Al species were produced, leading to a requirement of more binding sites on the injected polymer for bridging between micro-flocs and ballasting agent (BA) particles, and accordingly, the degree to which BA particles had been incorporated into the aggregate matrix seemed to largely account for ballasted floc formation. Besides, floc aggregates formed after breakage appeared larger than those after maturation, especially at higher coagulant dosages, possibly caused by a stretched conformation of long polymer chains providing more binding sites available within a higher-shear suspension. In an operational sense, poor incorporation should be maximally eliminated, since this undesirable behavior could produce a greater number of resultant flocs with fewer or even no BA particles, thus worsening the settling performance. This research would be helpful for thoroughly understanding ballasted floc formation mechanisms in either water or wastewater treatment operations.

Ferric sludge derived from the process of water purification as an efficient catalyst and/or support for the removal of volatile organic compounds

Ferric chloride solutions are used as coagulants or flocculants in water treatment operations for human consumption. This treatment produces large amounts of clay-type solids formed mainly of montmorillonite with iron oxides and humic substances. This ferric sludge can be used as an efficient catalyst for the removal of volatile organic compounds (VOCs) by total oxidation. This waste isolated in the purification process has been activated by calcinations in air, characterized by several physicochemical techniques and employed as a catalyst for the removal by total oxidation of representative VOCs: toluene, propane and mixtures of toluene/propane with or without water. This ferric sludge has shown a catalytic activity one order of magnitude higher than that of a commercial iron oxide. This high activity has been related to the composition of the sludge (as it contains active metal oxides such as oxides of iron and manganese) and to the porous structure (leading to a reasonably high surface area). Moreover, it can be also used as a support for platinum, showing comparable (or even higher) catalytic activity than a similar platinum catalyst supported on conventional γ-alumina. This work presents a double environmental perspective since the material employed as a catalyst is a waste sludge and the catalytic reaction studied deals about the elimination of pollutants.

Lonza to sell water treatment business

Lonza has signed a definitive agreement to sell its water treatment business to the private equity firm Platinum Equity for $630 million. The pharmaceutical and specialty ingredient maker says the divestment will allow it to focus on its core health care business. Lonza acquired the pool and industrial water treatment operation as part of its acquisition of Arch Chemicals in 2011.

Selective removal of dissolved organic matter affects the production and speciation of disinfection byproducts

The heterogeneity of dissolved organic matter (DOM) in natural and human impacted waters and the variety of drinking water treatment processes employed has made a mechanistic understanding of disinfection byproduct (DBP) formation challenging. In this study, we examined the formation of the regulated DBPs (Trichloromethanes, THM, and Haloacetic acids, HAA) during full-scale water treatment operations both with prechlorination treatment (normal operations for the drinking water plant) and without (altered operations); followed by coagulation, flocculation, filtration, and chlorination. The source water DOM concentration ranged 6.4 to 7.3 mg-C/L. DOM composition was moderately humic and degraded with a mix of microbial- and terrestrial-like characteristics. Removal of raw water prechlorination caused an average reduction in total THM and HAA concentrations of 52.7% and 40.0%, respectively, with the greater reduction noted for chlorinated-DBPs rather than brominated-DBPs. Prechlorination treatment resulted in a higher relative production of Cl3CH and BrCl2CH associated with aromatic, humic, and terrestrial-like DOM. Without prechlorination, the DBP pool had higher proportions of brominated-DBPs (Br3CH, Br2ClCH, Br2CHCOOH, BrClCHCOOH, and BrCH2COOH) associated with microbial-like, processed humic-like, and protein-like DOM. These observed patterns could not be explained by chloride demand and DOM concentration, indicating that DOM composition played an important role in DBP formation.

Formation of odorous and hazardous by-products from the chlorination of amino acids

The formation of odorous aldehydes and N-chloraldimines, and also nitriles, which are potentially hazardous to human health, was investigated in studies of the chlorination of amino acids (AAs) in both operational drinking water treatment plants and laboratory-based experiments. In the drinking water treatment plants studied, the concentration of total free AAs did not significantly change after treatment, even though good removal of DOC was observed. However, free AAs still contributed less than 3% of total nitrogen in the treated drinking waters, and no aldehydes, N-chloraldimines or nitriles of interest were detected in the treated waters, presumably due to the low concentrations of the precursor AAs in these water samples. Laboratory formation potential experiments showed that carboxylic acids can form from the degradation of aldehydes and nitriles. Volatile carboxylic acids could result in odour issues and some carboxylic acids may be of potential health concern. Therefore, carboxylic acids should also be considered as potential by-products of interest in distribution systems with long contact times of ≥ 7days. A higher proportion of nitrile formation, and promotion of carboxylic acid formation, was observed when the chlorine to AA ratio was greater than 4 compared to when this ratio was 2.8, indicating that the Cl:AA ratio is an important factor in DBP formation pathways. This suggests that results from laboratory formation studies undertaken at these low Cl:AA ratios cannot be directly applied to ‘real’ water systems, which typically have Cl:AA ratios that are orders of magnitude higher than 4. Laboratory formation potential experiments also showed that the short-term rate of formation of aldehydes and N-chloraldimines was reduced in the presence of ammonia, although formation over longer timescales (e.g. 7 days) was not significantly different between chlorination and chloramination experiments. Therefore, the use of chloramination instead of chlorination does not appear to reduce the formation of these by-products from AAs.

Drinking Water Source Monitoring Using Early Warning Systems Based on Data Mining Techniques

Improving drinking water source monitoring is crucial for efficiently managing the drinking water treatment process and ensuring the delivery of safe water. Data mining techniques could prove useful to help forecast source water quality. In this study, two approaches were used to forecast turbidity mean levels and peaks in the main drinking water source of the city of Quebec, Canada. Trend analysis was applied for the prediction of significant turbidity events (>99th percentile of data distribution). Artificial neural networks using antecedent moisture conditions as input parameters (all turbidity peaks) served to forecast daily turbidity time series. Results show that trend analyses help anticipate the timing of turbidity peaks ― with differences between the cold season (fall and winter) and the warm season (spring and summer) and mean anticipations between 45 and 85 min and 25 and 45 min, respectively ― and the magnitude of the peak. The artificial neural network model was developed and proven capable of predicting the mean levels of turbidity at the drinking water intake of the investigated catchment. These early warning systems could be applied to source water system forecasting and provide a framework for adjusting drinking water treatment operations.

Small Scale Photovoltaic-Driven Reverse Osmosis (PV-RO) Desalination Plant for Pure Water Production

Currently, renewable energies can provide a sustainable and alternative solution for generating reverse osmosis systems operating at high pressure. The production of fresh and potable water by solar water desalination remains a sustainable strategy and economic option to fill the water deficit in areas that do not have access to safe drinking water and electricity. For this, this principle is developed industrially for the desalination of the sea waters and the purification of the water. The main objective of the present work is the study of a small capacity (100 l/h) reverse osmosis plan intended for desalination and water treatment operation. We have especially worked on the effect of pressure and salinity on the production and quality of the water produced. The performed work is purely experimental and is part within the framework of improving the profitability of an RO device. Initiation of coupling of the reverse osmosis pilot to solar energy in order to reduce energy consumption (4 KW/1m3) is being investigated. During this period of experimentation a physicochemical and bacteriological analysis of the water before and after treatment were carried out.

WORKING CONDITIONS AT THE WATER TREATMENT PLANTS: ACTIVITIES, HAZARDS AND PROTECTIVE MEASURES

In operational sense, wastewater treatment plants and operators who work at those facilities present a proper basis for good water quality status. The basic aim of this paper is to assess the risk to which workers - water treatment operators - are exposed to within water treatment plants, as well as to propose preventive measures in order to reduce the level of occupational risk. The applied methodology consists of system analysis, with in-depth literature review. The usage of appropriate occupational safety systems in the water treatment control processes leads to a double effect: a higher quality of treated water in shorter periods of time, with energy and material savings, as well as safer and healthier working environment. Key words: water treatment plants, occupational hazards, occupational risks, protection measures.

Developing a Model-based Drinking Water Decision Support System Featuring Remote Sensing and Fast Learning Techniques.

Timely adjustment of operating strategies in drinking water treatment in response to water quality variations of both natural and anthropogenic causes is a grand technical challenge. One essential approach is to develop and apply integrated sensing, monitoring, and modeling technologies to provide early warning messages to plant operators. This paper presents a thorough literature review of the technical methods, followed by the development of a model-based decision support system (DSS). The DSS aims to aid water treatment operation via source water impact analysis. This model-based DSS featuring remote sensing and fast learning techniques can be easily applied by end-users and provide a visual depiction of spatiotemporal variation in water quality parameters of interest in source water. The system is able to forecast the trend of water quality one day into the future at a specific location and to nowcast water quality at water intake, thus helping the assessment of water quality in finished water against treatment objectives. The model-based DSS was assessed in a case study at a water treatment plant in Las Vegas, United States.

Coagulation of low temperature and low turbidity water: Adjusting basicity of polyaluminum chloride (PAC) and using chitosan as coagulant aid

Abstract This study evaluated the feasibility of integrating high-basicity polyaluminum chloride (PAC) and high-viscosity chitosan for the coagulation of low-temperature and low-turbidity water. The effects of PAC basicity on coagulation performance and residual Al control were also investigated. It was found that higher-basicity PAC with a larger proportion of Alc (colloidal Al species in PAC) and smaller proportion of Ala (monomeric Al species in PAC) was beneficial for removing turbidity and natural organic matter (NOM), as well as controlling the residual Al content. Further, the integration of PAC with a high basicity (90.3%) and chitosan with a high viscosity (500 mPa·s) realized the efficient removal of turbidity and NOM, with removal efficiencies of approximately 87%, 63%, and 82% for turbidity, dissolved organic matter (DOC) and UV254, respectively. It was speculated that larger and more settleable flocs tended to form via the synergistic effect of charge neutralization by Alb (polymeric Al species in PAC) and interparticle bridging by both the Alc species and chitosan, consequently leading to excellent coagulation performance. This study may provide a useful option to drinking water treatment operators for dealing with low-temperature and low-turbidity water in practice.

Optimisation of decontamination method and influence of culture media on the recovery of Mycobacterium avium subspecies paratuberculosis from spiked water sediments

The recovery of Mycobacterium avium subspecies paratuberculosis (Map) from the environment can be a laborious process – owing to Map being fastidious, its low number, and also high numbers of other microbial populations in such settings. Protocols i.e. filtration, decontamination and modified elution were devised to recover Map from spiked water sediments. Three culture media: Herrold's Egg Yolk Media (HEYM), Middlebrook 7H10 (M-7H10) and Bactec 12B were then employed to grow the organism following its elution. In the sterile sediment samples the recovery of Map was significant between the time of exposure for each of HEYM and M-7H10, and insignificant between both media (P < 0.05). However, in the non-sterile sediment samples, the HEYM grew other background microflora including moulds at all the times of exposure whilst 4 h followed by M-7H10 culture yielded Map colonies without any background microflora. Using sterile samples only for the Bactec 12B, the recovery of Map decreased as time of exposure increased. Based on these findings, M-7H10 should be considered for the recovery of Map from the natural environment including water sediments where the recovery of diverse microbial species remains a challenge. Significance of the studyMap is a robust pathogen that abides in the environment. In water treatment operations, Map associates with floccules and other particulate matter including sediments. It is also a fastidious organism, and its detection and recovery from the water environment is a laborious process and can be misleading within the abundance of other mycobacterial species owing to their close resemblance in phylogenetic traits. In the absence of a reliable recovery method, Map continues to pose public health risks through biofilm in household water tanks, hence the need for the development of a reliable recovery protocol to monitor the presence of Map in water systems in order to curtail its public health risks.

The beneficial usage of water treatment sludge as pottery product

The disposal of sludge from water treatment operations has become a major problem in Malaysia. The problem becomes acute because of scarcity of space for installation of sludge treatment facilities and disposal of treated sludge. Traditionally, treated sludge from water treatment plant will be sent to landfill for disposal. This method does not benefit anybody besides creating other problems. Instead of considering it as a waste, sludge must be considered as a quality by-product that can be changed into beneficial product for consumer. As a pilot study, this research only emphasize on characterization of water treatment sludge and its behaviour when mixed with clay. Mineralogical compositions were determined using XRD, XRF for chemical composition and physical testing including Atterberg limit test and particles size distribution. Identification of beneficial usage is based on the characteristics of water treatment sludge. Keywords : chemical composition; mineral composition; physical characteristics; pottery product; water sludge.

Design and assessment of an Orthogonal Defense Mechanism for a water treatment facility

An Orthogonal Defense Mechanism (ODM) was designed and implemented to improve the detection of cyber attacks on an operational water treatment plant (WTreat). Successive design iterations led to an architecture that was prototyped and experimentally evaluated. ODM unobtrusively monitors WTreat using an independent network and gathers data from multiple data sources to corroborate the state of the plant using a state model. ODM is independent of, i.e. orthogonal to, any detection and defense mechanism, such as rule-based intrusion detection, that may otherwise exist in WTreat. ODM uses invariants created from plant design to detect and report anomalies in processes. While the architecture of OD, and its prototype, are specific to a water treatment plant, the underlying design ideas are generic and could be applied to other public infrastructure systems.

Microbial Communities Shaped by Treatment Processes in a Drinking Water Treatment Plant and Their Contribution and Threat to Drinking Water Safety.

Bacteria play an important role in water purification in drinking water treatment systems. On one hand, bacteria present in the untreated water may help in its purification through biodegradation of the contaminants. On the other hand, some bacteria may be human pathogens and pose a threat to consumers. The present study investigated bacterial communities using Illumina MiSeq sequencing of 16S rRNA genes and their functions were predicted using PICRUSt in a treatment system, including the biofilms on sand filters and biological activated carbon (BAC) filters, in 4 months. In addition, quantitative analyses of specific bacterial populations were performed by real-time quantitative polymerase chain reaction (qPCR). The bacterial community composition of post-ozonation effluent, BAC effluent and disinfected water varied with sampling time. However, the bacterial community structures at other treatment steps were relatively stable, despite great variations of source water quality, resulting in stable treatment performance. Illumina MiSeq sequencing illustrated that Proteobacteria was dominant bacterial phylum. Chlorine disinfection significantly influenced the microbial community structure, while other treatment processes were synergetic. Bacterial communities in water and biofilms were distinct, and distinctions of bacterial communities also existed between different biofilms. By contrast, the functional composition of biofilms on different filters were similar. Some functional genes related to pollutant degradation were found widely distributed throughout the treatment processes. The distributions of Mycobacterium spp. and Legionella spp. in water and biofilms were revealed by real-time quantitative polymerase chain reaction (qPCR). Most bacteria, including potential pathogens, could be effectively removed by chlorine disinfection. However, some bacteria presented great resistance to chlorine. qPCRs showed that Mycobacterium spp. could not be effectively removed by chlorine. These resistant bacteria and, especially potential pathogens should receive more attention. Redundancy analysis (RDA) showed that turbidity, ammonia nitrogen and total organic carbon (TOC) exerted significant effects on community profiles. Overall, this study provides insight into variations of microbial communities in the treatment processes and aids the optimization of drinking water treatment plant design and operation for public health.

Power station condensers their design and failure modes

The steam condenser plays an essential part in conventional and nuclear power generation. It is often neglected, by not being inspected regularly, by not maintaining tubes in a clean condition and not ensuring the cooling water is in a suitable chemical state to preserve tube cleanliness. Consequently, its efficiency suffers and if tubes begin to fail then an expensive episode of repairs and unreliability becomes apparent. This paper explains the role that the condenser plays and describes some of the damage mechanisms that affect the entire condenser. Those mechanisms will continue to cause leaks until the root causes of the failures are identified and changes made to materials, water treatment, or plant operations to eliminate them. This article describes some of the more common condenser tube failure mechanisms and provides a brief discussion of how they might be prevented.

Online total organic carbon (TOC) monitoring for water and wastewater treatment plants processes and operations optimization

Abstract. Organic measurements, such as biological oxygen demand (BOD) and chemical oxygen demand (COD) were developed decades ago in order to measure organics in water. Today, these time-consuming measurements are still used as parameters to check the water treatment quality; however, the time required to generate a result, ranging from hours to days, does not allow COD or BOD to be useful process control parameters – see (1) Standard Method 5210 B; 5-day BOD Test, 1997, and (2) ASTM D1252; COD Test, 2012. Online organic carbon monitoring allows for effective process control because results are generated every few minutes. Though it does not replace BOD or COD measurements still required for compliance reporting, it allows for smart, data-driven and rapid decision-making to improve process control and optimization or meet compliances. Thanks to the smart interpretation of generated data and the capability to now take real-time actions, municipal drinking water and wastewater treatment facility operators can positively impact their OPEX (operational expenditure) efficiencies and their capabilities to meet regulatory requirements. This paper describes how three municipal wastewater and drinking water plants gained process insights, and determined optimization opportunities thanks to the implementation of online total organic carbon (TOC) monitoring.

Taylor-Couette flow with radial fluid injection.

Taylor-Couette cells have been shown to improve a number of industrial processes due to the wide variety of hydrodynamic flow states accessible. Traditional designs, however, limit the ability to introduce new fluids into the annulus during device operation due to geometric confinement and complexity. In this paper, a co- and counter-rotating Taylor-Couette cell with radial fluid injection has been constructed. The incorporation of 16 ports in the inner cylinder enables radial fluid injection during rotation of both cylinders. The design is also capable of continuous axial flow, enabling large injection volumes. The new inner cylinder design does not modify the critical Re for flow instabilities and can precisely inject a desired mass at a desired flow rate. A range of injection rates and masses were explored to quantify the effect of radial injection on the stability of the turbulent Taylor vortex structure. Only the highest injection rate and total mass studied (5.9 g/s, 100 g) modified the turbulent Taylor vortex structure after injection for a sustained period. The post-injection vortices remained larger than the pre-injection vortices, whereas at lower injection rates or masses, the vortex structure quickly returned to the pre-injection structure. This new system allows for in situ study of hydrodynamic effects on fluid-fluid (gas and liquid) mixing and multiphase complexation, growth, and structure. We demonstrated this new design's potential for studying the flocculation of bentonite using cationic polyacrylamide for enhancing water treatment operations.