Ultrasound Technology Integration into Drinking Water Treatment Train

Fresh water is one of the main sources for drinking water production. Due to increasing contamination caused by extreme weather events such as flood and drought as well as urbanization activities, the quality of this source continues to deteriorate. In order to maintain producing high-quality water from heavily contaminated sources, more chemicals are added to water in conventional treatment plants. This practice generates serious health problems such as the formation of disinfection by-products (DBPs) and the increase of coagulants residues (e.g., Al) in the treated water. Combining chemical-free techniques with conventional treatment processes can be a potential solution for such problems. When evaluating various techniques, ultrasound appears to be a sensible choice for improving contaminants removal from surface water. This chapter sheds light on the exacerbating problem of fresh water contamination and succinctly reviews chemical-free techniques’ options for water treatment. The focus of this chapter is directed toward providing critical and insightful discussion of fundamentals, mechanisms, and reaction pathways of ultrasound technology for water treatment application. Recommendations for the best location and operating settings of ultrasound application in conventional water treatment train will be provided based on energy saving and minimal downstream impact criteria

Energy conversion efficiency of pulsed ultrasound

Energy characterization of a pulsed ultrasonic system was carried out using a modified calorimetric method. Sonochemical efficiency (SE) for the oxidation of Fe+2 and the formation of H2O2 was determined for selected on:off ratios (R) and different power levels. The measured efficiency of the pulsed ultrasonic system of 60-70% in converting electrical energy into calorimetric energy was found to be constant for all Rratios and equivalent to that for continuous operation. SE of Fe+2 and H2O2 for pulsed ultrasound was higher than that of continuous ultrasound. The ratio R=0.2:0.1 had the highest SE values overall, while for long off-timeratios,R=0.1:0.6 recorded the highest value of SE. These results were supported by the production rates results for Fe+2 and H2O2

Biofuels from the fresh water microalgae Chlorella vulgaris (FWM-CV) for diesel engines

This work aims to investigate biofuels for diesel engines produced on a lab-scale from the fresh water microalgae Chlorella vulgaris (FWM-CV). The impact of growing conditions on the properties of biodiesel produced from FWM-CV was evaluated. The properties of FWM-CV biodiesel were found to be within the ASTM standards for biodiesel. Due to the limited amount of biodiesel produced on the lab-scale, the biomass of dry cells of FWM-CV was used to yield emulsified water fuel. The preparation of emulsion fuel with and without FWM-CV cells was conducted using ultrasound to overcome the problems of large size microalgae colonies and to form homogenized emulsions. The emulsified water fuels, prepared using ultrasound, were found to be stable and the size of FWM-CV colonies were effectively reduced to pass through the engine nozzle safely. Engine tests at 3670 rpm were conducted using three fuels: cottonseed biodiesel CS-B100, emulsified cottonseed biodiesel water fuel, water and emulsifier (CS-E20) and emulsified water containing FWM-CV cells CS-ME20. The results showed that the brake specific fuel consumption (BSFC) was increased by about 41% when the engine was fuelled with emulsified water fuels compared to CS-B100. The engine power, exhaust gas temperature, NOx and CO2 were significantly lower than that produced by CS-B100. The CS-ME20 produced higher power than CS-E20 due to the heating value improvement as a result of adding FWM-CV cells to the fuel

Natural and recycled materials for sustainable membrane modification: Recent trends and prospects

Despite water being critical for human survival, its uneven distribution, and exposure to countless sources of pollution make water shortages increasingly urgent. Membrane technology offers an efficient solution for alleviating the water shortage impact. The selectivity and permeability of membranes can be improved by incorporating additives of different nature and size scales. However, with the vast debate about the environmental and economic feasibility of the common nanoscale materials in water treatment applications, we can infer that there is a long way before the first industrial nanocomposite membrane is commercialized. This stumbling block has motivated the scientific community to search for alternative modification routes and/or materials with sustainable features. Herein, we present a pragmatic review merging the concept of sustainability, nanotechnology, and membrane technology through the application of natural additives (e.g., Clays, Arabic Gum, zeolite, lignin, Aquaporin), recycled additives (e.g., Biochar, fly ash), and recycled waste (e.g., Polyethylene Terephthalate, recycled polystyrene) for polymeric membrane synthesis and modification. Imparted features on polymeric membranes, induced by the presence of sustainable natural and waste-based materials, are scrutinized. In addition, the strategies harnessed to eliminate the hurdles associated with the application of these nano and micro size additives for composite membranes modification are elaborated. The expanding research efforts devoted recently to membrane sustainability and the prospects for these materials are discussed. The findings of the investigations reported in this work indicate that the application of natural and waste-based additives for composite membrane fabrication/modification is a nascent research area that deserves the attention of both research and industry

Nascent application of aerobic granular sludge for recirculating aquaculture system effluent treatment: Performance, granule formation, and microbial community

This study presents for the first time an evaluation of the feasibility of aerobic granular sludge (AGS) for treating recirculating aquaculture system (RAS) effluent in a sequential batch reactor configuration for nutrient removal. An AGS process was started using synthetic wastewater to grow the granules, and the feed was then switched to RAS effluent, and a systematically decreasing carbon supplementation was applied. Total nitrogen removal significantly decreased from around 75 % to as low as 13 %, but granules could restore their performance when allowed enough time (2 weeks) to acclimate to the change in feed. The dynamics of AGS microbial communities were followed by Illumina sequencing. A high abundance of microbial populations—indicating dense and stable granules—was observed after 97 days of operation with RAS wastewater. In particular, the genera Neomegalonema, Hydrogenophaga, Thauera, Bdellovibrio, Flavobacterium, and Pseudomonas represented most of the community, showing the heterotrophic, denitrifying, and phosphorus-accumulating potential of the studied operational design. The AGS showed promising results for a small-footprint solution for RAS treatment, but the energy consumption of aeration and carbon addition still requires further development

A critical review on processes and energy profile of the Australian meat processing industry

This review article addresses wastewater treatment methods in the red meat processing industry. The focus is on conventional chemicals currently in use for abattoir wastewater treatment and energy related aspects. In addition, this article discusses the use of cleaning and sanitizing agents at the meat processing facilities and their effect on decision making in regard to selecting the treatment methods. This study shows that cleaning chemicals are currently used at a concentration of 2% to 3% which will further be diluted with the bulk wastewater. For example, for an abattoir that produces 3500 m3/day wastewater and uses around 200 L (3%) acid and alkaline chemicals, the final concentration of these chemical will be around 0.00017%. For this reason, the effects of these chemicals on the treatment method and the environment are very limited. Chemical treatment is highly efficient in removing soluble and colloidal particles from the red meat processing industry wastewater. Actually, it is shown that, if chemical treatment has been applied, then biological treatment can only be included for the treatment of the solid waste by-product and/or for production of bioenergy. Chemical treatment is recommended in all cases and especially when the wastewater is required to be reused or released to water streams. This study also shows that energy consumption for chemical treatment units is insignificant while efficient compared to other physical or biological units. A combination of a main (ferric chloride) and an aid coagulant has shown to be efficient and cost-effective in treating abattoir wastewater. The cost of using this combination per cubic meter wastewater treated is 0.055 USD/m3 compared to 0.11 USD/m3 for alum and the amount of sludge produced is 77% less than that produced by alum. In addition, the residues of these chemicals in the wastewater and the sludge have a positive or no impact on biological processes. Energy consumption from a small wastewater treatment plant (WWTP) installed to recycle wastewater for a meet facility can be around $500,000

Biofouling in RO system: mechanisms, monitoring and controlling

The reverse osmosis (RO) technology offers a solution for the shortage of pristine water resources worldwide, through its capacity on treating all water kinds such as seawater, wastewater, ground water and surface water. The main concern in using RO technology for water treatment is fouling problems, and in particular biofouling. Biofouling negatively affects the quality of RO product and renders RO a costly technology for water treatment. The key solution to reduce the risk of biofouling in RO system lies in understanding the process of biofouling formation, choosing an adequate biofilm monitoring technique and applying effective biofouling control treatment for the RO membrane system. In this paper, the mechanisms of microbial adhesion to RO membrane are illustrated along with the key factors that influence the microbial adhesion process. In addition to that, the common strategies for biofilm monitoring in water flow systems are reviewed with highlighting applications, advantages and disadvantages of each strategy. The common biofouling control methods for reducing the formation of biofouling in the RO system are also presented in this paper. The application of the environmentally friendly physical disinfection techniques for biofouling control in the RO membrane system is suggested in this paper

Identifying the optimum process parameters for ultrasonic cellular disruption of e. coli

The aim of this work is to identify the optimum process parameters of sonication, manosonication and thermosonication for deactivating E. coli ATCC 25922 in water-based suspension. The influence of ultrasonic intensity, frequency, pressure, temperature and treatment time on the efficiency of ultrasonic treatments was investigated in this study theoretically and experimentally. The theoretical part of this study involved solving the Rayleigh-Plesset equation with different parameters and evaluating their effects on the collapse pressure of a bubble with initial radius of 0.01mm. The experimental part of the work was conducted using ultrasonic horn reactor at three levels of intensities; low (17.56 W/cm2), intermediate (21.49 W/cm2) and high (24.17 W/cm2) with fixed frequency. Thermosonication and manosonication experiments were conducted at the sub-lethal temperatures of E. coli; 45, 50, 55 and 60C and pressures of 2, 3 and 4 bars. The optimum treatment conditions of sonication, manosonication and thermosonication were evaluated through calculating the specific energy required to obtain 5 log reduction of E. coli in each treatment. Thermosonication treatment at 21.49W/cm2 and 45C for 4 minutes was found to be the optimum treatment conditions to deactivate E. coli in water-based suspension

Numerical and experimental study of microorganism disruption using shock treatment

The use of shock waves to destroy microorganisms is considered one of the newly developed methods in the field of cell disruption. This simulation part of this research work aims to determine the required shock pressure to disrupt a single yeast cell and the rupture location on the cell wall. As a step towards understanding the physical response of the microorganisms to dynamic pressure and shock treatments a Finite Element (FE) model has been developed using commercial software ABAQUS. Von Mises theory of failure is adopted in this work and the properties of Saccharomyces cerevisiae (S. cerevisiae) reported in the literature were used in the numerical and experimental work. The simulation results demonstrate that maximum dynamic σv/Pe (0.85) was found to be over three times that of the static σv/Pe (0.25) values. This suggests a location of the rupture within the cell wall when shock pressure loading is applied; such a result has not been previously reported in current literatures. In the experimental work, a gas gun tunnel was used to generate 100–400 MPa external pressure loading on a yeast suspension. The experimental results showed that the maximum yeast reduction of 95.7% resulted when a 336 Mpa pressure rise was applied

Evaluating the impact of operating parameters on biocidal effects of pulsed ultrasound in natural water disinfection

The knowledge available in the literature regarding the use of pulsed ultrasound for water disinfection is limited. Hence, this study was designed to provide a thorough investigation for the application of pulsed ultrasound disinfection in water treatment. High power low frequency pulsed ultrasound was used to disinfect natural water samples. Two levels of power, treatment time and On/Off ratio (R) of 40% and 70% amplitudes, 5 and 15 min and 0.2:0.1 and 0.1:0.6, respectively were tested. To scrutinize the effect of the operating parameters on pulsed ultrasound disinfection efficiency,rigorous statistical analyses were performed applying factorial design of 23. Total coliform Quantification was applied as a measure for disinfection efficiency. It was found that increasing power, treatment time or both had a positive effect on total coliform reduction, whereas increasing the off period of pulsed ultrasound resulted in lower total coliform reduction. The disinfection effects of 2-way interaction of power * R and 3-way interaction of power * treatment time * R were statistically insignificant (P > 0.05). Linear regression model was developed for predicting total coliform reduction under pulsed ultrasound effect. Cost analyses of the treatments were also conducted