Toward understanding the efficacy and mechanism of Opuntia spp. as a natural coagulant for potential application in water treatment

Historically, there is evidence to suggest that communities in the developing world have used plant-based materials as one strategy for purifying drinking water. In this study, the coagulant properties of Opuntia spp., a species of cactus, are quantitatively evaluated for the first time. Opuntia spp. was evaluated for turbidity removal from synthetic water samples, and steps were made toward elucidating the underlying coagulation mechanism. In model turbid water using kaolin clay particles at pH 10, Opuntia spp. reduced turbidity by 98% for a range of initial turbidities. This is similar to the observed coagulation activities previously described for Moringa oleifera, a widely studied natural coagulant. Although it has been reported that Moringa oleifera predominantly operates through charge neutralization, comparison of zeta potential measurements and transmission electron microscopy images of flocs formed by Opuntia spp. suggest that these natural coagulants operate through different mechanisms. It is suggested that Opuntia spp. operates predominantly through a bridging coagulation mechanism. Once optimized, application of these readily available plants as a part of point-of-use water treatment technology may offer a practical, inexpensive, and appropriate solution for producing potable water in some developing communities.     

Peer reviewed: understanding the water quality of pit lakes

The increase in deep pit mining in western North America raises concerns about the environmental impact of mine closure.     

A novel electro-fenton process for water treatment: reaction-controlled pH adjustment and performance assessment

A novel electro-Fenton (E-Fenton) process was developed, in which the desired pH for an effective E-Fenton reaction and for a neutral treated media could be obtained by utilizing the reaction-released H+ and OH- in stead of chemical addition. In the laboratory-scale process using three chambers, the substrate solution pH > 4.0 was designed to be adjusted in situ through three sequencing steps: (I) pH reduction, (II) pH keeping for the effective E-Fenton reaction, and (III) pH recovery to neutral while the E-Fenton reaction continued. Experimental results demonstrated that such three-step pH adjustment was successfully achieved in this novel E-Fenton process, and that the pH adjustment was controlled by the E-Fenton reaction process. The performance of the novel process was assessed in terms of dimethyl phthalate (DMP) degradation in aqueous solution. The results revealed that the novel process was effective to reduce the DMP concentration and the total organic carbon (TOC) at steps II and III. Also, through experiments, the initial DMP solution pH > 4.0 was selected to be reduced to 3.5 in Step I of the process. This pH adjustment not only allowed the E-Fenton reaction to occur in its favorable pH range, but also benefited any potential subsequent biological treatment process or a final discharge. Moreover, the iron species could be recycled in the process.     

Experimental design to optimize preparation of activated carbons for use in water treatment

A series of seven activated carbons was obtained for use in drinking water treatments by steam-activation of olive-waste cakes. This raw material is an abundant and cheap waste byproduct of oil production, making these activated carbons economically feasible. The activated carbons, prepared by the one step method, were characterized, and the evolution of their characteristics (yield, adsorption capacities, and porosity) was analyzed as a function of the experimental parameters (activation temperature and activation time), using the Doehlert matrix. The Doehlert matrix allows the response surface to be studied with a good quality parameter estimation of the quadratic model. Each response has been described by a second order model that was adequate to predict responses in all experimental regions. The coefficients of the postulated model were calculated from the experimental responses by means of least squares regression, using the NEMROD software. We determined the region in which the optimum values of both activation temperature and activation time were achieved for the preparation of activated carbons suitable for use in water treatments. The "optimal activated carbon" was experimentally obtained, and its characteristic parameters showed a good agreement with those calculated from the model. The results obtained for activated carbons prepared by the one-step method were compared with those for activated carbons prepared by the two-step method. The characteristics of activated carbons obtained by the one-step and two-step methods showed that "one-step" activated carbons have a highly developed porous texture formed mainly of large macropores and micropores, whereas "two-step" activated carbons have a predominance of mesopores and narrow micropores. These activated carbons from olive-waste cakes showed a high capacity to adsorb herbicides (2,4-dichlorophenoxyacetic acid, 2,4-D; and 2-methyl, 4-chlorophenoxyacetic acid, MCPA) from water, with adsorption capacity values higher than those corresponding to a commercial activated carbon used from drinking water treatments.     

Sources of parameter uncertainty in predicting treatment performance: the case of preozonation in drinking water engineering

This study investigates the factors that determine parameter uncertainty when applying predefined, existing models to predict the performance of a full scale treatment system from environmental engineering. The analysis is performed for ozonation of surface water, a technology applied in drinking water treatment for disinfection and oxidation of micropollutants. The pseudo first order rate constant of ozone decay k(O3) is characterized as a time dependent parameter and estimated from data obtained from three experimental setups representing upscaling stages in engineering design. To obtain meaningful uncertainty estimates, various factors need to be acknowledged: uncertainty about the model structure, uncertainty of other model parameters, uncertainty due to non-representative sampling, and errors in chemical analysis. It is concluded that an on-site automated sequencing batch reactor is best suited for estimating kinetics during operation of the full scale system. Furthermore, the transferability of information in upscaling from laboratory experiments to the full scale system is found to be critical. Although uncertainty analysis enhances the understanding of the system, it is also shown to be a subjective process depending on the knowledge and assumptions of the modeler and the availability and quality of data.     

The oral management of food: the bases of oral success and for understanding the sensations that drive us to eat

Everyone understands the verbs—to chew, to smell and to swallow. Most people subconsciously take eating for granted. As consumers, we enjoy eating without much need to understand how we succeed. But we do not all succeed equally, adapting as best we can with the teeth we have managed not to lose. Impaired dentitions lead to changes in food selection, style of cooking and other food preparation. The physiology of mastication is briefly reviewed. This process necessarily involves ingestion past the lips where temperature is monitored. Incision provides extremely sensitive detection of internal texture whilst the lips and tip of tongue detect external texture. Videofluorography (VFG) has provided the essential basis for visualizing and analyzing the processes by which food is moved to the cheek teeth and is subsequently manipulated. Data on the process of crushing food between the teeth explains the release of vapor and the sensation of food texture, which change progressively as the mouthful is chewed. Salivary flow rates and salivary proteins are critical for the developing coherence of the food bolus and its adhesion to the tongue prior to swallowing. The movement of odors from the mouth to the olfactory nerves in the roof of the nasal cavity involves the dynamic combination of tongue movement, continuing respiration and, late in the chewing sequence, the adhesion of the bolus to the moving tongue, which can be seen graphically on VFG. These coordinated interactive processes together provide the basis of oral success.     

Application of beech sawdust for removal of heavy metals from water: biosorption and desorption studies

In this work the efficiency of applying non-modified beech sawdust for the removal of Cu²⁺ and Cr³⁺ heavy metal ions from water solutions was examined. Parameters taken into consideration in the analysis of environment conditions were influence of sorbent concentration, initial concentration of metal ions, temperature effect, presence of additional substances in solution (NaCl and MgCl₂ inorganic salts and anionic and cationic surface-active compounds). Results of kinetic experiments were described by two models: pseudo-first-order and pseudo-second-order; equilibrium results were approximated with five non-linear isotherm models. Maximum sorption capacity at a temperature of 20 °C and pH 5.0 was 30.22 mg g^?1 for Cu²⁺ ions and 41.86 mg g^?1 for Cr³⁺ ions. The positive value of the thermodynamic parameter ΔH° indicates the endothermic nature of the process. Application of 0.1 M HCl as the eluent enables effective desorption of precious metals and reuse of sorbent for purifying water solutions of Cu²⁺ and Cr³⁺ ions.     

Phytochemicals and heavy metals content of hairless canary seed: A variety developed for food use

Canary seed is one of the top four specialty crops grown in Western Canada. Currently it is used entirely in food mixtures for caged birds but our previous studies have shown its unique composition and potential use in food and non-food applications. Through improvements by plant breeding a hairless variety was developed for human consumption and animal feeding. This study was aimed at investigating phytochemicals and heavy metals in hairless canary seed in comparison with the hairy variety and common wheat using three milling fractions (wholegrain, starchy flour and bran). The levels of bound and unbound phenolic acids, phytate, trypsin and amylase inhibitors tended to be similar in the three grains at a given level of processing. This was also true for most heavy metals tested although hairy canary seed exhibited a significantly higher concentration of copper while both canary seed varieties contained more nickel and zinc than wheat. Condensed tannins, alkaloids and deoxynivalenol (DON) were not detected in any of the crops while very low levels of aflatoxin were detected in all three grains. The results show that both hairless and hairy canary seed possess phytochemicals and heavy metals profile close to that of wheat demonstrating the potential of hairless canary seed as a food crop due to the absence of harmful hairs.     

Study of rosin softening point through thermal treatment for a better understanding of maritime pine exudation

The temperature of pine rosin softening point was studied to better understand the phenomenon of resin exudation on the surface of pine boards. This problem may decrease strongly the aesthetical performance of wood used outside and is an important concern for the industry. To perform a reliable measurement of rosin properties with a small amount of sample, differential scanning calorimetry (DSC) and thermo mechanical analysis (TMA) techniques were investigated and the results compared. DSC curves on industrial rosin and acetone rosin extractives from maritime pine show a behavior similar to a glass transition in polymers. TMA measurements carried out on the same industrial rosin showed that the softening point is in the midpoint of the transition phase observed by DSC. The softening point temperature is about 45 °C for industrial rosin and about 50 °C for rosin extractives from maritime pine boards. These values are significantly lower than those usually found on other rosins measured by the ASTM E28-14 standard using the ring-and-ball method. When using heat treatment, it was observed for the first time that the thermal history of the sample can change its softening point temperature. With these results, it could be possible to develop a new strategy to reduce rosin exudation for exterior wood siding.     

Listeria monocytogenes and listeriosis: a review of hazard characterisation for use in microbiological risk assessment of foods

Considerable effort has been put into the application of quantitative microbiological risk assessment for Listeria monocytogenes, and data are available for England and Wales (probably more so than most other countries) on the adverse health effects, together with incidence data on different age and risk groups for human L. monocytogenes infections. This paper reviews aspects of Listeria and human listeriosis, especially from a public health perspective and provide hazard characterisation data, i.e. the qualitative and/or quantitative evaluation of the adverse health effect associated with the hazard, which is the relationship between exposure levels (dose) and frequency of illness. The majority of cases of human listeriosis are food-borne; however, the disease process is complex with multiple routes of infection. The dose-response relationship is poorly understood, and data from human volunteer studies are not available and would be unethical to produce. Data are available from a range of different animal and in vitro models, although these poorly mimic the natural disease process in route of infection, end point, host and history of prior exposure to the bacterium. Epidemiological data provide some information on infective doses and dose responses, but because of the characteristics of the disease (the hugely variable and potentially very long incubation periods, the low attack rates and the rarity of identification of specific food vehicles), this also provides limited data for calculation of dose responses. There is some, albeit limited, evidence for strain variation, but this is an area of considerable uncertainty despite great advances in the genetic basis of the virulence of this bacterium, and almost all strains seem capable of causing serious disease. A variety of mathematical approaches have been used to model dose responses. The review is written to provide a clinical and epidemiological background to the mathematically oriented, as well as to outline the mathematical approaches to those interested in food-borne infection.     

Heat exchanger performance: the use of food colourings for estimation of minimum residence time*

Most indicator systems used in estimation of residence time are not compatible with food usage The food colours carbon black and copper chlorophyll were found to give satisfactory absorption properties without causing interaction problems when used in milks, cream and ice cream mixes for determination of residence times in a pilot-scale plate heat exchanger.     

Successful hazard analysis critical control point implementation in the United Kingdom: understanding the barriers through the use of a behavioral adherence model

Hazard analysis critical control point (HACCP), a system of risk management designed to control food safety, has emerged over the last decade as the primary approach to securing the safety of the food supply. It is thus an important tool in combatting the worldwide escalation of foodborne disease. Yet despite wide dissemination and scientific support of its principles, successful HACCP implementation has been limited. This report takes a psychological approach to this problem by examining processes and factors that could impede adherence to the internationally accepted HACCP Guidelines and subsequent successful implementation of HACCP. Utilizing knowledge of medical clinical guideline adherence models and practical experience of HACCP implementation problems, the potential advantages of applying a behavioral model to food safety management are highlighted. The models' applicability was investigated using telephone interviews from over 200 businesses in the United Kingdom. Eleven key barriers to HACCP guideline adherence were identified. In-depth narrative interviews with food business proprietors then confirmed these findings and demonstrated the subsequent negative effect(s) on HACCP implementation. A resultant HACCP awareness to adherence model is proposed that demonstrates the complex range of potential knowledge, attitude, and behavior-related barriers involved in failures of HACCP guideline adherence. The model's specificity and detail provide a tool whereby problems can be identified and located and in this way facilitate tailored and constructive intervention. It is suggested that further investigation into the barriers involved and how to overcome them would be of substantial benefit to successful HACCP implementation and thereby contribute to an overall improvement in public health.     

PET热灌装饮料生产线水处理设备定型分析以及循环回收系统的应用经验

在设计PET热灌装饮料生产线时,系统整合其水处理系统,以最大限度地发挥循环使用功能,节约用水。并对循环回收的经验加以阐述。     

印染废水深度处理及回用关键技术

"印染废水深度处理及回用关键技术"是由东华大学完成的国家35项印染行业节能减排先进技术项目之一,该技术的工艺流程,轻污染水生物接触 氧气化-生物滤池-复合反应器-陶瓷膜-达回用标准,部分污泥回流,陶瓷膜 过滤浓水与其他废水合并,得理后达标排放.     

Polyphenolic composition of a permanent pasture: variations related to the period of harvesting

Phenolics contribute to the micronutrient composition of forages, which in turn may affect animal product composition. To assess the importance of these compounds, the polyphenolic and botanical composition of a permanent mountain pasture in the Massif Central (France) were studied at three stages of growth. Phenolic fractions (acids, flavonoids and total) were analysed using HPLC and specific colorimetric methods over the whole pasture and in nine main species. On a botanical level, 43 species including 31 dicotyledons composed a mountain variant of Cynosurion grouping. Over time, the species growing on the field changed, the main plants being Festuca nigrescens and eight dicotyledons. In whole pasture, about 170 different compounds were separated by HPLC, of which only 30 were common to all stages. The total polyphenolic content was estimated as 31, 32 and 19 g kg^?1 DM for the three stages. They were mainly composed of dihydroxycinnamic derivatives (3,5‐di‐O‐caffeoylquinic, chlorogenic, 1,5‐di‐O‐caffeoylquinic acids), and of flavonoids in lesser proportions. Some polyphenols were peculiar to a few species and others were ubiquitous. The two major dicaffeoylquinic acids were identified for the first time in Achillea millefolium and Knautia arvernensis. Colorimetric measurements of phenolic fractions were in good agreement with HPLC analysis (P < 0.01) for all species studied. Thus, on the mountain pasture studied, a cow would be expected to ingest up to 500 g of polyphenols daily, which could affect the quality of animal products. Copyright © 2007 Society of Chemical Industry     

Public health consequences of macrolide use in food animals: a deterministic risk assessment

The potential impact on human health from antibiotic-resistant bacteria selected by use of antibiotics in food animals has resulted in many reports and recommended actions. The U.S. Food and Drug Administration Center for Veterinary Medicine has issued Guidance Document 152, which advises veterinary drug sponsors of one potential process for conducting a qualitative risk assessment of drug use in food animals. Using this guideline, we developed a deterministic model to assess the risk from two macrolide antibiotics, tylosin and tilmicosin. The scope of modeling included all label claim uses of both macrolides in poultry, swine, and beef cattle. The Guidance Document was followed to define the hazard, which is illness (i) caused by foodborne bacteria with a resistance determinant, (ii) attributed to a specified animal-derived meat commodity, and (iii) treated with a human use drug of the same class. Risk was defined as the probability of this hazard combined with the consequence of treatment failure due to resistant Campylobacter spp. or Enterococcus faecium. A binomial event model was applied to estimate the annual risk for the U.S. general population. Parameters were derived from industry drug use surveys, scientific literature, medical guidelines, and government documents. This unique farm-to-patient risk assessment demonstrated that use of tylosin and tilmicosin in food animals presents a very low risk of human treatment failure, with an approximate annual probability of less than 1 in 10 million Campylobacter-derived and approximately 1 in 3 billion E. faecium-derived risk.