Optimum Methods of Inactivation of Strongyloides stercoralis Larvae from Reclaimed Wastewater

Strongyloidiasis presents a major health hazard when reusing wastewater. Albendazol with a concentration of 4 mg/l, a contact time of 45 min, pH 1.2 and pH 10.2, killed the larva. The larva was also killed with a 0.03% concentration of iodine and a detention time of 30 min or a 0.04% concentration of iodine and a contact time of 10 min. The required detention time to inactivate larva in water was found to be 17 days. The minimum revealed residual chlorine to kill the larvae was 4 mg/l with 120 min of detention time, and a minimum contact time was found to be 80 min with a residual of 23 mg/l. Many methods are available to inactivate the Strongyloides stercoralis, which could be acids, alkaline chemicals, larvicidal chemicals, super chlorination, or just detention time. The best method must be determined according to the prevailing specific environmental site and the feasibility of the selected method(s).     

饮用水中病毒灭活效果的模拟研究

为了探索饮用水中病毒的灭活效果,我们采用次氯酸钙灭活饮用水中脊髓灰质炎Ⅰ型病毒(polio Ⅰ)的模拟实验研究.结果表明次氯酸钙对 polio Ⅰ病毒具有较强的灭活作用;当饮用水中余氯在0.45mg/L,接触时间为30min 时,次氯酸钙灭活病毒的效率为33.33%;而余氯在0.35mg/L,接触时间为60min,其灭活效率达到66.67%,本研究为饮用水、娱乐用水等水体的消毒处理提供了重要依据.     

水中的隐孢子虫卵囊及其检测与灭活

介绍了隐孢子虫卵囊（ＣＳＯ）的介水传播情况，对目前国内外检测，灭活水隐孢子虫卵囊的最新研究进展了比较全面的介绍。     

Virus inactivation during coagulation with aluminum coagulants

We used the bacteriophages Qβ and MS2 to determine whether viruses are inactivated by aluminum coagulants during the coagulation process. We performed batch coagulation and filtration experiments with virus-containing solutions. After filtering the supernatant of the coagulated solution through a membrane with a pore size of 50 nm, we measured the virus concentration by both the plaque forming unit (PFU) and polymerase chain reaction (PCR) methods. The virus concentration determined by the PFU method, which determines the infectious virus concentration, was always lower than that determined by the PCR-based method, which determines total virus concentration, regardless of infectivity. This discrepancy can be explained by the formation of aggregates consisting of several virus particles or by the inactivation of viruses in the coagulation process. The former possibility can be discounted because (i) aggregates of several virus particles would not pass through the 50-nm pores of the filtration membrane, and (ii) our particle size measurements revealed that the virus particles in the membrane filtrate were monodispersed. These observations clearly showed that non-infectious Qβ particles were present in the membrane filtrate after the coagulation process with aluminum coagulants. We subsequently revealed that the viruses lost their infectivity after being mixed with hydrolyzing aluminum species during the coagulation process.     

Bacteria inactivation by sulfate radical: progress and non-negligible disinfection by-products

● Status of inactivation of pathogenic microorganisms by SO₄^•− is reviewed. ● Mechanism of SO₄^•− disinfection is outlined. ● Possible generation of DBPs during disinfection using SO₄^•− is discussed. ● Possible problems and challenges of using SO₄^•− for disinfection are presented. Sulfate radicals have been increasingly used for the pathogen inactivation due to their strong redox ability and high selectivity for electron-rich species in the last decade. The application of sulfate radicals in water disinfection has become a very promising technology. However, there is currently a lack of reviews of sulfate radicals inactivated pathogenic microorganisms. At the same time, less attention has been paid to disinfection by-products produced by the use of sulfate radicals to inactivate microorganisms. This paper begins with a brief overview of sulfate radicals’ properties. Then, the progress in water disinfection by sulfate radicals is summarized. The mechanism and inactivation kinetics of inactivating microorganisms are briefly described. After that, the disinfection by-products produced by reactions of sulfate radicals with chlorine, bromine, iodide ions and organic halogens in water are also discussed. In response to these possible challenges, this article concludes with some specific solutions and future research directions.     

Development of a field enhanced photocatalytic device for biocide of coliform bacteria

A field enhanced flow reactor using bias assisted photocatalysis was developed for bacterial disinfection in lab-synthesized and natural waters. The reactor provided complete inactivation of contaminated waters with flow rates of 50 m L/min. The device consisted of titanium dioxide nanotube arrays, with an externally applied bias of up to 6 V. Light intensity, applied voltage, background electrolytes and bacteria concentration were all found to impact the device performance. Complete inactivation of Escherichia coli W3110(~ 8 × 10~3CFU/m L) occurred in 15 sec in the reactor irradiated at 25 m W/cm~2 with an applied voltage of 4 V in a 100 ppm NaCl solution. Real world testing was conducted using source water from Emigration Creek in Salt Lake City, Utah. Disinfection of natural creek water proved more challenging, providing complete bacterial inactivation after 25 sec at 6 V. A reduction in bactericidal efficacy was attributed to the presence of inorganic and organic species, as well as the increase in robustness of natural bacteria.