Detection of enteric viruses, Giardia and Cryptosporidium in two different types of drinking water treatment facilities.

In this study, two types of drinking water treatment facilities (two conventional drinking water treatment plants (DWTPs) and two compact units (Cus)) were compared referring to their production capacity. Water samples were collected from three main points: (a) different water treatment steps (b) washings of sand filters and (c) distribution system at different distances from the water treatment plants. Both viruses and protozoa were concentrated from each water sample by adsorption and accumulation on the same nitrocellulose membrane filters (0.45 microm pore size). Enteroviruses were detected by plaque infectivity assay in BGM cells and HAV, HEV and Norovirus were detected by RT-PCR. Giardia and Cryptosporidium were detected by conventional staining methods and PCR. The results revealed that enterovirus load at the intake ranged between 10-15 PFU/L for the two compact units and between 4.5 and 75 PFU/L for the two conventional DWTPs. The virus load in distribution system of the first type DWTPs at 1 km from the plant was the same as that of the intake. Viruses in the other type of treatment plants CUs at 1, 5 and 7 km, were much reduced. Investigation of raw water sediments of the two DWTPs showed enterovirus counts between 12 and 17.5 PFU/L. Virus count was reduced in sand of filters after washing. Giardia cysts were equally detected by microscopy and PCR in only intake samples of EL-Hawamdia CU (33.3%) and Meet Fares DWTP (50%). Cryptosporidium oocysts were equally detected by microscopy and PCR in intake samples of Abo EL-Nomros CU (100%), EL-Hawamdia CU (66.7%) and Fowa DWTP (50%). At Meet Fares DWTP three positive intake samples for Cryptosporidium were detected by PCR, compared with only two positive samples by microscopy. Giardia cysts and Cryptosporidium oocysts were detected in raw water sediment and sand of filters before washing. Only one sample from Meet Fares DWTP sand of filters after washing was positive for both Giardia and Cryptosporidium. It can be concluded that the poor microbial quality of the water may be due to improper operational skills and management of the various water treatment plants (especially at the two high capacity treatment plants).

RT-PCR and cell culture infectivity assay to detect enteroviruses during drinking water treatment processes.

In this study, 62 water samples were collected from two water treatment plants (WTPs) in Suez Canal cities (Port Said and Ismaillia) and one plant in Cairo (Giza WTP) in addition to the beginning of the two Nile river branches (Rosetta and Damietta). Viruses were concentrated by adsorption-elution ethod sing 142 mm-diameter nitrocellulose membrane of 0.45 microm pore size and eluted with 3% beef extract at pH 9.5. The concentrated samples were inoculated for 3 successive passages in three cell culture types (Vero, BGM and RD). Enterovirus RNAs in CPE-induced samples were extracted by guanidinium thiocyanate/ phenol/chloroform and heat shock methods and detected by RT-PCR and neutralization test. The results showed that eight samples [14.5% (8/62)] contained enteroviruses most of them were polioviruses [87.5% (7/8)] and coxsackievirus type B2 [12.5% (1/8)]. The three cell cultures were of the same sensitivity to detect the isolated viruses. Also, RT-PCR followed by neutralization assay facilitates and accelerate the results. The guanidinium thiocyanate extraction method was more sensitive than heat shock method. The results turned our attention to review our technology of water treatment and disinfection step in addition to the selection of suitable intake for the drinking water treatment plants.

Enteroviruses in sewage: comparison of different technologies for wastewater treatment and reuse.

Seven wastewater treatment plants were twice sampled to compare their different technologies for the removal of enteroviruses. These technologies are extended aeration, oxidation ditch, stabilization pond, aerated stabilization pond, submerged fixed film reactor, trickling filter and trickling filter followed by activated sludge in El-Serw, El-Rahamna, El-Adliya, Daqahla, El-Barashiya, Sohag and El-Fayoum wastewater treatment plants, respectively. Virus counts of raw sewage ranged between 2.7 x 10(3) and 20 x 10(3) PFU/L and for treated effluents was between 0 and 6 x 10(3). The percentage of virus removal was varied where trickling filter and tickling filter followed by activated sludge reduced virus counts by 95.7 and 99.9, respectively. Extended aeration removed 64.2%, oxidation ditch 66.5%, stabilization pond 44.9%, aerated stabilization pond 13.34%, and submerged fixed film reactor removed 53.4%. The neutralization test revealed five types of enteroviruses, poliovirus types 1,2 and 3 and Coxsackievirus types B4 and B5. The isolated polioviruses were vaccine strains. From the frequency distribution of the detected viruses, poliovirus type 2 was the most dominant.

New approaches to virus removal: the way to produce virus-free drinking water.

Virus control in drinking water is considered one of the serious problems to be encountered in the near future. Trials to remove viruses from drinking water were directed to enhance water treatment processes, use of different disinfectants or use of a good virus adsorbent material. In the present study, four materials were prepared, dimethylaniinoethyl chitin, chitosan and cellulose and starch acrylate and examined for adsorption of hepatitis A virus from drinking water. Also, three types of eluates (3% beef extract-glycine, 3% beef Virus control in drinking water is considered one of the serious problems to be encountered in the near future. Trials to remove viruses from drinking water were directed to enhance water treatment processes, use of different disinfectants or use of a good virus adsorbent material. In the present study, four materials were prepared, dimethylaniinoethyl chitin, chitosan and cellulose and starch acrylate and examined for adsorption of hepatitis A virus from drinking water. Also, three types of eluates (3% beef extract-glycine, 3% beef extract and glycine) were used for virus recovery from adsorbed materials. The results obtained showed that dimethylaminoethyl chitosan was a good adsorbent (99.16%) and the three eluents were poorly desorb viruses.

Novel antimicrobial compounds among naphthalene and methylenedioxyphenyl derivatives.

2-Benzoyl-2-phenyl-4,5,6,7-tetrachlorobenzo-1,3-dioxole (1) undergoes Stobbe condensation readily with dimethylsuccinate in the presence of potassium tert-butoxide to give the acid ester (2a), which is converted into benzocyclopentadienone and naphthalene derivatives via two different routes. The in vitro antimicrobial spectra of these compounds were evaluated. Anhydride (3), phenolic acid (5b), carbamate (5c) and hydrazide (5e) are shown to possess high activity against all tested pathogenic gram-negative organisms in addition to Staphylococcus aureus and the tested yeast species.

Bacterial food-poisoning versus coliforms-faecal streptococci and gamma radiation survival/dose.

All the species tested were sensitive to gamma radiation treatment, even at a dose as low as 0.001 Mrad. The spore-former Bacillus cereus (PCJ 213) proved to be more resistant than the rest of the tested species, while the Gram-negative organisms were more susceptible to irradiation treatment. The tolerance among those organisms is depicted by the descending order: Proteus vulgaris, irregular VI, Escherichia coli I, E. coli III, and Salmonella typhi-murium. Yet all the tested faecal streptococci species, with the exception of Streptococcus bovis, may be regarded as holding an intermediate position between the more resistant B. cereus (PCJ 213) and the more sensitive Gram-negative organisms.

Bacteriophages recovery from raw sewage of different texture.

Bacteriophages recovery was enhanced by the addition of Mg2+ divalent cation or when the raw sewage filtrate was adjusted to pH 4.5. On the other hand, when Mg2+ or Ca2+ divalent cations were added to the acidified sewage filtrate, all sensitive phase species were found to be phage-resistant.

Direct MPN for faecal coliform.

Samples of Nile and Ismailia canal water were subjected to direct inoculation and incubation at elevated temperatures. The results obtained showed that the use of MacConkey broth medium was better than EC broth. In addition, the Direct MPN technique revealed to be suitable and superior by 90% of the examined samples. A total of 300 isolates was recovered from Direct MPN-technique and identified by using IMViC reactions plus Eijkman test. 96% of the isolates were E. coli proper and 4% irregular types.