Distinct problems in the analysis of failure times with competing causes of failure include the estimation of treatment or exposure effects on specific failure types, the study of interrelations among failure types, and the estimation of failure rates for some causes given the removal of certain other failure types. The usual formation of these problems is in terms of conceptual or latent failu...

Background: The presence of lead in natural waters has become an important issue around the world. Lead has been identified as a highly toxic metal that can cause severe environmental and public health problems and its decontamination is of utmost importance. The aim of this work was to evaluate the adsorption of lead (Pb(II)) on waste tea leaves as a cheap purification method. Methods: In thi...

heavy metal contamination in the environment could cause harmful effects both to human health and aquatic life. numerous remediation methods had been developed to encounter with the contamination problem prior to degrade, decrease and to purify the contaminated water at minimal concentration as low as possible. therefore, in current study, commercialized chicken eggshells and hybrid akar putra ...

A synthetic wastewater with high concentration of sulfate and COD was treated in anaerobic baffled reactor (ABR) coupled with an activated sludge. The work was accomplished in two phases. In the first phase, the concentration of sulfate was kept constant at 500mg/l, but COD concentration was increased from (3000mg/l to 6000mg/l), consequently, COD and sulfate removal in ABR reached to 80% and 9...

The chlorothiophenoxy radicals (CTPRs) are key intermediate species in the formation of polychlorinated dibenzothiophenes/thianthrenes (PCDT/TAs). In this work, the formation of CTPRs from the complete series reactions of 19 chlorothiophenol (CTP) congeners with H and OH radicals were investigated theoretically by using the density functional theory (DFT) method. The profiles of the potential e...

Potentially harmful disinfection byproducts (DBPs), as a significant challenge in water treatment, are formed when oxidizing disinfectants react with natural organic matters (NOM). Unfortunately, an  unwanted  side  effect  is  the  formation  of  harmful by-products,  such  as  THMs  and  HAAs, following the chlorination stage. DBPs  cause a variety of diseases like cancer in humans.  In this ...

Background & Aims of the Study: High concentration of nitrogen compounds in water and wastewater can be caused various problems and diseases such as methhemoglobinemia and eutrophication. The aim of this study was investigated nitrification and denitrification from wastewater using integrated fixed film activated sludge (IFAS) includes powder activated carbon. Materias and Methods: The labo...

Introduction: As far as application of chemicals as disinfectants may have side effects on human health and causes drug resistance, the topic of herbal and natural products has been investigated in recent researches. Nevertheless, application of medicinal smokes in the treatment of many diseases, including bacterial and infectious diseases has long been popular in Iran. Smoke from the burning o...

Cadmium can be found in wastewater in high concentrations and can cause dangerous effect on aqueous environment and human health. At present, many methods have been used to heavy metals removal. Among this clean up techniques, adsorption techniques by using low-cost adsorbent are more considerable. In this study, batch adsorption experiments were conducted for removal of cadmium ions from a...