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The utilization of different industrial waste, by-products or other materials such as ground granulated blast furnace slag, silica fume, fly ash, limestone, and kiln dust, etc. as supplemen- tary cementing materials has received considerable attention in recent years. A study has been conducted to look into the performance of laterite as Supplementary Cementing Materials (SCM). The study focuses on compressive strength performance of blended cement containing different percentage of laterite. The cement is replaced accordingly with percentage of 2 %, 5 %, 7 % and 10 % by weight. In addition, the effect of use of three chemically different laterites have been studied on physical performance of cement as in setting time, Le-Chatlier expansion, loss on ignition, insoluble residue, free lime and specifically compressive strength of cement cubes tested at the age of 3, 7, and 28 days. The results show that the strength of cement blended with laterite as SCM is enhanced. Key words: Portland cement, supplementary cementing materials (SCM), laterite, compressive strength KUI – 6/2013 Received January 4, 2012 Accepted February 11, 2013

Research has been conducted on the Cryptosporidium parvum oocysts. The inactivation of these oocysts after the chemical, physical and environmental stress treatment has been investigated.

Research was conducted to examine the effects of sample turbidity on the recovery of Cryptosporidium parvum oocysts using two immunomagnetic separation (IMS) kits. The objectives of the study was to identify an IMS kit that generated high purified oocyst suspensions, to determine turbidity levels and to use the IMS kit for the evaluation of the effects of age on the recovery of C. parvum oocysts. Results indicate that IMS is a promising alternative to flotation procedures for the recovery of oocysts from turbid water matrices.

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7, the causative agent for haemolytic uraemic syndrome, has become a significant health concern, due to an increasing number of cases. The focus of this project was rapid (<8 h) detection of E. coli O157:H7 from source and finished waters samples, either directly or indirectly, by dovetailing the procedures with existing total coliform procedures. Evaluation of four immunological lateral diffusion assays determined a detection range between 1 x 104 and 1 x 106 CFU, with the Reveal® E. coli O157: H7 Test System (Neogen) being the most sensitive for detecting E. coli O157: H7. Evaluation of the BAX® System for molecular detection determined that as few as 10 CFU could be reproducibly detected. Coupling either of these detection procedures with organism propagation using Tryptic Soy Broth (TSB) enabled sufficient quantities of E. coli O157: H7, such that the Reveal® and BAX® detection methods could be used with the 8 h time frame. Examination of matrix effects on the overall procedure indicated little impact on method performance. [ABSTRACT FROM AUTHOR]

Ultraviolet light is now recognised to be very effective for inactivation of Cryptosporidium parvum oocysts; however, its application for disinfection of finished water necessitates validation of UV reactors prior to their installation. Although reactor performance will likely be assessed using non-pathogenic microorganisms as biodosimetry surrogates, it would be prudent for the water industry to simultaneously measure Cryptosporidium oocysts inactivation in controlled bench-scale studies using the water matrix intended for disinfection. The likelihood of that occurring is dependent upon the availability of infectivity measurement procedures that are more user-friendly than the mouse infectivity assays currently used. This study describes a modified cell culture procedure that would enable reliable measurement of changes in oocysts' infectivity following their UV treatment. Also, a number of different biodosimetry surrogates were examined and one selected for comparing the UV doses delivered between bench-scale and full-scale biodosimetry studies. Impacts of UV disinfection on production of disinfection byproducts, effects of lamp ageing on effectiveness of disinfection and the costs associated with employing this technology were also examined. [ABSTRACT FROM AUTHOR]

Cryptosporidium parvum and Giardia duodenalis can cause severe diarrhoea in infected individuals and their transmissive stages, oocysts and cysts, are voided in large numbers with the faeces of infected hosts. Contaminated sewage effluents are recognised as a potential source of waterborne (oo)cysts. In this investigation methods optimised for the recovery of both from a range of wastewaters were used to determine the occurrence of these organisms in influents, effluents and sludges from seven sewage treatment works in England. The data indicated the presence of small numbers of oocysts both in sewage influent and effluent samples whereas cysts were detected more frequently and at higher concentrations in both influents and effluents. Whilst sludge samples from 1/5 sites contained oocysts, cysts were detected from all five sites. These investigations indicate that discharge of sewage effluents into a watercourse, which may be used for potable water abstraction, can contaminate that watercourse with potentially infectious oocysts. In addition, the application of sludge to land can be responsible for contaminating watercourses with (oo)cysts following run-off or leaching. [ABSTRACT FROM AUTHOR]

For over a decade, despite continuous efforts, the methods for collection, isolation and detection of Cryptosporidium have remained time-consuming and inefficient. For example, two standard methods for Cryptosporidium are the United Kingdom Standing Committee of Analysts (SCA) method (Anon, 1990) and the U.S. Environmental Protection Agency (USEPA) Information Collection Rule (ICR) method (1996). Both these methods have relied on large volume filtration, elution using large quantities of a weak detergent solution, concentration with various centrifugation steps and then clarification of the target organisms by using specific density flotation, with either sucrose alone or in conjunction with Percoll. Because of the laborious nature of these methodsand their poor recovery efficiencies, the USEPA instigated the development of improved methodologies, with the objective that commercially available products could be incorporated into methods that would eventually lead to the development of reliable methods, with improved oocyst recoveries. This has resulted in the development of a method for surface waters and is based on collection of small sample volumes (10 L) through cartridge or membrane filters, elution of organisms andclarification by immunomagnetic separation followed by their detection by immunofluorescence. This USEPA method has been collectively termed Method 1622 (USEPA, 1998) and has undergone initial validation work and is currently in the round-robin testing phase. [ABSTRACT FROM AUTHOR]