Hydrologie : recherche actuelle

By aiming at correction of the existing standards of the Fermentation Tube Test (FTT) this article critically reviews one of the oldest statistical methodologies used in sanitary engineering clearly relevant to health science. The common practice of water works is to perform the FTT on water samples for detecting fecal bacteria contamination in raw water prior to technological processing. Analysis of the Fermentation Tube Test (FTT) statistics presented in the article is to support a hypothesis that “standard FTT procedures may not be compatible with the statistical tables of FTT in the Standard Methods (1998, 2005)”. The inconsistency can be seen from the observation that the standard FTT procedures require subsequent dilution of water samples, which implies the indirect sampling. At the same time, the Standard Methods (1998, 2005) statistical tables used for FTT interpretations result from the assumption of the direct water sampling. In the article a statistical context of the Most Probable Number of bacteria, MPN, for actual, i.e. indirect, procedures of water sampling is described. Theoretical background of the inconsistency is explained and the remedy proposed by means of a new formula for calculating Most Probable Number of Bacteria consistent with actual indirect sampling procedures. The inconsistency is illustrated with simple but realistic example. As the ultimate result of the research it is proposed to modify the existing MPN tables and thus eliminate the inconsistency between the standard FTT procedures and the FTT tables published in the Standard Methods (1998, 2005) and ISO (1988) standards.

The world’s chemical industries face formidable environmental regulatory challenges in treating their wastewater effluents. The present work aims at highlighting the various industrial wastewater treatment technologies currently available including physico-chemical and biological processes as well as constructed wetland and conventional or advanced oxidation processes. Activated carbon prepared from low cost material, Agricultural by-product materials or modified natural polymers, which is considerably efficient for removal of direct dyes from wastewater, is also discussed. Combinations of anaerobic and aerobic treatment processes are found to be efficient in the removal of soluble biodegradable organic pollutants. The use of membrane in final stage of industrial wastewater treatments is increasing. The chemical oxidation techniques to treat wastewater, classical chemical treatment and advanced oxidation processes, is discussed.

Faecal pollution on bathing beaches poses a potential threat to human health and as a result may also negatively affect the local economy. In instances where the source of such pollution is not obvious, it may be necessary to track such sources using a host-specific genetic markers technique. Bacteroides species are potential indicators for source tracking of faecal pollution in bathing waters. This study designed specific primer sets to amplify sections of the 16S rRNA gene unique to Bacteroides from domestic dogs and used quantitative PCR (qPCR) to quantify such genetic markers in environmental samples. The sensitivity and specificity of the primer sets was determined; they were specific in silico against known dog Bacteroides sequences and in vitro against Bacteroides sequences originating from human and livestock faeces. Dog faecal Bacteroides contamination was then detected in sea water during the bathing season at a local beach where dogs are banned during the summer months, in spite of the fact that these waters had met EU directive standards based on the culture-based enumeration of faecal indicator bacteria. Quantitative PCR was used to determine the limit of detection (LOD) of the dog Bacteroides genetic markers in these water samples. The copy number of dog Bacteroides genetic markers in the water was low and the LOD of those markers was 4 copies per reaction. The use of these dog primers has the potential to supply important additional information when source tracking faecal pollution at bathing beaches and maintaining water quality.

Monthly changes in water quality parameters (Physico-chemical) in Madikoppa pond were investigated from Feb 2012 to Jan 2013, to assess the suitability of this pond for pisciculture. The different Physico-chemical parameters like PH, temperature, turbidity, dissolved oxygen, carbon dioxide alkalinity, chloride, total hardness, BOD, COD, Phosphates, and nitrates were carried out. The values are within the range prescribed by “Guidelines for water quality management for fish culture in Tripura”, ICAR Research complex for NEH Region Tripura Centre, Lambucherra-799210 Tripura (West), publication No. 29, Year 2007.