Coliforms removal in full-scale activated sludge plants in India.

This paper investigates the removal of coliforms in full-scale activated sludge plants (ASP) operating in northern regions of India. Log2.2 and log2.4 removal were observed for total coliforms (TC) and fecal coliforms (FC), respectively. However, the effluent still contained a significant number of TC and FC which was greater than the permissible limit for unrestricted irrigation as prescribed by WHO. The observations also suggest that extended aeration (EA) process operating under high mixed liquor suspended solids (MLSS) and sludge retention time (SRT) is more efficient in the removal of coliforms. Further attempts have been made to establish the relationship between two key wastewater parameters, i.e. biochemical oxygen demand (BOD) and suspended solids (SS) with respect to fecal and TC. The relationships were observed to be linear with a good coefficient of correlation. The interrelationship of BOD and SS with coliforms manifest that improvement of the microbiological quality of wastewater could be linked with the removal of SS. Therefore, SS can serve as a regulatory tool in lieu of an explicit coliforms standard.

Municipal solid waste management in Indian cities - A review.

Municipal solid waste management (MSWM) is one of the major environmental problems of Indian cities. Improper management of municipal solid waste (MSW) causes hazards to inhabitants. Various studies reveal that about 90% of MSW is disposed of unscientifically in open dumps and landfills, creating problems to public health and the environment. In the present study, an attempt has been made to provide a comprehensive review of the characteristics, generation, collection and transportation, disposal and treatment technologies of MSW practiced in India. The study pertaining to MSWM for Indian cities has been carried out to evaluate the current status and identify the major problems. Various adopted treatment technologies for MSW are critically reviewed, along with their advantages and limitations. The study is concluded with a few fruitful suggestions, which may be beneficial to encourage the competent authorities/researchers to work towards further improvement of the present system.

Determination of lead, zinc, potassium, calcium, copper and sodium in human cataract lenses.

Concentrations of Pb, Zn, K, Ca, Cu and Na were determined in several human cataract and clear lenses, obtained from patients from two contrasting environmental regions in India, and the values were compared. When compared with the results obtained for samples of clear lenses, the mean concentration values of cataract lenses showed significant changes on the basis of the Mann-Whitney test. In cataract lenses, Pb and Zn showed an inverse correlation of r = -0.83; y = -1.64x + 457. Ca and K also showed an inverse correlation of r = -0.71; y = -0.34x + 3.6. No significant correlations were found between any other elements. The distribution of Pb, Zn, Ca and K were studied and their importance in ocular tissues is discussed. The molecules present in the eye lens lattice have undergone some conformational alterations due to intrusion of Pb and Ca ions and extrusion of Zn and K ions through the process of ion-exchange, thereby influencing the transparency of the lens.

New enzymatic method for serum uric acid at 500 nm.

We describe a manual method, well suited to mechanization, for quantitating serum uric acid at 500 nm. In the assay mixture (0.10 ml of sample and 3.00 ml of reagent) the hydrogen peroxide produced from uric acid by uricase is coupled with p-hydroxybenzoate and 4-aminoantipyrine in the presence of peroxidase to form a colored complex, which is measured. A separate sample blank is obviated by taking an initial absorbance measurement 20 s after the sample is added. The reaction is complete within 5 min; its sensitivity is 0.001 deltaA/mg per liter. Absorbances are linearly related to uric acid concentrations up to 120 mg/liter. Many substances that may be present in normal serum do not interfere, but bilirubin in moderately above-normal concentrations will interfere. The procedure can be modified to largely correct for this, when necessary. The proposed method (y) correlated well (r = 0.979) with the uric acid 293 nm reference method (x) and the relation is described by the equation y = 0.998x + 2.42.

New ultraviolet (340 nm) method for assay of uric acid in serum or plasma.

We propose a novel enzymatic method for assay of uric acid at 340 nm, which eliminates several disadvantages of both the colorimetric and enzymatic methods now in common use. Here, uric acid is catalytically oxidized to allantoin and hydrogen peroxide. The peroxide is reacted with ethanol in the presence of catalase to form acetaldehyde and water, and the acetaldehyde is reduced by NADH in the presence of alcohol dehydrogenase to ethanol. The decrease in absorbance at 340 nm caused by oxidation of NADH is directly proportional to the concentration of uric acid in the sample. Measurement of the change in absorbance between 20 and 200 s eliminates the need for a serum blank measurement. Absorbance and concentration are linearly related to 120 mg of uric acid per liter. The new method was compared with the uricase method in which decomposition of uric acid at 293 nm is directly measured. The results for the 47 patients' sera so examined can be expressed by the linear equation y340 = 1.0078x293 + 0.122 (r = 0.9984).