Volume 17 - 2015

Activated sludge is a biological floc composed of microorganisms, organics, and inorganics and plays an important role in wastewater treatment. The pH of an activated sludge suspension determines the acid – base behaviour and the charge of the microorganisms in water. In the present study, the determination of acid – base behaviour of activated sludge was performed using microelectrophoresis and Potentiometric Mass Titrations (PMT). For activated sludge that is a complicated biological system, direct microelectrophoresis is not a suitable method for the determination of its ζ-potential. This method leads to a variety of isoelectric point (iep) values due to the presence of different microorganisms in activated sludge. On the contrary, the PMT method used for the first time for activated sludge can provide the overall point of zero charge (pzc) value that is 8.2. In addition, a simple methodology is proposed for the quantitative determination of the overall solid charge as a function of solution pH, which requires only (a) the titration curves of an electrolyte suspension and of the blank electrolyte solution and (b) the calculation of the H⁺ ions consumed for the above titration curves. 

This study examined the trends in anthropogenic chemical contaminants in groundwater samples in rural areas of Ebonyi State, South-eastern Nigeria. Groundwater samples were collected from Ezza North (a quarry mining area) and Ezza South (an agricultural/commercial area) and were analysed using standard techniques. The target compounds evaluated were As(V), phosphate, nitrate, sulfate, chloride and other physicochemical parameters. Pearson’s correlation and factor analyses were used to distinguish the statistical relationship between the various analytes and possible contamination sources in the study areas respectively. The results obtained showed that the pH, temperature, total hardness, electrical conductivity, phosphate, nitrate, chloride and sulfate were within the permissible limits of Water Quality Standards (WQS). Also, 67% of the samples had turbidity and alkalinity values above the WQS, while 25% contained As(V) slightly above the WQS. The qualities of the groundwater samples were found to be influenced mainly by the geochemistry of the soil while commercial and agricultural activities were found to have slight effect on the water quality.  This study finally advocates adequate monitoring of As(V), and other potential toxic contaminants in groundwater in the areas.

The present study has been carried out for the trans-boundary Subansiri sub-basin of Brahmaputra river basin. Subansiri is the largest tributary of Brahmaputra within India and the river system has its practical importance as it holds a high water resources as well as hydropower potential for the country, which still remains highly under-developed. The probable impact of climate change has been analyzed using hypothetical climate scenarios to understand the behavior of total streamflow as well as snowmelt runoff under the changing conditions. Based on the simulations of a daily snowmelt runoff model (SNOWMOD) using six years of data, it has been observed that the total stream flow as well as the snowmelt runoff increase with temperature. Snowmelt runoff was found to increase by about 5% and 12% for the increase of 1°C and 2°C in temperature respectively.  However, not much change in snowmelt runoff was observed with changed precipitation scenarios. It has been found from this study that total stream flow changes in all scenarios of temperature (T) and precipitation (P). The observed maximum % increase in mean annual stream flow was about 6% for the T+2°C & P+10% scenario and the minimum % decrease in mean annual stream flow observed was about 11% for T+1°C & P-10% scenario. The present study aims to provide information for planning of climate change adaptation strategies for the Subansiri sub-basin of the Brahmaputra River.

Proper Hospital healthcare Waste Management (HCWM) is imperative for ensuring public health and environmental protection. In this context, three Prefectural hospitals of Mytilene, Agrinio, and Messolonghi, were studied with respect to planning and management of infectious wastes, cost, training of the white Staff involved, security measures to be taken, and also knowledge related to the implementation of the existing National and European Community, legislation. It was found that the existing legislative procedures were broadly applied. However deviations were reported and it was recognized that serious difficulties in the implementation of the legislation throughout the process i.e. from the phase of separation throughout the processing phase did exist. These deviations frequently originated from conflicts in the directions given by the legislation Joint [Governmental Gazette B1537/8-5-2012]. In order to achieve better implementation of HCWM, recommendations are proposed here.