Eutrophication problems in Emilia Romagna,Italy: Monitoring the nutrient load discharged to the littoral zone of the Adriatic Sea

The deteriorating eutrophic state of the northern Adriatic Sea led to the commissioning of a study between 1977 and 1979 to identify the sources and forms of the nutrients phosphorus and nitrogen discharged from the basin of the river Savio. The study investigated the reduction in the phosphorus load in sewage per head of population caused by a reduction in the phosphorus content of detergents used in the basin and by the use of septic tanks. The flow and nutrient loads carried by the river were monitored during dry and wet weather to establish annual nutrient loads carried to the sea. An extensive sampling programme was carried out to quantify the principal sources of nutrients of which the most important were pig farming, Man and chemical fertilisers. An attempt was made to balance the nutrient loads discharged from the basin.     

Evaluation of the nutritional quality of four unexplored aquatic weeds from northeast India for the formulation of cost-effective fish feeds

A study was conducted to evaluate the nutritional potential of four commonly available, unexplored aquatic weeds namely, Salvinia cuculata, Trapa natans, Lemna minor and Ipomoea reptans from northeast India for ascertaining their suitability for utilization as supplementary fish feed with the aim to reduce the cost of commercial feeds. Results of proximate analysis showed that the crude protein content of the aquatic weeds ranged between 11.0% and 32.2% (w/w), whereas crude fibre and ash contents varied between 4.2% and 20% (w/w), and 13.3% and 31.2% (w/w), respectively. Protein to energy ratio (P/E) of these weeds ranged between 30.7 mg/kcal and 95.3 mg/kcal and the highest value was displayed by I. reptans. All these aquatic weeds contained high amounts of vitamins E and C and mineral elements required for the normal growth and development of fish.     

Waste Stabilization Ponds: A Viable Alternative for Small Community Treatment Systems

Waste stabilization ponds are widely used in many European countries, such as France and Germany, for the treatment of wastewater from mainly small communities. There would seem to be no reason why they should not also be a suitable treatment process for populations of under 2000 in the UK. The relative advantages and disadvantages of ponds are compared to other small community treatment systems, such as rotary biological contactors, biological filters and reed-bed systems, particularly in relation to effluent standards with respect to algae, nutrient removal and relative costs.     

Initial results of remediation activities to restore hypereutrophic Villerest Reservoir (Roanne, France)

We examined the impacts of remediation activities aimed at improving the water quality of hypereutrophic Villerest Reservoir, in which Microcystis aeruginosa dominated during the summer. We also compared nutrients and chlorophyll a data from this study with the results of a previous study on the reservoir. Between the two studies, the nitrogen and phosphorus loads into the reservoir from the main tributary decreased by 70% and 80%, respectively. Within the reservoir, the quantities of ammonia‐nitrogen were similar in the two studies, and the total nitrogen was significantly higher in this study compared to the initial study. Both the phosphate‐phosphorus and total phosphorus concentrations decreased significantly between the two studies. However, the statistically significant decrease in phosphate‐phosphorus and total phosphorus did not always lead to a significant decrease in chlorophyll a concentrations. The nitrogen/phosphorus mass ratio during the present study remained well above five, the critical value below which summer blooms of Microcystis aeruginosa were observed in Villerest Reservoir. These study results indicated that the remediation activities being used to improve the water quality of Villerest Reservoir were off to a good start.