Spatial and temporal distribution of cyanobacteria in Batticaloa Lagoon

The necessity to understand the relationship between cyanobacterial species abundance and water quality variations in coastal lagoons is crucial to develop strategies to prevent further cyanobacterial proliferation. This paper evaluates the relationship between water quality variations on the distribution of cyanobacteria during a 12-month period in Batticaloa Lagoon (Sri Lanka) using Redundancy analysis and Pearson correlations. Drastic variations in pH, temperature, salinity, dissolved oxygen (DO) and total phosphorus (TP) levels were reported, but not turbidity and NO₃⁻. This brackish waterbody is hypereutrophic (TP levels > 0.1 mg/L). The cyanobacterial community contained 13 genera and 22 species. NO₃⁻, TP and turbidity levels positively influenced cyanobacterial abundance during all seasons indicating that nutrient (largely phosphorus) and sediment entry control is highly crucial along with periodic monitoring of cyanobacterial growth.     

Removing ammonium from water and wastewater using cost-effective adsorbents: A review

Ammonium is an important nutrient in primary production; however, high ammonium loads can cause eutrophication of natural waterways, contributing to undesirable changes in water quality and ecosystem structure. While ammonium pollution comes from diffuse agricultural sources, making control difficult, industrial or municipal point sources such as wastewater treatment plants also contribute significantly to overall ammonium pollution. These latter sources can be targeted more readily to control ammonium release into water systems. To assist policy makers and researchers in understanding the diversity of treatment options and the best option for their circumstance, this paper produces a comprehensive review of existing treatment options for ammonium removal with a particular focus on those technologies which offer the highest rates of removal and cost-effectiveness. Ion exchange and adsorption material methods are simple to apply, cost-effective, environmentally friendly technologies which are quite efficient at removing ammonium from treated water. The review presents a list of adsorbents from the literature, their adsorption capacities and other parameters needed for ammonium removal. Further, the preparation of adsorbents with high ammonium removal capacities and new adsorbents is discussed in the context of their relative cost, removal efficiencies, and limitations. Efficient, cost-effective, and environmental friendly adsorbents for the removal of ammonium on a large scale for commercial or water treatment plants are provided. In addition, future perspectives on removing ammonium using adsorbents are presented.     

Floristic composition of sandy shore vegetation at Uswetakeiya in Sri Lanka

This study was conducted at Uswetakeiyawa on the southwestern part of Sri Lanka. Twenty-two families, 42 genera and 52 species were recorded from the sandy shore vegetation. Approximately 3.8 % (2 species) were found to be endemic and 67.3 % (35 species) were found to be of medicinal importance. Ipomea pes-capre and Spinifex littoreus were the most abundant species at the study site. The average value for all the zone combinations was β = 0.693, and the highest similarity value was ISj = 0.276, corresponding to two non-contiguous zones. The results show that a variation in plant diversity is to be found across the gradient. The typical zoning nature of the sandy shore vegetation has been disturbed due to on-going development in Uswetakeiyawa. New policy decisions should be taken to restrict development activities in Uswetakeiyawa in order to protect the sandy shore vegetation.     

Re-examining log law velocity profile in smooth open channel flows

Environmental Fluid Mechanics - A comprehensive investigation of velocity distribution is presented, and the log law is re-examined using experimental data from a smooth uniform open channel flow....