Recently, algae have become significant organisms for biological purification of wastewater since they are able to accumulate plant nutrients, heavy metals, pesticides, organic and inorganic toxic substances and radioactive matters in their cells/bodies. Biological wastewater treatment systems with micro algae have particularly gained importance in last 50 years and it is now widely accepted that algal wastewater treatment systems are as effective as conventional treatment systems. These specific features have made algal wastewaters treatment systems an significant low-cost alternatives to complex expensive treatment systems particularly for purification of municipal wastewaters. By this method 70 % of biological oxygen demand, 66 % of chemical oxygen demand, 71 % total nitrogen, 67 % of phosphorus, 54 % volatile solid and 51 % of dissolved solid was reduced.
The deposition of acidifying compounds in Gdask region has been investigated. Bulk wet (in the open field), and throughfall (in the forest) stand, depositions were measured from 1994 till 2001. The deposition of sulphates, nitrates and ammonium salts has been analysed. The obtained results are compared with the critical deposition for sulphur and nitrogen related to the Gdask region. It has been stated that exceeding critical load was not observed for sulphur, while it was observed for nitrogen.
Two-dimensional variance analysis of the results of determination of NO₃⁻, SO₄²⁻, F⁻, Al³⁺, Cl⁻, NH₄⁺,PO₄³⁻, Fe³⁺, Ca²⁺, K⁺ and Mg²⁺, and pH and electrolytic conductivity of precipitation water samples collected in the Tricity area showed that transregional transport of pollutants affects air quality in this region. Over the large area of the Tricity agglomeration fluctuations in analyte concentrations in precipitation water samples are not affected on a statistically significant level by localizing sampling sites, but the area affected by transport direction of air mass movement.