Coagulation and precipitation as post-treatment of anaerobically treated primary municipal wastewater.

The main objective of this study was to investigate the feasibility of coagulation as a post-treatment method of anaerobically treated primary municipal wastewater. Both mesophilic and ambient (20 degrees C) temperature conditions were investigated in a laboratory-scale upflow anaerobic sludge bed (UASB) reactor. In addition, optimization of the coagulant, both in terms of type and dose, was performed.

Prevalence of astigmatism among students in northern Greece.

Purpose: To assess the prevalence of astigmatism in a sample of 1738 students (15-18 years old) from Northern Greece.

Methods: Collection of the sample was based on a questionnaire method. Statistical analysis included estimation of the prevalence of astigmatism and the distribution of students according to their cylindrical values.

Prevalence of myopia in a sample of Greek students.

Purpose: An epidemiological study, concerning the prevalence of myopia among the student population (15-18 years old) of Northern Greece, was carried out.

Methods: Specific questionnaires were used in order to collect data on the refractive condition of students.

Results: Myopia prevalence was 36.