treatment systems: drawbacks of existing prescriptions

The paper reviews and evaluates the basic steps in designing activated sludge systems based on process stoichiometry and mass balance. Appropriate system design requires the use of biodegradable COD as the main parameter, which sets a balance between substrate utilized, biomass generated and oxygen consumed. In practice, this balance is easily translated into excess sludge production and oxygen requirement. The evaluation first covers the necessary database for a rational design approach, with emphasis on relevant domestic wastewater characterization. Then it defines the excess sludge production, together with the daily oxygen demand. Principles outlined are illustrated in a numerical design example where the proposed rational approach is compared with the German Design Guidelines, A-131 for organic carbon removal

treatment systems: drawbacks of existing prescriptions

The paper reviews and evaluates the basic steps in designing activated sludge systems based on process stoichiometry and mass balance. Appropriate system design requires the use of biodegradable COD as the main parameter, which sets a balance between substrate utilized, biomass generated and oxygen consumed. In practice, this balance is easily translated into excess sludge production and oxygen requirement. The evaluation first covers the necessary database for a rational design approach, with emphasis on relevant domestic wastewater characterization. Then it defines the excess sludge production, together with the daily oxygen demand. Principles outlined are illustrated in a numerical design example where the proposed rational approach is compared with the German Design Guidelines, A-131 for organic carbon removal

engineering

The paper evaluates the scientific merit of doctoral studies on environmental sciences and technology, involving completed doctoral studies in Turkey between 2000-2007, as a case study. The investigation revealed 446 scientific papers derived from 170 completed doctoral studies. This level represented 22% of the total number of publications at departments with graduate programs in this field. 42 of the completed studies (25%) did not produce published papers other than the compulsory doctoral thesis. These publications received 2766 citations, corresponding to 6.2 citations per publication; 65 of 170 doctoral studies completed (38%) had no record of any citation, indicating that aside from 42 doctoral theses which did not produce any publications, results of 22 doctoral studies were published but received no citations. Impact factors of selected journals for publication varied within a wide range of 0.429 to 3.894 with an average value of 1.65, based on 2007 impact factor records