title: Optimization of conventional water treatment plant using dynamic programming.
abstract: In this research, the mathematical models, indicating the capability of various units, such as rapid mixing, coagulation and flocculation, sedimentation, and the rapid sand filtration are used. Moreover, cost functions were used for the formulation of conventional water and wastewater treatment plant by applying Clark's formula (Clark, 1982). Also, by applying dynamic programming algorithm, it is easy to design a conventional treatment system with minimal cost. The application of the model for a case reduced the annual cost. This reduction was approximately in the range of 4.5-9.5% considering variable limitations. Sensitivity analysis and prediction of system's feedbacks were performed for different alterations in proportion from parameters optimized amounts. The results indicated (1) that the objective function is more sensitive to design flow rate (Q), (2) the variations in the alum dosage (A), and (3) the sand filter head loss (H). Increasing the inflow by 20%, the total annual cost would increase to about 12.6%, while 20% reduction in inflow leads to 15.2% decrease in the total annual cost. Similarly, 20% increase in alum dosage causes 7.1% increase in the total annual cost, while 20% decrease results in 7.9% decrease in the total annual cost. Furthermore, the pressure decrease causes 2.95 and 3.39% increase and decrease in total annual cost of treatment plants.
authors.affiliation: Department of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran khezri@sharif.edu.
authors.forename: Khezri Seyed
authors.initials: KS
authors.lastname: Mostafa
authors.affiliation: Department of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran.
authors.forename: Ghafari
authors.initials: G
authors.lastname: Bahareh
authors.affiliation: Department of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Islamic Republic of Iran.
authors.forename: Dadvar
authors.initials: D
authors.lastname: Elahe
authors.affiliation: Department of Pharmaceutics, Tehran University of Medical Science, Tehran, Islamic Republic of Iran.
authors.forename: Dadras
authors.initials: D
authors.lastname: Pegah
mesh_terms: D000465:Algorithms; D000534:Alum Compounds / Q000737:chemistry; D011232:Chemical Precipitation; D003246:Conservation of Energy Resources / Q000191:economics / Q000379:methods; D017046:Cost Savings; D003365:Costs and Cost Analysis; D005246:Feedback; D005374:Filtration / Q000379:methods; D007492:Iran; D008962:Models, Theoretical; D010316:Particle Size; D012212:Rheology / Q000379:methods; D064449:Sequestering Agents / Q000737:chemistry; D013223:Statistics as Topic; D013597:Systems Analysis; D062065:Wastewater / Q000737:chemistry / Q000191:economics; D014867:Water / Q000737:chemistry; D014877:Water Pollution, Chemical / Q000191:economics / Q000517:prevention & control; D018508:Water Purification / Q000191:economics / Q000379:methods*; D014881:Water Supply / Q000191:economics
chemical_list: D000534:Alum Compounds; D064449:Sequestering Agents; D062065:Wastewater; D014867:Water; C041524:aluminum sulfate
keywords: Dynamic programming; optimization; water treatment plants