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Mathematical Problems in Engineering
Volume 2014 (2014), Article ID 313157, 5 pages
http://dx.doi.org/10.1155/2014/313157
Research Article

Wastewater Treatment Optimization for Fish Migration Using Harmony Search

1Department of Energy & Information Technology, Gachon University, Seongnam 461-701, Republic of Korea
2Department of Civil & Environmental Engineering, Chung-Ang University, Seoul 156-756, Republic of Korea

Received 3 October 2014; Accepted 20 November 2014; Published 4 December 2014

Academic Editor: Youqing Wang

Copyright © 2014 Zong Woo Geem and Jin-Hong Kim. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Certain types of fish migrate between the sea and fresh water to spawn. In order for them to swim without any breathing problem, river should contain enough oxygen. If fish is passing along the river in municipal area, it needs sufficient dissolved oxygen level which is influenced by dumped amount of wastewater into the river. If existing treatment methods such as settling and biological oxidation are not enough, we have to consider additional treatment methods such as microscreening filtration and nitrification. This study constructed a wastewater treatment optimization model for migratory fish, which considers three costs (filtration cost, nitrification cost, and irrigation cost) and two environmental constraints (minimal dissolved oxygen level and maximal nitrate-nitrogen concentration). Results show that the metaheuristic technique such as harmony search could find good solutions robustly while calculus-based technique such as generalized reduced gradient method was trapped in local optima or even divergent.