Because Bangkok is one of 76 provinces of Thailand, the admin- istrative areas are divided into 40 districts. Based on population density, Bangkok is divided into 3 strata: inner, middle, and outer. The inner zone is the area of the beginning of Bangkok settlement, which contains the highest density of population, as shown in Fig. 1. An increasing population would be the main reason to enlarge the City of Bangkok to the middle and outer zones, as seen in Fig. 1. However, the consecutive density of dwelling population could be placed on inner, middle, and outer zones, respectively. Bueng Makkasan pond has been created for the purpose of storage of wastewater drained from the repair factory of Royal Railways of Thailand (RRT) since 1931. It is located in the middle part of Bangkok at the elevation of about 1 m MSL, with area size of 92 Rai (1 rai equivalent to 1600 m 2 ) and depth of 15 m, and surrounding poor dwelling on the pond rim. There are two influent canals which induce polluted water through the conversion RRT pond systems together with the drained wastewater of the RRT factory. As indicated above, the RRT-pond conversion system is supposed to be a wastewater recycling unit. In other words, it functions as a wastewater treatment system to convert influent to effluent or treated wastewater. Naturally, biological treatment by phytoplank- ton/algae and submerged aquatic plants such as typha or cat tails would be dominant in the holistic system. Results of such biological treatment are sludge and sediment, which is the main factor in the decreased depth of RRT pond. However, no one took any responsibility to care for the greenery and healthy appearance. His Majesty the King Bhumibol had intentionally determined the importance of RRT pond as the conversion unit for treating wastewater. Then, H.M. the King paid a royal visit to Bueng Makkasan in the year of 1987