Material Flow Analysis of Nitrogen in Maeklong River Basin in Ratchaburi and Samut Songkhram Province, Thailand

Abstract

Eutrophication in the Gulf of Thailand can trigger serious ecological and economic impacts of Thailand. Maeklong River, one of the five major rivers flowing into the Gulf, carries nutrients into the Gulf of Thailand and causes eutrophication. This study aims to determine sources and amounts of nitrogen from man-made activities in Ratchaburi and Samut Songkhram Provinces where Maeklong river basin is located. The study applied mass flow concept to analyze nitrogen and its contribution ratio from anthropogenic activity, and recommended strategies to solve eutrophication problem in the Maeklong River. The scope of nitrogen flow analysis is classified into four main activities including agriculture (rice cultivation, livestock, and aquaculture), industry, households, waste management, and wastewater treatment. The results indicated that total nitrogen release into the river in 2010 is 25,911 tN. Livestock farming is the major activity discharging nitrogen into the river which accounted for 55 % (14,241 tN) of the total discharge nitrogen. Industry and household are the second and the third highest contributors of N stock into the river, respectively. Other activities have less significant contribution of discharging nitrogen into the river. To reduce N in the river, it is recommended increase efficiency and coverage areas of wastewater collection system and apply best practice technology to help reducing nitrogen discharge. Increase efficiency of water usages and water conservation in all activities can help reduce pollution at source and mitigate impacts from eutrophication.