Water Analysis for Agriculture in Hanoi : A comparison with national standards

Abstract

Water quality is a significant issue especially in developing countries like Vietnam but it has not received adequate consideration. The main objective of this thesis is to study the water quality of four inner Hanoi’s rivers and suggest a wastewater treatment method suitable to treat water for reusing in agriculture. Theories on water quality, particularly water constituents that affect the water capability to be reused in agriculture and aquaculture, were reviewed. A Water Quality Index model developed by a national organization was used to further assess the water quality. The subject of study was water in four inner Hanoi’s rivers, which regularly had wastewater from domestic, industrial and crafting villages discharged into. Data from various sources along these rivers were collected from secondary source, and were compared with National Technical Regulations on Surface Water Quality and National Technical Regulation on Irrigatied Agriculture as well as calculated through a Water Quality Index model. The results indicated heavy pollution in term of organic matters, microbial pathogens, heavy metals (Pb, Cd, Cr, As, Hg), oil and grease, and micropollutants. Water Quality Index calculations resulted in all four rivers unsuitable for use in any purposes. As the wastewater development plan by the authorities are a long way from complete, a constructed wetland system imitating natural reed bed namely Vertical Flow Bed was suggested. This is a design for decentralized wastewater treatment that is suitable for small scale peri-urban Hanoi farmers to treat wastewater from the rivers to reuse in their traditional agricultural and aquacultural practices.