Nakhon Sawan City (NSC) is the second largest city in the north of Thailand with an area of 27.87square kilometers and a population of 86,703 and population density of 3,111 persons per square kilometer. From the geographical aspect, NSC is the origin of Chao Phraya river, which is a merger of four smaller rivers: Ping, Wang, Yom, and Nan. Since NSC is located at the upstream area and adjacent to the country’s main river, it is the only city in the country which has raw water for water supply production all year round. The main policies of the city are as follows: access to good water quality for consumers; protection of water resources; wastewater treatment prior to discharge; construction and operation of a water supply system to cover the city’s area; and acquisition of raw water resources to feed the water supply that meet Thailand and WHO standards.

Water Supply Quality:

Results of the water supply quality monitoring of NSC have shown that it meets the national and WHO standards: (1) bacterial characteristics: E. coli bacteria; (2) physical-chemical characteristics: color, turbidity, taste and odor, heavy metals e.g. arsenic, cadmium, chromium, cyanide, fluoride, chloride, etc.; (3) pesticide and related chemicals: DDT, pentachlorophenol, etc.; (4) trihalomethane: chloroform, bromoform, etc.; and (5) radioactive substances.

Effluent Quality:

Results of the effluent monitoring of NSC have shown that it meets the national standard: pH (5.0-9.0), BOD (not exceeding 20 mg./liter), suspended solid (not exceeding 30 mg./liter), oil and grease (not exceeding 5 mg./liter), total nitrogen (not exceeding 20 mg.N/liter), total phosphorus (not exceeding 5 mg.P/liter).

On the management of water system for consumption, NSC is the only city in Thailand with water supply service covering the whole area of the city and approximately 2,000 households outside NSC. All types of buildings and construction: residential, governmental offices, academic institutes, religious institutes, shopping malls, business buildings etc can connect to the city’s water supply system. As the water resource for water supply production, Ping river with 15-20 million cubic meters per day flow rate and also from Bhumibol dam and groundwater could guarantee that the raw water using for water supply production is available even in dry season.

The highlight point of the water supply is that quality is tested at the beginning of the process. Data is used to guide the amount of chemical additives at precise level. This results in chemical substance cost reduction and less chemical residuals in the water for the safety of the consumers. The quality of the water supply in the system is randomly checked at the beginning (water treatment plant), in the middle (city area), and at the end (drinking water service points). The quality of the city’s water treatment meets the national standard which is equivalent to the standard of the World Health Organization, and is certified by the Department of Health, Ministry of Public Health, according to TIS 257-2549 standard since 2000 until present. Sediment sludge from the water treatment process can be discharged into the river without harming aquatic lives, while fishes are used as indicators. When considering the sustainability of the operation, it can be seen that NSC is capable of managing the expense and income of water supply service. The fact that the resulting profit is used in other aspects of local management is the evidence of the operation’s sustainability.


For the operation regarding wastewater, the mayor of NSC gives high priority on importance of the environment and supported the budget for providing sewerage system coverage all of the city-wide. The city also has issued a regulation which requires every building blueprints to include the wastewater discharge pipelines and their connections to the public sewerage system together with an installation of grease trap units in every buildings. Such regulation ensures the collection of wastewater everywhere in the urban area into the city’s sewerage system. Moreover, NSC is the first city of Thailand to succeed in the wastewater management and wastewater treatment using Modified Sequencing Batch Reactor (MSBR). The 5-step treatment results in the city’s effluent quality that meets corresponding standards. Sludge from wastewater treatment, is tested by the Office of Land Development and found to have high nutrient content with no chemical residuals, making it a great soil conditioner and plant fertilizer. This wastewater treatment plant has become a learning center for many organizations, domestic and international.

In regards to water conservation education programs, NSC has pioneered appropriate water usage and training at all levels. The city created a curriculum on locally-appropriate water conservation and manual of “Environment in School”. It has extended the operation based on the experience to all sectors such as a project which uses hyacinth and grass as grease traps in schools and households, wastewater treatment using vetiver grass, and simple water filtration equipment invention. The extensive operations of NSC and the cooperation of every sectors has made NSC the city with sustainable clean water.