Agriculture wastewater contains N and P nutrients too, but in quantities less than that of domestic wastewater. Major agricultural wastewater sources include animal wastes (pig, poultry, fish and shrimp) and fertilizers. Poultry farm discharges are different to control because there are both open and closed edges. Fertilizer from growing plants often
drains both nitrogen and phosphorus to rivers and lakes. On average about 10% of fertilizer is drained to a public water resource. Quantities of nitrogen and phosphorus from different agricultural wastewater sources are shown in Table 1. All these agriculture sources drain many nutrients to public water resources. It is difficult to control agricultural wastewater in Thailand because it is primarily a non-point source. Additionally, agriculture is very widespread being the principal livelihood for the population.