Author : Saiphou Lormaisim

Summary : Four studies were conducted to assess the production system and wastewater quality of four large commercial swine farms in Savannakhet, Lao PDR. Study 1 surveyed 73 farm workers and 83 residents near the farms about their perceptions on the environmental impact of the swine operation. Compliance with laws varies among growers, with issues such as animal welfare and antibiotic usage often disregarded, leading to penalties. Despite widespread awareness of laws covering wastewater and environmental protection, conflicts persist between swine farm operators and neighboring households due to concerns over pollution, water contamination, and adverse health effects experienced by residents and workers alike. Study 2 characterized the production system of the four farms covered in Study 1. MX and BSV farms have farrow to finish operation, ITQ farms has farrow to weaning, while TVX farms exclusively grow weanlings as fatteners. ITQ and TVX employ evaporative cooling in their housing and have biogas digesters. MX and BSV are air drying the manure collected. MX farms utilize evaporative cooling in breeder and nursery sections, and conventional open-type housing for fattening. BSV farms use conventional open-type housing with slatted or solid concrete flooring. All farms provide continuous access to water and use commercial feeds. They adhere to standards in terms of production and management practices. Study 3 analyzed the wastewater quality from the last pond of these farms. Except for ITQ, which has only one pond due to being new, all farms had values within Lao PDR standards for pH, BOD, COD, TSS, and TKN levels. In Study 4, two experiments were conducted. The first involved testing the biomass gain of Azolla as floating plants on five levels of wastewater dilutions (0%, 25%, 50%, 75%, and 100%). The results indicated that Azolla could only tolerate effluent dilution rates of less than 25%. Therefore, a second experiment was conducted using lower rates (0%, 5%, 10%, 15%, and 20%). The highest biomass gain was observed at the 5% dilution level, whereas the 20% dilution level did not promote further biomass gain. The same dilution rate resulted in the lowest BOD, COD, TSS, and TKN after the experiment indicating high level of removal efficiency. These studies have provided ample information for developing sustainable strategies in managing swine farm wastewater in Lao PDR.