Pig farming represents a key contribution to the economic development of Viet Nam as it creates jobs and raises income for millions of households in the country. However, rapid growth of the sector has recently resulted in negative impacts to the environment due to the large amount of untreated or improperly treated wastewater and manure discharges from the farms. A key related problem is the lack of accurate data on discharge pollutant loads, which leads to inaccurate forecasting of generated waste volumes and inappropriate design of treatment systems. This Action Program was therefore designed to plug this gap, and involved conducting a comprehensive, in-depth investigation of existing practices and technical approaches for wastewater and manure management involving 40 household pig farms and 25 large-scale pig farms located in five representative cities and provinces of the Red River Delta in Viet Nam ‒ Hanoi, Hung Yen, Thai Binh, Thanh Hoa and Bac Giang. An innovative methodology has been proposed to accurately estimate units of pollutant load discharged per pig head for different types of pigs. Both primary and secondary data (including from literature reviews, field surveys such as those using questionnaires, sampling and water quality analysis, and laboratory tests) have been collected as important inputs for estimation. As a result, a reliable and comprehensive set of Viet Nam contextspecific data on pollutant load discharge units from pig farms has been established and proposed for future use.

The study was conducted at 40 household pig farms and 25 large-scale pig farms across the selected provinces and cities in the Red River Delta, Viet Nam. For household farms, the survey was conducted in four provinces and cities, namely Thai Binh, Bac Giang, Thanh Hoa and Hanoi. In each province or city, 10 household pig farms were randomly selected from the obtained list of pig farms to conduct interviews using a questionnaire form. For large-scale pig farms, the survey was conducted in three provinces, namely Hanoi (in Ung Hoa, Son Tay, Gia Lam district), Hung Yen (Van Lam district) and Thanh Hoa (Van Xuong district). In each district, five large-scale farms were selected randomly to conduct the interviews and questionnaire surveys.

It was found that mixed waste (urine, manure, wastewater) led to complications in treatment. About 50% of surveyed households mixed waste prior to treatment and disposal at their pig farms; meanwhile this ratio rose to 65% in large-scale farms. The material flow in a life cycle for different types of pigs was estimated as shown in Figure 1. Accurate estimation of average pollutant load discharge units per pig (including urine, manure, and wastewater) in a life cycle plays an essential role for environmental protection and the decision-making process of policymakers. This data is crucial for calculating waste streams or flows when designing waste treatment systems/facilities as well as for the processes of inspection, pollution control and waste auditing carried out by state agencies. Quantifying pollutant load discharge units can also assist in calculating the greenhouse gas emission inventory due to pig production in Viet Nam. Results from the study have been utilised in the establishment of an effluent standard for livestock wastewater (QVCN62-2016/BTNMT).

Figure 1. Estimation of input and output flows in large-scale pig farms

• Currently, most pig farms in the Red River Delta of Viet Nam fail to satisfy the National Technical Regulation on the Effluent of Livestock QCVN 62-MT: 2016/BTNMT, and urgent action is needed.
  Mixing different types of waste (urine, manure, and wastewater) complicates treatment, thus improved architectural andprocedural design for farms is required.
• Separating solid and liquid contents of waste significantly reduces wastewater pollutants.
• Reducing cleaning/washing water in large-scale pig farms also leads to reduction of pollutants in wastewater.
• A combination or coordination of effective treatment options should be considered in both household level and largescalepig farms in Viet Nam.

Report of WEPA Action Program in 2017 (235 KB)