Chemical Oxygen Demand and Nutrient Profiling of Effluents from Piggery Farms in Anambra State

Piggery operations are among the most nutrient-intensive livestock activities, generating effluents with high concentrations of organic matter, nitrogen, and phosphorus that can contribute substantially to the eutrophication of receiving water bodies. This study profiles the chemical oxygen demand and key nutrient parameters of effluents from three piggery farms in Anambra State, South East Nigeria. Effluent samples were collected fortnightly over a three-month period from each farm's primary waste holding structure and discharge point. Parameters analysed include chemical oxygen demand, total Kjeldahl nitrogen, ammonia nitrogen, nitrate, total phosphorus, total suspended solids, and pH, following standard methods. Results show that chemical oxygen demand values ranged from 6,200 to 22,000 milligrams per litre, depending on farm size and waste management practices. Total Kjeldahl nitrogen concentrations averaged 980 milligrams per litre across sampled farms, substantially exceeding the Federal Ministry of Environment effluent discharge limit of 20 milligrams per litre for nitrogen. Farms employing rudimentary lagoon systems showed lower effluent concentrations than those discharging untreated waste directly. The study identifies critical gaps in waste management infrastructure at the assessed farms and recommends the adoption of anaerobic digestion systems, biogas recovery as a co-benefit, and phased enforcement of effluent treatment regulations for agricultural enterprises by the Anambra State Environmental Protection Agency. Keywords: piggery effluent, chemical oxygen demand, nutrients, Anambra State, water pollution