Chemical Evaluation of Wastewater from Abattoir Operations and Its Environmental Impact in Maiduguri, Borno State

Abattoirs processing large numbers of livestock daily generate substantial volumes of blood, rumen contents, manure, and washwater that, without treatment, impose severe organic and nutrient loads on receiving water bodies and soils. This study chemically evaluated abattoir wastewater from the main abattoir in Maiduguri, Borno State, and assessed its impact on adjacent surface drainage channels. Wastewater was sampled from three points within the abattoir processing area and from the receiving drainage channel at 100, 300, and 600 metre intervals downstream of the discharge point. Fifty-four samples were collected over three months and analysed for biological oxygen demand, chemical oxygen demand, total suspended solids, total nitrogen, ammonia, total phosphorus, grease and oil, faecal coliforms, and selected metals including copper, zinc, and iron. Abattoir wastewater biological oxygen demand was 2,840 mg/L, chemical oxygen demand was 7,460 mg/L, and total nitrogen was 484 mg/L, all massively exceeding FEPA permissible discharge standards. Faecal coliforms were 4.2 times 10 to the power of 8 colony forming units per 100 mL. Metal concentrations were within moderate ranges but elevated relative to baseline. Downstream drainage channels showed progressive water quality improvement with distance but remained significantly above background levels. These results confirm severe pollution from Maiduguri abattoir operations and recommend installation of a simple biological treatment system including screening, sedimentation, and constructed wetland polishing as a low-cost treatment solution appropriate for the North East Nigerian context.

Keywords: abattoir wastewater, biological oxygen demand, Maiduguri, Borno State, wastewater treatment