A waste stabilization pond (WSP) is a hole in which household wastewater and other types of sewage are stored for long periods of time so that organic materials existing in them are deposited, decomposed and stabilized through exposure to light and heat and growth of algae and microorganisms. In WSPs, deposition and stabilization processes take place simultaneously. Such features make WSPs suitable for treating industrial sewage such as wastewaters produced by slaughterhouses, dairy plants and canned food factories. The present study sampled wastewaters collected and treated by the treatment plant of a slaughterhouse in Ahvaz and compared the relevant measured parameters with the standards set by the Environmental Protection Organization of Iran in order to determine the efficiency of WSPs in treating wastewaters and making them usable for irrigation purposes. The results indicate that Turbidity, BOD5, PH, COD, TDS, and TSS values for the treated wastewaters stood at >1000 NTU, 912 mg/lit, 8.78, 1520 mg/lit, 1052 mg/lit, and 2180 mg/lit respectively. A comparison of these values with the standard values set by the Environmental Protection Organization of Iran revealed a significant difference. This finding shows that the wastewater treatment plant under study had a poor productivity and performance and that wastewater treated by that facility could not be used for irrigation or pumped into surface waters. Therefore, environmental management programs and solutions have been suggested in order to help control and reduce the adverse effects of treated wastewater.