The researchers evaluated the efficiency of wastewater treatment plants in Taiz City for irrigation. They studied two treatment plants and found that the treated wastewater had lower levels of harmful substances like total dissolved solids and fecal coliform. However, the treatment was not sufficient for safe irrigation according to standards. The industrial wastewater had high levels of pollutants, making it unsuitable for irrigation. The study suggests the need for improving the sewerage system, expanding the treatment plants, and using better treatment methods to meet irrigation standards.