Monitoring of irrigation with urban waste water

Commencing in 1992, a 5-year soil and crop monitoring program was conducted to evaluate irrigation of sugarcane with urban waste water from the Thabeban treatment works, Bundaberg. Macro and micro soil nutrients, heavy metals, and water quality criteris were monitored. Productivity data were recorded and compared to zone productivity levels. Data showed that there has been virtually no beneficial accumulation of nutrients in sites irrigated with waste water except for sulfur. Sodium levels appeared to rise, particularly on the gleyed podzolic soil. This agrees with the nutrient levels measured in secondary treatment waste water from the Thabeban facility. Leachate analyses found only minor levels of heavy metals, nitrates and phosphates in deep drainage waters, suggesting a low likelihood of significant accession of these to groundwater.