AWWA REUSE52070

Effluent reuse is not a new concept; controlled wastewater irrigation has been practiced on sewage farms in Europe, America and Australia since the turn of this century and the value of wastewater for crop irrigation is becoming increasingly important in arid and semi-arid countries. The health risks associated with wastewater application to crops has been studied, particularly the survival of enteric bacteria and viruses in soil and on plant leaves. However, enteric virus uptake in plant roots has been little researched. Viruses pose a unique problem associated with their stability and persistence in the environment. This study investigated the potential use of drip irrigation to minimize the risks associated with viruses. Two varieties of tomatoes were grown in ten-gallon buckets filled with Pima Clay Loam and Brazito Sandy Loam soil types. Plants were irrigated with secondary effluent using surface drip irrigation and subsurface drip irrigation. Irrigation water was periodically seeded with bacteriophages MS-2 and PRD-1, Poliovirus type 1 (PV1), Enteric Adenovirus 40 (Ead 40). No systemic up take of viruses into the plant tissues of both varieties was observed. Surface irrigation always resulted in surface contamination of roots, leaves and fruits on plants of both varieties. However no above ground surface contamination was observed with subsurface irrigation in both varieties of tomato plants. Includes 18 references, tables, figures.