Thesis (PhD)--University of South Australia, 2015. Includes bibliographical references (pages 182-198) Emitter clogging, often referred to as biofouling, has evolved as a major problem in the drip irrigation (DI) industry using recycled water for irrigation. Biofouling causes non-uniformity in the system requiring expensive remedial practice and often, replacement of the laterals. It is, therefore important that the biofouling process is properly understood in terms of all the variables involved. Growing evidence suggests that the soil thermal condition is a major determinant of clogging although very little or no measurable information is available. The main objective of the work presented in this thesis was, therefore, to quantify the clogging process in subsurface type emitters under different soil thermal condition. It also aimed at contributing towards the development of a nonchemical remedial practice against biofouling.