A new residential township, the Zone of Integration, is proposed for development by the Lesedi Local Municipality in an area situated between Heidelberg and Ratanda in the Gauteng province. This area falls within a sewage treatment works buffer zone and determination of an effective buffer zone for the proposed development was required for the completion of relevant screening procedures prescribed by the Gauteng Department of Agriculture, Conservation and Environment. In order to determine an effective buffer zone for the proposed development, KWP Landscape Architects and Environmental Consultants (the consultants for the project) contracted Softchem to complete an investigation with the following objectives:

•  to complete certain studies to assess the impacts of the sewage treatment works on the    proposed development, and

•  determine what the effective buffer zone would be around the existing sewage treatment    works.

Certain selected studies (that included an analysis of air pollution potential of treatment technology used , analysis of movement of pathogens , potential for the spread of disease by flies , analysis of the health impacts of effluent , analysis of the influence of wind on odour and air pollution dispersion , and the prescribed buffer for the Erwat Heidelberg sewage treatment plant ) were completed to assess various factors that would possibly impact on the effective buffer zone for the sewage treatment plant. Based on present data for climatological factors and the size of the plant, an effective buffer zone for the Erwat Heidelberg sewage treatment plant of 400 m was recommended for future planning purposes.