Study of the Environmental Impact in the use of sewage sludge in the agriculture

Abstract

The use of sewage sludge in agriculture is becoming more popular every day. It evident that contributions of nutrients and benefits of soil improvement, usually have economic advantages, with a favorable cost-benefit analysis to its application. Sewage sludge coming from biological treatment plants, primary, secondary or tertiary has a noticeable content of nitrogen, phosphorous, organic matter and other elements with nutritional value to crops. Their application benefits some soils properties such as water retention, texture and also structure. However, sewage sludge also has certain concentration of organic toxic, heavy metals and microorganisms that are undesirable due to potential health effects.
The paper describe an step by step methodology that could be used in environment impact assessment (EIA) of sewage sludge application in agricultural soils. Remarks on cost-benefit analysis and others key elements are given as general recommendation. The basic topic include:

. General information
· Location of the WWTP and the application site
· Data of the WWTP
· Actual land uses
· Current and future crops productivity
· Impacts by accidents (transport, roads and transportation vehicles)
· Impact by sludge characteristics (acceptability)
· Impact to the underground waters (Hydro geologic aspects)
· Impact to the surface waters (Hydrological Aspects)
· Impact to Habitats and the biodiversity
· Aesthetic Impacts and recreation related
· Impact to the air quality
· Health Impacts
· Acceptability of the neighboring communities
· Environmental monitoring
· Contingency Plans