Sources and composition of waste water: Threats to plants and soil health

Abstract

Industrialization has caused huge changes in the global budget of critical chemicals at the earth’s surface. Waste water is being added to the soil with or without treatment, causing accumulation of metals, salts, pathogens, toxins etc. in the soil. Accumulation of these substances in soil ultimately affects crop growth and human health. Metals, salts, pathogens are added into soils through various means like pesticides, fertilizer, waste water and municipal waste either remain in the soil by forming insoluble complexes with soil constituents or taken up by plants and/or may pass into drainage water. The waste water contains toxic material likely to affect plants and human health. For Agricultural irrigation may result sail salinity, sodicity and heavy metal accumulation. The untreated waste water coming from various sources contains nutrients and excess of these nutrients resulting eutrophication. However, the waste water might also bring benefits for agricultural crops as it contains organic matter and essential nutrients. The common processes which have been used to remove non-biodegradable pollutants from waste water are sedimentation, flocculation, membrane filtration, photo catalysis and use of different sorbent materials. The present chapter will provide general understanding about the different sources of waste water, its composition and impacts on soil and plant health.