Treatment of dairy cattle farming wastewater using constructed wetland system cultivated with rice
Abstract
The amount of waste produced each day by dairy cattle is one of the largest problems in intensive management systems. Therefore, disposing of residues from animal facilities has become a challenge for farmers and specialists due to its technical, sanitary, and economic aspects. Organic effluents from confined dairy production systems require proper dairy wastewater treatment before disposal. When discharged into water bodies without adequate treatment, these effluents can cause physical and chemical changes in water sources, posing risks to public health and water supply due to the presence of pathogens and/or toxic elements. This study evaluates the efficiency of a constructed wetland system (CWS) cultivated with rice (Oryza sativa) in removing pollutants from dairy cattle wastewater, while also assessing the crop yield as an integral indicator of the system’s performance. Given the limited number of samples collected, the results presented should be considered as a preliminary analysis, providing insights into the system’s performance and potential for future studies. The constructed wetland system has a surface area of 4 m² and operates with a flow of 500 L dia-1 and hydraulic retention time of 1.72 days; gravel was used as a support medium. The analyses conducted led to the conclusion that the constructed wetland system, cultivated with rice, demonstrated effective pollutant reduction, particularly excelling in the removal of organic matter (35%), turbidity (43%) and nitrite (36%). Rice cultivation showed adaptation to the constructed wetland system, exhibited satisfactory growth, and showed no signs of nutrient deficiency.
Keywords: biological treatment, cultivated beds, reuse, water resources.
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