Characteristics of WWTP sludge after drying in greenhouse for agricultural purposes

Abstract

The sludge generated by sewage treatment which meets regulatory standards can be used in agriculture. With this understanding, the focus of this study is the evaluation of the agricultural characteristics and inorganic substances in excess activated sludge, which was subjected to drying in a greenhouse. The variables (factor) evaluated during the drying process were: type of sludge (digested or not digested), addition of lime to the sludge, and the physical layout and rotation of sludge in the greenhouse. The parameters monitored for this assessment were moisture, volatile solids and pH. The greenhouse cover and sides were made of translucent plastic to allow the penetration of solar radiation and prevent water from entering. A impermeable floor was used. The sludge was generated in sewage treatment plants located in the metropolitan region of Grande Vitória, Espírito Santo, Brazil. The solar drying of wastewater sludge in a greenhouse presented satisfactory results.

Real scale environmental monitoring of zoonotic protozoa and helminth eggs in biosolid samples in Brazil

“…With the population increase and urbanization, biosolid production also has increased and the application of this residue to soil for fertilization purpose represents the best option for disposal as this is rich in nutrients (Guadagnini et al 2013;Hachich et al 2013;Lima et al 2012;Lu et al 2012;Silva et al 2012). However, inherent in its use in agriculture are concerns about its effects on public health due to uncertainties surrounding the presence of enteric parasites, which can be sources of contamination in both food and surface water and groundwater; the low infective dose of certain pathogens, especially Cryptosporidium and Giardia; the possible growth of pathogenic bacteria, such as coliforms, which are used as indicators of safety but do not predict the presence of other pathogens (Abreu-Acosta and Vera 2011); and the potential for diseases caused by unknown agents (Santamaria andToranzos 2003, Sidhu andToze 2009).…”

Optimizing Convective Drying for Efficient Reduction of Phosphate Sludge Moisture: Experimental Investigations and Mathematical Modeling

“…The model can be used to predict the drying process for any convective drying conditions of PS. It could also be used to predict the sludge drying characteristic for large quantities in different industrial convective dryers such a greenhouse solar dryer which is the most popular system to dry similar products [46][47][48].…”