PHYSICOCHEMICAL AND MICROBIOLOGICAL EVALUATION OF SEWAGE SLUDGE IN BÁVARO, DOMINICAN REPUBLIC: VIABILITY FOR USE AS AGRICULTURAL AMENDMENT

Abstract

Introduction:
The proper management of residual sludge generated in wastewater treatment plants is an increasing environmental and health challenge, especially in tourist areas like Bávaro, Punta Cana, where hotel activity generates significant volumes of domestic wastewater.
Objective:
To determine the agricultural use potential of the sewage sludge produced by a hotel complex treatment plant, through its physicochemical and microbiological characterization.
Materials and Methods:
A quantitative approach with descriptive design was applied. Sampling and analysis protocols from the United States Environmental Protection Agency (USEPA) were followed. Gravimetric analysis methods, inductively coupled plasma optical emission spectroscopy, ultraviolet-visible spectrophotometry, and scanning electron microscopy with energy-dispersive X-ray spectroscopy.
Results and Discussion:
The results indicated that heavy metal concentrations compiled with USEPA 40 CFR Part 503 limits and showed high agronomic value (OM 76,09%, N 2,26%, P 1,67%, K 0,73%). However, its classification as Class A biosolids is restricted due to the high microbial load, which includes 200 helminth eggs/4g TS, as well as the non-compliance with vector attraction reduction (TVS 88,13%, TS 11,97%).
Conclusions:
It is concluded that the residual sludge is safe regarding heavy metals and has agronomic potential, but its direct use is restricted due to organic instability and health risks. It is mandatory to apply stabilization and hygienization processes such as composting or thermophilic anaerobic digestion for its transformation into a safe biosolid.