Remoção de oxitetraciclina de águas contaminadas via destilação solar

Abstract

Pharmaceutical products are one of the most important sources responsible for water contamination, with an emphasis on veterinary antibiotics as their use has increased significantly in recent years. Veterinary oxytetracycline (OTC) is one of the most consumed antibiotics and has an important impact on the environment, however it is a persistent substance in conventional water and sewage treatments. Therefore, the present study aims to remove OTC from contaminated waters through an alternative technology that is distillation via solar energy, this technology consists of a low-cost and easy-to-operate system. A waterfall-type solar distiller was used to treat the contaminated water, this water was collected from an artesian well in the city of Barra de Santana/PB and combined with the antibiotic at a concentration of 30 mg.L-1, 45 mg.L-1 and 60 mg.L-1. Water characterization was carried out before and after the distillation process, due to the quantification of OTC in the water and physical-chemical analyses. In addition, water temperatures and glass temperatures were monitored, as well as data on ambient temperature, incidence of solar radiation, wind speed, relative humidity and distillate production. The internal and external heat transfer coefficients were determined. After the distillation process, the system was able to remove OTC in a range from 89.84% to more than 99.67% and water production reached 3,025.40 mL.m-2.day-1, in this day the incidence of average solar radiation was 628.38 W.m-2, following this, the maximum daily thermal efficiency obtained was 48.71%. Furthermore, considering the physical-chemical analyzes of contaminated and distilled water, maximum reductions in chloride content of 99.74%, electrical conductivity of 99.87% and maximum reduction level of 100% for total hardness, sodium and potassium were achieved. in distilled water, reaching values in accordance with the potability standards required by the current Ministry of Health Ordinance. The annual unit cost of drinking water is estimated at 0.11 R$.L-1.m2. It is concluded that the solar distillation system used has a real capacity to remove OTC and produce water to serve small communities in locations where there is a high incidence of solar radiation.