II-1198 - TECHNICAL AND FINANCIAL COMPARISON OF THE DISINFECTION EFFICACY OF PERACETIC ACID AND SODIUM DICHLOROISOCYANURATE FOR DISINFECTING TREATED SEWAGE SAMPLES FROM THE DANCING DAYS SEWAGE TREATMENT PLANT

• DOI: https://doi.org/10.22533/at.ed.317562520053

• Palavras-chave: Disinfection, Treated Sewage, Chemical Product, Disinfection Efficiency, Chemical Product Cost, Peracetic Acid, Sodium Dichloisocyanurate, Jar-test, Thermotolerant Coliforms.

• Keywords: Disinfection, Treated Sewage, Chemical Product, Disinfection Efficiency, Chemical Product Cost, Peracetic Acid, Sodium Dichloisocyanurate, Jar-test, Thermotolerant Coliforms.

• Abstract:

  The sewage treatment carried out at sewage treatment plants (STPs) has the function of removing the contaminants present, with the aim of leaving the treated sewage in a condition to be discharged into the receiving bodies. One of the main contaminants in sewage is pathogenic microorganisms and in order to eliminate this risk to public health and the environment, sewage disinfection processes are carried out. 
  Disinfection aims to inactivate the pathogenic microorganisms naturally present in sewage using various physical-chemical processes, the main ones being the application of chemical products (chlorine compounds, ozone, phoracetic acid, etc.) and ultraviolet (UV) radiation. The use of chemical products is the most common practice in the disinfection of sewage from COMPESA's sewage treatment plants, so we need to constantly buy various chemical products available on the market, which are constantly changing in price and have a direct impact on the company's operating costs. 
  Therefore, in this work, bench tests were carried out with jar-tests at COMPESA's Sewage Laboratory, in which the disinfectant products sodium dichloroisocyanurate and peracetic acid were tested on the sewage treated at the Dancing Days WWTP. In these tests we applied the products under different conditions of application dosage and contact times with the aim of reducing the Thermotolerant Coliform Concentration, the microbiological parameter measured, below the limit of 1,000NMP/100mL recommended by the state legislation of Pernambuco (IN 03/2018 of the CPRH). With this laboratory data and the costs of the products, we can assess which has the best disinfection efficiency and its financial viability, as well as estimating the performance of the products under operational conditions in the treatment units of the WWTPs.

  The treated sewage used in the tests was collected at the Dancing Days sewage treatment plant, which is a conventional COMPESA sewage treatment plant operated by BRK Ambiental in Recife/PE, and has a UASB reactor design followed by a Percolator Biological Filter and Secondary Decanter, later followed by a contact tank with the application of a sodium dichloroisocyanurate solution to disinfect the treated effluent.