use of ozone during advanced primary treatment of wastewater for its reuse in agriculture: an approach to enhance coagulation, disinfection and crop productivities

• Published in: Water science and technology 2008-01, Vol.57 (6), p.955-962
• Main Authors: Campos-Reales-Pineda, A E, de Velasquez, M T Orta, Rojas-Valencia, M N
• Format: Article
• Language: English
• Subjects: Agricultural wastes; Agriculture; Agriculture - methods; Animals; Chemical oxygen demand; Chlorination; Chlorine; Coagulants; Coagulation; crop production; Crops, Agricultural - growth & development; Disinfection; Disinfection - instrumentation; Disinfection - methods; dose response; Effluents; Eggs; Germination; helminths; Helminths - drug effects; irrigated farming; Irrigation; Lactuca sativa; optimization; ova; Ovum - drug effects; Ovum - growth & development; Ozone; Ozone - pharmacology; Parasite Egg Count; phytotoxicity; Removal; Reuse; seed germination; Seeds; Settleable solids; Settling rate; Settling velocity; Suspended particulate matter; Total suspended solids; Toxicity; Turbidity; Waste Disposal, Fluid - instrumentation; Waste Disposal, Fluid - methods; Wastewater; wastewater irrigation; Wastewater treatment; Water Purification - instrumentation; Water Purification - methods; water reuse; Water Supply; Water treatment
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2008.204

The purpose of this work was to evaluate the effect that ozone (O(3)) has on the advanced primary treatment (APT) and disinfection of wastewaters for their reuse in agriculture. The enhancement and optimization of APT was done by applying low O(3) doses during coagulation. By applying an ozone dose of 2 mg/L during APT, the required coagulant dose may be reduced by up to 25% to achieve a similar turbidity removal (and up to 50% for total suspended solids removal), when compared to a conventional APT treatment. When the same coagulant dose was applied (60 mg/L), the volume of settleable solids was reduced from 31.0 to 25.5 mL/L, and the settling velocity increased from 0.111 to 0.139 m/min. Disinfection was also improved by the use of ozone, which leads to better plant germination rates than when using chlorination, because of reduced toxicity of the ozonated effluents. Additionally, helminth eggs content was reduced by applying ozone.