Sunlight disinfection of domestic effluents for agricultural use

摘要: Abstract The photochemical method of disinfecting domestic effluents planned for use as irrigation water edible crops was developed further, reaching a stage at which it can be used on an industrial scale. This disinfection uses sunlight the activation energy source; oxygen dissolved in (DO) oxidizing agent; and dye-sensitizer (methylene blue) intermediary absorption transfer to activate DO and/or destabilize organic matter molecules microorganisms oxidation target. study carried out experimental pilot-scale plant, capable treating up 50 m3/h effluent supplied by activated sludge sewage treatment plant located Tel-Aviv area. consists series 10 identical photoreactors (6 × 2 0.3 m3), installed unpaved road with 2% slope ensures free overflow treated through pilot plant. Preceding there is mixing reactor (2 1 m3) supplies (> 6 g O2/m3), MB (0.7 ± 0.1 g/m3) calcium hydroxide (33 3 pH correction (8.7–8.9). Operating flow rate 33 (effluent detention time: 35 min), intensities 700–2600 μEm−2 s−1, following decreases microbial counts were observed (log counts): coliforms −3.2 0.3; fecal coli −3.12 0.2; streptococci −3.9 poliovirus −1.9 0.25. did not show regrowth these during 7 days storage photoreactors, form impermeable crust when infiltrated into sandy soils. cost “sunlight plant” producing 200 m3 disinfected per hour estimated U.S.$ 3.95 100 m3.