Static mixer continuous chemical coagulation-flocculation for cattle feedlot wastewater treatment

GARCÍA, ANA ROSA; CASSANELLO, MIRYAN; DE LOS SANTOS, CHRISTIAN NAHUEL; DE LOS SANTOS, CHRISTIAN NAHUEL; FLEITE, SANTIAGO NICOLÁS; DE IORIO, ALICIA FABRIZIO; FLEITE, SANTIAGO NICOLÁS; DE IORIO, ALICIA FABRIZIO; GARCÍA, ANA ROSA; CASSANELLO, MIRYAN

DESALINATION AND WATER TREATMENT

DESALINATION PUBL

Lugar: Hopkinton; Año: 2020 vol. 189 p. 98 - 107

1944-3994

Feedlots generate a large amount of manure-contaminated runoff wastewater that is accumulatedin reservoirs and should be treated promptly before disposal. A promising alternative to reduce theorganic level while recovering the nutrients in a timely manner is a physicochemical treatment basedon coagulation?flocculation. This work aims at optimizing the coagulation?flocculation stage of afeedlot wastewater treatment. First, batch experiments were carried out to define and optimize thedose of coagulants. Then, continuous coagulation was examined inside a horizontal tube, empty andprovided with static mixers. Iron chloride, calcium hydroxide and magnesium hydroxide were testedas coagulants. The best strategy found was a combined addition of iron chloride followed by calciumhydroxide. Removal efficiencies of around 98% (phosphorus and organic matter) were achieved with adose of 10 mM iron (III) plus the calcium hydroxide required for neutralization. The use of a Koflo typestatic mixer was found to be the best configuration, promoting the formation of flocs with excellentsettling properties. Settler areas up to eight times smaller would be required if the flocculation waspromoted in the static mixer rather than in a stirred tank. The proposed method would be convenientfor both small and large feedlot establishments to self-treat wastewater shortly after a rainfall.