Treatment of sugarcane vinasse by combination of coagulation/flocculation and Fenton’s oxidation

Abstract

The efficiency of individual and integrated processes applied to organic matter reduction and biodegradability improvement of a biodigested sugarcane vinasse wastewater was assessed. Strategies considered were Fenton's oxidation (Strategy 1), coagulation/flocculation (Strategy 2) and the combination of both processes (coagulation/flocculation followed by Fenton's reaction) - Strategy 3. It was found that Fenton's oxidation per se allowed reducing the organic matter, increasing the wastewater biodegradability and a non-toxic effluent was generated; however the cost of treatment was very high (86.6 R$/m(3) - 21.2 €/m(3)). Under optimized conditions, coagulation/flocculation provided a slight increase in effluent's biodegradability, toxicity towards Vibrio fischeri was also eliminated and moderate removals of total organic carbon - TOC - (30.5%), biological oxygen demand - BOD5 - (27.9%) and chemical oxygen demand - COD - (43.6%) were achieved; however, the operating costs are much smaller. The use of dissolved iron resulting from coagulation/flocculation (270 mg/L) as catalyst in the second stage - Fenton's oxidation - was shown to be an innovative and economically attractive strategy. Under optimal conditions overall removals of 51.6% for TOC, 45.7% for BOD5 and 69.2% for COD were achieved, and a biodegradable (BOD5:COD ratio = 0.54) and non-toxic effluent was obtained. In order to increase the efficiency of the process but using less hydrogen peroxide, the Fenton's oxidation was performed by gradually adding the oxidant. This procedure allowed to obtain the highest organic matter removal efficiency (as compared with the addition of all hydrogen peroxide at the beginning of the reaction). This way it was possible to minimize the reagent consumption and, consequently, reduce the treatment cost.

Improvement of anaerobic digestion of landfill leachate by using coagulation‐flocculation, Fenton's oxidation and air stripping pretreatments

“…It was observed that COD removal from leachate at pH 7 was 35%. On the other hand, Guerreiro et al [4] showed that the best removal of COD and BOD 5 was obtained at pH 3. In fact, the increase of the solution pH resulted in a reduction in the retention of ferric chloride particles.…”

“…Anaerobic digestion (AD), the most popular biological treatment, produces moderate amounts of sludge, quite effective for young leachate and generates energy from the methane produced making this process economically and environmentally advantageous [3,4]. Anaerobic digestion (AD), the most popular biological treatment, produces moderate amounts of sludge, quite effective for young leachate and generates energy from the methane produced making this process economically and environmentally advantageous [3,4].…”

“…The main idea of this study was to propose an alternative approach for the treatment of a leachate generated in a controlled discharge in Tunisia. Anaerobic digestion (AD), the most popular biological treatment, produces moderate amounts of sludge, quite effective for young leachate and generates energy from the methane produced making this process economically and environmentally advantageous [3,4].…”

Using the Combined Fenton-MBR Process to Treat Cutting Fluid Wastewater

“…Ligia F. Guerreiro et al [33] treated sugarcane vinasse using a combination of coagulation/ flocculation and Fenton's oxidation, and COD removal efficiency was 69.2%. Jaime Martin-Pascual et al [40] studied the MBBR-MBR technology under 10 h and 24 h of HRT and three filling ratios (20%, 35%, and 50%) at temperatures between 2.5°C and 17.3°C, and COD removal was ultimately 86.4%.…”

Recuperação e tratamento de água proveniente de vinhaça biodigerida e sua utilização em processos de produção de bioenergia

“…Por isso, para alterar essa propriedade e conseguir remover as impurezas faz-se uso inicialmente do processo de coagulação/floculação que é aplicado facilmente e com baixos custos de operação (GUERREIRO et al, 2016). Nesse processo, é necessária a adição de um coagulante químico, como o sulfato de alumínio amplamente usado no Brasil, que reage com a água gerando íons positivos que atraem as impurezas carregadas com carga negativa, ocasionando na formação de partículas grandes.…”