Alcohol Consumption & Winery Wastewater Treatment
The worldwide total alcohol consumption in 2018 reached 6.2 liters of pure alcohol per person aged 15 years and older. Consequently, winery wastewater originates from various stages in the production process. One source is the fresh water used for cleaning, including equipment and facility washing, while other streams are directly linked to wine, such as effluent from filtration units and byproducts.
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Major Pollutants To Be Degraded In Winery Wastewater Treatment
Winery wastewater contains organic substances like ethanol, sugars, organic acids, phenolic compounds, and more. Additionally, there are toxic compounds from pesticides used on grapes. Discharging winery wastewater without treatment would lead to soil pollution. Conventional sewage treatment facilities are inadequate for processing winery wastewater, resulting in high levels of acidity (PH value) and chemical oxygen demand (COD). Due to variations among wineries, such as wine types, unique components, and wastewater volume, the treatment of winery wastewater needs to be specific. Moreover, even within the same winery, the effluent varies depending on the operation period and season.
A recent review provides a summary of the processes currently utilized or tested for treating winery wastewater, including physicochemical, biological, membrane filtration and separation, advanced oxidation processes, and combined biological and advanced oxidation processes. Physicochemical processes can be employed as pre-treatment to reduce total suspended solids (TSS).
Biological treatment processes employing membrane bioreactors show promise and effectively reduce organic load. Advanced oxidation processes (AOPs), particularly anodic oxidation via boron doped diamond electrode as post-treatment in combination with other methods, demonstrate higher efficiency in COD reduction. The mechanisms and limitations of each method have been reviewed elsewhere, offering guidance for selecting the appropriate approach based on specific conditions.
Henan XXX Winery Industry is one of the major manufactures and distributors of alcoholic beverages in Henan province.
Parameters of effluents from the wine manufacturer, after Boromond’s industrial wastewater treatment technologies, a combination of various pre-treatment and electrochemical oxidation:
COD 3490 mg/L
TOC 1320 mg/L
NTU 15.2
Combined BDD electrolysis and photolysis processes exhibit higher efficiency in degradation rate and energy consumption due to their synergistic effect. These processes can be implemented either separately or integrated together. The anodic oxidation section processes the wastewater and generates OH radicals, which are subsequently decomposed by light radiation in the photolysis section.
Initially, a two-chamber cubic reactor was proposed but faced challenges with foam formation during aeration. To address this, the reactor was modified into two divided columns, increasing economic efficiency by reducing the voltage from 15 to 5 V. To minimize the electrode gap, the reactor system was designed with two vertically connected columns. When treating real winery wastewater, this system exhibited improved efficiency in degrading total organic carbon (TOC) and reducing color compared to initial laboratory studies.
Both studies investigating simulated winery wastewater using Boromond trial module achieved complete elimination of color. Additionally, both studies achieved nearly 75% TOC reduction rates. However, the efficiency decreased with increased TOC concentration, as higher concentrations reduce the availability of ·OH radicals.
Anodic oxidation with boron-doped diamond (BDD) electrodes demonstrates the ability to process real effluents with high concentrations of COD, TOC, and more than 40 organic compounds. The addition of electrolytes like NaCl and Na2SO4, along with high-density currents, enhances oxidation efficiency, leading to total mineralization in 400 minutes.
The superior efficiency of this process stems from the larger number of radicals, which originate from weakly bonded HO· radicals on the BDD electrode with high O2-overpotential, as well as the generation of other radicals such as S2O82− and active chlorine species through the addition of salt, the whole process generates two kinds of radicals, HO· and SO4−·, with a higher yield of SO4−·, which can be converted into HO·. The S2O82− radical exhibits higher efficiency than H2O2 in removing COD (96%) and organic matter,TOC reduction increasing efficiency from around 50–71% .
Henan XXX Winery Industry can be utilized for removal purposes. In the operation of the anodic oxidation process, optimization of PH, H2O2 concentration, which yields 90% TOC removal, with 54% attributed to adsorption and 36% to the anodic oxdiation process.
Considering the complex organic components and toxicity of winery wastewater, each method aims to increase the effectiveness of radicals. Further studies on reactor optimization, utilization of multiple radicals, and novel catalyst synthesis are worthwhile endeavors.
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