This work proposes an integrated leachate treatment strategy, combining a solar photo-Fenton reaction, to enhance the biodegradability of the leachate from an aerated lagoon, with an activated sludge ...process, under aerobic and anoxic conditions, to achieve COD target values and nitrogen content according to the legislation. The efficiency and performance of the photo-Fenton reaction, concerning a sludge removal step after acidification, defining the optimum phototreatment time to reach a biodegradable wastewater that can be further oxidized in a biological reactor and, activation sludge biological process, defining the nitrification and denitrification reaction rates, alkalinity balance and methanol dose necessary as external carbon source, was evaluated in the integrated system at a scale close to industrial. The pre-industrial plant presents a photocatalytic system with 39.52 m2 of compound parabolic collectors (CPCs) and 2 m3 recirculation tank and, an activated sludge biological reactor with 3 m3 capacity.
Leachate biodegradability enhancement by means of a solar driven photo-Fenton process was evaluated using direct biodegradability tests, as Zahn–Wellens method, and indirect measure according to average oxidation state (AOS), low molecular carboxylic acids content (fast biodegradable character) and humic substances (recalcitrant character) concentration. Due to high variability of leachate composition, UV absorbance on-line measurement was established as a useful parameter for photo-Fenton reaction control.
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•Pre-industrial plant for leachate treatment using chemical and biological systems.•Leachate biodegradability enhancement using a solar photo-Fenton reaction.•Nitrogen removal using biological nitrification and denitrification processes.
In Mexico, mezcal production generates huge amounts of vinasses (mezcal vinasses) that cause negative environmental impacts. Thus, mezcal vinasses treatment is necessary before discharging to water ...bodies. Although there is no information for mezcal vinasses, similar effluents have been treated by biological processes (i.e., anaerobic and aerobic), usually complemented by oxidative chemical pretreatments (ozonation) and physicochemical methods. In this work, mezcal vinasses were first ozonated and then subjected to batch aerobic biological degradation. In the ozonation stage, organic matter removals were 4.5 to 11 % as COD, whereas the removal of aromatic compounds and phenols was 16 to 32 % and 48 to 83 %, respectively. In aerobic post-treatment, COD depletions up to 85% were achieved; removals in ozone-pretreated vinasses were higher (80–85 %) than those in raw vinasse (69 %). It seems that ozonation preferentially attacked the recalcitrant fraction of organic matter present in the vinasses and increased its aerobic biodegradability.
There is increasing concern about chemical pollutants that have the ability to mimic hormones, the so-called endocrine-disrupting compounds (EDCs). One of the main reasons for concern is the possible ...effect of EDCs on human health. EDCs may be released into the environment in different ways, and one of the most significant sources is industrial wastewater. The main objective of this research was to evaluate the treatment performance of different wastewater treatment procedures (biological treatment, filtration, advanced oxidation processes) for the reduction of chemical oxygen demand and seven selected EDCs (dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate, bisphenol A and nonylphenol) from wastewaters from a mill producing 100 % recycled paper. Two pilot plants were running in parallel and the following treatments were compared: (i) anaerobic biological treatment followed by aerobic biological treatment, ultrafiltration and reverse osmosis (RO), and (ii) anaerobic biological treatment followed by membrane bioreactor and RO. Moreover, at lab-scale, four different advanced oxidation processes (Fenton reaction, photo-Fenton reaction, photocatalysis with TiO₂, and ozonation) were applied. The results indicated that the concentrations of selected EDCs from paper mill wastewaters were effectively reduced (100 %) by both combinations of pilot plants and photo-Fenton oxidation (98 %), while Fenton process, photocatalysis with TiO₂ and ozonation were less effective (70 % to 90 %, respectively).
According to the characteristics of aniline dyeing wastewater, aerobic biological treatment was adopted herein, and high-throughput sequencing technology was used to analyze the changes to the ...microbial community structure and diversity in the aerobic sludge acclimation stage. As a result, according to the experimental study on the effects of different biomass, the initial pH value and the salinity with the aerobic biological treatment, the chemical oxygen demand (COD) degradation rate can increase linearly with the increase in biomass under different biomass conditions. The organic matter degradation rate is 6.24 mg/L COD·h−1·(mg/L·MLSS)−1, with a correlation coefficient (R2) of 0.98704. When the initial pH value is less than 7.0 ± 0.2, the COD degradation rate increases with the increase in the initial pH value and then decreases gradually. The optimal sludge concentration is 4 g/L; the optimal initial pH value is in the range of 7.0–8.0; the optimal salinity is 1.7%. When the initial concentration of COD is 3000 mg/L, the COD value gradually stabilizes and decreases to 1500 mg/L after 32 h, the degradation rate reaches 50%, and the pH decreases from 7.5 to 4.5. Sphingopyxis has been detected in sludge samples from the third cycle of acclimation, which can biodegrade aromatic compounds, anthraquinone dyes, and their intermediates, and the relative abundance of Sphingopyxis increased from 0.18% to 5.08%, indicating a potential biodegradation ability of aniline dyeing wastewater.
Background
Biological treatment technology is good for the recovery of resources and energy from municipal solid waste (MSW) and cutting down biodegradable components in landfill waste. Recently, the ...aerobic biological treatment of MSW has increased in rural areas of China. These facilities are usually open setup and close to nearby residents, and complaints tend to be received regarding odorous gases. A semi-in-vessel setup facility was built in recent years, and its impact on the environment and personnel is not clear.
Results
Ammonia was the predominant compound released from the windrow and its concentration was one order of magnitude higher than those of other compounds. Terpenes and reduced sulfur compounds (RSCs) persisted throughout the entire active fermentation process, with only slight decreases. The biofilter pool had a greater odor impact on the surrounding neighborhood than the waste unloading and sorting operation. The concentrations of most compounds were reduced by the biofilter pool. Ten major substances that caused odors at the facility were analyzed, where most comprised RSCs. The odor impact of the facility was low, but it was associated with a carcinogenic risk to the operators, thereby indicating the need to improve personal protection.
Conclusions
Large amounts of ammonia and volatile organic compounds were released from the composting units, but they had a low odor impact on the environment because of the semi-in-vessel setup. The odor impact of the facility was low but it was associated with a carcinogenic risk to the operators. This technology can be popularized in rural areas.
Thermal Effects Ye, Jie; Zhang, Panyue; Zeng, Guangming ...
Water environment research,
October 2014, Letnik:
86, Številka:
10
Journal Article
Recenzirano
Odprti dostop
This review is on the research literature published in 2013 on topics relating to thermal effects in water pollution control. The review is divided into the following sections: membrane preparation ...and separation, adsorbent preparation and adsorption process, aerobic biological treatment, anaerobic biological treatment, natural treatment, resource recover and water environment.
Milk fat/protein degrading microorganisms were isolated from different locations of a dairy wastewater treatment system with the goal of developing an inoculum for bioaugmentation strategies. Eight ...isolates, identified by 16S rRNA gene sequence analysis as belonging to the genera
Bacillus,
Pseudomonas, and
Acinetobacter, were tested for their ability to remove COD and protein from a milk-based medium (3000
mg/L COD) and compared to a commercial bioaugmentation inoculum. The
Acinetobacter isolate exhibited a pellet-type growth in liquid culture, a property that could potentially aid in the separation of microbes and liquid phase following treatment. Based on the individual degradation capacity and growth behavior of the isolates, three microorganisms were further selected and tested together. This consortium exhibited a COD removal similar to the commercial inoculum (57% and 63%, respectively), but higher protein (consortium: 93%; commercial inoculum: 54%), and fat removals (consortium: 75%; commercial inoculum: 38%).
An air micro-bubble bioreactor (AMBB) using a free self-adapted microbial population, 15 dm3 working volume, was used for aerobic treatment of winery wastewater. This reactor utilizes a Venturi ...injector in conjunction with mass transfer multiplier nozzles, which allow an efficient oxygen transfer. The reactor can operate in batch or continuous conditions. The dynamics of chemical oxygen demand (COD), biomass and total contents of polyphenolic compounds was followed throughout each trial. The wastewater COD ranged between 4.0-8.0 kg COD m(-3) and the efficiency of the batch treatment was about 90.0 +/- 4.3%, after 6 days of operation. The maximum efficiency obtained was achieved after 15 days of treatment (99%). In continuous conditions, the loading rate and the treatment efficiency ranged between 0.45-1.00 kg COD m(-3) d(-1) and 93.3 +/- 2.0%, respectively. The AMBB hydraulic retention time was 15 days. To assess the suitability of treated water in relation to vineyard irrigation, the effluent was physico-chemical analysed and direct toxicity bioassays with effluent matrix were carried out using Lepidium sativum L. seeds. The results showed the water quality required to be reutilised minimizing water consumption. This study will contribute for the implementation of an efficient water use plan, aiming the preservation of the water resource and the reduction of the wastewater production.
The degradation of the organic pollutants present in winery wastewater was carried out by the combination of two successive steps: an aerobic biological process followed by a chemical oxidation ...process using Fenton's reagent. The main goal of this study was to evaluate the temporal characteristics of solids and chemical oxygen demand (COD) present in winery wastewater in a long term aerated storage bioreactor. The performance of different air dosage daily supplied to the biologic reactor, in laboratory and pilot scale, were examined. The long term hydraulic retention time, 11 weeks, contributed remarkably to the reduction of COD (about 90%) and the combination with the Fenton's reagent led to a high overall COD reduction that reached 99.5% when the mass ratio (R = H(2)O(2)/COD) used was equal to 2.5, maintaining constant the molar ratio H(2)O(2)/Fe(2+)=15.
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