2种典型餐厨垃圾资源化处理工艺的环境影响分析

为了评估餐厨垃圾资源化处理工艺对环境的影响,运用生命周期评价的方法,比较了2种典型的资源化处理工艺——好氧堆肥和湿热处理对环境的影响。结果表明,2种餐厨垃圾资源化处理工艺对全球变暖、生态毒性、酸化和富营养化的影响各有不同。其中,好氧堆肥对全球变暖的贡献较大,碳排放为337.7 kg CO_2eq./t。湿热处理为163.1 kg CO_2eq./t。在环境影响负荷方面,湿热处理工艺中的高能耗加重了毒性的影响。但由于其对环境的酸化、富营养化的不利影响较小,湿热处理的环境影响负荷总值是好氧堆肥的62.5%。总体上,湿热处理是一种对环境影响较小的餐厨垃圾处理工艺。     

循环流化床锅炉燃煤技术热电厂生命周期评价

运用生命周期评价方法,应用Gabi5.0软件对采用循环流化床锅炉燃煤技术的热电企业进行资源耗竭和环境影响分析,计算各生产单元生命周期清单的全球变暖潜值、酸化效应潜值、富营养化潜值、非生物资源耗竭潜值、人体毒性潜值以及光化学烟雾和臭氧生成潜值等主要环境影响类型,对燃煤发电过程进行生命周期评价。结果表明,全球变暖和非生物资源耗竭为发电运行过程中主要的环境影响因素,分别占53%和15.05%;锅炉燃烧阶段的环境影响最重,占整个生命周期影响值的77.12%,并且除生物耗竭潜值外的其他5项指标均为发电运行阶段各个单元中最高。采用SNCR脱硝技术减少燃烧过程中NOx的排放量,并对该技术方案进行生命周期评价,比较方案实施前后的环境影响。     

广州市生活垃圾高温有氧静态堆肥的生命周期分析

运用生命周期分析(LCA)方法,对广州市生活垃圾高温有氧静态堆肥系统进行分析,计算出全生命周期的资源消耗和环境影响潜值,同时与垃圾焚烧典型工艺的LCA数据进行对比。结果表明,堆肥处理的环境影响负荷为0.023PET90,资源消耗系数为9.238mPET90。环境影响类型中光化学臭氧合成造成的影响最大,占环境总影响的43.8%。与焚烧处理方式相比,高温有氧静态堆肥的环境总影响较小,环境影响负荷相比于焚烧减少20.3%,在降低酸化的影响方面有较为显著的作用。     

Life Cycle Assessment as Part of Sustainability Assessment for Chemicals (5 pp)

Background LCA is the only internationally standardized environmental assessment tool (ISO 14040-43) for product systems, including services and processes. The analysis is done ‘from cradle-to-grave’, i.e. over the whole life cycle. LCA is essentially a comparative method: different systems fulfilling the same function (serving the same purpose) are compared on the basis of a ‘functional unit’ - a quantitative measure of this function or purpose. It is often believed that LCA can be used for judging the (relative) sustainability of product systems. This is only partly true, however, since LCA is restricted to the environmental part of the triad ‘environment/ecology - economy - social aspects (including intergenerational fairness)’ which constitutes sustainability. Standardized assessment tools for the second and the third part are still lacking, but Life Cycle Costing (LCC) seems to be a promising candidate for the economic part. Social Life Cycle Assessment still has to be developed on the basis of known social indicators.Method and Limitations LCA is most frequently used for the comparative assessment or optimization analysis of final products. Materials and chemicals are difficult to analyse from cradle-to-grave, since they are used in many, often innumerable product systems, which all would have to be studied in detail to give a complete LCA of a particular material or substance! This complete analysis of a material or chemical is evidently only possible in such cases where one main application exists. But even if one main application does exist, e.g. in the case of surfactants (chemicals) and detergents (final products), the latter may exist in a great abundance of compositions. Therefore, chemicals and materials are better analysed ‘from cradle-to-factory gate’, leaving the analysis of the final product(s), the use phase and the ‘end-of-life’ phases to specific, full LCAs.Conclusion A comparative assessment of production processes is possible, if the chemicals (the same is true for materials) produced by different methods have exactly the same properties. In this case, the downstream phases may be considered as a ‘black box’ and left out of the assessment. Such truncated LCAs can be used for environmental comparisons, but less so for the (environmental) optimization analysis of a specific chemical: the phases considered as ‘black box’ and left out may actually be the dominant ones. A sustainability assessment should be performed at the product level and contain the results of LCC and social assessments. Equal and consistent system boundaries will have to be used for these life cycle tools which only together can fulfil the aim of assessing the sustainability of product systems.     

Development of freshwater sediment management standards for organic matters, nutrients, and metals in Korea

Korean water quality managers are required to promptly develop national assessment standards for freshwater sediment quality due to the Four Major River Restoration Project in Korea in 2009. We conducted this study to develop sediment management standards (SMSs), determining obviously and severely polluted sediment, which could have adverse impacts on water quality and aquatic ecosystem. The SMSs values were derived from the 95th percentile of concentration distribution for organic matter and nutrients in sediment quality database. For the SMSs of metals, foreign sediment quality guidelines (SQGs) were adopted. As a result, 13 % for loss on ignition (LOI), 1,600 mg/kg for total phosphorus (TP), and 5,600 mg/kg for total nitrogen (TN) were set as the SMSs for freshwater sediment in Korea. These values were higher than the range of heavily polluted sediment from USEPA Region 5 guideline derived by the similar approaches for the Great Lakes harbor sediments, and similar or lower than the severe effect level (SEL) from provincial sediment quality guideline (PSQG) of Ontario, Canada by screening level concentration (SLC) approach. However, SMSs in the present study are appropriate considering the concentration ranges and the Korean SMSs’ definition for freshwater sediments in Korea. The Puget Sound marine sediment cleanup screening level (CSL) in Washington State, USA were adopted as the Korean SMSs for As (93 mg/kg), Cd (6.7 mg/kg), Cr (270 mg/kg), Cu (390 mg/kg), Pb (530 mg/kg), and Zn (960 mg/kg) in freshwater sediments. Hg concentration (0.59 mg/kg) of CSL was too low to determine the polluted freshwater sediments in Korea, and the SEL of Ontario, Canada for mercury concentration (2 mg/kg) was selected as the SMS for Hg. These values were found reasonable through the assessment of applicability with the datasets from locations directly affected by obvious point sources. These results indicate that SMSs for organic matter, nutrient, and metals derived within the present study can successfully determine obviously and severely polluted sediment in Korea. However, the SMSs have limits to specifically determine the effects of polluted sediment on water quality and aquatic ecosystem in Korea. Thus, we will revise and specify SMSs considering those effects and further sediment quality assessment framework in the near future.     

Optimal regulation of N/P in horizontal sub-surface flow constructed wetland through quantitative phosphorus removal by steel slag fed

High concentration of nitrogen and phosphorus and imbalance of N/P can lead to the formation of water and the malignant proliferation of toxic microalgae. This study put forward the advanced nutrient removal with the regulation of effluent N/P as the core in order to restrain the eutrophication and growth of poisonous algae. According to the preliminary study and review, the optimal N/P for non-toxic green algae was 50:1. The horizontal sub-surface flow constructed wetland was filled with steel slag and ceramsite to achieve the regulation of effluent N/P. The results showed that steel slag had the stable P removal capacity when treating synthetic solution with low P concentration and the average removal rate for 1.5, 1.0, and 0.5 mg/L synthetic P solution was 2.98 ± 0.20 mg kg−1/h, 2.26 ± 0.15 mg kg−1/h, and 1.11 ± 0.10 mg kg−1/h, respectively. Combined with P removal rate and P removal task, the filling amount of steel slag along the SSFCW (sub-surface flow constructed wetland) was 3.22 kg, 4.24 kg, and 4.31 kg. In order to ensure the stability of dephosphorization of steel slag, the regeneration of P removal capacity was investigated by switching operation of two parallel SSFCW in 20 days for cycle. The N removal was limited for the deficiency of carbon source (COD (chemical oxygen demand)/TN = 3–4), and was stable at 18.5–31.9% which was less affected by temperature. Therefore, by controlling the process of quantitative P removal of steel slag, the effluent N/P in SSFCW can be stable at 40–60:1 in the whole year, so as to inhibit the malignant proliferation of toxic algae.     

Sensitivity of urban ozone formation to chlorine emission estimates

Recent evidence has demonstrated that chlorine radical chemistry can enhance tropospheric volatile organic compound oxidation and has the potential to enhance ozone formation in urban areas. In order to investigate the regional impacts of chlorine chemistry in southeastern Texas, preliminary estimates of atmospheric releases of atomic chlorine precursors from industrial point sources, cooling towers, water and wastewater treatment, swimming pools, tap water, reactions of chlorides in sea salt aerosols, and reactions of chlorinated organics were developed. To assess the potential implications of these estimated emissions on urban ozone formation, a series of photochemical modeling studies was conducted to examine the spatial and temporal sensitivity of ozone and a unique marker species for chlorine chemistry, 1-Chloro-3-methyl-3-butene-2-one (CMBO), to molecular chlorine emissions estimates. Based on current estimates of molecular chlorine emissions in southeastern Texas, chlorine chemistry has the potential to enhance ozone mixing ratios by up to 11–16 ppbv. Impacts varied temporally, with emissions from cooling towers primarily responsible for a morning enhancement in ozone mixing ratios and emissions from residential swimming pools for an afternoon enhancement. Maximum enhancement in CMBO mixing ratios ranged from 59 to 69 pptv.     

Performance evaluation of a decentralized wastewater treatment system in India

A Decentralized Wastewater Treatment System (DEWATS) provides an economically feasible and efficient wastewater treatment solution especially in developing countries. It has an enormous potential for developing a sustainable environmental sanitation system. In this study, the treatment efficiency of eight DEWATS plants was evaluated in the state of Maharashtra, India, for their performance in terms of selected physico-chemical parameters of the wastewater. Although the efficiency of some of the plants was lower than that reported in literature, the effluent quality of all the plants was within the permissible discharge limits of the Central Pollution Control Board for all the parameters. Comprehensive assessment of Plant I was carried in terms of its technical and socio-economic aspects. Moreover, LCA tool has been utilized to evaluate the environmental impacts of the operation stage of DEWATS. The midpoint, CML 2001 (April 2015) methodology was adopted, in which 11 impact categories were considered. From the life cycle impact assessment and interpretation, the main impacts are identified as releases of COD, P-PO₄^3?, and N-NH₄⁺ to water bodies and disposal of sludge. Due to negligible energy consumption, the operation stage was found to be less damaging to the environment. It was concluded that DEWATS can be a good alternative for treating wastewater with negligible energy and chemical consumption.

     

A systematic review and meta-analysis of lead and cadmium concentrations in cow milk in Iran and human health risk assessment

The aim of the current research was to systematically review and summarize the studies that evaluated the concentration of lead (Pb) and cadmium (Cd) in cow milk in different regions of Iran and to perform a meta-analysis of the findings. Moreover, the non-carcinogenic and carcinogenic risks of Pb and Cd through milk consumption in adult and child consumers were assessed. As a result of a systematic search in the international and national databases between January 2008 and October 2018, 17 reports involving 1874 samples were incorporated in our study for meta-analysis. The pooled concentrations of Pb and Cd were estimated to be 13.95 μg mL−1 (95% CI 9.72–18.11 μg mL−1) and 3.55 μg mL−1 (95% CI − 2.38–9.48 μg mL−1), respectively, which were lower than the WHO/FAO and national standard limits. The estimated weekly intake (EWI) of Pb and Cd through consuming milk was 16.65 and 7 μg day−1 for adults of 70 kg and 45 and 34 μg day−1 for children of 26 kg, respectively, which was well below the risk values set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). The maximum target hazard quotient values (THQs) of Pb and Cd were 5.55E−5 and 5.55E−5 for adults and 5.55E−5 and 5.55E−5 for children, respectively, which were lower than 1 value, suggesting that Iranian consumers are not exposed to non-carcinogenic risk through consuming milk. Moreover, the incremental lifetime cancer risk (ILCR) of Pb estimated to be 2.96E−04 in adults and 1.0E−03 in children, indicating that consumers in Iran are at threshold carcinogenic risk of Pb through consuming milk (ILCR > 10−4). Therefore, planning and policy making for the sustainable reduction of these toxic metals in milk, particularly in industrial regions of Iran, are crucial.     

Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion

Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C.     

The effect of variability in industrial emissions on ozone formation in Houston, Texas

Ambient observations have indicated that high concentrations of ozone observed in the Houston/Galveston area are associated with plumes of highly reactive hydrocarbons, mixed with NO_x, from industrial facilities. Ambient observations and industrial process data, such as mass flow rates for industrial flares, indicate that the VOCs associated with these industrial emissions can have significant temporal variability. To characterize the effect of this variability in emissions on ozone formation in Houston, data were collected on the temporal variability of industrial emissions or emission surrogates (e.g., mass flow rates to flares). The observed emissions variability was then used to construct regionwide emission inventories with variable industrial emissions, and the impacts of the variability on ozone formation were examined for two types of meteorological conditions, both of which lead to high ozone concentrations in Houston. The air quality simulations indicate that variability in industrial emissions has the potential to cause increases and decreases of 10–52 ppb (13–316%), or more, in ozone concentration. The largest of these differences are restricted to regions of 10–20 km², but the variability also has the potential to increase regionwide maxima in ozone concentrations by up to 12 ppb.     

The atmosphere in England and Wales: an environmental management review

Air pollution in England and Wales is reviewed to identify priorities for management and research. The main human drivers of emissions are the production and consumption of energy and materials, disposal of waste, transport and land use. Pollutants are assigned to seven types: (i) nuisance (e.g. odour, noise), (ii) toxic, (iii) acidifying/eutrophying, (iv) photochemical oxidant precursors, (v) radionuclides, (vi) stratospheric ozone depleting substances and (vii) greenhouse gases. Dominant trends in activity and emissions are highlighted. New technologies and fuels are partially decoupling emissions from activity in power generation, industry and transport, but the gains are being offset by growth in demand and output in all major sectors. The evidence for impacts on human health, the atmosphere and other environmental systems is discussed. Priorities for management are climate change, ground-level ozone, acidification and eutrophication by nitrogen, urban air quality and nuisance pollution. Management responses require greater foresight, technological improvements and new instruments to control polluting activities. More scientific information is needed on the impacts on human health, quality of life and ecosystems, and on the links between different types of pollution. The policy challenges include generating energy sustainably, reducing transport impacts, devising effective economic instruments, improving societal awareness and contributing to cleaner global development.     

Modeling the impacts of the Finnish Climate Strategy on air pollution

This paper presents an example of how air pollution models can be used together with energy system models to study the impacts of climate change mitigation strategies on air pollution. As many mitigation measures of greenhouse gases (GHGs) affect the use of fossil fuels in energy production, they can have important side-effects on other air pollution problems. This paper studies on a national scale the impacts of the planned GHG reduction measures on multiple air pollution problems in Finland, concentrating on acidification of forest soils and lakes, tropospheric ozone levels harmful to humans and vegetation and on emissions of fine particles. The air pollutant emission scenarios with the alternative energy choices are calculated for about 200 large point sources, assuming the present emission limit legislation. Disperse emissions are treated at municipality level. The analysis extends to the year 2020. The implementation of the Kyoto protocol in Finland would induce notable reductions of multiple air pollutant emissions and related environmental impacts. A 6–11% reduction in ecosystems threatened by acidification in Southern and Central Finland would be achieved with the Finnish Climate Strategy alone. Substantial improvement in ozone levels would be reached in all scenarios compared to the current situation. The measures of the Climate Strategy could reduce the harmful ozone levels by a further 3%. The measures of the Climate Strategy would not significantly affect the primary particulate emissions in the future because the emissions from large power plants are already effectively controlled. Contrary to the fuel choices of the large units, expanded use of small-scale wood combustion can result in considerable increases of both fine particulate and VOC emissions.     

Economic Development,Rural livelihoods,and Ecological Restoration: Evidence from China

This article uses a case study in Southeast China to demonstrate how the substantial changes in rural livelihoods have been driven by a combination of “pull” forces from external economic development, and “push” forces from local areas, leading to a shift in rural household economic activities: household outmigration and de-population of the countryside, changes in energy consumption, and most importantly, changes in land uses and eventually, ecological restoration. Such dramatic changes are becoming common across the Chinese countryside. It is pointed out that economic development has generally caused a deterioration of the environment at least at the early period of economic growth, but the positive impacts, especially in some ecosystem in rural areas, have become more apparent.     

反应气耦合等离子体降解沙林模拟剂

采用水蒸气、氨气、过氧化氢气雾和臭氧4种气体对沙林模拟剂氟磷酸二异丙酯(DFP)进行降解研究,发现臭氧对DFP具有较好的降解作用,在流量200 L/h,DFP初始浓度50 mg/m3时,降解率最高可达56.1%。对高浓度DFP(大于80 mg/m3)进行降解研究时,等离子体单独作用最高降解率为89%,而添加臭氧后的降解率都在95%以上。计算得到臭氧作用的能量利用率为0.05 mg/(W·h),等离子体的能量利用率为0.55 mg/(W·h),而添加臭氧后的等离子体能量利用率为0.68 mg/(W·h)明显高于臭氧和等离子体能量利用率之和,因此对高浓度DFP进行处理时,臭氧与等离子体存在耦合作用。对等离子体和臭氧耦合等离子体降解DFP反应进行了产物分析,发现主要的降解产物基本一致,但是臭氧的存在能使降解更加彻底。     

Distribution,sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface water in industrial affected areas of the Three Gorges Reservoir,China

Water samples were collected from wastewater treatment plant (WWTP), drain water (DW), major tributaries (MT), and main course of the Yangtze River (MY) in areas of three industrial parks (IPs) in Chongqing city in the Three Gorges Reservoir (TGR). Sixteen EPA priority polycyclic aromatic hydrocarbon (PAH) pollutants were quantified to identify the effects of industrial activities on water quality of the TGR. The results showed that 11 individual PAHs were quantified and 5 PAHs (naphthalene (Nap), acenaphthylene (Acy), benzo[k]fluoranthene (BkF), indeno[1,2,3-cd]pyrene (InP), and benzo[g,h,i]perylene (BgP)) were under detection limits in all of the water samples. Three-ring and four-ring PAHs were the most detected PAHs. Concentrations of individual PAHs were in the range of not detected (nd) to 24.3 ng/L. Total PAH concentrations for each site ranged from nd to 42.9 ng/L and were lower compared to those in other studies. The mean PAH concentrations for sites WWTP, DW, MT, and MY showed as follows: DW (25.9 ng/L) > MY (15.5 ng/L) > MT (14.0 ng/L) > WWTP (9.3 ng/L), and DW contains the highest PAH concentrations. Source identification ratios showed that petroleum and combustion of biomass coal and petroleum were the main sources of PAHs. The results of potential ecosystem risk assessment indicated that, although PAH concentrations in MT and MY are likely harmless to ecosystem, contaminations of PAHs in DW were listed as middle levels and some management strategies and remediation actions, like strengthen clean production processes and banning illegal sewage discharging activities, etc., should be taken to lighten the ecosystem risk caused by PAHs especially risks caused by water discharging drains.     

Life Cycle Assessment of Fuel Selection for Power Generation in Taiwan

Abstract

Life cycle assessment (LCA) was applied to performance data from 1997–2002 to evaluate the environmental impacts of the energy input, airborne emission, waterborne emission, and solid waste inventories for Taiwan’s electric power plants. Eco-indicator 95 was used to compare the differences among the generation processes and fuel purification. To better understand the environmental trends related to Taiwan’s electric power industry, three fuel scenarios were selected for LCA system analysis. Results indicate that there are differences in characteristic environmental impact among the 13 power plants. Scenario simulation provided a basis for minimizing environmental impacts from fuel selection targets. Fuel selection priority should be a gas-fired combined cycle substituted for a coal-fired steam turbine to be more environmentally friendly, particularly in the areas of the greenhouse effect, acidification, winter smog, and solid waste. Furthermore, based purely on economic and environmental criteria, it is recommended that the gas-fired combined cycle be substituted for the oil-fired steam turbine.     

印染废水水解酸化处理中填料式反应器与UASB反应器的比较

根据印染废水的特点和印染废水处理工程实例,从适用性、与其他工艺的衔接、工程造价、运行费用及水解效果等方面对UASB水解酸化反应器和填料式水解酸化反应器进行比较研究。研究表明,UASB水解酸化反应器在适用性和工程造价两个方面具有一定的缺陷;但是UASB水解酸化反应器对印染废水中COD、SS和色度去除率能够分别达到50%、73%和75%,明显高于填料式水解酸化反应器;且UASB水解酸化反应器每降解1 kg COD所需电量为(0.23±0.05)kW·h,优于填料式水解酸化反应器。     

Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO_x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO_x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO_x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality (mostly in October). The truck pathway tends to cause a much wider fluctuation in degradation or improvement of ozone air quality: percentage changes in peak ozone concentrations are approximately −0.01% to 0.04% for the assumed 9% market penetration, and approximately −0.03% to 0.1% for the 20% market penetration. Moreover, the 20% on-site pathway occasionally results in a decrease of about −0.1% of baseline ozone pollution. Compared to the current ambient pollution level, all three hydrogen pathways are unlikely to cause a serious ozone problem for market penetration levels of HFCVs in the 9–20% range.     

Electrooxidation of industrial wastewater containing 1,4-dioxane in the presence of different salts

The treatment of 1,4-dioxane solution by electrochemical oxidation on boron-doped diamond was studied using a central composite design and the response surface methodology to investigate the use of SO₄ ^2? and HCO₃ ^? as supporting electrolytes considering the applied electric current, initial chemical oxygen demand (COD) value, and treatment time. Two industrial effluents containing bicarbonate alkalinity, one just carrying 1,4-dioxane (S1), and another one including 1,4-dioxane and 2-methyl-1,3-dioxolane (S2), were treated under optimized conditions and subsequently subjected to biodegradability assays with a Pseudomonas putida culture. Electrooxidation was compared with ozone oxidation (O₃) and its combination with hydrogen peroxide (O₃/H₂O₂). Regarding the experimental design, the optimal compromise for maximum COD removal at minimum energy consumption was shown at the maximum tested concentrations of SO₄ ^2? and HCO₃ ^? (41.6 and 32.8 mEq L^?1, respectively) and the maximum selected initial COD (750 mg L^?1), applying a current density of 11.9 mA cm^?2 for 3.8 h. Up to 98 % of the COD was removed in the electrooxidation treatment of S1 effluent using 114 kWh per kg of removed COD and about 91 % of the COD from S2 wastewater applying 49 kWh per kg of removed COD. The optimal biodegradability enhancement was achieved after 1 h of electrooxidation treatment. In comparison with O₃ and O₃/H₂O₂ alternatives, electrochemical oxidation achieved the fastest degradation rate per oxidant consumption unit, and it also resulted to be the most economical treatment in terms of energy consumption and price per unit of removed COD.