Semi-coking wastewater contains a rich source of toxic and refractory compounds. Three-dimensional electro-Fenton (3D/EF) process used CuFe2O4 as heterocatalyst and activated carbon (AC) as particle electrode was constructed for degrading semi-coking wastewater greenly and efficiently. CuFe2O4 nanoparticles were prepared by coprecipitation method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS). Factors like dosage of CuFe2O4, applied voltage, dosage of AC and pH, which effect COD removal rate of semi-coking waste water were studied. The results showed that COD removal rate reached to 80.9% by 3D/EF process at the optimum condition: 4 V, 0.3 g of CuFe2O4, 1 g of AC and pH?=?3. Trapping experiment suggesting that hydroxyl radical (?OH) is the main active radical. The surface composition and chemical states of the fresh and used CuFe2O4 were analyzed by XPS indicating that Fe, Cu, and O species are involved into the 3D/EF process. Additionally, anode oxidation and the adsorption and catalysis of AC are also contributed to the bleaching of semi-coking waste water. The possible mechanisms of 3D/EF for degrading semi-coking waste water by CuFe2O4 heterocatalyst were proposed.
The objectives of this study were to establish an on-line controlling system for nitrogen and phosphorus removal synchronously
of municipal wastewater in a sequencing batch reactor (SBR). The SBR for municipal wastewater treatment was operated in sequences:
filling, anaerobic, oxic, anoxic, oxic, settling and discharge. The reactor was equipped with on-line monitoring sensors for
dissolved oxygen (DO), oxidation-reduction potential (ORP) and pH. The variation of DO, ORP and pH is relevant to each phase
of biological process for nitrogen and phosphorus removal in this SBR. The characteristic points of DO, ORP and pH can be
used to judge and control the stages of process that include: phosphate release by the turning points of ORP and pH; nitrification
by the ammonia valley of pH and ammonia elbows of DO and ORP; denitrification by the nitrate knee of ORP and nitrate apex
of pH; phosphate uptake by the turning point of pH; and residual organic carbon oxidation by the carbon elbows of DO and ORP.
The controlling system can operate automatically for nitrogen and phosphorus efficiently removal.
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Translated from Water & Wastewater Engineering, 2006, 26(5): 728–733 [译自: 给水排水] 相似文献
ABSTRACTThe aim of this study is to investigate of how the concept of ‘integrated food and energy systems’ or IFES production networks could be applied – within the specific context of Eastern Cuba’s agricultural and agro-industrial sectors – as an innovative approach to improve food and energy security. The Province of Santiago de Cuba in southeast Cuba was the focus of this study; its existing operations, infrastructure, resource flows and scarcities, and actor relationships provide the basis of the data used for the evaluation.The authors investigated the regional context, identify potential members of an agricultural and agro-industrial network in three municipalities of the province, and identify the main residuals and by-products of key facilities. Potential avenues for by-product valorization are investigated along with the possible influence/impacts on the sustainability of the surrounding systems and actors. A conceptual model for a regional network for integrated food and energy production is then provided based upon the development of three agricultural/agro-industrial scenarios: influence at the farm level, regional agro-industrial networks, and ‘anchor tenant’ eco-industrial systems. The main challenges and opportunities for the development of the networks are described with recommendations for addressing such where possible. 相似文献