ABSTRACT

The poultry slaughterhouse wastewater has a high pollutant load, mainly organic matter, and nutrient content. The nitrogen and phosphorus discharge can cause eutrophication of the receiving water bodies. Electrocoagulation has been studied for several pollutants removal from different sources. The objective of this work was to evaluate the electrocoagulation process in the poultry slaughterhouse wastewater treatment using both iron and electrodes to remove total nitrogen and phosphorus. After the raw and polished wastewater characterisation, a 2³ Central Composite Rotatable Design was applied to evaluate the current density, initial pH, and electrocoagulation time influence on the nutrients removal and to find the optimum condition of nutrients removal. Once the optimum condition for nutrient removal was stablished, other physicochemical, microbiological, and ecotoxicological parameters, as well as the treatment cost, were investigated to determine which electrode material was the most efficient. For raw wastewater, applying the optimum treatment condition of 20 mA cm⁻² current density, initial pH 6.2, and time of 20 min, the nitrogen and phosphorus removal presented similar for both electrode materials. Besides being cheaper ($ 4.13 m⁻³), iron electrode treatment presented better Chemical Oxygen Demand, oils and greases, solids, and ecotoxicity removal. For polished wastewater, the treatment with aluminum electrode was more efficient under the applied current density of 30 mA cm⁻², initial pH 8 and time of 10 min, obtaining the lowest cost $ 3.89 m⁻³. In the iron electrode case, the final pH exceeds the limits established by local legislation requiring correction for release into water bodies.

摘要

家禽屠宰场废水污染物负荷高，主要是有机物和营养成分。氮和磷的排放会导致受纳水体富营养化。已经研究了电凝聚法从不同来源去除几种污染物。这项工作的目的是评估使用铁和电极去除总氮和磷的家禽屠宰场废水处理中的电凝聚过程。在对原始和抛光废水进行表征之后，应用 2³ 中心复合可旋转设计来评估电流密度、初始 pH 值和电凝聚时间对营养物质去除的影响，并找到营养物质去除的最佳条件。一旦确定了去除养分的最佳条件，其他物理化学、研究了微生物和生态毒理学参数以及处理成本，以确定哪种电极材料最有效。对于原废水，采用 20 mA cm 的最佳处理条件^-2电流密度、初始 pH 值 6.2 和 20 分钟时间，两种电极材料的氮和磷去除率相似。除了更便宜（$ 4.13 m ^-3）之外，铁电极处理表现出更好的化学需氧量、油和油脂、固体和生态毒性去除。^{对于抛光废水，在施加电流密度为 30 mA cm -2} 、初始 pH 值为 8 和时间为 10 min的条件下，铝电极处理效率更高，成本最低，为 $3.89 m ^-3。在铁电极的情况下，最终的 pH 值超过了当地立法规定的限制，要求对释放到水体中进行校正。