Making cheese manufacturing environmentally sustainable is a major concern in the integrated management of this industrial sector. This concern is mainly due to the environmental impact of the discharge of its wastewaters, carrying heavy loads of salinity, nutrients, organic matter, solids and oils and fats. These discharges must meet increasingly stringent quality requirements. Some physicochemical (e.g. coagulation-flocculation, precipitation, oxidation) and biological (e.g. aerobic and anaerobic bioreactors and wetlands) treatments have been studied to address this problem. However, these treatments involve costs that some producers cannot sustain, face difficulties with biological reactor operational stability and often fail to consistently produce effluents compatible with discharge standards. In this context, aiming at the design of a simple and economical treatment method, several precipitation processes were tested using a fixed dosage of CaCO3 (75 g/L), combined with different dosages of FeCl3, FeSO4 or Ca(OH)2. The goal of the treatment was to produce a supernatant that would be evaluated as to its suitability for discharge into natural water courses or municipal treatment systems, or for reuse applications. The generated sludge would be evaluated for possible agricultural valorization. Through the measurement of the relevant supernatant quality parameters and using statistical analysis, it was possible to choose the best dosages for each of the tested coagulants (1.0, 1.0 and 0.6 g/L for FeCl3, FeSO4 and Ca(OH)2, respectively). Among these, the most efficient treatment was obtained with CaCO3 75 g/L + FeSO4 1.0 g/L. For this best-case scenario, the treatment led to removal yield values of 55.1% for chemical oxygen demand (COD), 92.0% for total phosphorus, 95.7% for turbidity, 59.1% for total phenols, 94.3% for nitrates, 71.0% for nitrites, 51.0% for total solids (TS) and 97.2% for oils and fats. The treatment did not produce an effluent supernatant with adequate quality for direct discharge into water courses, serving however as an efficient pretreatment for agricultural reuse. All the sludges generated in these treatments showed good potential for agricultural valorization due to their high nutrient content, along with pH and conductivity values within the acceptable ranges for soil application. Thus, this work contributes for a better integration of the cheese manufacturing industry in the overall aims of water and nutrient resources recovery in rural, agricultural areas.

中文翻译：

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奶酪生产废水通过组合的理化过程进行处理，以进行再利用和化肥生产。

使奶酪制造在环境上可持续发展是该工业部门综合管理中的主要问题。这种关注主要是由于其废水排放对环境的影响，这些废水承载着大量的盐分，养分，有机质，固体以及油脂。这些排放物必须满足日益严格的质量要求。为了解决这个问题，已经研究了一些物理化学（例如混凝，絮凝，沉淀，氧化）和生物（例如需氧和厌氧的生物反应器和湿地）处理。然而，这些处理涉及一些生产者无法承受的成本，面临生物反应器运行稳定性的困难，并且经常不能始终如一地生产与排放标准兼容的废水。在这种情况下，为了设计一种简单且经济的处理方法，使用固定剂量的CaCO3（75 g / L）结合不同剂量的FeCl3，FeSO4或Ca（OH）2，测试了几种沉淀过程。处理的目的是产生上清液，对其上清液是否适合排放到天然水道或市政处理系统中或再利用应用进行评估。将对产生的污泥进行可能的农业价值评估。通过测量相关的上清液质量参数并使用统计分析，可以为每种测试的混凝剂选择最佳剂量（FeCl3，FeSO4和Ca（OH）2分别为1.0、1.0和0.6 g / L） 。其中，最有效的处理方法是使用75 g / L的CaCO3 + 1.0 g / L的FeSO4。对于这种最佳情况，处理导致的去除率值为化学需氧量（COD）为55.1％，总磷为92.0％，浊度为95.7％，总酚为59.1％，硝酸盐为94.3％，亚硝酸盐为71.0％，总固体为51.0％ （TS）和97.2％的油脂。该处理没有产生足够质量的废水上清液，无法直接排放到水道中，但是可以用作农业再利用的有效预处理。在这些处理过程中产生的所有污泥，由于它们的高养分含量以及在土壤应用可接受范围内的pH值和电导率值，具有很好的农业增值潜力。因此，这项工作有助于将奶酪制造业更好地整合到农村，农业地区水和养分资源回收的总体目标中。