Purpose

Pyrogenic char (PC) materials derived from the pyrolysis of dairy processing sludge (DPS) could be a cost effective option to develop carbonaceous adsorbent for phosphorus (P) removal from wastewater. The main objectives of the present work were to: (1) determine the efficacy of DPS derived PC (DPS-PC) to remove P from synthetic and dairy wastewater samples, (2) identify possible P removal mechanisms, and identify parameters that could be used to quickly identify the P removal capacity of a char and (3) propose a ranking system for the selection of DPS-PC which includes energy, char yield and P removal criterion.

Methods

DPS-PC samples were obtained from the pyrolysis process (700 °C) of two sludge streams: (1) bio-chemically treated mixed sludge and (2) lime treated dissolved air floatation (DAF) sludge. Herein, 12 DPS-PC samples were assessed and pre-screened in batch experiments to determine the P removal efficacy from both synthetic and dairy wastewater solutions. The effect of solid to liquid dosage, contact time, pH and P concentration was investigated. Statistical regression and correlation analyses were performed to understand P removal mechanism. The quantitative assessment of char yield, energy balance and P removal performance were combined to propose a ranking system for DPS feedstock selection.

Results

P removal varied across DPS-PC type and composition, with mixed sludge derived char exhibiting 85–98% P removal at a dose of between 10 and 50 g/L, whereas, those from DAF sludge removed > 99% at 3 g/L. The P removal process was associated with a number of strongly significant mineral phase correlations pertaining to mineral composition (i.e. availability of Ca, Mg and Si) of the DPS-PC samples. A quick water extractible P test together with knowledge of the major P locking minerals can be used to pre-screen the potential of PC for P removal application. This study also provides a physicochemical reference and ranking of DPS feedstock selection, which will be useful for future investigation on the pyrolysis of DPS at pilot-scale and subsequently, to develop PC based efficient adsorbent for application in wastewater treatment.

Graphic Abstract

中文翻译：

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乳品加工污泥衍生的高温煤焦（DPS-PC）的新型用途，用于去除废水中的磷

目的

源自乳制品加工污泥（DPS）热解的热解炭（PC）材料可能是开发含碳吸附剂以去除废水中磷（P）的经济有效的选择。本工作的主要目标是：（1）确定DPS衍生的PC（DPS-PC）从合成和乳品废水样品中去除P的功效，（2）确定可能的P去除机理，并确定可能的P去除机理。 （3）提出了一种用于选择DPS-PC的排序系统，该系统包括能量，炭产量和P去除标准。

方法

DPS-PC样品是从两种污泥流的热解过程（700°C）中获得的：（1）生化处理的混合污泥和（2）石灰处理的溶解气浮（DAF）污泥。在本文中，对12个DPS-PC样品进行了评估，并在分批实验中进行了预筛选，以确定从合成废水和乳品废水中去除磷的功效。研究了固体对液体剂量，接触时间，pH和P浓度的影响。进行统计回归和相关分析以了解P去除机理。结合了焦炭产量，能量平衡和除磷性能的定量评估，提出了用于DPS原料选择的分级系统。

结果

磷的去除因DPS-PC类型和组成的不同而不同，混合污泥衍生的焦炭在10至50 g / L的剂量下可去除85-98％的磷，而DAF污泥中的磷在3 g / L时可去除> 99％ 。除磷过程与许多与DPS-PC样品的矿物成分（即，Ca，Mg和Si的有效性）有关的非常重要的矿物相相关性。快速的水可萃取P测试以及主要的P锁定矿物知识可用于预筛选PC去除P的潜力。这项研究还提供了DPS原料选择的理化参考和排名，这将有助于将来对DPS的热解进行中试规模的研究，并随后开发基于PC的高效吸附剂，用于废水处理。

图形摘要