Abstract

Rendering plants produce large amounts of wastewater that could be reused at the plant with adequate treatment. Membrane fouling is the main problem during the treatment of this type of wastewater by nanofiltration (NF) and reverse osmosis (RO). In order to reduce membrane fouling, the rendering plant secondary effluent was pretreated with two types of ultrafiltration (UF) membranes: MW as a flat sheet and ZW-1 as a hollow fiber membrane. The fouling on NF/RO flat sheet membranes (NF90, NF270, and XLE) was evaluated with the resistance-in-series model, while the fouling mechanisms were assessed with crossflow models. The UF, NF, and RO permeates were characterized to determine its suitability for reuse in the rendering plant. ZW-1 reduced the flux decline by 67.0% for NF270, 1.6% for NF90, and 38.0% for XLE; while MW reduced the flux decline by 72.4% for NF270, 50.1% for NF90, and 68.1% for XLE. The pretreatment with MW resulted in higher fouling reduction and a permeate that is appropriate for industrial reuse (washing purposes in the rendering plant). In terms of fouling resistance, NF270 and XLE membranes showed less fouling resistance during the treatment compared to NF90. The highest quality of permeate was obtained with XLE membrane, satisfying the water requirements for steam generation. The predominant fouling mechanisms for NF/RO were partial and complete pore blocking. The best combination for rendering plant secondary effluent reclamation was UF with MW membrane and RO with XLE membrane.

Graphic abstract

摘要

提炼厂产生大量废水，经过适当处理后可在工厂再利用。在通过纳滤（NF）和反渗透（RO）处理这类废水的过程中，膜结垢是主要问题。为了减少膜污染，用两种类型的超滤（UF）膜预处理提炼厂的二级废水：MW为平板，ZW-1为中空纤维膜。使用串联电阻模型评估NF / RO平板膜（NF90，NF270和XLE）上的结垢，而使用错流模型评估结垢机理。UF，NF和RO渗透液经过表征，以确定其是否适合在提炼厂中重复使用。ZW-1将NF270的通量下降降低了67.0％，NF90的通量下降了1.6％，XLE的通量下降了38.0％；而兆瓦减少了72的通量下降。NF270为4％，NF90为50.1％，XLE为68.1％。用MW进行预处理可进一步减少结垢，并产生适合工业重复使用的渗透物（提炼厂中的洗涤目的）。就防污性而言，与NF90相比，NF270和XLE膜在处理过程中显示出较小的防污性。使用XLE膜可获得最高质量的渗透液，可满足产生蒸汽所需的水量。NF / RO的主要结垢机制是部分和完全堵塞孔。使工厂二次废水回收的最佳组合是带MW膜的UF和带XLE膜的RO。用MW进行预处理可进一步减少结垢，并产生适合工业重复使用的渗透物（提炼厂中的洗涤目的）。就防污性而言，与NF90相比，NF270和XLE膜在处理过程中显示出较小的防污性。使用XLE膜可获得最高质量的渗透液，可满足产生蒸汽所需的水量。NF / RO的主要结垢机制是部分和完全堵塞孔。使工厂二次废水回收的最佳组合是带MW膜的UF和带XLE膜的RO。用MW进行预处理可进一步减少结垢，并产生适合工业重复使用的渗透物（提炼厂中的洗涤目的）。就防污性而言，与NF90相比，NF270和XLE膜在处理过程中显示出较小的防污性。使用XLE膜可获得最高质量的渗透液，可满足产生蒸汽所需的水量。NF / RO的主要结垢机制是部分和完全堵塞孔。使工厂二次废水回收的最佳组合是带MW膜的UF和带XLE膜的RO。满足产生蒸汽的水需求。NF / RO的主要结垢机制是部分和完全堵塞孔。使工厂二次废水回收的最佳组合是带MW膜的UF和带XLE膜的RO。满足产生蒸汽的水需求。NF / RO的主要结垢机制是部分和完全堵塞孔。使工厂二次废水回收的最佳组合是带MW膜的UF和带XLE膜的RO。

图形摘要