A Pilot-Scale Treatment of Steel Plant Wastewater by PVDF Hollow Fiber Ultrafiltration Membrane with Low Packing Density

Yangang Zhang,Liudong He,Chunhong Shi,Zhangfu Yuan,He Bai,Linfei Zhao

doi:10.3390/separations9020037

Yangang Zhang, Liudong He + Show 4 more

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https://doi.org/10.3390/separations9020037

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Abstract

The treatment of wastewater from the iron and steel industry is difficult due to its complex and changeable characteristics. This paper introduces the application of polyvinylidene fluoride (PVDF)-pressurized ultrafiltration membrane with low packing density that produced via thermally induced phase separation (TIPS) in wastewater of iron and steel industry, to study the effects of packing density of ultrafiltration membrane modules as well as the membrane performance under different operation conditions, in order to provide guidance for the subsequent development of other ultrafiltration applications in wastewater of iron and steel. The results show a significant positive effect of smaller packing density on the transmembrane pressure difference (TMP) reducing and higher permeability. Under 30 min filtration cycle and 65 L m−2 h−1 (LMH) operation flux, the permeability can be stabilized to 200 L/(m2·h)/0.1 MPa, which is two times higher than that of the membrane module with 0.3 m2/m3 higher packing density under the same condition. It is obvious that compared with enhanced flux maintenance (EFM), chemically enhanced backwash (CEB) is a more effective cleaning method for iron and steel wastewater, which maintains TMP (30 kPa) without any significant increase under the premise of ensuring the high-flux (65 LMH) operation. The results also suggest reasonable parameters based on the test water quality, which include the filtration cycle and operation flux. The scanning electron microscopy (SEM) analysis and the turbidity of the permeate show that the ultrafiltration membrane has good intercept ability and high anti-pollution performance.

Highlights

As an important natural resource, water is an indispensable resource for human life and production
This paper focused on the changes of the membrane permeability and transmembrane pressure difference (TMP) to evaluate the influence of packing density on the membrane filtration performance by continuous monitoring
The comparison results of the two membrane modules showed that, under similar effective membrane fiber lengths and same operation conditions, modules with lower packing density had more benefits for the whole system in terms of permeability and TMP; the SMT900-P80 module with lower packing density significantly reduced the average TMP, up to 60–70%, and increased permeability, up to 100%, which would indirectly lead to the difference in cleaning frequency and service life

Summary

Introduction

As an important natural resource, water is an indispensable resource for human life and production. It is of great significance for promoting social and economic development and promoting the progress of civilization [1,2,3]. In order to alleviate the water crisis, the recycling of industrial wastewater has become an important way to solve the water crisis, alleviate the shortage of water resources, and increase the supply of water resources [5,6,7,8]. The iron and steel industry is one of the five major water-consuming industries in China. To realize the sustainable development of the iron and steel industry, it is necessary to strengthen the recycling of wastewater resources. The complexity, fluctuation, and high conductivity of water make wastewater treatment more difficult [13,14]

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