Hollow fiber membrane integrity warning device based on laser extinction particles detection technology

Role of inorganic foulants in the aging and deterioration of low-pressure membranes during the chemical cleaning process in surface water treatment: A review

Low-pressure membrane (LPM) filtration, including microfiltration (MF) and ultrafiltration (UF), is a promising technology for the treatment of surface water for drinking and other purposes. Various configurations and operational sequences have been developed to ensure the sustainable provision of clean water by overcoming fouling problems. In the literature, various periodic physical and/or chemical approaches to the cleaning of LPMs have been reported, but little data is available on the aging of MF/UF membranes that results from the interaction between the foulants and the cleaning agent. Periodic physical cleaning of the membrane is expected to return the membrane to its original performance capacity, but it only recovers to a certain level because the remaining foulants cause irreversible fouling. Chemical cleaning can then be employed to recover the membrane from this irreversible fouling but, in the process, it can cause irrecoverable damage to the membrane. In this review, the foulants responsible for irrecoverable damage to MF/UF membranes are summarized, and their interaction with cleaning agents and other foulants is described. The impact of these foulants on various membrane parameters, including filtration efficiency, flux decline, permeability, membrane characterization, and membrane integrity are also summarized and discussed in detail. In addition, mitigation options and future prospects are also discussed with regard to increasing the operational life span of a membrane in a cost-effective manner. Ultimately, this review suggests an advanced control system based on membrane-foulant interactions under the impact of various operational parameters to mitigate the integrity loss of membranes.

The status of potable water reuse implementation

A review of the current status of direct and indirect potable water reuse (DPR/IPR) implementation has been conducted, focusing on the regulatory and practical aspects and with reference to the most recent published literature. The review encompasses (a) the principal contaminant types, their required removal and the methods by which their concentration is monitored, (b) regulatory approaches and stipulations in assessing/ratifying treatment schemes and maintaining treated water quality, and (c) existing full-scale installations. Analytical methods discussed include established in-line monitoring tools, such as turbidity measurement, to more recent polymerase chain reaction (PCR)-based assay methods for microbial detection. The key risk assessment tools of quantitative microbial risk assessment (QMRA) and water safety plans (WSPs) are considered in relation to their use in selecting/ratifying treatment schemes, and the components of the treatment schemes from 40 existing IPR/DPR installations summarised. Five specific schemes are considered in more detail. The review reveals:Whilst there are a number of ongoing projects where RO is not used because of the challenge imposed by disposal of RO concentrate, the prevalence of the sequential RO-UV combination implies the importance of quantifying the impact of process upsets on these unit operations.

Application of UV-vis absorption spectrum to test the membrane integrity of Membrane bioreactor (MBR)

In this work, UV-vis absorption spectrum of the membrane integrity analysis based on slopes of log-transformed absorbance spectra, differential absorbance spectroscopy (DAS), and absorption coefficient α(254) were studied at different number of breakage fibers and filtration times. Moreover, we analyze the influence of Fe²⁺ and Ca²⁺concentration on UV spectrum detection results. Cluster analysis and the change ratio R_s were used to determine the dissolved organic matter (DOM) leakage stages. As a result, the correlation coefficient between slope_280-350 value and the number of breakage fibers is 0.901. Seven gaussian bands were successfully model from the DAS, and A4 (312 nm), A5 (339 nm), A6 (367 nm) were chosen to indicate the extent of breakage fiber. Peak 4(A4) is minimally affected by ions concentration. The α(254) could be used as a good indicator for detecting industrial wastewater treatment process which correlation coefficient between the number of breakage fibers is 0.955. The DOM leakage process was divided into three stages which were bulk leakage stage, development stage and stabilization stage. The UV-vis absorption spectrum can effectively detect the membrane integrity more sensitive than particle counter and three analyse methods are suitable for different substance in feed water.