Gravity driven membrane filtration system to improve the water quality in rainwater tanks

Abstract

The characterisation of rainwater in metropolitan Sydney and in rural New South Wales was undertaken. The results showed that factors such as the lack of vehicular traffic, air pollution and urban contamination meant that rural rainwater water quality was better. The rain water collected in both metropolitan and rural areas generally complied with the 2004 Australian Drinking Water Guidelines except for parameters such as the pH in both the metropolitan and rural rainwater tanks and the turbidity, and lead levels from the metropolitan tanks. This paper also reports the results of a laboratory and a pilot scale study with a deep bed filter (granular activated carbon, GAC) and microfiltration (MF) hollow fibre membrane filter system used to treat raw rainwater collected from a metropolitan rainwater tank. The results of the laboratory experiment and pilot scale systems focus on the non-compliant parameters of the sampling program, i.e. turbidity, lead and dissolved organic carbon (DOC). It was found that rainwater treated by the GAC filter removed the majority of the turbidity and organic substances. The treatment system reduced the concentration of turbidity, lead and DOC to below the Australian Drinking Water Guidelines limits. The pilot plant experiment demonstrated that a GAC filter system and gravity driven membrane could result in low cost and low maintenance operation.

A low pressure gravity-driven membrane filtration (GDM) system for rainwater recycling: Flux stabilization and removal performance

“…However, Kus et al (2013a) reported a good DOC removal performance in GAC filter and GDM process. The reason was that nearly 71% of the DOC was removed by the GAC filter, and membrane post-treatment only contribute to 7% removal efficiency.…”

“…Results showed a good removal performance of heterotrophic bacteria and coliform, but viruses and adenovirus were not effectively removed by the filtration system. Kus et al reported a hybrid process of combination granular activated carbon (GAC) filter and gravity-driven membrane filtration (GDM) for rainwater treatment in lab and pilot scales, and the system reduced the concentration of organics, turbidity and lead below the standards of Australian Drinking Water Guidelines (Kus et al, 2013a, b). Also, they found that after the initial flux decline, the flux reached stable with the value of 0.47 L/m 2 h consistently over the 60 days of the experiment (Kus et al, 2013b).…”

Performance of an innovative gravity-driven micro-filtration technology for roof rainwater treatment

“…As pointed out elsewhere, the GDM process may exhibit excellent performance for bacteria and turbidity removals, but the removal efficiencies of organic matter and ammonia nitrogen were undesirable [36][37][38][39]. For example, Peng and Diamantis have reported that the micro-filtration were capable to remove majority of the suspended solids, colloidal particles and pathogens, but the removal rate of dissolved organic matters by alone micro-filtration process was generally lower than 20% [40,41].While Kus et al observed that a GDM process only contribute to 7% removal efficiency of DOC [42]. Similarly, Wu et al have recorded that a pilot GDM systems were able to remove almost all of the particles (i.e., turbidity), 94% of viable cells, and most of TEP (41-85%) [43].…”

“…Emerged as a low energy consumption and chemical free technology, the gravity driven membrane (GDM) filtration process is receiving more attentions and has been introduced to treat rainwater prior to use [12][13][14]. Although the GDM process has demonstrated an excellent performance in removing the bacteria and suspended particles in surface water and wastewater treatment, however, this energy-saving technology still has some disadvantages, such as, the removal of low molecular-weight substances is not ideal [15].…”

Untitled

“…Thomas y Greene (1993), investigando la calidad de las aguas de lluvia en contacto con los diversos materiales de los techos en áreas rurales, urbanas e industriales, concluyeron que los materiales de los techos tienen influencia sobre la calidad del agua de lluvia y que las aguas pluviales contaminadas colectadas de los techos se debe principalmente a la contaminación difusa de la deposición atmosférica y del número de días secos que anteceden a un evento lluvioso. Kus et al (2013) también verificaron que los factores como la intensidad Rev. Ambient.…”