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In many areas of the world, rainwater has been collected and consumed by people. Our research aims to assess the use of rainwater and the impact of operation and maintenance activities of the rainwater system on drinking water quality in rural areas where there is no access to a public drinking water system. Through the questionnaire, direct visits, interviews and sampling of water at surveyed households (HHs), it was found that 100 and 98% of surveyed HHs used rainwater for drinking and cooking, respectively. Nearly, 80% of them were aware of the necessity of frequent reservoir cleaning as well as first-flush removal. Cleaning the water reservoir had a significant impact on water quality, in particular the total dissolved solids (p-value < 0.05). The use of strainers and more frequency of cleaning the catchment roofs and gutters would make the lower turbidity in water. However, the use of strainers would reduce the dissolution of oxygen in the reservoirs. A recommendation on the frequency of maintaining the rainwater harvesting systems was proposed after assessment of the operation and maintenance behaviors at surveyed HHs.

The capability of modifying ultrafiltration (UF) membranes with different base-polymers using a newly synthesized hydrophilic additive was investigated in this study. Five typical base-polymers were tested: cellulose acetate (CA), polyetherimide (PEI), polyethersulfone (PES), polysulfone (PS), and polyvinylidene fluoride (PVDF). The changes in characteristics and performance of the membranes were analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle analysis, and solute transport tests. It was found that the effect of the hydrophilic additive was different for each polymer.Higher additive contents resulted in higher permeation flux. A visible effect on water content and permeability was obtained but the impact was not shown clearly in contact angles, possibly the additive's concentration was not sufficiently high at the surface. In term of flux enhancement the PES and PVDF membranes benefited the most by the addition of the hydrophilic additive.

Fixed-film biofilm reactors are considered one of the most effective wastewater treatment processes, however, the cost of their plastic bio-carriers makes them less attractive for application in developing countries. This study evaluated loofah sponges, an eco-friendly renewable agricultural product, as bio-carriers in a pilot-scale integrated fixed-film activated sludge (IFAS) system for the treatment of municipal wastewater. Tests showed that pristine loofah sponges disintegrated within two weeks resulting in a decrease in the treatment efficiencies. Accordingly, loofah sponges were modified by coating them with CaCO3 and polymer. IFAS pilot tests using the modified loofah sponges achieved 83% organic removal and 71% total nitrogen removal and met Vietnam’s wastewater effluent discharge standards. The system achieved considerably high levels of nitrification and it was not limited by the loading rate or dissolved oxygen levels. Cell concentrations in the carriers were twenty to forty times higher than those within the aeration tank. Through 16S-rRNA sequencing, the major micro-organism types identified were Kluyvera cryocrescens, Exiguobacterium indicum, Bacillus tropicus, Aeromonas hydrophila, Enterobacter cloacae, and Pseudomonas turukhanskensis. This study demonstrated that although modified loofah sponges are effective renewable bio-carriers for municipal wastewater treatment, longer-term testing is recommended.