Rejection change by nuclepore microfiltration membranes with solution environment was investigated by using the RNA coliphages Qβ, MS2, fr and DNA coliphage T4. The obtained rejection results showed a higher rejection at lower pH than at higher pH for all viruses were obtained at pH closer to their isoelectric points and also the rejection variation indicates a similar pattern of behavior. This phenomenon of higher virus rejection at lower pH is explained with a possible viruses aggregation with each other due to their own electrostatic charge and isoelectric points. Also it was observed that the virus rejection was enhanced when they are in mixed environment. Finally the effect of protein was studied where, the virus rejection below pH 5.0 showed protein influence.

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This review assesses the leachate quality from waste disposal sites in tropical climate zone. Through this review, data from 228 leachate samples from 145 waste disposal sites from 18 countries in the tropical region were analyzed. The 12 types of sites were considered for the analysis based on the climatic conditions, age, and the operating condition of the site. Tropical rainforest, tropical monsoon, and tropical savanna climates were identified for the climatic zone classification. Age of site was classified as young and old. The operating conditions were classified as engineered landfill and open dump site. Eighteen leachate quality parameters were included in the analysis. Leachate pollution index indicated that young sites from tropical rainforest zone and tropical monsoon zone have higher pollution potential, while the pollution potential in tropical savanna zone did not demonstrate considerable difference in pollution potential in terms of age of the landfill. Considering the operating method of the sites, open dumpsites pose higher pollution potential. Positive correlation could be seen among biological oxygen demand, chemical oxygen demand, total dissolved solids, and total Kjeldahl nitrogen. pH negatively correlated with organic pollutants as well as heavy metals. Analysis of emerging contaminants present in landfill leachate is limited in tropical region; thus, it is recommended to conduct studies on emerging contaminants. Further, the leachate treatment options considered in tropical region are discussed in this review.

The hydraulic loading rate (HLR) plays a vital role in pollutant removal in constructed wetlands. This study evaluated the effects of HLR variation on pollutant removal in continuously fed vertical subsurface flow (VSSF) constructed wetlands in tropical conditions. Three VSSF wetland beds (Length: 1.4 m, Width: 0.5 m and Depth: 0.6 m), filled with 10-20 mm gravel media, were set up in a tropical region. Two beds were planted with a locally available emergent macrophyte narrow-leaf cattail (Typha angustifolia), and the remaining bed was used as a control without plants. The performance of these wetland mesocosms was tested at different HLRs of 2. 5, 5, 7.5, 10, 12.5, 15, 20, 25, and 30 cm day À1 changing at 2 week intervals in two phases over a period of 6 months. The results revealed that both VSSF wetland systems are capable of substantial reduction of pollutants with a good buffering capacity up to 25 cm day À1 HLR.