Potential use of fruit seeds and plant leaves as coagulation agent in water treatment

The treatment of turbid water by coagulation-flocculation was found to be the most common and cost-effective method. Over the years, chemical coagulants have been widely applied to enhance the coagulation process. However, the utilisation of chemical coagulants exhibits several drawbacks, including generation of voluminous sludge and being non-biodegradable as well as toxic compounds to aquatic life. Due to global concerns over the harmful effects, the application of natural coagulants is a promising solution. Therefore, this study was conducted to investigate the potential of plant-based natural coagulants to replace chemical coagulants for water treatment. Fruit seeds (Carica papaya, Nephelium mutabile, and Euphoria malaiense seeds) and plant leaves (Pandanus, Centella asiatica, and Cymbopogon citratus leaves) were selected as natural coagulants in this study. A series of jar tests were performed using raw water from a water treatment plant. The effects of pH and coagulant dosage were evaluated based on the turbidity removal and coagulation activity. Of all the examined plants, the Carica papaya seeds appeared to be the best coagulant for water treatment. An optimum dose of 130 mg/L of this coagulant resulted in a 95.5% turbidity removal and 94% coagulation activity, at optimum pH 7.5. Overall, this study reveals the potential use of fruit seeds and plant leaves as coagulation agents in the water treatment process

Initialization, enhancement and mechanisms of aerobic granulation in wastewater treatment

Aerobic granulation is a promising technology that has increasingly attracted global attention due to its potential as a cost effective system, and its application in a wide range of wastewaters. Aerobic granules are highly structured suspended microbial aggregates capable of degrading biodegradable compounds with excellent settling properties, good pollutant removal and high resistance to toxic compounds. However, evidences show that granules formation in high strength wastewaters takes relatively much longer time at initial stages. This article reviews the state-of-the-art of the researches done on the factors influencing granulation at initial stage, with particular focus on the aggregation of microbial cells. In addition, this review discusses the effective approaches adopted for the enhancement of initial development of aerobic granules. Moreover, the current article highlights the mechanism of aerobic granulation at its initial stage, as well as other different approaches. Finally, future research directions to improve aerobic granules formation at the initial stage are discussed

Natural-based polymers for wastewater treatment

Natural and synthetic polymers have been long used in wastewater treatment. In this study, two positive charge polymers (natural and synthetic) were selected. These polymers were than tested for its ability to treat the wastewater with polymer dosages ranging from 1-20 mg/L. Both synthetic and natural have almost similar performance in turbidity removal. The highest removal rate of 90% was obtained at a dose of 20 mg/L. The removal of humic acid in demineralized water and wastewater was compared. Humic acid removal at 70% was reached in demineralized water, and 30% in wastewater. The removal of COD and phosphate is also reported