Simultaneous removal of inorganic and organic compounds in wastewater by freshwater green microalgae

Abstract

Batch experiments were carried out for 7 days to investigate the simultaneous removal of various organic and inorganic contaminants including total nitrogen (TN), total phosphorus (TP), metals, pharmaceuticals and personal care products (PPCPs), endocrine disrupting chemicals (EDCs), and estrogenic activity in wastewater by four freshwater green microalgae species, Chlamydomonas reinhardtii, Scenedesmus obliquus, Chlorella pyrenoidosa and Chlorella vulgaris. After treatment for 7 days, 76.7-92.3% of TN, and 67.5-82.2% of TP were removed by these four algae species. The removal of metals from wastewater by the four algae species varied among the metal species. These four algae species could remove most of the metals efficiently (>40% removal), but showed low efficiencies in removing Pb, Ni and Co. The four algae species were also found to be efficient in removing most of the selected organic compounds with >50% removal, and the estrogenic activity with removal efficiencies ranging from 46.2 to 81.1% from the wastewater. Therefore, algae could be harnessed to simultaneously remove various contaminants in wastewater. Environmental impactDomestic wastewater contains various inorganic and organic contaminants, which could pose risks to the environment and public health. To avoid these adverse effects, wastewater must be treated prior to its nal discharge into the receiving environment. Unfortunately, incomplete removals have oen been reported for these contaminants in wastewater by conventional wastewater treatment technologies. The use of microalgae in the treatment of wastewater has gained great interest over the past few years. However, previous studies on wastewater treatment by algae have been limited and most of them are focused on the removal of inorganic or organic pollutants in articial wastewaters. This study investigated the simultaneous removal capacity of inorganic (nitrogen, phosphorus and metals) and organic pollutants (PPCPs and EDCs) by four freshwater microalgae, and also evaluated the elimination of estrogenic activity in the wastewater by these algae species. The results demonstrated that simultaneous removal of various contaminants in wastewater was achieved, which showed potential application of these algae species in the wastewater treatment.

Occurrence, environmental implications and risk assessment of Bisphenol A in association with colloidal particles in an urban tropical river in Malaysia

“…Warm seasons coupled with ample rainfall and increased flow discharge may largely lead to dilution of BPA. Normally, biodegradation rates are faster at high temperature degrees 32 , and adsorption by microalgae, which blooms in warmer periods, can lead to BPA biotransformation in water 33 . High water temperatures can also enhance sorption of BPA by particulate and colloidal organic carbon 33 .…”

Investigation of pharmaceuticals, personal care products and endocrine disrupting chemicals in a tropical urban catchment and the influence of environmental factors

“…Chlorophyll a, an indicator of algal biomass, was found to be negatively correlated with caffeine, salicylic acid, acetaminophen, BPA, and triclosan. Zhou et al (2014) described the high efficiencies (N 75%) of freshwater green algae in removing BPA, estrone, salicylic acid and triclosan from wastewater with similar removal mechanisms as activated sludge treatment. Similarly, algal content in the studied catchment would probably elevate the biodegradation, photodegradation and uptake of these chemicals.…”

Exploring micropollutant biotransformation in three freshwater phytoplankton species

“…Studies on wastewater treatment in e.g. algal ponds and bioreactors also suggest that some micropollutants can be degraded by algae to different extents [7][8][9][10] . As phototrophs, phytoplankton do not rely on organic chemicals as carbon sources, however the presence of biotransformation in algae is potentially a detoxification mechanism, as suggested for dichlorophenol degradation 11 , or a consequence of enzyme promiscuity or reactivity with compounds similar to their natural substrates (as suggested e.g.…”