Removal of total dissolved solids from wastewater using a revolving algal biofilm reactor

Abstract

Total dissolved solids (TDS) comprising inorganic salts and organic matters are pollutants of concern to aquatic systems and water for human use. This work aimed to investigate the use of revolving algal biofilm (RAB) reactors as a sustainable and environmental friendly method to remove TDS from industrial effluents and municipal wastewaters. The wastewaters contained chloride, sodium, potassium, calcium, magnesium, and sulfate as the major components. The RAB reactors fed with synthetic industrial effluent with high TDS level demonstrated the best algal growth, with the highest TDS removal efficiency (27%) and removal rate (2,783 mg/L-day and 19,530 mg/m 2 -day). A suspended algal culture system only removed 3% TDS from the same wastewater. The TDS removal by the RAB reactors was considered due to several mechanisms such as absorption by the algae cells, adsorption by extracellular polymeric substance of the biofilm, and/or precipitation. Collectively, this research shows that the RAB reactors can serve as an efficient system in wastewater remediation for TDS removal. © 2019 Water Environment Federation • Practitioner points• Total dissolved solids (TDS) in wastewater are pollutants of concern. • The RAB reactors can remove TDS from various types of wastewater. • The RAB reactors removed TDS by adsorbing ions elements such as Cl, Na, K, Ca, Mg, and S. • The algal biomass absorbs ions through extracellular polymeric substance.

Organic matter parameters in WWTP – a critical review and recommendations for application in activated sludge modelling

“…The difference between analyses for total solids and suspended solids is the respective salinity or organic dissolved compounds. Peng et al (2020) indicate a TDS content in artificial industrial wastewater (WW) of 3.4-12.1 g/L, real municipal WW was analyzed with a TDS of 0.8 g/L. According to WHO & IPCS (1996) dissolved solids affect the taste of drinking water (good between 0.3 and 0.6 g/L, unacceptable .1.2 g/L).…”

Nutrients removal from integrated multi-trophic aquaculture (IMTA) water using waste stabilization ponds (WSP)

“…The photosynthesis process would also synthesize the new biomass of phytoplankton. As water column productivity increased, the growth from microorganisms would then consume ions from the treated IMTA water [15,16,17]. This biomass production was also related to the dynamics of turbidity in the WSP pond.…”

Improving biological treatment of textile wastewater

“…The increase in TDS and EC might also arise from mineralization, i.e., the conversion of organic Carbon into smaller and simpler organic compounds. TDS and Conductivity decreased with increased retention time, that's why in 3 days TDS and EC increased (Peng et al 2020). Maximum increase of TDS and conductivity occurred at pure domestic wastewater whereas optimum removal occurred at 60% textile wastewater when the treatment was conducted for 18 days.…”

“…When graphs deviate to the negative side means that there was an increase in TDS and Conductivity to the system and vice versa on positive side. However, the increase of TDS and conductivity decreased with increasing textile wastewater and increase in retention time (Figure 7) Therefore, the increase in TDS and conductivity in 3 days might be caused by the addition of inoculum to the system and low retention time which limit time for reaction (Peng et al 2020). The increase in TDS and EC might also arise from mineralization, i.e., the conversion of organic Carbon into smaller and simpler organic compounds.…”