Reclamation Potential of Onsite Wastewater Post-Treatment with Microalgae: Chemical Elements Perspective

Abstract

Algae-based wastewater treatment is a promising technology with various applications for excess biomass such as biofertilizer production or valuable elements extraction. The benefits of the technology have been discussed for larger wastewater treatment plants (WWTPs), but the use of microalgae in decentralized wastewater treatment has been barely reported. The current study screens the possible resource recovery potential of onsite technology, which adds algae-based post-treatment to the conventional biological treatment of domestic wastewater. The effluent from the onsite sequencing batch reactor (SBR) of a household was further processed in laboratory conditions using an SBR technology with two local monocultures of algae—Klebsormidium nitens (Kützing) Lokhorst and Tetradesmus obliquus (Turpin) M. J. Wynne. The decant and the generated algal biomass were analyzed in terms of their element content. The post-treated effluent has a slightly better quality for irrigation purposes than the effluent of the onsite treatment facility—up to 1.6 times increased concentration for macro-elements and up to 1.9 times for micro elements. However, the generated algal biomass shows promising potential for re-use as a fertilizing agent since it contains valuable macro- and micro-elements and the heavy (hazardous) metal content is considerably lower than the limiting values in the current European and national legislations. The K. nitens strain may attract interest since it accumulates valuable metals such as chromium (36 mg/kgDS), nickel (83 mg/kgDS), and silver (0.7 mg/kgDS) that can be derived from the biomass and turn the technology to a circular one.

Sustainable Treatment of Swine Wastewater: Optimizing the Culture Conditions of Tetradesmus cf. obliquus to Improve Treatment Efficiency

“…The cells of T. obliquus are rhombic, in coenobia of 2, 4, and 8 cells. The aggregated cells of T. obliquus are generally found as four-celled coenobia, with a length of 10-21 µm and a width of 3-9 µm [23,24]. The cellular morphology of strain ZYY1 was similar to that of T. obliquus.…”

Panoramic Semiquantitave Analysis for Multielement Characterization of Liquid and Solid Waste Samples

“…The most suitable technique for the management of sewage sludge is its utilization in agriculture as fertilizer [37]. The content of hazardous pollutants, including PTEs, may cause serious damage to the environment [15], causing soil pollution and plant toxicity [10,38].…”