Swine wastewater treatment by combined process of iron carbon microelectrolysis-physical adsorption-microalgae cultivation

Role of microalgae-bacterial consortium in wastewater treatment: A review

In the global effort to reduce CO2 emissions, the concurrent enhancement of pollutant degradation and reductions in fossil fuel consumption are pivotal aspects of microalgae-mediated wastewater treatment. Clarifying the degradation mechanisms of bacteria and microalgae during pollutant treatment, as well as regulatory biolipid production, could enhance process sustainability. The synergistic and inhibitory relationships between microalgae and bacteria are introduced in this paper. The different stimulators that can regulate microalgal biolipid accumulation are also reviewed. Wastewater treatment technologies that utilize microalgae and bacteria in laboratories and open ponds are described to outline their application in treating heavy metal-containing wastewater, animal husbandry wastewater, pharmaceutical wastewater, and textile dye wastewater. Finally, the major requirements to scale up the cascade utilization of biomass and energy recovery are summarized to improve the development of biological wastewater treatment.

Response surface methodology for process optimization in livestock wastewater treatment: A review

With increasing demand for meat and dairy products, the volume of wastewater generated from the livestock industry has become a significant environmental concern. The treatment of livestock wastewater (LWW) is a challenging process that involves removing nutrients, organic matter, pathogens, and other pollutants from livestock manure and urine. In response to this challenge, researchers have developed and investigated different biological, physical, and chemical treatment technologies that perform better upon optimization. Optimization of LWW handling processes can help improve the efficacy and sustainability of treatment systems as well as minimize environmental impacts and associated costs. Response surface methodology (RSM) as an optimization approach can effectively optimize operational parameters that affect process performance. This review article summarizes the main steps of RSM, recent applications of RSM in LWW treatment, highlights the advantages and limitations of this technique, and provides recommendations for future research and practice, including its cost-effectiveness, accuracy, and ability to improve treatment efficiency.

Strategies for livestock wastewater treatment and optimised nutrient recovery using microalgal-based technologies

Global sustainable development faces several challenges in addressing the needs of a growing population. Regarding food industries, the heightening pressure to meet these needs has resulted in increased waste generation. Thus, recognising these wastes as valuable resources is crucial to integrating sustainable models into current production systems. For instance, the current 24 billion tons of nutrient-rich livestock wastewater (LW) generated yearly could be recovered and valorised via biological uptake through microalgal biomass. Microalgae-based livestock wastewater treatment (MbLWT) has emerged as an effective technology for nutrient recovery, specifically targeting carbon, nitrogen, and phosphorus. However, the viability and efficacy of these systems rely on the characteristics of LW, including organic matter and ammonium concentration, content of suspended solids, and microbial load. Thus, this systematic literature review aims to provide guidance towards implementing an integral MbLWT system for nutrient control and recovery, discussing several pre-treatments used in literature to overcome the challenges regarding LW as a suitable media for microalgae cultivation.

Ultratrace Aromatic Anhydride Dopant as Intermediate Island to Promote Charge Transfer of Graphitic Carbon Nitride for Enhancing the Photocatalytic Degradation of Rhodamine B

In this work, 0.75 wt ‰ 2,3-pyridinedicarboxylic anhydride (PDA) as a novel dopant was utilized to obtain modified graphitic carbon nitride with ultratrace doping (3MCN-PDA3) by facile thermal polymerization. Characterization of the microstructure, surface state, and porosity properties of the samples indicated that 3MCN-PDA3 has a thinner sheet-like, larger-scale, and tighter lamellar stacking structure than that of pristine graphitic carbon nitride (3MCN). Based on photo/electrochemical analysis, the PDA dopant formed an extended coplanar conjugated system by anhydride-amine thermal condensation with heptazine rings, and the channels of amide covalent bonds and superconjugation of the solitary pair of electrons of the nitrogen atoms of PDA synergistically promoted the charge transport performance of 3MCN-PDA3. Under visible light, the photodegradation efficiency of Rhodamine B (RhB) over 3MCN-PDA3 reached 92.4% in 60 min and realized almost entire removal in 200 min (99.2%), 1.43 times that of 3MCN. Furthermore, the experimental results and generalized density theory calculations confirmed that PDA acts as an intermediate molecular island and constructs an efficient carrier transfer pathway between different heptazine units. The results indicate that PDA is a promising candidate to enhance the charge transfer performance through ultratrace doping in the large-scale preparation and application of the graphitic carbon nitride photocatalyst.