Sustainable kitchen wastewater treatment with electricity generation using upflow biofilter-microbial fuel cell system.

The microbial fuel cell (MFC) is considered a modern technology used for treating wastewater and recovering electrical energy. In this study, a new dual technology combining MFC and a specialized biofilter was used. The anodic materials in the system were crushed graphite, either without coating (UFB-MFC) or coated with nanomaterials (nano-UFB-MFC). This biofilter served as a barrier to retain and remove turbidity and suspended solids, while also facilitating the role of bacteria in the removal of organic pollutants, phosphates, nitrates, sulfates, oil and greases. The results demonstrated that both systems exhibited high efficiency in treating kitchen wastewater, specifically greywater and dishwashing wastewater with high detergent concentrations. The removal efficiencies of COD, oil and grease, suspended solids, turbidity, nitrates, sulfates, and phosphates in first UFB-MFC were found to be 88, 95, 89, 86, 87, 75, and 94%, respectively, and in Nano-UFB-MFC were 86, 99, 95, 91, 81, 88, and 95%, respectively, with a high efficiency in recovering bioenergy reaching a value of 1.8 and 1.5 A m-3, respectively. The results of this study demonstrate the potential for developing MFC and utilizing it as a domestic system to mitigate pollution risks before discharging wastewater into the sewer network.

Immobilization of mixed bacteria by novel biocarriers extracted from Cress and Chia seeds for biotreatment of anionic surfactant (SDS)-bearing real wastewaters.

Selection of biocarrier type is an essential element for successful bacterial cells immobilization. The present investigation aimed to evaluate a novel application of Cress and Chia seeds as biocarriers for immobilization of mixed bacterial cells. Being an environmentally friendly, non-polluting, inexpensive, and non-toxic substances makes them promising biocarriers. On the other hand, there is an increasing concern about contamination by surfactants, sodium dodecyl sulfate (SDS) is among the most commonly used surfactant. The Cress and Chia seeds were cross-linked with PVA to prepare two types of beads; CrE-PVA and ChE-PVA, respectively. The beads were utilized for the SDS biodegradation in four kinds of actual SDS-bearing wastewaters originated from; carwash garage (CWW), laundry facility (LWW), and household detergent industry (HWW), in addition to domestic wastewater (DWW). The results revealed that maximum efficiencies of SDS elimination in DWW, LWW, HWW, and CWW were 98.12, 94.32, 93.04, and 99.08%, respectively, using CrE-PVA and 99.04, 94.96, 94.71, and 99.27%, respectively using ChE-PVA. Finally, both types of beads were recycled for five times without losing their stability and efficiency for SDS biodegradation. Four kinetic models were adopted which were Blackman, Monod, Haldane, and Teissier. Results revealed that Teissier model well fitted the experimental data.

Adsorptive performance of a mixture of three nonliving algae classes for nickel remediation in synthesized wastewater.

PURPOSE: The present study provided a comprehensive description regarding the application of a mixture of three nonliving classes of algae as a promising and inexpensive biosorbent for removing toxic nickel (Ni(II)) ions from the aqueous medium. METHODS: The biosorption process was tested by varying several experimental parameters such as pH (2-8), contaminant concentration (20-300 mg/L), biosorbent content (0.2-2 g/100 mL), and temperature (20-40 °C). In addition, the competition effects of the presence of Pb(II), Cu(II), and Zn(II) ions on the Ni(II) removal efficiency was studied by varying their concentrations from 30 to 40 mg/L. RESULTS: The microscopic analysis of algae demonstrated that the used biosorbent consisted mainly of Chrysophyta (80%), Chlorophyte (14%), and Cyanophyta (6%). Results demonstrated that these environmental parameters influenced the removal efficiency with a different degree and there was no stable effects rank at conditions under examination. FT-IR and SEM analysis revealed that the biosorbent surface consists of many strong and active groups of negative valences such as hydroxyl and carboxyl groups, thus exhibiting several morphological properties of interest. Further, it was found that the Temkin model best fitted the isotherm biosorption data. The kinetic study showed that the Ni(II) biosorption was rapid within first 20 min of reaction time, thereby following a pseudo-second-order model, which in turn demonstrated a chemisorption process of Ni(II) ions reaction with the biosorbent binding sites. Also, the thermodynamic study suggested that the biosorption process of Ni(II) onto algal biomass was a spontaneous and endothermic in nature. The maximum uptake of Ni(II) was 9.848 mg/g under optimized conditions and neutral environment. CONCLUSIONS: Thus, this significant finding suggested a favorable and eco-friendly treatment mechanism for removal of Ni(II) ions from aqueous medium via biosorption onto the used mixture of nonliving algal biomass.