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Composting is an integral component of sustainable Municipal Solid Waste (MSW) management within the circular bio-economy platform. However, it faces challenges due to malodorous emissions that impact environmental and societal equilibrium. The present study aims to minimize odorous emissions and expedite compost maturation using a novel, efficient microbial consortium. Bacteria sourced from open dump sites in Sri Lanka were carefully screened based on concurrent enzyme production. Five developed consortia were tested for their performance in reducing malodors during the composting process of MSW. Consortium No. 5 (C5), comprised of Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, demonstrated outstanding performance with a significant (p < 0.05) reduction in odorous emissions. Additionally, consortium C5 exhibited impressive control over gas emissions, maintaining VOC, CH4, NH3, and H2S concentrations within ranges of 0.5-6 ppm, 0.5-0.8 ppm, 0.3-0.5 ppm, and 0.5-0.6 ppm, respectively, compared to control concentrations of 4.5-10.2 ppm, 0.5-5.5 ppm, 0.3-5.5 ppm, and 0.5-6.4 ppm, respectively. Additionally, comprehensive Electronic nose (E-nose) analysis substantiated C5's efficiency in attenuating Methane-Aliphatic compounds, Sulfur and Aromatic compounds, along with low-polarity aromatic and alkane compounds, all with statistical significance (p < 0.05). Further, the developed consortium could reduce the composting time from 110 ± 10 days to 17 ± 3 days, offering a sustainable solution for global MSW management. [ABSTRACT FROM AUTHOR]

Biochar (BC) is a well-established physical treatment method. The high-cost BC limits their use as adsorbents in wastewater. Thus, deriving BC from cheap and locally available waste materials is needed to develop a feasible waste removal technology. Nowadays, BC technology makes it possible to envision a new strategy to manage invasive plants by converting them into value-added products like BC. Hence, the present study was designed to evaluate the potential utilization of BC as an efficient filter medium made by invasive aquatic plants, Salvinia spp., and Eichhornia spp. A mass of 50 g of prepared activated and nonactivated BC was incorporated in a sand and gravel filter to treat rubber-manufactured wastewater. Wastewater was passed through the filter, and both raw and treated water samples were analyzed for pH, Total Suspended Solids (TSS), Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), Ammoniacal- Nitrogen (NH3-N), Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Phosphates (TP), Nitrate (NO3-N), turbidity and heavy metals (Zinc, Chromium). The control filter was developed only with sand and gravel, excluding BC. Fourier Transform-Infrared Spectroscopy (FT-IR) and Scanning electron microscopy (SEM) were used to analyze BC's chemical and physical characteristics. A brine shrimp lethality assay was carried out for toxicological evaluation. OH stretching (3,550-3,200 cm-1), C=C aromatic stretching (1400-1660 cm-1), and Phenol-O-H bending (1,300-1,400 cm-1) were recorded in all BC samples that involved the adsorption mechanism. Observed images indicated differences in surface morphology of both activated and nonactivated BC were observed under SEM observation. The study concludes that the filter unit incorporated with activated Eichhornia spp. Gave the best treatment efficiency when compared to filter units incorporated with other activated and nonactivated BC. The toxicity assay revealed 100% mortality in the control setup and raw wastewater but only 60-70% in the nonactivated BC integrated filters. Activated BCincorporated filters showed no mortalities. Hence, the study's outcomes suggest a green approach using invasive aquatic plants for sustainable wastewater treatment. [ABSTRACT FROM AUTHOR]

Urbanization and rapid industrialization have led to the escalation of municipal solid waste generation and accumulation. Composting is widely recognized as a sustainable solution for solid waste management. However, its long-term investment is considered a disadvantage. The present research study discusses the rapid biotransformation of solid waste into valorized compost. Bacteria were isolated from soil, solid waste, and leachate samples from open dump sites. From the 18 different bacterial consortia created using potential isolates, the five most promising consortia were selected based on concurrent different enzyme production. These selected consortia were incorporated into typical compost bins with Municipal Solid Waste (MSW). Daily monitoring of enzymatic activity, pH, conductivity, bulk density, moisture, and temperature, along with other composting parameters, was conducted. The study’s results demonstrated that consortium No. 5, comprising Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, exhibited significant (p<0.05) enzyme activity of cellulase, amylase, lipase and proteinase enzymes during composting compared to the control and other treatment setups. Consortium No. 5 also facilitated rapid and successful composting, as evidenced by significant alterations of composting parameters by exhibiting a shorter average composting time, reducing it from 110±10 days to 20±3 days, showcasing the potential applicability of formulated bacterial consortium as a sustainable and greener approach to the global solid waste problem. The novelty of this study lies in the isolation of local bacterial strains from open dump sites soil, MSW, and MSW leachate samples, which were then utilized in the composting organic fraction of MSW, enhancing the potential for effective waste management. [ABSTRACT FROM AUTHOR]

The CYN degradation kinetics of each bacterial species were studied using High Performance Liquid Chromatography. The greatest CYN degradation (28.22 ± 0.24%) was shown by the bacterium B. cereus-S in 5.0 mg/L CYN within 14 days. The CYN degradation by the other strains was lower than 10% under the same conditions. Further studies employing different initial concentrations of CYN revealed that B. cereus-S could degrade lower CYN concentrations at a higher percentage (1.0 mg/L, 2.5 mg/L, and 5.0 mg/L of CYN removal percentages were 36.83 ± 2.43%, 32.25 ± 1.25%, and 24.72 ± 0.40%, respectively, after 14 days of incubation at 28℃ and pH 7). The maximum average degradation rates were recorded for 1.0 mg/L, 2.5 mg/L, and 5.0 mg/L CYN on the 6th (0.05 ± 0.00 mg/L/day), 8th (0.04 ± 0.01 mg/L/day), and 12th (0.02 ± 0.01 mg/L/day) days of incubation, respectively. The study showed the potentiality of the bacterium B. cereus-S on the application for degrading CYN among the tested bacteria species. [ABSTRACT FROM AUTHOR]

Detrimental effects imposed by petrochemical plastics on the environment are among the most often discussed concerns in the current era. Although the scientific community has discovered numerous eco-friendly alternatives, the cost of manufacture has restricted the usage of such material. The present study focused on the direct utilization of naturally existing cyanobacterial blooms to extract biodegradable poly-ß-hydroxybutyrate (PHB) aiming to minimize the cost of production by eliminating the need for growing of cyanobacterial monocultures. This attempt provides remedies for plastic pollution and hazardous cyanobacterial blooms simultaneously. Fresh cyanobacterial bloom samples were collected from the hypereutrophic Beira Lake, Colombo. They were maintained under in vitro conditions for 7 days, provided with a 12/12 hours light/dark cycle, and deprived of an external supply of nutrients. PHB production was optimized for Nitrogen, Phosphate, and Carbon sources: glucose, sucrose, and lactose. The extracted PHB was quantified by spectrophotometric analysis. Structure confirmation was carried out using FTIR and Raman spectroscopy. The mean percentage weight of PHB yield was 7.13 ± 0.12% w/w. Optimization studies showed that nitrate deficiency and the presence of glucose as an exogenous carbon source imposed a stimulatory effect for PHB accumulation by cyanobacteria. The maximum amount of PHB (9.6% w/w) was found to be accumulated by cyanobacteria on the fourth day following the bloom sample collection. Hence, the present study proposes a sustainable utilization method of cyanobacterial blooms as a promising source for PHB production. [ABSTRACT FROM AUTHOR]

Biochar (BC) is a viable wastewater treatment agent. Water lettuce (Pistia spp.) an invasive aquatic plant in Sri Lanka has been used in this study to produce BC by pyrolysis. Industrial water was filtered through activated and non-activated BC samples having 65-125 mm and 125-250 mm particle sizes. Filter with sand and gravel served as standard for comparison. The filter unit containing activated BC showed higher treatment efficiency. pH was reduced from 8.72 ± 0.01 to 6.87 ± 0.01; biological oxygen demand (BOD5) from 57 ± 1.73 to 15.67 ± 1.15 ppm; chemical oxygen demand (COD) from 512 to 128 ppm, total Kjeldahl nitrogen (TKN) from 158.67 ± 2.89 ppm to 33 ppm, ammoniacal nitrogen from 22.63 to 3.13 ± 0.01 ppm; chromium from 0.0625 to 0.0245 ppm, and zinc from 0.9886 to 0.2105 ppm. Optimization study revealed that the BC integrated filter units could be used to treat wastewater in three cycles. Thereafter their efficiency is reduced. The BCs with small particle size (65-125 mm) recorded the highest treatment efficiency. This particle size showed 99.72% turbidity reduction. Reduction of total phosphate, ammoniacal nitrogen, total suspended solids, COD, nitrate, BOD5 and TKN was recorded as 97.82%, 91.49%, 88.38%, 88.18%, 87.44%, 84.38% and 84.38% respectively. BC derived from Pistia spp. has proven to be promising adsorbent for wastewater treatment. Findings of the study show a long-term green wastewater treatment method that makes effective use of an invasive aquatic plant. [ABSTRACT FROM AUTHOR]