Project description:The hydrothermal-alkaline treatment (HAT) is an efficient sludge reduction method. However, the roles of HAT in tannery sludge reduction are not very clear. In this study, the sludge reduction mechanism of HAT was explored. The results showed that HAT had good performance for the organic dissolution of tannery sludge. The reduction of the sludge mass was calculated by the mass of the separated wet sludge solid (4000 rpm, 10 min) before and after HAT. The HAT parameters for sludge reduction (SR) were optimized by the Box-Behnken, and the sludge reduction was 62.5% under optimal conditions (198 °C, 87 min and 8.7 g L-1 NaOH). The soluble organics, especially a polysaccharide (PS) and ammonia nitrogen (NH3-N), showed a close correspondence with the SR ratio. The rheological properties of the sludge indicated that the reticular structures in the sludge were destroyed after HAT. The tannery sludge solid became more pyknotic than raw sludge after the hydrothermal-alkaline treatment. The tannery sludge reduction can be attributed to the damage of reticular structures, organic dissolution and release of bound water.

| S-EPMC9051940 | biostudies-literature

activated sludge metagenome

Project description:Tannery Effluents Metagenome

| PRJNA251558 | ENA

Dynamics of archaeal community in soil with application of composted tannery sludge.

Project description:Application of composted tannery sludge (CTS) could promote a shift in the structure of soil microbial communities. Although the effect of CTS on bacterial community has been studied, it is unclear how the composition and diversity of archaeal community respond to CTS amendment and which environmental factors drive the community over time. Here, we hypothesize that the Archaea structure and composition respond to CTS amendment over the time. CTS had been previously applied annually along 6 years and this assessment occurred for 180 days following the application in the 7th year by using different rates (0, 2.5, 5, 10 and 20 ton ha-1). We used amplicon 16S rRNA sequencing to assess the changes in the structure of the archaeal community. Thaumarchaeota and Euryarchaeota were the most abundant phyla found in soils with application of CTS, with Thaumarchaeota dominating the sequences in all samples with relative abundances of >98%. We observed a decreasing trend on the archaeal diversity over the time with increasing CTS application rate, together with an increase in the community similarity. The redundancy analyses (RDA) explained 43% of the total variation in operational taxonomic units and identified Na, pH, Cr and P as the main drivers of the archaeal community over time after application of highest CTS rates. CTS application changes the structure of Archaea community, with significant increase of Thaumarchaeota and Aenigmarchaeota groups, which can be further explored for its biotechnological use in contaminated soils.

| S-EPMC6517401 | biostudies-literature

Hexavalent chromium release over time from a pyrolyzed Cr-bearing tannery sludge.

Project description:Pyrolysis in an inert atmosphere is a widely applied route to convert tannery wastes into reusable materials. In the present study, the Cr(III) conversion into the toxic hexavalent form in the pyrolyzed tannery waste referred to as KEU was investigated. Ageing experiments and leaching tests demonstrated that the Cr(III)-Cr(VI) inter-conversion occurs in the presence of air at ambient temperature, enhanced by wet environmental conditions. Microstructural analysis revealed that the Cr-primary mineral assemblage formed during pyrolysis (Cr-bearing srebrodolskite and Cr-magnetite spinel) destabilized upon spray water cooling in the last stage of the process. In the evolution from the higher to the lower temperature mineralogy, Cr is incorporated into newly formed CrOOH flakes which likely react in air forming extractable Cr(VI) species. This property transforms KEU from an inert waste to a hazardous material when exposed to ordinary ambient conditions.

| S-EPMC10539330 | biostudies-literature

Probing horseradish peroxidase catalyzed degradation of azo dye from tannery wastewater.

Project description:Biocatalysis based effluent treatment has outclassed the presently favored physico-chemical treatments due to nil sludge production and monetary savings. Azo dyes are commonly employed in the leather industry and pose a great threat to the environment. Here, we show the degradation of C. I. Acid blue 113 using horseradish peroxidase (HRP) assisted with H2O2 as a co-substrate. It was observed that 0.08 U HRP can degrade 3 mL of 30 mg/L dye up to 80% within 45 min with the assistance of 14 μL of H2O2 at pH 6.6 and 30°C. The feasibility of using the immobilized HRP for dye degradation was also examined and the results show up to 76% dye degradation under similar conditions to that of free HRP with the exception of longer contact time of 240 min. Recycling studies reveal that the immobilized HRP can be recycled up to 3 times for dye degradation. Kinetics drawn for the free HRP catalyzed reaction marked a lower K m and higher V max values, which denotes a proper and faster affinity of the enzyme towards the dye, when compared to the immobilized HRP. The applicability of HRP for treating the actual tannery dye-house wastewater was also demonstrated.

| S-EPMC3736071 | biostudies-literature

Biological treatment of tannery wastewater by using salt-tolerant bacterial strains.

Project description:BackgroundHigh salinity (1-10% w/v) of tannery wastewater makes it difficult to be treated by conventional biological treatment. Salt tolerant microbes can adapt to these saline conditions and degrade the organics in saline wastewater.ResultsFour salt tolerant bacterial strains isolated from marine and tannery saline wastewater samples were identified as Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Staphylococcus aureus. Growth factors of the identified strains were optimized. Tannery saline wastewater obtained from a Common Effluent Treatment Plant (CETP) near Chennai (southern India) was treated with pure and mixed consortia of four salt tolerant bacterial strains. Experiments with optimized conditions and varying salt content (between 2 and 10% (w/v) were conducted. Salt inhibition effects on COD removal rate were noted. Comparative analysis was made by treating the tannery saline wastewater with activated sludge obtained from CETP and with natural habitat microbes present in raw tannery saline wastewater.ConclusionSalt tolerant bacterial mixed consortia showed appreciable biodegradation at all saline concentrations (2%, 4%, 6%, 8% and 10% w/v) with 80% COD reduction in particular at 8% salinity level the consortia could be used as suitable working cultures for tannery saline wastewater treatment.

| S-EPMC2397378 | biostudies-literature

Aspergillus oryzae strain:SC01new | isolate:isolate from tannery

Project description:Aspergillus oryzae strain:SC01new | isolate:isolate from tannery Genome sequencing

| PRJNA1308737 | ENA