Reuse of textile effluent treatment plant sludge in building material

Abstract This study examines the potential reuse of textile effluent treatment plant (ETP) sludge in building materials. The physico-chemical and engineering properties of a composite textile sludge sample from the southern part of India have been studied. The tests were conducted as per Bureau of Indian Standards (BIS) specification codes to evaluate the suitability of the sludge for structural and non-structural application by partial replacement of up to 30% of cement. The cement-sludge samples failed to meet the required strength for structural applications. The strength and other properties met the Bureau of Indian Standards for non-structural materials such as flooring tiles, solid and pavement blocks, and bricks. Results generally meet most ASTM standards for nonstructural materials, except that the sludge-amended bricks do not meet the Grade NW brick standard. It is concluded that the substitution of textile ETP sludge for cement, up to a maximum of 30%, may be possible in the manufacturing of non-structural building materials. Detailed leachability and economic feasibility studies need to be carried out as the next step of research

Unravelling the ecological ramifications of biodegradable microplastics in soil environment: A systematic review

Plastic pollution, especially microplastics (MPs), poses significant environmental challenges, with biodegradable plastics (BPs) often presented as sustainable alternatives. However, incomplete degradation of BPs in soil environment leads to the creation of biodegradable microplastics (BMPs), whose impacts remain inadequately understood. This systematic review synthesizes findings from 85 publications to assess the effects of BMPs on soil ecosystems, encompassing physical, chemical, and biological properties. BMPs influence soil texture, porosity, nutrient cycling, microbial diversity, and plant growth, with varying impacts depending on polymer type, concentration, and soil conditions. While BMPs can enhance soil organic matter and microbial activity at low concentrations, higher concentrations often alter nutrient availability and soil stability. Soil biota shows differential responses to BMPs, with potential implications for nutrient cycling and soil ecosystem functioning. Contradictory research findings underscore the need for long-term, field-based studies under varied environmental conditions. The insights from this review contribute to a deeper understanding of the ecological ramifications of BMPs in soil ecosystems, highlighting critical research gaps, advocating for multidisciplinary approaches to comprehensively evaluate impacts of BMPs

Application of Sulfate-Reducing and Sulfide-Oxidizing Bacterial Symbiosis for Wastewater Treatment

Abstract This investigation attempted to advance the state of the art of the process which utilizes the symbiotic relationship between the sulfate-reducing bacteria (SRB) and sulfide oxidizing bacteria (SOB) for degradation of organic matter present in wastewater. Major emphasis has been on the development of the desired microbial system without any external seed and comparative evaluation of the two types of multistage reversing flow bioreactor (MRB) systems. Biological vessels (BVs) in the MRB systems simulate conditions which correspond to configurations described as upflow sludge blanket and stationary fixed film. Two bench-scale models – one designed to achieve self granulation of sludge (SGS), and the second designed to promote growth of SRB/SOB on additional nonreactive surface – were set up and operated over a period of 4 months. Domestic wastewater supplemented with organic matter from sugar cane molasses was used as feed to develop the desired microbial population. Several visual and microscopic observations confirmed the presence of a significant number of SRB and SOB in all the biological vessels. Results indicated that it is possible to develop SGS and a microbial population of SRB and SOB which could attach to the nonreactive surface without any external seeding. Domestic wastewater could serve as a source of these organisms. Immobilized growth conditions and suspended growth conditions in BVs yield similar results in terms of organic matter utilization. The empirical formula for MRB biomass can be expressed as C11O12H36N5S.</jats:p