The meat processing industry produces a huge quantity of by-products, approximately 150 million tonnes per year. The live weight of the animals is distinguished as edible, inedible, and discardable by-products, with the discardable parts equating to 66%, 52%, and 80% of the overall live weight of cattle, lamb, and pigs, respectively. Only a small percentage of those by-products are nowadays exploited for the production of high added value products such as animal feed, glue, fertilizers, etc., whereas the main management method is direct disposal to landfills. As such, the current disposal methodologies of these by-products are problematic, contributing to environmental contamination, soil degradation, air pollution, and possible health problems. Nevertheless, these by-products are rich in collagen, keratin, and minerals, being thus promising sources of high-value materials such as bioenergy, biochemical and other biomaterials that could be exploited in various industrial applications. In this paper, the possible utilization of slaughterhouse by-products for the production of various high added value materials is discussed. In this context, the various processes presented provide solutions to more sustainable management of the slaughterhouse industry, contributing to the reduction of environmental degradation via soil and water pollution, the avoidance of space depletion due to landfills, and the development of a green economy.

The rapid growth of textile industries in Ethiopia plays an important role in economic development. However, the sludge from these wastewater treatment plants, which is not an integral part of the treatment process, is often considered hazardous as it is contaminated with heavy metals of dyestuffs and chemicals. The customary transfer routines such as landfilling and incineration may not be suitable because the leachate from the landfilling destinations and the buildups from the incinerators lead to optional contamination. Moreover, such transfer choices are not financially practical. Therefore, there is a growing need to look for various applications of sludge handling for sustainable development. This study attempts to find out an environmentally friendly solution for the management of the textile sludge by incinerating the sludge and using it for partial replacement of cement in concrete production. Concrete is a composite material formed by the combination of cement, sand, coarse aggregate, and water in a particular proportion so that concrete produced meets the needs regarding its workability, strength, durability, and economy. Typical textile sludge was having high heavy metal contents as per the United States Environmental Protection Agency (USEPA) guideline and should be properly disposed of. The sludge upon incineration at 625°C for four hours gives 78.1% moisture content, 61.2% volatile organic matter, and 59.6% inorganic ash content. The main reactive oxide elements such as SiO₂, Fe₂O₃, CaO, and Al₂O₃ were found to be 18.51, 3.19, 23.87, and 12.73% by weight in the ash. The calorific value determined from the dried sludge were found to be 1973 cal/gm. Concrete block was manufactured by replacement of cement with 10, 20, 30, 40, and 50% incinerated textile sludge ash, and the manufactured block was evaluated in terms of their compressive strengths, leaching behavior, and water absorption. The replacement cement by the ash increases the hydration time reduced, and up to 20%, sludge ash incorporation in the concrete mix design gives the designed compressive strength. Eventhough water absorption increases with increasing content of the incorporation of the ash, for the 20% replacement of cement, the lethal concentration of heavy metals was obtained to be below the permissible limit set by USEPA. Consequently, the experiment work indicates that the potential use of textile sludge ash for cement concrete gives the possibilities of reduction of heavy metal contamination to surroundings upon sludge disposal, reduces the use of raw materials for producing cement and reduces environmental pollution during cement production.

Aiming at the classic problem of dyeing of polyester–cotton blended fabric one-bath one-step dyeing of PC blends with disperse dye after surface modification of cotton were studied. Surface modification of cotton was carried out using fibrous acetylation methods. The optimum value for surface modification was obtained with a concentration of acetylation agent 16% and time of reaction 2.5 h, gave a percent acetylation of 34. Surface chemistry and thermal decomposition were studied by using FTIR spectra and TGA. The tear strength crease recovery, pilling and abrasion resistance were evaluated. The experiment result of dyeing showed that the optimum value was obtained with dye concentration above 1% at a temperature of 120 °C warp tensile strength decreased by 12% and weft tensile strength was decreased by 9% from the control half-bleached fabric. Results of this study showed that one-step one bath dyed modified PC blend with disperse dye fabric presents good fastness property and color strength values compared with conventional two-bath dyed fabric.

The continued expansion of industrial growth has contributed significantly to the economic development of many countries. However, untreated discharge from the textile factory significant impacts freshwater and public health. The aim of this study is to explore the economical-local wastewater treatment for local textile industries. The experiment used the waste bones as a source of calcium-phosphate nanopowder (CNP) biocomponent, adsorbent for azo dye effluent treatment. An isolated biocomponent was analyzed using FTIR and UV-VIS, and its adsorption isotherm was also calculated. The FTIR analysis of CNP showed carbonates, amide, and high-intensity phosphate peaks of 1008cm⁻¹ and 1337cm⁻¹. The effect of contact time analyzed by UV-VIS absorption spectra revealed that 70 of color removal was achieved within 30minutes and 60minutes for disperse red 1 dye (DR1D) and DCT reactive blue 109 dyes (RB109D), respectively. In addition, the effects of the condition parameters on percentage color removal were analyzed using DOE response surface methodology. The maximum color removal performances are 98.65 and 96, respectively, for DR1D and RB109D at neutral pH. The Langmuir isotherm was observed in the adsorption of RB109D effluent with an R2 value of 0.994 and the Freundlich isotherm in the adsorption of DR1D with an R2 value of 0.993. Finally, the gauge of the effectiveness of treatment was analyzed by COD, BOD, and TSS values before and after treatment. The maximum deduction percentages of COD, BOD, and TSS were 82, 87, and 70 from RB109D; 89, 90, and 89 from DR1D; and 82, 89, and 71 from the industry sample, respectively. Generally, the study showed that the current adsorbent was a good substitute for synthetic adsorbents.

Industrial effluents have a serious problem on our ecosystem. Tannery effluent contains a huge amount of pollutant compounds such as toxic substances which need to be treated using either synthetic or natural products. The present study focussed on the treatment of tannery effluents using water hyacinth plant leaf extract. Though some researchers have tried to use this extract for the same, the researchers have experimented only to treat that of Cr³⁺ and there are a bit of difference in the methodology they followed. In addition, the scope of this research was wider. In this study, fresh raw WH leaves were collected from around Lake Tana, Ethiopia, cleaned and made to powder and then extraction was performed using different solvents. The solvent effects were examined using the ANOVA test. The tannery wastewater was treated with the extracts and parts of the effluents were kept as a control for comparison. Treated and untreated tannery effluents were compared using standard methods such as SLC 22, SLC 8, APHA 2540C, APHA 2540D, and Hack LCK 139 to determine Cr⁶⁺, Cr³⁺, TDS, TSS, and TKN, respectively. The highest amount of Cr⁶⁺, Cr³⁺, and TKN were removed at 30 water hyacinth leaves extracted by distilled water solvent and that of the least was found at hyacinth leaves extract by ethanol solvent but by acetone in BOD and COD treatment. In addition, though it was out of the permissible limit, by using the same amount of the material extracted by distilled water solvent some amounts of BOD and TDS were removed from the wastes compared to that of untreated tannery effluents. Generally, water hyacinth leaf extract is found effective material for the treatment of tannery effluents and can be used in the sector industries. Future studies may be required for setting the most optimum extract concentration for better results.

Usually, the two-bath dyeing process using disperse dyes and reactive dyes separately was employed for the dyeing of PC blends. The cost of the double bath, dyeing cycle, energy consumption and chemical consumption is quite higher than the one-step or single bath dyeing methods. In this study, the one-bath dyeing process using one kind of dye was investigated. Polyester cotton blends dyed in one-bath one-step dyeing methods with disperse dye after surface modifications of cotton by acetylation methods were studied. Surface modification of cotton was carried out using fibrous acetylation methods. The effect of acetic anhydride and time on percent acetyl content at room temperature was studied. Modified polyester/cotton was carried out in HTHP dyeing machine incorporates with different dye concentrations and dyeing temperature. Surface chemistry, thermal decomposition property and moisture regain of modified polyester/ cotton blend are evaluated. The color strength of the dyed fabrics and their fastness properties to washing, light, and rubbing as well as tear strength and abrasion resistance were evaluated. The effect of dye concentration and temperature color strength, tensile strength warp and weft direction was assessed. The optimum value for surface modification was obtained with a concentration of acetylation agent 16% and time of reaction 2.5 hours, gave percent acetylation of 34. An FTIR spectrum shows acetylation resonance. The experiment result of dyeing showed that the optimum value was obtained with dye concentration above 1% at a temperature of 120oC, warp tensile strength decreased by 12% and weft tensile strength was decreased by 9% from the control half-bleached fabric. Results of this study showed that a one-step one-bath dyed modified polyester/cotton blend with disperse dye fabric presents good fastness property compared with conventional two-bath dyed fabric as well as colour strength values.