effect of adding probiotic bacteria on bauxite waste mud

Bauxite waste sludge is quite dangerous when polluted into the surrounding environment. The number is increasing with the higher mining production. The utilization is still not maximized hence it is unbalanced to the increasing number, and it is necessary to use on a large scale. Sub-grade soil could use a lot of bauxite waste sludge but in reality, this waste is unsafe to use and its characteristics are mud the requirements of bearing capacity according to the AASHTO and USCS Classification unfulfilled. This study aims to determine the effect of the use of probiotic bacteria in bauxite waste on its physical characteristics and pH value. This experimental research method develops test objects according to ASTM standards with the same weight of bauxite waste and variations in the number of probiotic bacteria, namely 25 ml, 50 ml, 75 ml, and 100 ml and the incubation time of bacteria is 7 days, 14 days, 21 days, 28 days, 35 days, and 42 days. The results showed that the test specimens with more bacteria and longer incubation times resulted in lower pH values and physical characteristics that fulfilled the requirements for sub-grade soil.

Application of Pier Waste Sludge for Catalytic Activation of Proxy-monosulfate and Phenol Elimination From a Petrochemical Wastewater

This investigation aimed to remove phenol from a real wastewater (taken from a petrochemical company) by activating peroxy-monosulfate (PMS) using catalysts extracted from pier waste sludge. The physical and chemical properties of the catalyst were evaluated by FE-SEM/EDS, XRD, FTIR, and TGA/DTG tests. The functional groups of O-H, C-H, CO32-, C-H, C-O, N-H, and C-N were identified on the catalyst surface. Also, the crystallinity of the catalyst before and after reaction with petrochemical wastewater was 103.4 nm and 55.8 nm, respectively. Operational parameters of pH (3-9), catalyst dose (0-100 mg/L), phenol concentration (50-250 mg/L), and PMS concentration (0-250 mg/L) were tested to remove phenol. The highest phenol removal rate (94%) was obtained at pH=3, catalyst dose of 80 mg/L, phenol concentration of 50 mg/L, PMS concentration of 150 mg/L, and contact time of 150 min. Phenol decomposition in petrochemical wastewater followed the first-order kinetics (k> 0.008 min-1, R2> 0.94). Based on the reported results, it was found that the pH factor is more important than other factors in phenol removal. The catalyst stability test was performed for up to five cycles and phenol removal in the fifth cycle was reduced to 42%. Also, the energy consumption in this study was 77.69 kw.h/m3. According to the results, the pier waste sludge catalyst/PMS system is a critical process for eliminating phenol from petrochemical wastewater.

Investigation of the possibilities of dewatering sewage sludge by the method of electroosmosis in order to prevent land littering

Wastewater sludge from industrial enterprises is disposed of at disposal sites. This leads to a negative impact on the soil cover. The well-known methods of dehydration of moisture-containing materials have been studied. The chemical composition of sewage sludge was investigated. A technical solution for reducing the volume of wastewater sludge formation is considered on the example of cardboard and paper production. An electroosmotic installation is proposed. To study the process of sludge dewatering, a series of experiments was carried out on the installation with variable parameters of the voltage between the electrodes. A model of the particle velocity in the medium under study was presented. It has been proven that with the help of an electroosmotic device, up to 70% of moisture is effectively removed from the volume of waste sludge waste. This makes it possible to significantly reduce their volumes, reduce areas for possible or temporary placement and reduce the environmental load on the environment.

RECYCLING OF WASTE SLUDGE FROM WWTP "GORIĆ" VALJEVO USING THE PROCESS OF STABILIZATION AND SOLIDIFICATION

The efficiency of wastewater treatment is not only measured by the quality of treated wastewater, but also by the efficiency of treatment and permanent disposal of sludge that is separated. In addition to harmless, the sludge also contains hazardous substances that are released from wastewater during treatment. This work aims to obtain a neutral and harmless product by treating waste sludge with a stabilization and solidification process using modified MID-MIX technology. Physico-chemical analysis has shown that the obtained solidification or neutral, completely inert material, which has a use-value, can be safely disposed of in a sanitary landfill following EU (European Union) regulations. In terms of chemical composition, it is a mixture of crystal-bound organo-calcium, hydrophobic salts with a low moisture content of 5.8%. The results show that the method is the most environmentally friendly and most economical for the treatment of sludge, which can be applied to other types of waste with minor modifications.

Facile Extraction and Characterization of Calcium Hydroxide From Paper Mill Waste Sludge of Bangladesh

Herein, paper mill waste sludge (PMS) from two different sources has been investigated to extract calcium hydroxide, Ca(OH)2 by a facile and inexpensive extraction process. This green process exploits typical chemical precipitation (CP) in an aqueous medium at room temperature to develop an economically and industrially viable technique for the effective utilization of calcium-containing waste sludge. PMS samples, collected from local paper mill plants of Bangladesh, were the main precursors wherein HCl and NaOH were utilized for chemical treatment. The as-synthesized products were analyzed by a variety of characterization tools including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, Scanning electron microscopy (SEM), and Energy Dispersive X-ray (EDX) elemental analyses. Our studies confirm that the extracted product contains Ca(OH)2 as a major content, albeit it also includes CaCO3 phase formed owing to the inescapable carbonation process from the surrounding environment. The particle size of the synthesized products is in the range of 450 - 500 nm estimated from SEM micrographs. The crystallite domain size of the same estimated from XRD analyses and was found to be ~47 nm and ~31 nm respectively for product-A and product-B considering major (101) Bragg peak of Ca(OH)2. The yield percentage of the isolated products is about 65% for samples collected from both sources.