scholarly journals Effect of Oxidizers on Sulphide Removal from Hair Dissolving Liming Wastewater in Tannery

2022 ◽  
Vol 12 (3) ◽  
pp. 67-72
Author(s):  
Md Abul Hashem ◽  
Mst Nazmin Zaman Khan ◽  
Protima Roy ◽  
Md Anik Hasan

Liming and unhairing is the conventional operation in the tannery where raw animal skins are treated with sodium sulphide and calcium hydroxide to remove keratin proteins e.g., hair and wool epidermis and to dissolve nonstructural proteins. The hair dissolving liming process discharges wastewater containing soluble sulphide. In acidification, the sulphide in wastewater generates toxic hydrogen sulphide, which has a negative impact on the environment. In this present study, the efficiency of hydrogen peroxide (H2O2) and sodium chlorite (NaClO2) oxidizers are compared to remove sulphide from the hair dissolving liming wastewater. The soluble sulphide in the raw liming wastewater was 3666 mg/L. At optimized dose and pH for H2O2 and NaClO2 soluble sulphide in the solution were 109.2 and 54.6 mg/L, respectively. The sulphide removal efficiency for H2O2and NaClO2 were 97.0% and 98.5%, respectively at an optimum pH (pH 7). Before and after treatment the physicochemical parameters of the liming wastewater were analysed by observing different water quality parameters viz: pH, TDS, EC and salinity. At optimized condition TDS and salinity removal efficiency was 47.2%, 52.3% and 8.1%, 11.2% for H2O2 and NaClO2, respectively. This simple and easy method would be effective for treating hair dissolving liming wastewater in reducing soluble sulphide discharge from the tanneries. Journal of Engineering Science 12(3), 2021, 67-72

Author(s):  
Anda David ◽  
Mohamed Ali Marouani

This chapter focuses on the external effects of emigration on non-migrants, and particularly on the interactions with labor market outcomes in Tunisia before and after the revolution. Using the new Tunisia Labor Market Panel Survey (TLMPS), we conduct an in-depth analysis of the structure and dynamics of migration, including the profile of migrants and their origin households, mainly in terms of skills and spatial composition. We investigate transition matrices, employment status, income for current migrants and returnees, and the evolution of remittances. Our analysis confirms the role of emigration as a safety valve for the Tunisian labor market. Moreover, origin households of migrants have a significantly higher wealth index. Our analysis also tends to confirm the effects of remittances on labor supply of non-migrants, which can have a negative impact on Tunisia’s unemployment rate when a crisis in destination countries affects the remittance rate negatively.


2019 ◽  
Vol 20 (5) ◽  
pp. 1282-1291
Author(s):  
Sanjay Dhamija ◽  
Ravinder Kumar Arora

The article examines the impact of regulatory changes in the tax on dividends on the payout policy of Indian companies. The tax law was recently amended to levy tax on dividends received by large shareholders. As the promoters group is the largest shareholder, this is expected to have a negative impact on the payout policy of companies. Furthermore, companies with larger promoter holdings have a higher motivation to reduce their payout. The study covers 370 companies present in the BSE 500 Index and compares the dividend payout of the companies before and after the introduction of tax levy. The study finds that the newly introduced tax indeed caused a shift in the dividend policy of companies, particularly those companies which have high levels of inside ownership. The findings have significant implications for companies, investors and the government.


2002 ◽  
Vol 14 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Ulla Eloniemi-Sulkava ◽  
Irma-Leena Notkola ◽  
Kaija Hämäläinen ◽  
Terhi Rahkonen ◽  
Petteri Viramo ◽  
...  

Objectives: To investigate what kind of changes spouse caregivers of demented patients experience after the onset of dementia (a) in the general atmosphere, happiness, and relations of marriage and (b) in the sexual side of marriage. Design: Semistructured telephone interviews of spouse caregivers of demented patients. Setting: Community-living demented patients and their spouse caregivers in eastern Finland. Participants: The spouse caregivers of 42 demented patients recruited from a previous intervention study. Measures: The questionnaire covered different areas of marriage from the time before and after the onset of dementia. Results: A statistically significant decline had occured in extent of happiness (p = .012), in equal relations (p = .001), and in patients' expressions of sexual needs (p < .001) when compared the time before and after dementia. Twenty-five (60%) of the caregivers reported that the demented patient had shown at least one negative sexual behavioral change during the course of dementia. Seven male patients (24%) had shown the behavioral symptom of constantly expressing need for making love. One in 10 caregivers had experienced positive sexual behavioral changes. In one third of the patients, the expressions of tenderness towards the caregiver had increased. Dementia did not affect significantly the general atmosphere of the marriage. Out of those still in home care, at 3 years from the onset of dementia, 19 couples (46%) continued to practice intercourse, at 5 years the number was 15 couples (41%), and at 7 years it had declined to 7 couples (28%). Conclusions: Dementing illness has a major negative impact on many dimensions of marriage. However, there are also positive changes and preserved aspects of marriage. Dementia seems to have a surprisingly little impact on whether the couple continues to have intercourse when compared with the general aging population.


2018 ◽  
Vol 115 (3) ◽  
pp. 312 ◽  
Author(s):  
Rowaid Al-khazraji ◽  
Yaqiong Li ◽  
Lifeng Zhang

Boron (B) removal by slag refining using CaO–SiO2–CaCl2 was investigated in metallurgical-grade silicon (MG-Si) and 75 wt% Si–Sn alloy. Experiments were conducted at 1500 °C for 15 min. The microstructure was characterized before and after refining. The effects of acid leaching, basicity, and slag/Si mass ratio on B removal were investigated. Experimental results showed that acid leaching had no effect on B removal from MG-Si but had a clear effect on the refined Si–Sn alloy after slag refining. The final B concentration was highly affected by the CaO/SiO2 mass ratio with minimum value, where the content of B was reduced from 18.36 ppmw to 5.5 ppmw at the CaO/SiO2 = 1.2 for MG-Si slag refining and from 18.36 ppmw to 3.7 ppmw at CaO/SiO2 = 1.5 for 75 wt% Si–Sn alloy. Increasing the slag mass ratio by 2:1 mass ratio also increased B removal efficiency by approximately 15–20% more than an increase by 1:1.


2018 ◽  
Vol 19 (4) ◽  
pp. 1066-1072
Author(s):  
Q. H. Jin ◽  
C. Y. Cui ◽  
H. Y. Chen ◽  
Y. Wang ◽  
J. F. Geng ◽  
...  

Abstract Adsorption (ADS) and dielectrophoresis (DEP) techniques were combined (ADS/DEP) to efficiently remove As(V) in industrial wastewater. Fly ash, activated carbon, corncob and plant ash were tested to determine the best adsorbent by their adsorption capacity. Plant ash showed the highest adsorption capacity compared with the others. Different parameters such as solution pH and adsorbent dose were explored. The maximum As(V) removal efficiency was 91.4% at the optimized conditions (pH 9.0, adsorbent dose 5 g/L) when the initial concentration of As(V) was 15 mg/L. With the ADS/DEP technique, the plant ash particles with adsorbed As(V) were trapped on the electrodes in a DEP device. The ADS/DEP process could increase the removal efficiency of As(V) to 94.7% at 14 V even when the initial concentration of As(V) was 15 mg/L. And the residual concentration of As(V) decreased to 0.34 mg/L after two series of the ADS/DEP process. The adsorbents before and after DEP were examined by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis. After the DEP process, the weight percentage of As(V) on the adsorbent surface increased to 0.96% from 0.5%. The ADS/DEP process could be a new efficient way to remove arsenic pollutant at high concentrations.


2017 ◽  
Vol 65 (3) ◽  
pp. 495-508
Author(s):  
William Bauer ◽  
Paulo Cesar Abreu ◽  
Luis Henrique Poersch

Abstract Water quality, chlorophyll a, phytoplankton, proto and mezo-zooplankton abundance were spatiotemporally evaluated in an estuary receiving effluents from a Pacific white shrimp Litopenaeus vannamei farm in Patos Lagoon estuary, Southern Brazil. Samples were taken before (BD) and; 1 day (1 PD) 5 days (5 PD), 10 days (10 PD), 20 days (20 PD) and 30 days (30 PD) after the effluents discharge. Some water quality parameters were affected by the effluents discharge; however, these changes were restricted to a distance of 20 m from the effluent discharge channel for a period of 5 days. The microbial community was dominated by chlorophyceae, followed by diatoms, cyanobacteria and ciliates. There was an increase in the abundance of different groups on the 1 PD sampling compared to BD. The zooplankton abundance was low in practically all sites, except for 30 PD sampling. The meso-zooplanktonic organisms were represented by copepods, mostly Acartia tonsa. Despite some effects on water quality and phytoplankton and protozooplankton abundance until 5 PD sampling, these alterations dissipated in a short period of time. We conclude that the environment quickly assimilated the effluents discharge, and the water quality parameters remained within the limits stipulated by standard guidelines.


2021 ◽  
Author(s):  
Daniel Osuna Gómez ◽  

This paper estimates the impact of the capture of leaders of criminal organizations on the labor market in municipalities where these organizations operated between 2004 and 2006. The difference-in-difference analysis compares different employment outcomes in cartel locations and the rest, before and after the capture of cartel leaders. The results show that captures caused a decrease in nominal wages and paid employment in cartel municipalities. Using Economic Census Data, I find that captures also caused a fall in the number of establishments and had a negative impact on other establishment outcomes. This document focuses exclusively on the impact of the capture of leaders of criminal organizations on the labor market until 2011 without studying other possible consequences, and thus does not make an integral assessment of this policy


2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.


2021 ◽  
Vol 11 (19) ◽  
pp. 9036
Author(s):  
Guostė Antanavičienė ◽  
Eglė Zasčiurinskienė ◽  
Dalia Smailienė ◽  
Nomeda Basevičienė

(1) Background: This retrospective study aimed to examine the change of gingival recessions (GR) before and after orthodontic treatment (OT). (2) Methods: Patients who had at least one GR on the vestibular surface of maxillary/mandibular teeth mesial to first molars were included. GR was measured on good quality plaster models before and after OT. (3) Results: Significant improvement of mean GR at patient level was found between T0 and T1 (0.45 mm, 95% CI: 0.28, 0.62) (p < 0.001). In 51.4% of patients GRs became better, in 37.8% GRs did not change. and in 10.8% GRs became worse. At tooth level the mean GR improvement was 0.54 mm (CI: 0.42, 0.65; median 0.55 mm Q1; Q3: 0.12, 0.96) (p < 0.001). GR improved in 67 teeth (58.7%), did not change in 41 (36.0%), and worsened in 6 (5.3%). Full healing was observed in 15 teeth. A reduced GR improvement was found in cases with pre-treatment open bite (OR 3.89; CI: 1.35, 11.16; p = 0.008) and dental Class III patients (OR 2.6; CI: 1.11, 6.0; p = 0.026). (4) Conclusion: There was an improvement of GR after OT in more than half of the patients. Class III malocclusion and reduced pre-treatment overbite had a negative impact on GR improvement.


2019 ◽  
Vol 41 (3) ◽  
Author(s):  
Pham Hoang Long ◽  
Nguyen Hoai Chau ◽  
Nguyen Chi Thanh ◽  
Ngo Quoc Buu

This research aims to study on the disinfection efficiency of Hoa Sen medical instrument sterilizing equipment based on the application of ECA technology at General Hospital and Obstetrics and Paediatrics Hospitals in Tra Vinh. Disinfection using ECA technology is a method that does not require the introduction of special oxidizing agents except of water and salt. ECA solution - Anolyte solution has very strong oxidants, which oxidize components such as protein, lipid, etc. (usually of the bacterial cell membrane) that make the cell membrane decomposed, reducing 77−93% of the respiratory ability of bacterial cells, weakening them and eventually being destroyed. Hoa Sen medical instrument sterilizing equipment has a similar construction form as a regular double washing table with two wash basins, wherein one sink with a faucet which produces purified water, while other one has a faucet that gives anolyte solution for sterilization. Both faucets are based on a touch support. At the bottom of the sink an anolyte solution production system was installed. Valorization of the disinfection ability of the Hoa Sen medical instrument sterilizing equipment was based on the determination of the number of microorganisms on the surface of the instrument before and after being soaked with an antiseptic washing table. Microbiological criteria are the number of aerobic bacteria, E. Coli and Coliforms. Analytical samples were quantified by culture method on agar plates. Analysis of total aerobic bacteria, E. Coli and Coliforms bacteria according to Vietnam Standard TCVN 4884:2015, TCVN 6846:2007 and TCVN 6848:2007, respectively. The results showed that bacterial removal efficiency was elevated with a novel Hoa Sen sterilizing equipment anolyte. In laboratory scale, E. Coli and Coliforms bacteria with a density of 105 CFU/mL were completely removed in 30 sec contact with an anolyte solution of 300 mg/L active chlorine concentration. In hospital scale, the removal efficiency of total aerobic bacteria on the surface of medical instruments after surgery was 99% for one minute disinfection time. For E. Coli and Coliforms bacteria, the results of the analysis were not detected in both cases before and after sterilization. 


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