scholarly journals Leaching Behaviors of Chromium(III) and Ammonium-Nitrogen from a Tannery Sludge in North China: Comparison of Batch and Column Investigations

2020 ◽  
Vol 17 (16) ◽  
pp. 6003
Author(s):  
Xiangke Kong ◽  
Yanyan Wang ◽  
Lisha Ma ◽  
Guoxin Huang ◽  
Zhaoji Zhang ◽  
...  
Keyword(s):  
North China ◽  
Ph Value ◽  
Release Kinetics ◽  
Critical Evaluation ◽  
Ammonium Nitrogen ◽  
Disposal Site ◽  
Tannery Sludge ◽  
Leaching Condition ◽  
Positive Correlation Coefficient ◽  
Dynamic Leaching

Tannery sludge usually has high content of trivalent chromium (Cr(III)) and ammonium-nitrogen (NH4+-N). It is important to make a critical evaluation of the releasing behaviors of Cr(III) and NH4+-N from tannery sludge before its use on improving soil fertility in agricultural applications. For this purpose, static batch and dynamic leaching experiments with different mathematical models were carried out to simulate the Cr(III) and NH4+-N releasing kinetics from tannery sludge sampled in a typical tannery disposal site in North China, and their influencing factors were also discussed. The results showed that a larger solid-liquid ratio, a higher temperature, and a lower pH value of the leaching solution were beneficial for the release of Cr(III) and NH4+-N from the tannery sludge. The release kinetics of Cr(III) and NH4+-N followed parabolic diffusion and simple Elovich models both in the static and dynamic leaching conditions, indicating that the release was a complex heterogeneous diffusion process. The NH4+-N was easy to be leached out and its released amount reached 3.14 mg/g under the dynamic leaching condition (pH 7), whereas the released amount of the Cr(III) was only 0.27 μg/g from the tannery sludge. There was a positive correlation coefficient between dissolved Fe and Cr(III) in the leachate under different leaching conditions, and the calculated average ratio of Fe/Cr(III) concentration was 3.56, indicating that the small amount of the released Cr(III) came from the dissolution of Cr0.25Fe0.75(OH)3 minerals in tannery sludge.

scholarly journals Some indicators of water quality of the Tamis river

2011 ◽  
Vol 17 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Nada Babovic ◽  
Dejan Markovic ◽  
Vojkan Dimitrijevic ◽  
Dragan Markovic
Keyword(s):  
Water Quality ◽  
Ph Value ◽  
Ammonium Nitrogen ◽  
Field Analysis ◽  
Total Hardness ◽  
Chemical Parameters ◽  
Physico Chemical

This paper shows the results obtained in field analysis performed at the Tamis River, starting from the settlement Jasa Tomic - border between Serbia and Romania to Pancevo - confluence of Tamis into the Danube. The Tamis is a 359 km long river rising in the southern Carpathian Mountains. It flows through the Banat region and flows into the Danube near Pancevo. During the years the water quality of the river has severely deteriorated and badly affected the environment and the river ecosystem. In situ measurements enabled determination of physico-chemical parameters of water quality of the Tamis River on every 400 m of the watercourse, such as: water temperature, pH value, electrical conductivity, contents of dissolved oxygen and oxygen saturation. The main reason of higher pollution of Tamis is seen in connection to DTD hydro system. Sampling was performed at 7 points with regard to color, turbidity, total hardness, alkalinity, concentration of ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, iron, chlorides and sulphates in samples. The aim of the present work was to evaluate water quality in the Tamis River taking into account significant pollution, which originates from settlements, industry and agriculture, and to suggest appropriate preventive measures to further pollution decreasing of the river's water.

Selective Leaching Nickel from the Pre-Reduced Limonitic Laterite Ore at Atmospheric Pressure

2012 ◽  
Vol 560-561 ◽  
pp. 494-498
Author(s):  
Yong Feng Chang ◽  
Chuan Lin Fan ◽  
Bin Chuan Li ◽  
Xiu Jing Zhai ◽  
Ting An Zhang
Keyword(s):  
Atmospheric Pressure ◽  
Ph Value ◽  
Test Results ◽  
Selective Leaching ◽  
Nickel Extraction ◽  
Extraction Degree ◽  
Leaching Solution ◽  
Novel Method ◽  
Leaching Condition ◽  
Laterite Ore

In this paper a novel method for selective leaching nickel from pre-reduced laterite ore at atmospheric pressure was reported. The reduced calcine was leached in thin acid liquor to liberate the nickel and iron together firstly. By properly controlling the leaching condition, the leached iron ion could hydrolyze as goethite precipitate and regenerate the acid consumed in the leaching procedure. Finally, the nickel is selectively extracted into the leaching solution. The main factors in the leaching process, such as reduction degree of the laterite ore, acidity of the leaching solution were investigated as influence on the nickel extraction. The test results showed that selectively leaching of nickel could be achieved with an extraction degree up to 90% by reducing most of the iron in the lateritic ore to wuestite and controlling the pH value of the leaching solution below 2.5.

scholarly journals NH<sub>3</sub>-promoted hydrolysis of NO<sub>2</sub> induces explosive growth in HONO

2018 ◽  
Author(s):  
Wanyun Xu ◽  
Ye Kuang ◽  
Chunsheng Zhao ◽  
Jiangchuan Tao ◽  
Gang Zhao ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Ph Value ◽  
Primary Source ◽  
Field Measurements ◽  
Oh Radicals ◽  
The North ◽  
The North China Plain ◽  
First Time ◽  
Hydrolysis Of

Abstract. The study of atmospheric nitrous acid (HONO), which is the primary source of OH radicals, is crucial to atmospheric photochemistry and heterogeneous chemical processes. The heterogeneous NO2 chemistry under haze conditions was pointed out to be one of the missing sources of HONO on the North China Plain, producing sulfate and nitrate in the process. However, controversy exists between various proposed mechanisms, mainly debating on whether SO2 directly takes part in the HONO production process and what roles NH3 and the pH value play in it. In this paper, never before seen explosive HONO production (maximum rate: 16 ppb/hour) was reported and evidence was found for the first time in field measurements during fog episodes (usually with pH > 5) and haze episodes under high relative humidity (usually with pH 

Study on Treatment of Ammonium Nitrogen in Desulfurization and Denitrification Wastewater with Sodium Hypochlorite

2013 ◽  
Vol 864-867 ◽  
pp. 438-441
Author(s):  
Zhen Zhou ◽  
Da Long Hu ◽  
Chu Qiao Zhang ◽  
Xue Lian Shen ◽  
Chun Hua Wu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Sodium Hypochlorite ◽  
Ph Value ◽  
Ammonium Nitrogen ◽  
Molar Ratio ◽  
Distillation Method ◽  
Good Reliability ◽  
Initial Concentration ◽  
N Removal ◽  
Effects Of Ph

Based on the investigation of measurement method of ammonium nitrogen (NH4-N) desulfurization and denitrification wastewater (DDW) by distillation method, effects of pH, Cl/N and the initial concentration of NH4-N on the removal of NH4-N in DDW by sodium hypochlorite were studied. Results of parallel test and standard recovery test demonstrated good reliability and accuracy of the distillation method for the measurement of NH4-N in DDW. The NH4-N removal efficiency increased with pH from 5.0 and 8.0, and then decreased with pH higher than 8.0. Therefore, the optimum pH value was 8.0 with NH4-N removal efficiency of 74.7%. NH4-N removal efficiency was increased from 16.9% to 84.1% with Cl/N molar ratio rose from 1 to 5. The initial concentration of NH4-N showed insignificant effect on the removal amount of NH4-N, and the removed NH4-N was about 12~13mg/L with the addition of 4.86mmol/L sodium hypochlorite.

scholarly journals Effect of Ellagic Acid on Fermentation Quality and Bacterial Community of Stylo Silage

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 256
Author(s):  
Xuan Zou ◽  
Dandan Chen ◽  
Hongjian Lv ◽  
Qing Zhang ◽  
Peng Zheng
Keyword(s):  
Bacterial Community ◽  
Ellagic Acid ◽  
Crude Protein ◽  
Dry Matter ◽  
Ph Value ◽  
Ammonium Nitrogen ◽  
Coliform Bacteria ◽  
Fresh Matter ◽  
Fermentation Quality ◽  
Matter Basis

This study was conducted to investigate the effect of ellagic acid on the bacterial community and fermentability of stylo silage. Three treatments of stylo silage were used: control (CK) and treated with 1% or 2% ellagic acid (EA1 and EA2) on a fresh matter basis. All silage was stored at ambient temperature and opened on days 3, 7, 14, and 30. Fermentation characteristics, protein fraction, and bacteria community of all periods of silage were analyzed. Results showed that dry matter and crude protein content were increased, and pH value, number of coliform bacteria, contents of acetic acid, and ammonium nitrogen were decreased with the addition of ellagic acid. The antioxidant activity of 1% and 2% ellagic acid treated silages was significantly higher than the control. Meanwhile, the relative abundance of Klebsiella and Clostridium was decreased with the addition of ellagic acid, and the abundance of Lactobacillus, Weissella, and Enterococcus was increased with prolonged days of ensiling. Adding ellagic acid to stylo silage could improve the fermentation quality and preservation of protein, and reduce the abundance of harmful bacteria.

ANALYSIS OF THE WORK EFFICIENCY OF SANDED AND CARBON FILTERS IN THE TREATMENT SCHEME OF WASTEWATER OF THE PRODUCTION OF VEGETABLE OILS AND FATS

2019 ◽  
Author(s):  
Д.В. АЛТУХОВА ◽  
Т.Г. КОРОТКОВА
Keyword(s):  
Vegetable Oils ◽  
Suspended Solids ◽  
Ph Value ◽  
Local Treatment ◽  
Rapeseed Meal ◽  
Ammonium Nitrogen ◽  
Quantitative Composition ◽  
Steam Boiler ◽  
Boiler Plant ◽  
Treatment Facilities

Представлены результаты мониторинга эффективности работы локальных очистных сооружений ООО «Пищевые ингредиенты» (Краснодарский край), производящего специализированные жиры и осуществляющего прием жидких растительных масел, патоки, подсолнечного и рапсового шротов, за период январь–апрель 2018 г. Определен качественный и количественный состав загрязненных сточных вод в аварийной емкости предприятия: рН 6,325; азот аммонийный 12,358 мг/л; фосфаты 10,630 мг/л; содержание жира 2418 мг/л; содержание мыла 0,005%; взвешенные вещества 581,3 мг/л; хлориды 972,7 мг/л; железо общее 8,333 мг/л. Установлено, что в схеме локальных очистных сооружений ООО «Пищевые ингредиенты» предусмотрено прохождение сточной воды после ее биологической очистки через песчаный и угольный фильтры с последующим обеззараживанием на установке ультрафиолетового облучения и подача очищенной воды в парокотельный цех для дальнейшего ее использования в производстве. Мониторинг работы песчаного и угольного фильтров за указанный период показал эффективность их работы: в очищенной воде отсутствовали взвешенные вещества, концентрация азота аммонийного была меньше 0,1 мг/л, ХПК не превышало 30 мгО2/л, значение рН находилось в пределах 7, что ниже допустимых уровней для этих показателей. Results of monitoring of efficiency of work of local treatment facilities of LLC «Pishchevye ingredienty» (Krasnodar region) making specialized fats and performing reception of liquid vegetable oils, molasses, sunflower and rapeseed meal for the period January–April, 2018 are presented. The qualitative and quantitative composition of contaminated wastewater in the emergency capacity of the plant is defined: pH 6,325; ammonium nitrogen 12,358 mg/l; phosphates 10,630 mg/l; content of fat 2418 mg/l; content of soap 0,005%; suspended solids 581,3 mg/l; chlorides 972,7 mg/l; iron total 8,333 mg/l. It is established that in the scheme of local treatment facilities of LLC «Pishchevye ingredienty» the passage of wastewater after its biological treatment through sand and coal filters with subsequent disinfection at the installation of ultraviolet irradiation and supply of purified water to the steam boiler plant for its further use in production is provided. Monitoring of operation of sand and carbon filters for the specified period showed the effectiveness of their work: in purified water suspended solids were absent, the concentration of ammonium nitrogen was less than 0,1 mg/l, COD did not exceed 30 mg O2/l, the pH value was within 7, that below acceptable levels for these indicators.

Drivers on The Halophytes' Rhizosphere Bacteria Community and Functions in North China Salinized Areas

2021 ◽  
Author(s):  
Fating Yin ◽  
Fenghua Zhang ◽  
Zhibo Cheng ◽  
Haoran Wang
Keyword(s):  
Bacterial Community ◽  
North China ◽  
High Throughput Sequencing ◽  
Environmental Changes ◽  
Rhizosphere Soil ◽  
Ph Value ◽  
Northern China ◽  
Soil Bacterial Community ◽  
Leymus Chinensis ◽  
Soil Bacterial

Abstract Soil salinity is a serious environmental issue in arid China. Soil bacteria play a fundamental role in soil systems and respond rapidly to environmental changes. However, the responses of soil bacterial community to the different halophytes remains poorly understood. We investigated rhizosphere soil bacterial community changes under different halophytes in north China using high-throughput sequencing. Three typical halophytes were Leymus chinensis (LC), Puccinellia tenuiflora (PT), Suaeda glauca (SG). The dominant phyla were Proteobacteria, Actinobacteria, and Chloroflexi across three halophytic vegetation. These bacteria have important assistance for halophytes adapt to saline soil. PICRUSt forecasts demonstrated that energy metabolism, amino acid metabolism and carbohydrate metabolism are main bacterial functions in halophyte vegetation soil, and the abundance of metabolism these bacterial functions in SG was significantly higher than that in LC and PT. The pH value of different halophyte rhizosphere soils has a more significant effect on bacterial diversity than EC and soil trophic status, and soil water content (SWC) was important effect factors leading to differences in bacterial functions. These results give us a deeper understanding of the diversity and functional differences of rhizosphere soil bacterial communities in the typical halophytic vegetation of northern China.

scholarly journals Chromium recovery from tannery sludge and its ash, based on hydrometallurgical methods

2019 ◽  
Vol 38 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Erasmia Pantazopoulou ◽  
Anastasios Zouboulis
Keyword(s):  
Sodium Hydroxide ◽  
Chromium Content ◽  
Ph Value ◽  
Trivalent Chromium ◽  
Tannery Sludge ◽  
Sludge Treatment ◽  
Solid Ratio ◽  
Temperature Liquid ◽  
Dried Sludge ◽  
Chromium Recovery

The recovery of chromium from tannery sludge and from its respective ash constitutes an alternative process of tannery sludge treatment in order to ensure safe disposal. Chromium recovery was investigated based on simple hydrometallurgical processes, that is, leaching using aqueous solutions of acids. Leaching was applied either directly to air-dried sludge or to its respective ash, which results from thermal treatment of the air-dried sludge under anoxic conditions. The major parameters that influence the effectiveness of the leaching process were investigated to optimize chromium leaching. Specifically, contact time, pH value, temperature, liquid per solid ratio, and leaching agent (H2SO4 or HCl) were tested. Leached chromium, obtained directly from the initial tannery waste after 100 min leaching with H2SO4 at pH 1 and at 60°C, was used for the trivalent chromium precipitation by adding magnesia, calcium hydroxide, and sodium hydroxide as precipitation agents. The results revealed satisfactory leaching of trivalent chromium directly from the air-dried sludge. The chromium content in the solid precipitated using sodium hydroxide was about 59 wt %. In contrast, chromium was difficult to leach from the respective ash.

Sign in / Sign up

Export Citation Format

Share Document