scholarly journals Purification of Cr(VI)-containing wastewater by chemical precipitation: test results of an experimental-industrial installation

Author(s):  
А.V. Suvorin ◽  
M.N. Shorokhov ◽  
M.A. Ozheredova ◽  
O.N. Bliznjuk ◽  
I.M. Ryshchenko ◽  
...  

We present the main results of experimental and industrial study of the developed process and pilot plant for purification of the Cr(VI)-containing rinse water by chemical precipitation. This technique implies full or partial return of treated water to rinse workpieces after chromium plating and prepare working solutions (precipitators). We characterize the manufacturing scheme of the pilot plant and the mode of its performance. Saturated aqueous solutions of Са(ОH)2 and Ва(ОH)2 were used as precipitating reagents. The tests confirmed the possibility of automatic dosing the reagents with due regard for the pH value of a medium, which can be used in both continuous and periodic rinsing. The operating conditions of rinsing the workpieces after electrochemical chromium plating were justified. We derived the equation for the calculation of the total salt content in the rinse water after its purification. We determined the duration of the rinsing without the need to renew the bath volume. The performed calculations substantiated the possibility of reducing the consumption of fresh water supplied for rinsing by the recycling of wastewater without deteriorating the quality of the rinsed workpieces. The reduction of water consumption by 35% was observed as compared with that stated by the regulations.

1998 ◽  
Vol 37 (2) ◽  
pp. 65-73 ◽  
Author(s):  
Antoine Montiel ◽  
Bénédicte Welté

The renovating of a new water treatment plant in Paris which produces 15% of the capital's drinking water supply is described: an original treatment plant consisting of a preozonation, a flotation with a low level of coagulant coupled with contact coagulation. Coagulation on filter has been tested on a pilot plant. The results are excellent (95 to 99%) and have led to the building of a new water treatment plant with very flexible operating conditions depending on the quality of the water.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6527
Author(s):  
Muhamad Amir Mohd Fadzil ◽  
Haslinda Zabiri ◽  
Adi Aizat Razali ◽  
Jamali Basar ◽  
Mohammad Syamzari Rafeen

The quality of feedstock used in base oil processing depends on the source of the crude oil. Moreover, the refinery is fed with various blends of crude oil to meet the demand of the refining products. These circumstances have caused changes of quality of the feedstock for the base oil production. Often the feedstock properties deviate from the original properties measured during the process design phase. To recalculate and remodel using first principal approaches requires significant costs due to the detailed material characterizations and several pilot-plant runs requirements. To perform all material characterization and pilot plant runs every time the refinery receives a different blend of crude oil will simply multiply the costs. Due to economic reasons, only selected lab characterizations are performed, and the base oil processing plant is operated reactively based on the feedback of the lab analysis of the base oil product. However, this reactive method leads to loss in production for several hours because of the residence time as well as time required to perform the lab analysis. Hence in this paper, an alternative method is studied to minimize the production loss by reacting proactively utilizing machine learning algorithms. Support Vector Regression (SVR), Decision Tree Regression (DTR), Random Forest Regression (RFR) and Extreme Gradient Boosting (XGBoost) models are developed and studied using historical data of the plant to predict the base oil product kinematic viscosity and viscosity index based on the feedstock qualities and the process operating conditions. The XGBoost model shows the most optimal and consistent performance during validation and a 6.5 months plant testing period. Subsequent deployment at our plant facility and product recovery analysis have shown that the prediction model has facilitated in reducing the production recovery period during product transition by 40%.


2012 ◽  
Vol 531 ◽  
pp. 362-365 ◽  
Author(s):  
Hai Ying Zhang ◽  
Guo Liang Yuan ◽  
Guo Xian Ma

Fly ash collected from municipal solid waste (MSW) incinerator have been characterized in terms of chemical constituents, mineralogical components, acid neutralizing capacity and total salt content. It was found that the fly ash is rich in SiO2, Al2O3, CaO, Fe2O3 and MgO, which may act as glass-formers (SiO2 and Al2O3), melting (Fe2O3) and stabilizing agents (Fe2O3) during thermal treatment process. Major mineralogical components of fly ash involve SiO2, CaCl2, Ca3Si2O7, Ca2SiO40.35H2O, Ca9Si6O21H2O, K2Al2Si2O83.8H2O and AlCl34Al(OH)34H2O. Aqueous solution of fly ash is alkaline with pH over 11. pH and liquid to solid ratio followed the following equation: y=14.905x-0.0338, in which y represents pH value and x liquid to solid ratio. Total salt content is 61%.


Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.


1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.


1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.


1981 ◽  
Vol 46 (2) ◽  
pp. 368-376 ◽  
Author(s):  
Josef Veselý

Titration of sulphates with lead perchlorate employing lead ion selective electrode indication was studied using additions of various organic solvents at different pH' and ionic strength values. As the optimum emerged systems with 60-70% 1,4-dioxane, pH' 5.3-5.6. After dehydration with sodium hydroxide, dioxane must be freed from the electrode surface-oxidizing impurities by their reduction with sodium metal and subsequent distillation. The method was applied to determination of sulphates in mountain spring waters. Units of ppm can be determined; the limit of determination, however, depends considerably on the content of dioxane, total salt content in the sample, and speed of the semi-automatic titration. Lead can be determined with EDTA in concentrations down to c(Pb2+) = 5 . 10-6 mol l-1.


Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 586
Author(s):  
Eddy Plasquy ◽  
José María García Martos ◽  
María del Carmen Florido Fernández ◽  
Rafael Rubén Sola-Guirado ◽  
Juan Francisco García Martín

Harvesting at high temperatures and bulk transport can negatively influence the quality of olives and lead to undesirable alterations in the extracted oil. Cooling the fruit in the field would be the most logical solution, but it means that the olives arrive too cold at the mill for immediate processing. In this work, the use of warm water in the washing tub to warm up the fruit before grinding instead of flash heat treatment on the paste was assessed in two experiments. In the first one, at the laboratory level, the temperature after milling was determined in three olive cultivars, previously stored at 5 or 10 °C, and then submerged at different water temperatures (25, 30, and 35 °C) for 15, 30, 45, and 60 s. In the second one, two batches of olives were cooled in the field at 5 °C and then conditioned with washing water to obtain a paste at the entrance of the pilot plant malaxer at 27 °C. The temperature of the olives was measured at five points from the discharging up to their entering, as paste, into the malaxer. The results demonstrated the feasibility of the method as the temperature of the ground olives was kept at the desired temperature (28 ± 1 °C). The trials highlight the potential for automating an even more precise adjustment of the temperature of the olives before milling once the washing tub is equipped with a safe heating system.


Sign in / Sign up

Export Citation Format

Share Document