Electrocoagulation and Adsorption Treatments of Effluents in Offset Printing Graphic Processes

Predmet doktorske disertacije je uklanjanje neorganskih i organskih polutanata iz efluenata ofset tehnike štampe (otpadnog razvijača i otpadnog sredstva za vlaženje) u cilju minimiziranja njihovog štetnog uticaja na životnu sredinu. Uklanjanje polutanata sprovedeno je primenom elektrokoagulaciono/ flotacionog (EKF) tetmana, adsorpcionog (AD) tretmana i kombinacijom navedenih tretmana. Izvodljivost i efikasnost tretmana analizirana je ispitivanjem uticaja karakterističnih operativnih promenljivih u okviru procesa na smanjivanje količine polutanata. Mehanizmi EKF i AD tretmana definisani su na osnovu teorijskih matematičko kinetičkih modela. Za rešavanje problema odlaganja mulja nastalog nakon EKF tretmana primenjen je solidifikaciono/stabiliza-cioni tretman sa odgovarajućim imobilizacionim agensima. Razvijen je efikasan model kombinacije tretmana efluenata grafičkih procesa ofset štampe kojim je omogućena konverzija efluenata u proizvode kompatibilne sa principima i normativima životne sredine.The topic of this doctoral dissertation is the removal of inorganic and organic pollutants from the offset printing effluents (waste developer and waste fountain solution) in order to minimize their damaging influence onto the environment. The removal of the pollutants has been performed by electrocoagulation/flotation (ECF) treatment, adsorption (AD) treatment and the combination of the two said treatments. Feasibility and efficacy of the treatments has been analyzed by investigating the effect of characteristic operational variables within the process on the decrease in the quantity of pollutants. The mechanisms of ECF and AD treatments have been defined on the basis of theoretical mathematical-kinetic models. For the solution of the problem of sludge disposal, originating from the ECF treatment, a solidification/stabilization treatment with immobilization agents has been applied. An efficient model that combines the offset printing effluent treatments has been developed, the one which enables the conversion of effluents into products compatible with environmental principles and norms

Emissions of total volatile organic compounds during the digital printing process

The impact of the type of digital machine on increasing of total volatile organic compounds (TVOCs) in the ambient air of the digital printing office was analysed in this study. For that purpose, the TVOCs concentrations in gas samples were measured by mobile gas chromatograph Voyager-Photovac. The cumulative concentrations values of TVOCs for the single-color digital machine were in the range from 0.56 to 5.90 ppm and almost 4 and 25 times below compared to the same values for the four-color digital machine (14.01 - 24.84 ppm). The obtained results could be useful for the future risk assessment of indoor exposure of TVOCs, and for the creation of printing indoor air quality guidelines of the Republic of Serbia

Disadvantages of electrocoagulation-flotation treatment of offset printing effluents

The efficiency of electrocoagulation-flotation (ECF) treatment was estimated based on the quantity of pollutants (cooper, turbidity, and organic substances) in printing effluents (waste offset printing developer and waste offset fountain solution) at selected process parameters. Four sets of aluminum or/and iron electrode combinations were applied, each with a current density of 2, 4, and 8 mA cm−2 and interelectrode distances of 0.5, 1.0, and 1.5 cm. In the progress of the ECF treatment, samples were taken at certain process times (1, 5, 10, 20, 40, and 60 min). Based on the obtained results, the disadvantages of ECF treatment of offset printing effluents are defined

Electrocoagulation removal of heavy metals from wastewater generated by washing a screen printing plate

The possibility of applying electrocoagulation treatment to remove heavy metals (zinc, copper, and chromium) from wastewater generated during the washing process of the screen printing plate was carried out. The electrocoagulation efficiency is estimated based on reducing the concentrations of detected heavy metals in the screen wastewater at defined process parameters such as electrode material, current density, interelectrode distance, and operating times

The heavy metals in the processing screen printing inks

The contents of heavy metals were analyzed in the two types (solvent-based and water-based) of processing screen printing inks. Mass concentrations of heavy metals (copper, iron, zinc, manganese, chromium, nickel, cadmium, and lead) were determined in the tested screen inks by combining the gravimetric method and atomic absorption spectroscopy. The results indicated that the measured mass concentration of copper (2049.9 mg kg-1 ) in solvent-based cyan ink is 2.4 times higher than in water-based cyan. Other detected metals show higher concentration values with water-based processing inks

Characterization of the organic load of the waste fountain solution

The qualitative analysis of the organic loads of waste fountain solution (WFS) was investigated in the paper. Two liquid/liquid (L/L) extraction methods were used for WFS sample preparation: L/L extraction with methylene chloride and sequential L/L extraction with n-pentane, methylene chloride and methylene chloride at pH 2. Qualitative characterization of the organic load profile of offset effluent was performed using a gas chromatographic/mass spectrometric method

Pollution from meat processing factories

A basic understanding of the nature of meat plant wastewaters and factors that influence these wastewaters is essential for the control of wastewater volume and waste loads. Analyzing waste characteristics of the meatpacking industry is not a simple matter. It is difficult to characterize a “typical” plant and its associated wastes, owing to the many procedures and facets of meat-processing operations. However, some similarities have emerged during extensive study and research

The immobilization of copper from waste printing developer sludge

The electrocoagulation (EC) treatment of the waste printing developer in laboratory conditions was produced the sludge with a high amount of copper. The solidification/stabilization (S/S) treatment of electrocoagulation sludge (ECS) has been conducted with four immobilization agents: Portland cement, calx, bentonite, and local clay. The efficiency of the S/S treatment was monitored by applying standard German (DIN 38414-4) leaching test. The characterization of ECS in terms of its toxicity was evaluated by comparing the copper concentration levels in the leaching solution with maximum allowed concentrations according to current regulations

The combined electrocoagulation/flotation and adsorption processes for organic substances regeneration of waste printing developer

This paper investigates the possibility of reducing the content of organic substances in waste printing developer using a combination of electrocoagulation/flotation (ECF) and adsorption (AD) processes. The content of organic substances in waste printing developer was monitored by analysis of total organic carbon (TOC), chemical oxygen demand (COD) and biological oxygen demand (BOD5) before and after the ECF and AD processes, respectively. When combining the two processes, a removal of 99.4, 92.9 and 96.0% of the TOC, COD and BOD5 was achieved, respectively. Obtained results confirm the improvement in the printing industrial effluent quality and height removal of organic substances by the combined ECF and AD treatments