No abstract

The aim of the research is to improve the technological scheme of treatment of iron-containing wastewater from etching operations by creating combined systems, including reagent wastewater treatment, their mutual neutralization, regeneration of etching solutions, deep post-treatment using a magnetic device. The main volume of wastewater is treated in centralized systems with partial return of water to the production process. Spent solutions from etching operations are subject to regeneration with return to the production process and partial dosing into the main wastewater stream from flushing operations. The consumption of commercial HCl is reduced by 50%. The use of hydrogen peroxide can increase the effect of extracting iron from etching solutions by 30% (total purification effect of 70%). Given that deep purification from iron-containing impurities is provided using a magnetic device, the possibilities of practical implementation of reverse osmosis to obtain "pure" water in centralized systems, which can be used for preparation of process solutions and in a mixture with technical water - for flushing operations, increase. In experimental and industrial conditions the expenses of reagents, their concentrations, dosing time are established

The object of research is the methods of purification of iron-containing wastewater from etching operations, the subject of the study is spent technological solutions of etching and wastewater from the operations of washing enterprises of hardware products. Spent etching solutions are characterized as highly concentrated solutions, and wash water belongs to the category of concentrated solutions containing toxic impurities: heavy metal ions, acids, surfactants. The main problem in the etching area is the processing of used etching solutions. The most progressive creation of combined systems in which the bulk of wastewater is treated in centralized systems with partial return of water to the production process. With such wastewater treatment, the problem arises of reducing the total concentration of iron to less than 1 mg/l. That is why, in accordance with the requirements of environmental legislation on nature management, there is a need for deep additional treatment of such wastewater. The study used the methods of potentiometric titration and chemical deposition, as well as the method of photometric determination. Magnetic cleaning was studied in an experimental magnetic deposition apparatus. The paper presents the results of studies evaluating methods for purifying iron-containing wastewater from etching operations. Improvement is achieved by the creation of technological combined schemes for the purification of iron-containing wastewater, including a magnetic device as an auxiliary element. At the same time, the main volume of wastewater is treated in centralized systems with a partial return of water to the production process. Waste solutions from etching operations are subject to regeneration with return to the production process and partial dosage into the main wastewater stream from washing operations. Deep purification from iron-containing impurities using a magnetic device expands the possibilities of practical implementation of reverse osmosis to obtain «clean» water in centralized systems. This water is applicable for the preparation of process solutions and mixed with industrial water for flushing operations.

No abstract

For the functioning of integrated systems for processing dairy raw materials in the cheesemaking industry, it is proposed to consider the basic concepts of synthesis of production systems. In order to implement the concept of waste minimization, it is proposed to separate the industrial wastewater into flows based on the concentration and values of the main parameters, as well as to protect the cheese whey from entering the water treatment facilities and direct it for disposal. The possibilities of implementing the concepts of deep raw materials processing into a target product have been analyzed, as well as the full utilization of raw and auxiliary materials. To this end, an experimental study was performed on the extraction of protein clots and adjusting the buffer capacity of infant dairy products using cheese whey. The study results indicate the insufficient effect of extracting the protein clot from whey (5–50 %) by combining the thermal and chemical processes. It was established that the redox conditions of the medium, in terms of the Eh indicator, can significantly affect the results, in close connection with the pH parameter and the estimated value of rH2. It was found that the optimal conditions for the functioning of lactic acid microflora in the production of soft cheeses can be ensured by adjusting the Eh indicator through the introduction of whey of pH=4.4–4.6 units, Eh≤–0.1 V. Whey is introduced at the stage of dairy raw material fermentation, which creates optimal conditions for the formation of a clot until reaching rH2 in the range from −5 to –7, and increases the product output by 1.5–7 %. The results of the experimental study indicate the high potential of using whey desalinated by ion exchange in order to reduce the buffer capacity in terms of acidity and adjust the redox conditions for infant milk mixtures until achieving rH2=15.5–15.9. The research reported in this paper could be the basis for the further development of systems for the integrated processing of dairy raw materials in the cheesemaking industry