Optimization of Floccular Cleaning and Drainage of Thin Dispersed Sludges

Abstract

The efficiency of solid phase retention and dehydration of finely dispersed products of a coal processing plant and a metallurgical enterprise on the module for cleaning and dewatering sludge is investigated. A technique for selecting the operating parameters of equipment based on the determination of the strength criterion of flocs is proposed. A methodology for technological tests has been developed to control the flocculation process and optimize the flow of flocculant depending on the concentration of the solid phase. Industrial tests on the module for wastewater treatment and sludge dewatering using flocculants proved the effectiveness of the developed methodology. It is shown that the conditions for conducting tests on flocculation should correspond to the operating conditions of the circuit apparatus for cleaning and dewatering sludge. These conditions include sludge performance, sludge flow rate in the cross section of pipes and apparatuses, and the flow time from the flocculator to the centrifuge. During the testing of the Module, the solids retention efficiency of 97–99 % was achieved with the strength criteria of flocs in front of a centrifuge of 2–2.5 mm/s. The conditions for the high efficiency of the apparatus chain are the optimization of the aggregation process itself. It is revealed that for the formation of strong flocs it is necessary to regulate the concentration of the solid phase. For coal sludge, the concentration of the solid phase before the flocculant is fed must be maintained no higher than 50–60 g/l, and for gas treatment sludge – no higher than 20–25 g/l. Correction of the concentration of sludge before the flocculator is possible by diluting it with clarified water to the optimum concentration for aggregation. It is found that the moisture content of the sediment and the efficiency of the retention of the solid phase depend on the strength criterion of the flocs. Therefore, the optimization of the flocculant flow rate is possible by controlling and the residual floccule deposition rate after mechanical action in front of the dewatering equipment. The flocculant flow rate must be adjusted depending on the concentration of the solid phase in the sludge to achieve the desired criterion for the strength of the flocs

The Results of Surface Wastewater Treatment of a Machine-Building Enterprise From Petroleum Product Contamination

“…One of the promising methods of treating such wastewater at the enterprise can be physical and chemical treatment using coagulants and flocculants with subsequent settling or flotation. Violations of the aggregative stability of finely dispersed suspensions using flocculation-coagulation methods are widely used to purify finely dispersed and polydispersed suspensions [15,16]. However, there are no clear recommendations and dependencies that can be used to clean polluted water.…”

Environmental management implementation in wastewater treatment at a machine-building enterprise: From theory to practice

“…For a specific production, some wastewater parameters affecting flocculation efficiency remain constant on average, and some may change over time. Most often, the solid phase concentration in wastewater changes during the day, which has the greatest impact on the flocculation efficiency [19]. This requires flocculant dosing system constant monitoring and adjustment to ensure optimal conditions for the stable flocs formation and to achieve treated wastewater highest quality.…”