Sludge stabilization of sewage treatment facilities with waste from production and application of urea-formaldehyde resins

Abstract

The article describes the variants of reagent stabilization, which is an essential stage of sludge treatment of sewage treatment facilities There are many variants of stabilization, which are based on the mineralization of organic matter, the impact on microorganisms (heating, treatment with chemicals, which have a bactericidal effect, adjustment of pH and humidity) to suppress their activity. In comparison with biological methods reagent stabilization requires minimal capital costs and provides carrying out the process in a short time. Promising method is to be used while stabilizing of waste containing organic substances with microstatic and microbocide action, and which do not change the composition of sediments. In this paper as reagents to stabilize was used the liquid waste and wastewater generated in the production and application of urea-formaldehyde resins (UFR), which are characterized by high levels of formalde-hyde. Flow rate of liquid waste (formaldehyde content of 14.2 g/dm3) was changed in the ranges from 1 : 100 to 20 : 100, the flow of wastewater (formaldehyde content of 0.5 −7.0 g/dm3) in the varies from 1 : 10 to 1 : 2. Investigations were carried out on the excess activated sludge (solids content 18.1 −27.7 g/dm3). In the investigated ranges the flow of stabilizing agent, that provides long-term stability, depends linearly on both the solids content of the excess ac tivated sludge, as well as on the content of formaldehyde in the stabilizing agent. Processing of excess activated sludge with waste from production and use of urea-formaldehyde resins reduces the resistivity to filtering more than 7 times.