Research on physico-chemical pretreatment of wastewater from the production of wood coating materials

Abstract

This paper presents the results of the research conducted on the installation designed for physico-chemical pretreatment of technological wastewater in the volume of up to 5.0 m 3 /day discharged from the production of protective and decorative coating materials used for wooden surfaces. The subject-matter installation constructed on a mobile pallet, consisted of a storage-averaging tank where concentrations were equalised with the use of circulation aeration and mixing. A variant, preliminary pre-oxidation with the use of hydrogen peroxide was conducted in this tank. A substantial installation set for the wastewater treatment plant consisted of two preliminary tube reactors, one cylindrical-conical processing reactor, stations for preparing and dispensing reagents and the sediment dewatering station. Considerable reductions in main chemical indicators of water pollution were obtained in the installation: both total suspended solids (TSS) and ether extract (EE) -more than 98%, chemical oxygen demand (COD) -46-54%, biochemical oxygen demand (BOD5) -39-46%, and free formaldehyde (HCHO) -14-27% due to the use of pre-oxidation and the acid -alkaine double coagulation by applying the ALCAT 105 -SAX 25 system. The use of pre-oxidation with hydrogen peroxide in doses 250.0-450.0 mg/l and then two-stage coagulation resulted in an increase in the reduction of: COD and BOD5 by ca 10-15%, and HCHO by ca 58-66% with reference to the water pretreatment without pre-oxidation. The assessment of sediments formed during the process of pretreatment was made determining the leachable forms of metals (Cu, Ni and Ti) according to methodology of TCLP in compliance with the US EPA Method 1311.

The influence of treated oleo-chemical wastewater applications on the metal speciation forms in soils

“…The problem may become important as regards cultivation technology and practical usability of plants cultivated on such irrigated arable grounds (Lepp 1981). The investigated production of technical fats of vegetable and animal origin was carried out by a small oleo-chemical factory in the countryside and the research results presented here are the continuation of the previous study (Z ˙ak, Rauckyte 2008b).…”

“…To compare analytical results concerning the heavy metals content, the area of the experiment plots was irrigated and fertilized separately by mixed raw wastewaters after their defatting and by pretreated ones. In the literature, numerous reports can be found on agroutilization of wastewaters from animal or vegetable fats production, including changes in the total content of heavy metals induced by agro-utilization (Lepp 1981;Rattan et al 2005;Russell et al 1993;Z ˙ak, Rauckyte 2008a, b;Lassat 2002;Rauckyte et al 2008;Manz et al 1999;Paredes et al 1986Paredes et al , 1987Tardioli et al 1997).…”

“…This problem seems to be particularly interesting because the total content of heavy metals does not show transformations which take place with their participation or the components of wastewater load (or possible products of their metabolism in soil) during a multi-year supply of those substances into soil. In that case, mean daily volumes of wastewaters from individual processing lines were as follows: from the production of vegetable originated fatty acids, 5.5Á10.0 m 3 /day, and from the production of technical greases of animal origin by using the ''wet method,'' 7.5Á12.0 m 3 /day (Rauckyte et al 2008;Z ˙ak, Rauckyte 2008a). Collecting raw wastewaters in the storage-equalizing tank aimed at stabilizing the contents (1), regulating the ratio of N:P:K, cooling (the temperature of raw wastewaters directly from the production was not less than 80 8C) and defattening by induced air flotation (IAF).…”

Physico-Chemical Analysis of Wastewater Discharge from Selected Paint Industries in Lagos, Nigeria

“…[10]. Paint effluent often contains all the components of the precursor paints with insignificant dilution [11]. They could be clean-up waters composed of residual acids, plating metals and toxic chemicals [12].…”

Polymer Coatings for Protection of Wood and Wood-Based Materials

“…One more aspect of eco-friendliness is minimizing concentration of harmful components in processing wastewater which is generated during production of water dilutable protective and decorative paints for wooden surfaces [7]. This wastewater often contains all components of parent paints but only in significant dilution [8].…”