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.

This paper presents a developed method of pretreating wastewaters coming from small-tonnage oleochemical production and also the research results on the variability of concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) in the soil irrigated and fertilized with wastewater from this production. The processing wastewater pretreatment was carried out at two stages. The first stage eliminated fatty substances by using dispersed air flotation aided with hydrogen peroxide as an oxidizer. The second stage included coagulation and chemical precipitation with milk of lime, flocculation, final dissolved air flotation (DAF), and also oxidation with hydrogen peroxide. Field experiments, the aim of which was to compare variability levels for speciation fractions of heavy metals, were carried out according to Tessier's method for four years. The study revealed that the average concentrations of the given metals fractions in soil samples where raw wastewaters were directed did not significantly change during the experiment, which clearly justifies the need for their physicalÁchemical pretreatment and further agro-utilization without the risk of soil environment degradation. The successive decrease of exchangeable fraction, the increase in the content of the fraction bound with carbonate forms, and stability of the fraction bound with hydrated iron and manganese oxides as well as organic and residual fractions were found in soil samples treated with pretreated wastewaters.

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Total lead (TPb) exists in Crude Wastewater (CW) from production of Lead-Acid Batteries (LABs) in water (WPb) and solid phase (SPb) as colloids and suspended solids. Sludges produced in chemical treatment of these wastewater were dewatered in Chamber Pressure Press (CPP). Samples of dewatered sludges (Ss) were analyzed with Toxicological Characteristic Leaching Procedure (TCLP) to determine concentration of Pb in the extract (Ex(TCLP)). Selected sludges were also analyzed using Tessier’s procedure for fractions. Concentration of lead in filtrates (Fs) as well as in the sludges were different, depending on the mechanisms involved in converting soluble lead to its less soluble forms. Sludges produced in chemical treatment with 10% NaOH and Lime Milk (LM), CaO or Ca(OH)2, followed by coagulation with (Ixonos Na3T ®) contained lowest concentration of lead. The TPb in filtrates below 0.4 mg/L at pH > 8.90±0.3, and Ex(TCLP) of less than 5.0 mg/L were obtained in this treatment. Potential recovery of lead from sludges have been investigated.