CHEMICAL UPGRADING OF THE NORTH-BUDAPEST WASTEWATER TREATMENT PLANT

Abstract

In the past decade, the development of chemical technologies has opened the way to use low doses of metal salts (with or without polymers), in wastewater treatment. Then this led to a combination of chemical and biological processes driven by different goals, Available experiences suggest that chemical upgrading is an efficient method to increase the capacity of biological treatment plants (with primary sedimentation), The specific problem of the North-Budapest Wastewater Treatment Plant (NB- WWTP) is that on the short run the flow to the existing treatment plant can be tripled (which would lead to a 50 - 60% hydraulic overload of the presently under-utilized capacity, 140 000 m3/d), while on the longer run the flow may reach 400 000 m3/d. The costs of meeting European Union standards with a proposed advanced biological nutrient removal are extremely high (several hundred million S) and the future flow is uncertain. Since financial resources are scarce, a cost-effective intermediate solution (say for the coming ten years) based on the upgrading of the existing facility should be sought to cope with the increased wastewater flow. In the frame of the present study, first laboratory jar tests were conducted to study the applicability of chemical enhancement which was followed by a three-week full-scale experiment performed with low chemical dosage during the fall 1993. The experiments showed the ability of chemical upgrading to maintain (or improve) current treatment plant performance under flow increased by at least 50%.