Arkadiusz Ostojski

Rural domestic wastewater treatment in Norway and Poland: experiences, cooperation and concepts on the improvement of constructed wetland technology

This article describes Norwegian and Polish experiences concerning domestic wastewater treatment obtained during nearly 20 years of operation for constructed wetland (CW) systems in rural areas and scattered settlements. The Norwegian CW systems revealed a high performance with respect to the removal of organic matter, biogenic elements and faecal indicator bacteria. The performance of the Polish CW systems was unstable, and varied between unsatisfied and satisfied treatment efficiency provided by horizontal and vertical flow CWs, respectively. Therefore, three different concepts related to the improvement of CW technology have been developed and implemented in Poland. These concepts combined some innovative solutions originally designed in Norway (e.g. an additional treatment step in biofilters) with Polish inspiration for new CWs treating rural domestic wastewater. The implementation of full-scale systems will be evaluated with regard to treatment efficiency and innovative technology; based on this, a further selection of the most favourable CW for rural areas and scattered settlements will be performed.

PRE-FEASIBILITY STUDY FOR TREATMENT WETLAND APPLICATION FOR WASTEWATER TREATMENT IN DISPERSED DEVELOPMENT

The aim of the paper is to present the conducted analyses of pre-feasibility study of different approaches for wastewater management in a settlement of 180 persons. In the assessment both technical and economic aspects were analyzed. The costs were calculated for three different and, at the same time, most popular as well as possible technical solutions like: (i) construction of local wastewater treatment plant with gravitational and pressurized networks, (ii) construction of single family wastewater treatment plants, (iii) construction of sealed septic tanks. Carried out analyses of investment and maintenance costs revealed that at the stage of construction the most expensive is local sewer network with treatment plant, while the construction of a single family treatment plant has similar cost regardless of the technology used. When the long term operation and investment cost are accounted the most economical reasonable solution is the application of wetland treatment for household wastewater treatment.

The Concept of a Sewage-Sludge Management System for an Individual Household

Individual farms in rural areas often face problems with domestic sewage collection and treatment. In many cases investment costs of sewerage systems and central wastewater treatment plants (WWTPs) are too high, due to long distances from one farm to another and terrain configuration. Treatment wetlands for individual farms can solve this problem. In the present study, an overview of individual treatment wetlands in Europe and Poland is reviewed. On this basis, the conception of domestic sewage and sewage sludge management for an individual farm was developed within the project “Innovative solutions for wastewater management in rural areas”. The concept was aimed at preparation of a ready-to-implement solution of the problem of sewage and sludge management of a local community in a rural area by treatment wetlands serving individual households. The proposal of an innovative sanitary system is based on an idea of a closed cycle of matter in the environment. The nutrient substances: N, P and K compounds present in sewage and sludge should be recycled to the soil. Three configurations of hydrophyte beds will be tested in order to select the optimal solution. The implementation of the project has already started at the catchment area of river Borucinka at the municipality Stezyca, Pommerania Region, Poland.

The legal regulations of sewage sludge management

Abstract Both preliminary and excessive sludge can contain microorganisms and toxic compounds (heavy metals and organic compounds) which may be potentially hazardous for the biota and environment. The objective of the paper is to present the technological possibilities of sludge utilization in terms of continuously changing regulations. Among the presented methods of sewage sludge utilization, a thermal one seems to be the most developed and long-term way. The landfiling of sludge will be not economical reasonable and also become illegal in the nearest future. Agricultural application (as a fertilizer or recultivation), although consistent with the idea of organic matter circulation in the environment, will be more and more difficult due to restrictive requirements.