Enhanced Pollution Removal with Heat Reclamation in a Small Hungarian Wastewater Treatment Plant

The aim of the research is to outline the possibilities of utilizing waste heat in small municipal wastewater treatment plants. The facility, which was chosen as case-study, accepts about 2,300 m3 of raw sewage daily. In wintertime the wastewater temperature decreases to 10-14 °C which results in lower nitrification capacity based on measurement and validated model results. The excess heat of the wastewater would serve to increase the temperature of the aeration tank in order to enhance the microbiological activity and thus the efficiency of pollutant removal. The amount of reusable waste heat is calculated and with the help of dynamic simulation the effluent quality was determined to compare it with the original results. Increasing the temperature by 6 °C in the aerated tank, ammonium removal could be improved by 61%. This way not only the heat, but the nutrient pollution could be mitigated, too

Impact of water as raw material on material circularity - A case study from the Hungarian food sector

Measuring circularity is necessary to prove the feasibility of transforming linear technologies into circular ones. However, most of the circular economic researches consider water only as a medium. Food industry processes are excellent examples of systems that are hard to break free from linearity, albeit not impossible. This paper explores solutions to include water in circularity calculations using a Hungarian poultry processing plant as a case study. Two circular economic indicators, the questionnaire-type Circular Economy Indicator Prototype (CEIP) and the product-centric Material Circularity Indicator (MCI and MCI’) and the Water Footprint were examined in detail and modified to fit the needs of assessing circularity with water included as raw material. The calculations were supported by Life Cycle Assessment (LCA). The impact on circularity and the environment were quantified by considering different reuse scenarios. As the results of CEIP show, including water reuse in the technology or recycling for irrigation could increase the indicator values from low to medium-high level of circularity. However, the level of improvement highly depends on the amount of water used. LCA highlighted the significant environmental effects of packaging (<2% of product mass) and the relative benefits of recycling and reuse. The MCI’ values (including water as raw material) increased from 0.171 to 0.848 when water demand was reduced by 50% and 100% reused within the processes. This led to a reduction of 76% in the environmental effect. On the other hand, Water Footprint analysis showed that 99% of the water is incorporated in the product itself; therefore, technological water consumption should be treated separately from broiler breeding. The results show that a fairly linear process can be directed towards circularity. However, environmental benefits are not guaranteed with higher circularity points, and recycling may lead to unexpected results