Efficient decomposition of organic material using biomass adapted to sewage network conditions

The project entitled “Modernisation of the operation of the Dabas Wastewater Treatment Plant” (PIAC-13-1-2013-0030) employed innovative methods to improve the operation of the Dabas sewage network and wastewater treatment plant so as to reduce the periodically occurring significantly larger hydraulic and organic material loads of the plant, which exceed its rated capacity. The research and development was aimed at reducing daily peak hydraulic loads (making the flow of wastewater volumes to the wastewater treatment plants more even) and at examining the possibilities of pretreatment of the wastewater in the sewage network.

The novel aspects of the research and development work were the system-level optimisation of the operation of the wastewater sewer network based on graph theory and the development of the methodology of bioaugmentation in the sewage network (cultivation of bacterial preparations from a master solution and dosing into the sewage network).

Among the objectives of the project, the reduction of peak loads can be achieved by developing system-level control for the sewage pumps in the sewage network, while wastewater can be pretreated using bioaugmentation methods, i.e. the dosing of special bacterial preparations (bacterial cultures and/or enzymes) into the sewage network and using the network itself as a bioreactor.

In order to reduce peak loads, after a comprehensive review of the wastewater network, new pumps were installed in the sewage pump shafts of the system. By coordinating the operation of the pumps, it was possible to reduce peak loads at the plant. The installation of pump control software that matches the characteristics of the network and local communal water usage patterns was required. Using the results of the measurements performed as a part of the project, a new, tailored algorithm was produced, which, based on a graph theoretical model of the system, is able to regulate the operation of the sewage pumps in the Dabas network so as to ensure that the capacity of the sewage network and the pump shafts is utilised during the operation of the system.

In order to optimise the operation of the wastewater treatment plant, computer simulation software was used to build a mathematical model of the sequences of functional units. This allowed the changes resulting in the operation of the wastewater treatment plant from various optimisation efforts to be examined.

As regards the reduction of the organic material content of the wastewater arriving at the wastewater treatment plant, bioaugmentation agents with various compositions selected for efficiency were tested in laboratory conditions in order to choose the preparations and doses that are the most suitable for the quality of wastewater found. Subsequently, additional experiments were conducted with the bioaugmentation preparations in a bioreactor of semi-operational size. In order to ensure that the bacterial culture chosen is adapted to the wastewater arriving at the treatment plant as well as possible, a new, experimental bacterial culture was created. In the cultivation reactor, activated sludge from the wastewater treatment plant was inoculated with the commercially available bioaugmentation mixture that was used in the sewage network experiments and the activity of the resulting biomass was tested. The results of the tests using the bioreactor showed that the biomass adapted to the wastewater arriving at the treatment plant exhibited well-measurable activity in decomposing organic material (cold wastewater and under-aired conditions). In summary, it has been found that it is possible to create a biomass adapted to sewage network conditions that was able to decompose organic material efficiently in experimental conditions.

Further information: http://www.bioreaktor.hu/#publikacio