Strategies for achieving energy neutrality in biological nutrient removal systems – a case study of the Slupsk WWTP (northern Poland)

Abstract

The paper presents a model-based evaluation of technological upgrades on the energy and cost balance in a large biological nutrient removal (BNR) wastewater treatment plant (WWTP) in the city of Slupsk (northern Poland). The proposed upgrades include chemically enhanced primary sludge removal and reduction of the nitrogen load in the deammonification process employed for reject water treatment. Simulations enabled to estimate the increased biogas generation and decreased energy consumption for aeration. The proposed upgrades may lead the studied WWTP from the energy deficit to energy neutrality and positive cost balance, while still maintaining the required effluent standards for nitrogen. The operating cost balance depends on the type of applied coagulants/flocculants and specific costs of electric energy. The choice of the coagulant/flocculent was found as the main factor determining a positive cost balance.

Pilot plant demonstration of stable and efficient high rate biological nutrient removal with low dissolved oxygen conditions

“…Achieving energy neutral or energy positive operation of a WWTP often requires a combination of increasing energy production and reducing energy consumption (Kroiss and Cao, 2014). To increase energy production, facilities receive external organic waste to augment biogas generation (Gao et al, 2014, Gómez et al, 2006, use alternative sources of renewable energy, such as solar or wind power (Argaw, 2003, Chae andKang, 2013), or redirect the majority of the wastewater organics to the anaerobic digester via enhanced primary settling (Jenicek et al, 2013, Remy et al, 2014, Zaborowska et al, 2016. Decreasing energy consumption relies on upgrading equipment to more energy efficient technology (Appelbaum, 2002), reducing heat losses (Chae and Kang, 2013), and minimizing pumping of biosolids, liquid streams, and air supplies (Hoppock and Webber, 2008).…”

Aeration Process in Bioreactors as the Main Energy Consumer in a Wastewater Treatment Plant. Review of Solutions and Methods of Process Optimization

“…This approach is also viable when one wishes to compare various strategies of achieving energy neutral condition. The performance of wastewater treatment plants can also be evaluated using multi-objective approach with dynamic process model involving LCA, detailed energy models, GHG and operational costs [10][11][12][13][14][15][16].…”

“…Under these circumstances, the use of advanced technology solutions is also highly recommended, e.g., mathematical models, computer simulations and computational hardware control allow conducting the analysis of many different technological solutions in a short time and with low investigation budget, besides carrying out various scenarios and control strategies in reality. Model complexity is increasing; the advancements of computational hardware and open source platforms for model integration support the development of new solutions and tools [10][11][12][13][14][15][16]. Modelling becomes an integral part of the design and operation of wastewater treatment systems in gaining knowledge on the mechanisms and operational strategies playing an important role in this optimization process [17][18][19].…”

Soft Sensor Application in Identification of the Activated Sludge Bulking Considering the Technological and Economical Aspects of Smart Systems Functioning

“…Despite the many problems with data acquisition, with their reliability and with the costs of measurements, researchers [56,57] still strive to improve the predictive power of models. The approach calls for some criticism, not being fully consistent with the latest trends, as these tend to focus on cost minimization [58][59][60][61]. On the other hand, systems that enable an on-line process control, taking into account the potential failures of measurement schemes, are required.…”