A decision modelling approach for selection of biological nutrient removal systems for wastewater

Abstract

This paper proposes a decision model built on a hierarchical network for optimal selection of biological nutrient removal systems (BNR) in wastewater treatment plants. BNR is an important component of a sustainable wastewater management wherein resource recovery from wastewater becomes an integral part of the municipal wastewater treatment plants (WTP). However, selection of the most appropriate technology or systems requires a multiple criteria analysis. This study focuses on the following criteria namely 1) Economic aspect; 2) Technical aspect; 3) Environmental Aspect; and 4) Space Requirement. The following alternatives were then evaluated: 1) 3 Stage Pho-redox (A2O); 2) 5 Stage Bardenpho (5BP); 3) University of Cape Town (UCT); 4) Virginia Initiative Plant; 5) Sequencing Batch Reactor (SBR); 6) Membrane Bioreactor (MBR). A fuzzy ANP approach with Monte Carlo simulation was used to derive the overall priorities of these alternatives. This decision modelling approach addresses the uncertainty and complexity involved in the selection of appropriate BNR in Metro Manila’s WTP.

Key Sectors Perspective in Selecting Optimal Biological Nutrient Removal Technologies for Sewage Treatment in the Philippines

“…Lastly, the alternatives are 3-stage phoredox (A 2 O), 5-stage Bardenpho (5BP), sequential batch reactors (SBR), and membrane bioreactors (MBR). The alternatives were selected based on the assessment conducted by Pausta et al and Promentilla et al [4,14]. Pausta et al discussed that BNR technologies such as University Cape Town (UCT) and Virginia Initiative Plant (VIP) are least preferred to be installed in urban areas in the Philippines [4].…”

“…The alternatives were selected based on the assessment conducted by Pausta et al and Promentilla et al [4,14]. Pausta et al discussed that BNR technologies such as University Cape Town (UCT) and Virginia Initiative Plant (VIP) are least preferred to be installed in urban areas in the Philippines [4]. The 3-stage phoredox (A 2 O) consists of three tanks where wastewater is treated at anaerobic, anoxic, and oxic conditions.…”

“…Untreated wastewater is the main cause of water pollution as it carries excessive amount of nutrients (nitrogen and phosphorus) to water bodies [1][2][3]. It promotes the growth of algal blooms which depletes the oxygen source essential to aquatic life [3,4]. With polluted waters, there will be limitations in providing sufficient water supply for various applications to future cities [1,2].…”

“…In 2016, the Department of Environment and Natural Resources -Environmental Management Bureau (DENR -EMB) released an administrative order requiring all establishments to upgrade their treatment facilities in limiting ammonia-nitrogen (NH3-N), nitrate-nitrogen (NO3-N) and phosphates (PO4 3-) concentrations [5]. To comply with the stringent requirements, stakeholders are considering in upgrading their facilities to biological nutrient removal (BNR) technologies [4].…”

“…There are several studies that investigated the effect of flowrates, tank configuration, chemical addition for food source or phosphate precipitation, and other parameters to optimize the nutrient removal capability [8][9][10]. However, in the selection of the most suitable BNR technology, the different perspectives among decision makers, and the financial, operational, and socio-environmental aspects are considered to reach a conclusion [4,11,12]. This can be solved by utilizing multiple-criteria decision analysis (MCDA) tools which have provided sound analysis in several multiattribute complex problems such as selection of optimal technologies, materials, and suppliers [4,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”