Rahman, Arifur, Rahman

Dr. Rahman is currently working as a Wastewater Technologist at Jacobs (Dallas, TX) and has been involved with the functional design of numerous water...

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About Rahman, Arifur

Dr. Rahman is currently working as a Wastewater Technologist at Jacobs (Dallas, TX) and has been involved with the functional design of numerous water resource recovery facilities (WRRFs) across the USA. His technical interests and expertise include energy recovery, carbon and nutrient redirection and capture from domestic wastewater, nutrient removal, pilot-scale reactor design and operation. For climate change adaptation and mitigation, he is actively providing his wet weather flow management and treatment expertise to many WRRFs including automated operation and control. He has published more than 20 journals and 17 conference papers.

Rahman, Arifur

Titles from this speaker

Description: Boehnke and Beyond: A History of Advancements in High-Rate Activated Sludge for...

Boehnke and Beyond: A History of Advancements in High-Rate Activated Sludge for Energy Efficient Wastewater Treatment

Abstract

Introduction
While other two-stage treatment processes had been utilized as early as the 1960s, it was the adsorption-biooxidation (AB) process (Figure 1), developed and patented by Dr. Botho Boehnke in 1978 (German Patent DE2803759C3) that became the most successful, with dozens facilities implemented in Germany, the Netherlands, and other Western European cities. The heart of the A-B process was the initial high-rate activated sludge (HRAS) process, which is a biologically enhanced primary treatment process that can maximize carbon redirection and harvesting from wastewater. The popularity of this technology (and other two stage processes) began to decline in the 1990s as effluent requirements for nitrogen and phosphorus became more stringent (Boehnke et al., 1998). However, efforts over the past decade toward low energy operations and maximization of biogas production, in some cases with the goal of becoming energy neutral, has led utilities and researchers to reinvestigate the potential of HRAS technologies. Such reexamination has led to a much greater understanding of HRAS concepts, including breakthrough technologies and operating strategies going well beyond the original concepts laid out by Boehnke. This paper will provide an overview of the history and evolution of HRAS technologies including the original A-stage concept, as well as further research developments that have led to technology advancements such as the alternating activated adsorption (AAA) process and high-rate contact-stabilization (CS).
A-Stage Process
Boehnke et al. (1997, 1998) first reported A-B process for treating industrial and municipal wastewater in Europe. Based on Boehnke concept, A-stage is defined as a biological primary treatment process (carbon removal) which treats raw wastewater and removes particulates and colloidal matter through extracellular adsorption processes. The A-stage of A-B process by Boehnke et al. includes a short hydraulic retention times (HRT) (30 minutes or less) and SRT (0.125-0.5 d), and high food to microorganism (F/M) ratio (2-10 kgBOD/kgVSS/d) operated at near zero dissolved oxygen (DO) concentrations. Newer Developments on A-stage As noted previously, interest declined in HRAS technologies in the 1990s, but research resumed in the 2000s, which coincided with the greater interest in the industry in energy efficiency and the goal to becoming energy neutral. This included the work by Haider et al. (2003), which investigated the wastewater and biomass characteristics from high-rate systems. More recently, a detailed fundamental study on A-stage (0.3-to-1-day SRT) was examined by Jimenez et al. (2015) to evaluate carbon removal efficiency, carbon capture, impact of DO on removal efficiency and extracellular polymeric substance (EPS) contributions. This development provided leverage on further aerobic A-stage investigations as Jimenez et al. (2015) found that a minimum DO (0.5 mg/L) was necessary for maximum carbon capture efficiency. This finding was corroborated by Cao et al. (2019), which compared aerobic and anaerobic A-stage (similar to Boehnke et al study) performance and found that carbon capture in an aerobic A-stage was 10% higher than A-stage without aeration. Some studies also implemented A-stage with chemical addition for improved bio-flocculation to enhance sludge settleability, which further improved carbon capture.
Alternating A-stage
- AAA One of the most recent advancements of A-stage treatment is the alternating activated adsorption (AAA) process (Figure 1) was first developed by Wett et al. (2021). This technology is a compact design of A-stage system which acts as sequencing batch reactor. The unique feature of this technology is that simultaneous bottom feeding and top effluent discharging provides increased particulate substrate capture efficiency. This technology can be easily applied to existing systems and currently has full-scale installation at the Strass WWTP, Austria and the Rottenburg WWTP, Germany. AlSayed et al. (online in 2021, article issue on 2022) published a detail study on the performance of the AAA process in lab-scale systems treating synthetic wastewater, indicating that this can be a competitive technology for A-stage. However, they reported that the AAA system suffered poor settleability treating low strength wastewater. Bringing Abandoned 'Feast-Famine Technology' to Life â€“ High-Rate Contact-Stabilization While A-stage and AAA technology maximize carbon capture through the biosorption (extracellular adsorption and intracellular storage) mechanism, this phenomenon was first examined by Ullrich and Smith (1951) in a contact stabilization (CS) process in 1951. Later, the development of low-rate CS configuration (SRT > 3 days) was moved forward through several studies between 1975 and 1980 (Gujer and Jenkins, 1975; Benefield and Randall, 1976; Alexander et al., 1980). However, the application of CS process for wastewater treatment gradually decreased in the USA due to its unstable process conditions, and stringent nitrogen and phosphorus limits based on its applied design considerations in that time period (1951 â€“ 1980). From 1980 to 2015, this technology has not received much attention to utilize its promising potential as an HRAS system to recover energy from wastewater. After almost 35 years, Meerburg et al. (2015, 2016), Rahman et al. (2016, 2017, 2019, 2020) and Dolej et al. (2016) studied the fundamental mechanisms of high-rate CS (<2 days) systems in detail by operating bench and pilot-scale studies (Figure 1). Their research also focused on influent total COD mass balance for carbon distribution into different pathways (oxidation, WAS, effluent COD). The establishment of famine/starvation regimes in the 'stabilization zone' was found to promote the adsorption/storage phenomena in the 'contact zone' under feast conditions. A major fraction of the adsorbed organic material is unmetabolized in the contact zone and can thus be captured through WAS as an energy recovery source (Meerburg et al., 2015; Rahman et al., 2016). Ngo et al. (2021) recently reported a successful implementation of full-scale CS for improving clarifier performance and capacity at DC Water's Blue Plains AWTP. The evolution and history of HRAS technologies provide guidelines and recommendations for critical design parameters (Figure 2, 3, Table 1 to 3) that need to be considered for full-scale design.
Conclusions
The full manuscript will highlight key design factors based on the authors' and industry experience for implementing HRAS systems, including: - Operational parameters (i.e., SRT, HRT, DO â€“ aerobic vs. anaerobic) correlating with carbon removal efficiency, redirection and capture from wastewater - Operational flexibility of HRAS systems for downstream nutrient removal technology application - Role of EPS productions in HRAS systems and associated critical factors - Nitrogen and phosphorus removal/redirection from HRAS technologies

This paper will provide an overview of the history and evolution of HRAS technologies including the original A-stage concept, as well as further research developments that have led to technology advancements such as the alternating activated adsorption (AAA) process and high-rate contact-stabilization (CS).

SpeakerRahman, Arifur

Presentation time

08:30:00

08:50:00

Session time

08:30:00

10:00:00

TopicAdvanced Level, Energy Production, Conservation, and Management, Municipal Wastewater Treatment Design, Research and Innovation

Author(s)

Rahman, Arifur

Author(s)Arifur Rahman1; Tim A. Constantine2; Emma Shen3

Author affiliation(s)Jacobs Engineering Group, Inc., Dallas, TX1; Jacobs Engineering Group, Inc., Toronto, ON, Canada2;Jacobs Engineering Group, Inc., Toronto, ON, Canada 3

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158491

Volume / Issue

Content sourceWEFTEC

Word count17

Description: Soft Sensing Influent Concentrations with Airflow Rates by Digital Twins: A Real...

Soft Sensing Influent Concentrations with Airflow Rates by Digital Twins: A Real Case Study from Oldham WwTW

Abstract

With the abundance of data availability across treatment facilities, artificial intelligence is paving the way for unique optimization opportunities. The examples provided encompass the Agua Nueva Water Reclamation Facility (WRF), which concentrates on minimizing aeration energy expenses and enhancing nutrient management, as well as the Wilmington WWTF, emphasizing the optimization of disinfection chemicals. Several artificial intelligence (AI) and Bayesian modeling frameworks were developed with both sites using AI algorithms with mean absolute percentage errors < 10% for both forecasting of future conditions at a facility, as well as causal inferencing for predicting water quality. Post deployment, both sites are regularly achieving anywhere from 10-30% savings in energy or chemical usage. These case-study demonstrates significant progress in the successful implementation of AI at a treatment facility and the ability to aid in the empowerment of treatment plant operators while improving efficiencies in wastewater treatment.

United Utilities initiated a case study using already available data to predict the real-time influent concentrations to optimize chemical addition for phosphorus removal without installing physical sensors. This paper proposes a novel soft sensor mechanism that successfully estimates the high-resolution influent profiles with a digital twin model plus regular measurements (e. g. airflows, flows and lab measurements). The soft sensor overcomes the lack of dynamic profiles in DT applications.

SpeakerYang, Cheng

Presentation time

14:00:00

14:20:00

Session time

13:30:00

15:00:00

SessionPlanning and Process Improvement Case Studies: Winning with Twinning

Session locationRoom S505b - Level 5

TopicAdvanced Level, Energy Production, Conservation, and Management, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Yang, Cheng

Author(s)C. Yang 1; B. Johnson 2 ; J. Registe 3; T. Johnson 4; A. Rahman 5; J. Kenyon 6; C. Yang 1;

Author affiliation(s)Jacobs 1; Jacobs 2 ; Jacobs 3; Jacobs 4; 5; 6; Jacobs 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159227

Volume / Issue

Content sourceWEFTEC

Word count18

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