Isaac Owusu-Agyeman

KTH Royal Institute of Technology | KTH · Department of Industrial Biotechnology

Shifting the concept of municipal wastewater treatment to recover resources is one of the key factors contributing to a sustainable society. A novel concept based on research is proposed to recover four main bio-based products from municipal wastewater while reaching the necessary regulatory standards. The main resource recovery units of the propos...

Prospective life cycle assessment (LCA) studies are widely used for evaluating emerging resource recovery systems. Simulations, engineering-based process calculations and stoichiometric methods are frequently used methods to generate life cycle inventory (LCI) in prospective LCAs. The engineering-based upscaling calculation is an efficient method f...

The key factor for promoting bioeconomy and circularity in the cities is to examine waste streams such as municipal wastewater, sludge, solid waste, food waste, bakery industry waste, and pulp and paper industry waste as raw materials rather than wastes to be disposed. In this regard, biorefinery concept is promising for converting biomass into val...

Alkaline co-fermentation of primary sludge and external organic waste (OW) is studied to elucidate the influence of substrate ratios and long-term system robustness and microbial community dynamics using batch and semi-continuous reactors. Volatile fatty acid (VFA) production increased with increasing OW fraction in the substrate due to synergistic...

The influence of hydraulic retention time (HRT of 3–5 h) and temperature (20–25 °C) on performance and microbial dynamics of two pilot-scale upflow anaerobic sludge blanket (UASB) reactors with different granule size distribution (UASB1 = 3–4 mm and UASB2 = 1–2 mm) were investigated for 217 days. Increasing the HRT to 5 h even at a lower temperatur...

The effects of direct enzyme cocktail addition and other pretreatment methods on VFA production through co-fermentation of primary sludge and external organic waste were studied under initial alkaline (pH 10) and acidic (pH 5) conditions. Besides the direct enzymes addition, 24-h enzymatic, ultrasonic, ultrasonic+24-h enzymatic and thermal were the...

Increased awareness of environmental sustainability with associated strict environmental regulations has incentivized the pursuit of novel materials to replace conventional petroleum-derived plastics. Polyhydroxyalkanoates (PHAs) are appealing intracellular biopolymers and have drawn significant attention as a viable alternative to petrochemical ba...

Volatile fatty acids (VFAs) are intermediates of anaerobic digestion with high value and wide range of usage. Co-digestion of sewage sludge and external organic waste (OW) for VFA production can help achieve both resource recovery and ensure sustainable and innovative waste management. In view of this, the effect of substrate proportions on VFA pro...

The aim of this study has been to investigate the environmental impacts of an innovative food waste management system and compare it with landfilling as a conventional waste management option. The investigated system is still in the laboratory research and development phase. Therefore, inventory data of the laboratory scale food waste management sy...

Volatile fatty acids (VFAs) have higher value and wider usage range than biogas. The study sought to devise a strategy to shift anaerobic digestion production from biogas to VFA by systematically investigating the impact of substrate ratio of sewage sludge and external organic waste (OW). Co-digestion was carried out in batch reactors of 500 mL vol...

This study was carried out to investigate the relationship between the methane-producing pathways and the characteristics of anaerobic granules treating municipal wastewater. Two pilot-scale upflow anaerobic sludge blanket (UASB) reactors with different granular size distribution treating the same municipal wastewater under identical operational co...

This study was carried out to investigate the relationship between the methane producing pathways and the characteristics of anaerobic granules treating municipal wastewater. For this purpose, two pilot scale upflow anaerobic sludge blanket reactors with different granule size distribution (1–2mm and 3–4 mm) were investigated at operating temperatu...

In the context of decentralised brackish water treatment in development applications, the influence of water quality on membrane separation was investigated with real waters. High ionic strength (low net driving pressure) on fluoride (F) retention by nanofiltration (NF) and reverse osmosis (RO) was investigated over a wide pH range (2–12). Further,...

Bio-based volatile fatty acid (VFA) production from waste-stream is getting attention due to increasing market demand and wide range usage area as well as its cost-effective and environmentally friendly approach. The aim of this paper is to give a comprehensive review of bio-based VFA production and recovery methods and to give an opinion on future...

Real water pH and ionic strength vary greatly, which influences the performance of membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Systematic variation of pH (3 − 12) and ionic strength (2–10 g/L as total dissolved solids (TDS)) was undertaken with a real Tanzanian water to investigate how water quality affects retention me...

High fluoride (F) levels in drinking water can result in fluorosis. The WHO recommends F limit of 1.5 mg/L in drinking water, however, up to 300 mg/L has been recorded [1]. The issue of high F levels usually occurs in rural areas in developing country where alternative sources are unavailable. Nanofiltration (NF) and reverse osmosis (RO) efficient...

The impact of pH and humic acid (HA) on the retention of fluoride (F) and inorganic carbon (IC) by nanofiltration (NF) and reverse osmosis (RO) membranes was determined. Synthetic waters were prepared using realistic ranges of F, IC and HA for carbonaceous waters found for example in the fluoride rich waters in Tanzania. These waters were filtered...

The anaerobic ammonium oxidation (Anammox) process is one of the most cost-effective technologies for removing excessive nitrogen compounds from effluents of wastewater treatment plants. The study was conducted to assess the feasibility of using ion exchange and reverse osmosis methods to concentrate ammonium to support partial nitritation/Anammox...

Upflow anaerobic sludge blanket (UASB) technology has been applied for treatment ofwastewater with production of biogas. However the technology does not remove nitrogen.ANaerobic AMMonium OXidation (Anammox) is cost effective process which was mostrecent process developed for the removal of nitrogen from wastewater with relatively highammonium conc...

World energy demand is increasing day by day and at the same time wastewater treatment for sustainable development. Especially in rural areas, the energy scarcity is very high and at the same time need to build healthy environment to them by wastewater management. Most of the present energy sources are not sustainable for environment (fossil fuel)...

Anammox is one of the main processes discovered quite recently for removal of ammonium from wastewater. Anammox process is cost effective, in that low energy and carbon source is needed. Partial nitritation is a perquisite for anammox in wastewater treatment for removal nitrogen and therefore partial nitritation/Anammox technology is studied substa...