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Tang LY, Wong NH, Chieng TA, Kiu AKJ, Choo CS, Li Y, Tan CP, Yaser AZ, Khaerudini DS, Chen GH, Sunarso J. Physicochemical characteristics of grease-trap wastewater with different potential mechanisms of FOG solid formation, separation, and accumulation inside grease traps. WATER RESEARCH 2024; 256:121607. [PMID: 38640568 DOI: 10.1016/j.watres.2024.121607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/21/2024]
Abstract
This work investigates the physicochemical characteristics of grease-trap wastewater discharged from a large community market. It proposes potential mechanisms of fat, oil, and grease (FOG) solid formation, separation, and accumulation inside grease traps. Sixty-four samples, i.e., the floated scum, suspended solid-liquid wastewater, and settled sludge, were collected from the grease-trap inlet and outlet chambers. A lower pH of 5-6 at 25-29 °C inside the grease trap than those reported under the sewer conditions (pH 6-7) was revealed. A significant difference in solid and dissolved constituents was also discovered between the inlet and outlet chambers, indicating that the baffle wall could affect the separation mechanism. The sludge samples had 1.5 times higher total solids (TS) than the scum samples, i.e., 0.225 vs. 0.149 g g-1 TS, revealing that the sludge amount impacted more significantly the grease trap capacity and operation and maintenance. In contrast, the scum samples had 1.4 times higher volatile solids (VS) than the sludge samples, i.e., 0.134 vs. 0.096 g g-1 VS, matching with the 64.2 vs. 29.7% of carbon content from CHN analysis. About 2/3 of the free fatty acids (FFAs) with palmitic acids were the primary saturated FFAs, while the remaining 1/3 of unsaturated FFAs were found in the solid and liquid samples. Although up to 0.511 g g-1 FOG can be extracted from the scum samples, none from the sludge samples. More diverse minerals/metals other than Na, Cl, and Ca were found in the sludge samples than in the scum samples. Grease-trap FOG solids and open drain samples exhibited similar physicochemical properties to those reported in the literature. Four potential mechanisms (crystallization, emulsification, saponification, and baffling) were presented. This work offers insights into the physicochemical properties of grease-trap wastewater that can help explore its FOG solid formation, separation, and accumulation mechanisms inside a grease trap.
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Affiliation(s)
- Ling Ying Tang
- Research Centre for Sustainable Technologies, Faculty of Engineering, Computing and Science, Swinburne University of Technology, Jalan Simpang Tiga, 93350 Kuching, Sarawak, Malaysia
| | - Ngie Hing Wong
- Research Centre for Sustainable Technologies, Faculty of Engineering, Computing and Science, Swinburne University of Technology, Jalan Simpang Tiga, 93350 Kuching, Sarawak, Malaysia.
| | - Thion Am Chieng
- Research Centre for Sustainable Technologies, Faculty of Engineering, Computing and Science, Swinburne University of Technology, Jalan Simpang Tiga, 93350 Kuching, Sarawak, Malaysia
| | - Alex Kwong Jun Kiu
- Research Centre for Sustainable Technologies, Faculty of Engineering, Computing and Science, Swinburne University of Technology, Jalan Simpang Tiga, 93350 Kuching, Sarawak, Malaysia
| | - Chung Siung Choo
- Centre for Innovative Society, Faculty of Engineering, Computing, and Science, Swinburne University of Technology, Jalan Simpang Tiga, 93350 Kuching, Sarawak, Malaysia
| | - Yali Li
- Centre of Smart Infrastructure and Digital Construction, Department of Civil and Construction Engineering, Swinburne University of Technology, Victoria 3122, Australia
| | - Chin Ping Tan
- Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Selangor, Serdang, 43400, Malaysia
| | - Abu Zahrim Yaser
- Faculty of Engineering, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia
| | - Deni Shidqi Khaerudini
- Research Center for Advanced Materials, National Research and Innovation Agency (BRIN), Bld. 440 Kawasan Puspiptek Serpong, South Tangerang 15314 Banten, Indonesia
| | - Gui Hua Chen
- School of Pharmaceutical and Chemical Engineering, Taizhou University, Jiaojiang 318000, PR China
| | - Jaka Sunarso
- Research Centre for Sustainable Technologies, Faculty of Engineering, Computing and Science, Swinburne University of Technology, Jalan Simpang Tiga, 93350 Kuching, Sarawak, Malaysia
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Chaiyarat A, Saejung C. Continuous valorization of food waste and oily food waste using bacteria-pumice and bacteria-smectite nanocomposites: Alternative cell immobilization and zooplankton lifespan impact. BIORESOURCE TECHNOLOGY 2024; 400:130694. [PMID: 38614149 DOI: 10.1016/j.biortech.2024.130694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 04/15/2024]
Abstract
Recycling waste into commercial products is a profitable strategy but the lifetime of immobilized cells for long-term waste treatment remains a problem. This study presents alternative cell immobilization methods for valorizing food waste (FW) and oily food waste (OFW) to microbial carotenoids and proteins. Carriers (pumice or smectite), magnetite nanoparticles, and isolated photosynthetic bacteria were integrated to obtain magnetically recoverable bacteria-pumice and bacteria-smectite nanocomposites. After recycling five batches (50 d), chemical oxygen demand removal from FW reached 76% and 78% with the bacteria-pumice and bacteria-smectite nanocomposite treatments, respectively, and oil degradation in OFW reached 71% and 62%, respectively. Destructive changes did not occur, suggesting the durability of nanocomposites. The used nanocomposites had no impact on the lifespan of Moina macrocopa or water quality as assessed by toxicity analysis. Bacteria-pumice and bacteria-smectite nanocomposites are efficient for food waste recycling and do not require secondary treatment before being discharged into the environment.
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Affiliation(s)
- Anuwat Chaiyarat
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Chewapat Saejung
- Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
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