Anaerobic mono and co-digestion of food waste and palm oil mill effluent for phosphorus recovery
Anaerobic digestion (AD) is a process by which microorganisms break down biodegrable material in the absence of oxygen. The process involves hydrolysis, acedogenesis and methanogensis stages. This technology have gained interests as a technique to recover resources such as energy and nutrient. Ad...
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| Format: | Thesis |
| Language: | English |
| Published: |
2016
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/17503/1/Anaerobic%20mono%20and%20co-digestion.pdf |
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| Summary: | Anaerobic digestion (AD) is a process by which microorganisms break down
biodegrable material in the absence of oxygen. The process involves hydrolysis,
acedogenesis and methanogensis stages. This technology have gained interests as
a technique to recover resources such as energy and nutrient. Additionally, it can
help in reducing waste volume as well as greenhouse gases. To improve the
production of anaerobic digestion products, co-digestion of different substrates is
being introduced. The benefits of co-digestion are to increase the efficiency of
digestion process as the co-substrates can supply the missing nutrient in the main
substrates. So far, there are no studies have been carried out for applications of
anaerobic co-digestion of food waste (FW) with palm oil mill effluent (POME) to
recover phosphorus. FW is a type of municipal solid wastes which abundantly
available. It has high organic content and can cause various environmental
problems if disposed on landfill. While POME is a largest wastewater produced by
palm oil mill industry that contain significant nutrient content. It has been reported
that phosphorus is a limited and non-renewable mineral source that is essential in
our daily life especially for agricultural industry as fertilizers. Therefore, this study
aims to investigate phosphorus recovery from FW using anaerobic co-digestion
with POME. The physicochemical properties of the samples were determined to
study the suitability to be used in anaerobic digestion. The results showed that the
total solids and volatile solid of FW and POME were 15%, 3% and 94% and 68%,
respectively. pH were, 3 and 5, respectively. These results suggested that FW and
POME were appropriate to undergo anaerobic co-digestion for phosphorus
recovery. The anaerobic digestion was performed using batch anaerobic digester
at mesophilic condition at 37°C (± 1) and pH between 6.8-7.2. Mono-digestion of
single FW and POME was carried out to investigate phosphorus recovery at
different digestion period for 40 days. It was found the optimum days to recover
phosphorus was within 30 days with 89% and 77%, phosphorus recovery from FW
and POME, respectively. Therefore, the co-digestion was performed for 30 days at
different ratios of FW to POME, namely 70:30% and 30:70%. The results showed
co-digestion increased phosphorus recovery to 183-247%, compared to mono-digestion,
with 70:30 (FW:POME) was the highest, followed by 30:70 (FW:POME),
100% FW and 100% POME with percentages 247%, 183%, 89% and 77%,
respectively. When expressed in mg P/g, the values were, 6.70 mg P/g, 3.00 mg
P/g, 4.90 mg P/g and 0.68 mg P/g, respectively. From the results, this study
suggested that phosphorus recovery can be improved using co-digestion with FW
as the main substrates and POME was a suitable co-substrate in anaerobic co-digestion.
While the waste reduction was presented by total solid and volatile solid
reduction with 41% and 45%, respectively from the result. |
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