Characterization of kitchen wastes for phosphorus recovery
Kitchen waste is one of the municipal wastes which produced everyday by individuals, hence it can be found abundantly in nature. It has high organic content and can cause various problems to environment. Phosphorus, a limited and non-renewable mineral source, is an essential element in our daily l...
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Format: | Academic Exercise |
Language: | English |
Published: |
2015
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Online Access: | https://eprints.ums.edu.my/id/eprint/18519/1/Characterization%20of%20kitchen%20wastes.pdf https://eprints.ums.edu.my/id/eprint/18519/ |
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Summary: | Kitchen waste is one of the municipal wastes which produced everyday by individuals,
hence it can be found abundantly in nature. It has high organic content and can cause various problems to environment. Phosphorus, a limited and non-renewable mineral
source, is an essential element in our daily life especially for agricultural industry.
Despite its importance and scarcity, the excess phosphorus applied into soil as fertilizer
can be leached into water bodies and caused a phenomenon called eutrophication.
Therefore, a study was conducted to determine the physical and chemical
characteristics of kitchen wastes for phosphorus recovery, via anaerobic digestion
(AD). This study has been carried out by using two types of sample liquids namely
Kitchen Wastes Liquid (KWL) which obtained from raw sample and Kitchen Wastes
Digested Liquor (KWDL), obtained from digested sample of 15 days digestion period.
The results showed that the pH of kitchen wastes used in this study were in the range
of 6.0 - 7.0. Total solids (TS) and volatile solids (VS) for raw sample was high which
were 42.9% and 94.29%, respectively. This was due to the addition of distilled water
and this procedure was carried out in order to determine the amount of organic
loadings in the sample. If the %TS and %VS reached ~20% and ~90%, respectively;
it indicates that the organic content in the sample is higher, therefore the sample is
considered suitable for an anaerobic digestion. For the AD samples, TS and VS were
degraded from AD sample Day 1 until AD sample Day 15; where for AD sample Day 1,
the %TS and %VS were 6.34% and 40.96%, respectively; while for AD sample Day
15, the %TS and %VS were 2.79% and 17.78%, respectively. The concentration of
magnesium (Mg²⁺) increased from KWL to KWDL, which is 45.73 mg/L for KWL and
114.00 mg/L for KWDL due to the solubilisation of Mg Mg²⁺ during the AD process. The
concentration of ammonium (NH₄⁺), on the other hand, decreased from 192.0589
mgN/L in KWL to 73.8688 mgN/L in KWDL which might due to the loss of nitrogen to
biogas in the form of ammonia, NH3 gas. The concentration of phosphate (PO4³⁻) which
is the most vital nutrient in this study, increased from 509.18 mg/L in KWL to 554.04
mg/L in KWDL. The amount of PO4³⁻ that increased was not contented enough, as the
AD process was expected to release huge amount of PO4³⁻. This might due to the loss
of PO4³⁻ ions during filtration and sample storage. The amount of phosphorus (P)
recovered in this study was determined theoretically by assuming in terms of struvite
formation, the weight of VS degraded during the AD process and the concentration of
PO4³⁻ in raw sample and digested sample; which has gave values of 0.46 g/L struvite
in KWL and 1.00 g/L struvite in KWDL, 4.31 g/g of P from VS degradation and 8.8% P
from PO4³⁻ ions that formed in raw and digested sample, respectively. These significant
values of P recovery shows that anaerobic digestion is a reliable method for recovering
P from organic wastes such as kitchen wastes, garden wastes, palm oil mill effluent
(POME) and empty fruit bunches (EFB).
Kitchen waste is one of the municipal wastes which produced everyday by individuals,
hence it can be found abundantly in nature. It has high organic content and can cause various problems to environment. Phosphorus, a limited and non-renewable mineral
source, is an essential element in our daily life especially for agricultural industry.
Despite its importance and scarcity, the excess phosphorus applied into soil as fertilizer
can be leached into water bodies and caused a phenomenon called eutrophication.
Therefore, a study was conducted to determine the physical and chemical
characteristics of kitchen wastes for phosphorus recovery, via anaerobic digestion
(AD). This study has been carried out by using two types of sample liquids namely
Kitchen Wastes Liquid (KWL) which obtained from raw sample and Kitchen Wastes
Digested Liquor (KWDL), obtained from digested sample of 15 days digestion period.
The results showed that the pH of kitchen wastes used in this study were in the range
of 6.0 - 7.0. Total solids (TS) and volatile solids (VS) for raw sample was high which
were 42.9% and 94.29%, respectively. This was due to the addition of distilled water
and this procedure was carried out in order to determine the amount of organic
loadings in the sample. If the %TS and %VS reached ~20% and ~90%, respectively;
it indicates that the organic content in the sample is higher, therefore the sample is
considered suitable for an anaerobic digestion. For the AD samples, TS and VS were
degraded from AD sample Day 1 until AD sample Day 15; where for AD sample Day 1,
the %TS and %VS were 6.34% and 40.96%, respectively; while for AD sample Day
15, the %TS and %VS were 2.79% and 17.78%, respectively. The concentration of
magnesium (Mg²⁺) increased from KWL to KWDL, which is 45.73 mg/L for KWL and
114.00 mg/L for KWDL due to the solubilisation of Mg Mg²⁺ during the AD process. The
concentration of ammonium (NH₄⁺), on the other hand, decreased from 192.0589
mgN/L in KWL to 73.8688 mgN/L in KWDL which might due to the loss of nitrogen to
biogas in the form of ammonia, NH3 gas. The concentration of phosphate (PO4³⁻) which
is the most vital nutrient in this study, increased from 509.18 mg/L in KWL to 554.04
mg/L in KWDL. The amount of PO4³⁻ that increased was not contented enough, as the
AD process was expected to release huge amount of PO4³⁻. This might due to the loss
of PO4³⁻ ions during filtration and sample storage. The amount of phosphorus (P)
recovered in this study was determined theoretically by assuming in terms of struvite
formation, the weight of VS degraded during the AD process and the concentration of
PO4³⁻ in raw sample and digested sample; which has gave values of 0.46 g/L struvite
in KWL and 1.00 g/L struvite in KWDL, 4.31 g/g of P from VS degradation and 8.8% P
from PO4³⁻ ions that formed in raw and digested sample, respectively. These significant
values of P recovery shows that anaerobic digestion is a reliable method for recovering
P from organic wastes such as kitchen wastes, garden wastes, palm oil mill effluent
(POME) and empty fruit bunches (EFB). |
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