Mukda Phatthanawanichchai. Cadmium analysis in pig farm and canal system of the Mae Klong river. Master's Degree(Technology of Environmental Management ). Mahidol University. : Mahidol University, 2008.
Cadmium analysis in pig farm and canal system of the Mae Klong river
Abstract:
This study aims to evaluate the accumulation of cadmium (Cd) in the Huai Rong
Canal of the Mae Klong River and the large-scale pig farm in Pak Tho District, Ratchaburi
Province. The Huai Rong Canal receives wastewater from several small and medium-scale pig
farms situated along the canal. Samples were collected for six months from September 2005 to
February 2006 at two sampling stations of Wang Manao Sub-District and Wan Dao Sub-
District (Ban Khok Khi Lek), Pak Tho District, Ratchaburi Province. Four types of samples of
water, sediment, aquatic plant (roots and leaves of Ipomoea aquatica) and aquatic animal
(Pomacea canaliculata) were collected. For the large-scale pig farm in Pak Tor District,
Ratchaburi Province, seven types of sample were collected: pig feed, sludge (dry manure),
wastewater in collector tank, treated wastewater from UASB reactor, water and sediment in
constructed wetlands and reused water. The samples were digested with Microwave Digestion
instrument. The amount of Cd in the samples was determined by Graphite Atomic Absorption
Spectrophotometer.
Cd concentrations in the Huai Rong Canal of the Mae Klong River, which receives
wastewater from the small and medium-scale pig farms, can be presented in descending order
as follows: P. canaliculata > I. aquaticas root > sediment > I. aquaticas leaf > water. The
results also showed the bioaccumulation of Cd in snail species P. canaliculata on the canal
sediment. For the large-scale pig farm, Cd concentrations in the wastewater treatment system
can be presented in descending order as follows: wastewater in collector tank > treated
wastewater from UASB reactor 1 > treated wastewater from UASB reactor 2 > water from
constructed wetlands 1 > water from constructed wetlands 2 > water from constructed
wetlands 3 > reused water. The results clearly showed the efficiency of wastewater treatment
system in Cd reduction. In the case of solid samples, it was found that Cd concentrations in
sludge (dry manure) were higher than those in feed. Cd in sediment from constructed wetlands
was found in low amounts. From the results of the present study the application of dry sludge
(dry manure) from pig farm on plants must be used with caution. The high Cd concentration
in the sludge (dry manure) of pig farm undoubtedly comes from feed, therefore it is very
important to reduce Cd concentrations in pig feed. In conclusion, the present study showed the
necessity of wastewater treatment system for pig farms in Cd reduction and the need for
further studies of Cd reduction in pig feed