This project established the potential of the water hyacinth plant (E. crassipes) to reduce water pollution, i.e. to alleviate the heavy metal contamination and eutrophication in polluted waterways; and to demonstrate its viability as a low-cost, efficient, and accessible alternative to expensive conventional wastewater treatment systems by subjecting the macrophytes in 20 various controlled conditions in a 20-liter fish tank. On the other hand, for the uncontrolled environment, an ambient water quality analysis was performed in the installed water hyacinth wetland systems in Estero de Binondo.
The heavy metal content of water hyacinths was expected to increase as they accumulated heavy metal, but the results of the on-site samplings in Estero de Binondo showed otherwise. The results of the laboratory-scale study showed that water hyacinth can accumulate copper, chromium, cyanide, and lead in its tissues, mostly in the roots and stolon.
Background and Problem
The PRRC is mandated to rehabilitate and restore the water quality of Pasig River and its tributaries to Class C level, based on Executive Order 54 series of 1999 and as amended by Executive Order 65. In line with this, the PRRC has embarked on testing and assessing the effectiveness of several pollution-reduction technologies. One of them is the use of water hyacinth, an invasive aquatic plant found in Pasig River and other water bodies throughout the country, to reduce heavy metals and nutrients in polluted waterways. The water hyacinth’s application in wastewater treatment has been studied for years, but a laboratory-scale and on-site study that exhibits and validates its efficiency in assimilating certain pollutants in the priority tributaries has yet to be conducted.
Solution and Impact
Water and water hyacinth samples were gathered regularly for the whole month of June 2016 to determine its impact on water quality improvement and capacity to bioaccumulate heavy metals. The water hyacinth’s root, stolon, petiole, and leaf were tested for copper, chromium, lead, and cyanide. Its ability to absorb nutrients was analyzed through the Total Nitrogen (N) and Total Phosphorus (P) content of the water. Meanwhile, a separate water quality analysis was performed in the water hyacinth wetland system in Estero de Binondo. A series of ambient water quality sampling was conducted in three sampling points within the project site. The water and water hyacinth samples from the site were subjected to the same tests as those from the controlled group.
It was later found out that the water hyacinth wetland treatment system represents a viable low-cost treatment for heavy metal contamination in Pasig River and its tributaries. Findings in previous studies also substantiate the effectiveness of the water hyacinth in improving the water quality of deteriorated bodies of water. It is highly efficient and accessible. It also exhibits low operating cost, so it is easy to replicate, replace, or remove if needed. However, due to its invasive nature, it must be subjected to a controlled, floating, and manageable habitat.
The project installed operational constructed wetland system with water hyacinth in Estero de Binondo including the design of the laboratory-scale set-up in Talayan, Quezon City. Complete fabrication, installation and placement of water hyacinth are accomplished within the planned timeline which is eventually followed by the laboratory-scale study on the bioaccumulation of heavy metals and nutrient absorption potential of the water hyacinth plant.
PRRC also monitored the trained members of the community with regard to handloom weaving (with the harvested water hyacinth as the raw material) which is a potential source of livelihood for the communities in the area. PRRC also conducted consultation with the Department of Science and Technology (DOST) as well as the Department of Trade and Industry (DTI) in marketing the products produced. Orientation and collaboration with the local government, stakeholders, and beneficiaries are also continuous.
Note: This initiative is based on the Public Management Development Program (PMDP) Re-Entry Plan of Ms. Merliza S. Bonga of the PMDP Middle Manager Class Batch 10 (Binhi).