Bonga, M. S. (2016). Potential use of water hyacinth (eichhornia crassipes) for water quality improvement of polluted waterways (Unpublished master's thesis). Public Management Development Program, Development Academy of the Philippines.

Public Management Development Program Middle Managers Class Batch 10 Thesis (MMC)--Development Academy of the Philippines.

The Pasig River Rehabilitation Commission (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 (Eichhornia crassipes), 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 on-site study that exhibits and validates its efficiency in assimilating certain pollutants in the priority tributaries has yet to be conducted. For this reason, a Re-entry Project (ReP) entitled "Potential Use of Water Hyacinth (Eichhornia crassipes) for Water Quality Improvement in Polluted Waterways" was implemented. This ReP explored the use of water hyacinth in the reduction of heavy metal contamination and eutrophication in polluted waterways by subjecting the macrophytes in 20 various controlled conditions in a 20-liter fish tank. Water and water hyacinth samples were gathered regularly for the whole month of June 2016. 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. While the heavy metal content of water hyacinths was expected to increase as they accumulated heavy metal from the estero, the results of the samplings showed otherwise. This trend can be attributed to the varying heavy metal concentration of individual water hyacinths at the beginning of the experiment, the amount of which was not established to touch the riverbed where heavy metals are concentrated. Other challenges beset the study in Estero de Binondo, including the early onset of the rainy season, which required the immediate removal of the wetland system as it could impede the flow of water in the waterway. 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. Its heavy metal concentration increased by up to 12 times when exposed to an environment rich in heavy metals. However, due to unforeseen plant death and decomposition, the ability of water hyacinths to remove significant amounts of nutrients from its surrounding was not established. Nonetheless, 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 already substantiate the effectiveness of the water hyacinth in improving the water quality of deteriorated bodies of water. It is highly efficient, cost-effective, accessible, and readily available. 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. Taking into consideration the challenges, issues, and concerns met during the implementation, the wetland system must be supplemented with policy that will optimize its utilization. Regulations and other monitoring measures must be strictly integrated to ensure its efficiency.