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    • Book chapter

      Domestic effluents and pollution in Imbang River, Negros Occidental 

      GA Gonzales - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
      Domestic effluents, or waste waters from human settlements, were sampled from eight stations along Imbang River in Negros Occidental from July 1993 to February 1995. Three types of domestic waste waters were produced by communities along Imbang River. Waste waters from clothes washing, house cleaning, and bathing, including washings of domestic animals and holding pens and run-off from rains and storms were conveyed by open canals and ditches to the river. This type of domestic effluents were well aerated and had the least potential to degrade the rivers. Waste waters from kitchens and markets carried large volumes of food scraps and other solid wastes, were unsightly, and smelled bad from the decomposition of garbage. Overflows from septic tanks were the most objectionable domestic effluents with offensive visual and olfactory properties. Domestic effluents had pH 4–7.6, dissolved oxygen of 0.5–7.2 ppm, and biochemical oxygen demand ranging from 2 to 240 ppm. The overflows from septic tanks were of the worst quality, with BOD 20x greater than household washings, and 6x more than kitchen and market effluents. Fecal coliform bacteria made up 93% of the total coliforms in the septic tank overflows, 86% in kitchen and market waste waters, and 39% in household washings. The domestic effluents from the communities around Imbang River had higher than allowable levels of BOD and solids. The 11 barangays with 16,486 households and 85,535 people loaded about 3,4000 m3 of waste water into the river every day. Along with the waste water were 180 mt/yr of BOD, 590 mt/yr of total solids, plus large quantities of nutrients, surfactants, and fecal coliform bacteria.
    • Article

      Effect of detention time on aerobic waste stabilization pond performance in Southeast Asia 

      OM Millamena - Bulletin of Environmental Contamination and Toxicology, 1994 - Springer Verlag
      The rising level of pollution in rivers, lakes and other bodies of water has created problems of significant magnitude in Southeast Asia. Apart from the aesthetic desirability of clean rivers are the pressing dangers to health and detrimental effects on aquatic life. Pollution of these sources must be controlled so as not to interfere with the waters' legitimate uses.

      Waste stabilization ponds are well-accepted as an effective and economical means of waste disposal. A "stabilization pond" is an artificially created body of water intended to retain sewage or organic wastes until biological processes have rendered the wastes stable. The stabilization process consists of bacteria and algae interaction. Bacteria oxidize the wastes and produce sludge, carbon dioxide and ammonia. The nutrients produced from bacterial oxidation, along with light energy, supply the requirements for algal photosynthesis. Algae produce oxygen needed to sustain the treatment process. Optimum detention time refers to the average length of time required for waste to become stabilized within a pond.

      Properly designed and operated, a stabilization pond can provide treatment comparable to a more costly waste treatment plant. However, the design criteria for a particular climate may not be applicable to other climates. This study was conducted to establish suitable detention times for aerobic stabilization ponds in Southeast Asia.
    • Book chapter

      Households, agriculture, industry, fishing, and fish farming along Imbang River, Negros Occidental 

      RC Sanares - In T Bagarinao (Ed.), Research Output of the Fisheries Sector Program, 2007 - Bureau of Agricultural Research, Department of Agriculture
      Interviews were conducted among respondents identified from the households, agriculture farms, sugar mills, and fish farms along the whole stretch of Imbang River, Malisbog River, and Muyao Creek, down to Barangay Balaring at the coast of Silay City in Negros Occidental. Among the 1,073 households, 11% used river water for washing clothes, but 20% also used the rivers for disposal of waste waters, 11% for human wastes, and 13% for animal wastes. Among the 30 respondents from the agriculture sector, 70% discharged water into the river. The two sugar mills in the area treated waste waters partially before release into the rivers; one sugar mill also released wastes in a nearby rice field. Milling wastes such as bagasse, molasses, and mud press were reused and not dumped into the river. Imbang River was both the water source and wastewater sink for seven fish farms.
    • Article

      Ozone treatment of slaughterhouse and laboratory wastewaters 

      OM Millamena - Aquacultural Engineering, 1992 - Elsevier
      Ozonation as a method of treatment for highly polluted slaughterhouse wastewater and slightly polluted laboratory wastewater was investigated. The results showed that use of a low concentration ozone stream (0·11 g h−1) for removal of the majority of organics in slaughterhouse wastewater was not feasible, whereas application of the technique for less polluted chemical laboratory wastewater was feasible for ultimate disposal purposes.