Ecology, Environment and Conservation Paper

Vol 27, Issue 4, 2021; Page No.(1465-1473)


Watcharapong Wararam, Thanit Pattamapitoon, Onanong Phewnil, Noppawan Semvimol, Kasem Chunkao, Thanawat Jinjarak, Kittipong Angchanpen, Pavin Wichittrakarn and Parkin Maskulrath


The research aims to determine the appropriated period of hydraulic retention time (HRT) for treating high organic-concentrated wastewater from pla-som production by the combined treatment systems of 50-mm plastic screen, five 3.5 m3 oil-grease trap tanks (2-day HRT), four 2.1 m3 anaerobic tanks (1-day HRT), 16.7 m3 oxidation pond one (7-day HRT), 12 m3 oxidation two (3-day HRT), and 8.2 m3 plant filtration plot (1-day HRT). The production of the wastewater was from the process of washing fresh raw fishes, the raw fishes were sliced in small pieces and converted into ground fish meat by the blender machine. The fish meat was rinsed for 8 rounds with the 1, 2, 3, 5, 6 and 7 by rice-wash-water and the 4 and 8 rounds by tap water before mixing with salt, garlic, steamed rice and monosodium glutamate. This is followed by plastic wrapping for 48-day before edibility. During pla-som production processing, the rinsed wastewater about 7 m3/day was fed to the treatment systems and fully stagnating storage in its components. The 700-kg raw fish was taken as wastewater producer which had to be treated by the said treatment systems. The result was satisfied in treatment efficiency with 32% for TDS, 98% for SS, 93% for BOD, 95% for COD, 81% for TOC, 100% for oil and grease, 53% for TKN, 66% for ammonia and 50% for total-P. However, it was still not favorable for quantitative quality of TDS, SS, BOD, COD, TOC, TKN, ammonia, Total-P, and phosphate due to the slow bacterial organic digestion rates from inhibiting garlic and salt components of the wastewater. The results evidently indicated that the contaminants of small pieces of fish meat and fish blood needed more than 3-day HRT in the trapping oil-grease and anaerobic tanks rather than aerobic oxidation ponds and plant filtration plot for providing anaerobic organic digestion process. Changing the first oxidation pond into another anaerobic tanks is surely expected to add more 7-day HRT which becomes to 8-day HRT for converting small pieces of fish meat and fish blood into inorganic materials through an anaerobic digestion process.