No abstract

The wastewater from a hatchery was dissimilar from a production farm in terms of quality and quantity of waste. The sources of wastewater were basically from uneaten food and fish feces. Biological treatment was a very promising process for removing dissolved organics from refinery wastewater. However, the low availability of clean water has become a critical issue to the shrimp grower. Further, carbon and phosphorus are the main constituents of most wastes, and removal of such elements from waste effluents can reduce the environmental stress and minimize ecosystem deterioration. The purpose of this study is to evaluate the factors affecting the removal of chemical oxygen demand (COD) and total phosphorus (TP) in the contaminated wastewater from hatchery industry. The factors were: ratio acclimatized mixed culture (AMC) to synthetic wastewater (SW) (1:3 and 2:3), the presence and absence of support media (Yes and No), agitation (0 rpm and 100 rpm) and retention time (4 days and 8 days). The responses were COD and TP removal. Design Expert software was used to construct experimental design where all the factor was randomized. As a result, ratio AMC to the SW, agitation and retention time were the most contributing factors to all the responses. The best conditions for the contaminated wastewater from hatchery industry were at ratio (1:3) AMC:SW, present of support media, 0 rpm agitation and 4 days retention time. At this condition the removal for COD and TP were 26.5% and 42.9% respectively. However, by separating the best condition for COD and TP, the removal can achieve 69% and 75.7% respectively. It can be concluded that the biological treatment using AMC can treat contaminated wastewater from hatchery industry.

This study was conducted to evaluate the most influential factors contributing to the removal of chemical oxygen demand (COD), nitrate-N, and total phosphorus in hatchery wastewater to optimize the removal process with the application of acclimatized mixed culture (AMC). The factors, namely, the ratio of AMC to synthetic wastewater (SW), support media, agitation speed, and retention times, were selected and were analyzed through two-level factorial analysis. The results suggested that the best conditions for maximum removal of each response was the ratio of 1 to 3 AMC: SW, absence of support media, 0 rpm agitation, and 4 days of retention time; where the removal values of COD, nitrate-N, and total phosphorus were 26.5%, 76.5%, and 42.9%, respectively. The two largest contributing factors obtained from the factorial analysis were analyzed by the Design-Expert software to determine the optimum conditions for waste removal through the central composite design of the Response Surface Methodology (RSM). The obtained removal values were up to 62%, 94%, and 46% for COD, nitrate-N, and phosphorus at each optimum condition. The results obtained were higher than those from factorial analysis for all responses. To sum up, the treatment of contaminated wastewater through biological treatment via acclimatized mixed culture can be applied. The optimum conditions determined from this study should bee helpful in scaling up the wastewater treatment process.