The objective of this research is to construct the appropriate forecasting model for the export quantity of concentrated latex by the three time series analysis methods which are Box-Jenkins method Winters’ multiplicative exponential smoothing method and combined forecasting method. Time series data from the website of Office of Agricultural Economics during January 1998 to February 2014 (194 values) are used and divided into two series. The first 182 values from January 1998 until February 2013 for the models prediction and the last 12 values from March 2013 until February 2014 for comparison the performance of forecasting models via the criterion of the lowest root mean squared error and the criterion of the highest correlation coefficient between existing values and forecasted values. Research findings indicated that for all forecasting methods that have been studied the most powerful method is the combined forecasting and the forecasting model is where and represent the single forecasts at time t from Box-Jenkins method and Winters’ multiplicative exponential smoothing method respectively.

This study surveyed seventeen wastewater treatment plants in concentrated latex rubber and seafood industries in southern Thailand. The researchers concerned mainly in the bulking sludge problems caused by filamentous bacteria. Wastewaters from those factories contained high organic contents high BOD5 and TKN concentrations. All of the existing activated sludge process were equipped with other pre- and post-treatments. Sixteen of them were concerned with only carbon and suspended removal. They were operated with high hydraulic retention time (HRT) and low food per microorganism ratio (F/M ratio) which are the main causes of bulking sludge problem. Most operators faced up with this problem but could not realize the reasons and solutions. This study observed their settle ability and presented filamentous bacteria in each plant. It can be evidently seen that some filamentous bacteria such as type 0041 and Nostocoida limicola II appeared at seafood treatment plants only and type 1863 found in rubber treatment plants only. This can be affirmed to the nature of influent composition of wastewater.