Effects of aluminium sulfate and Klaraid on physico-chemical characteristics of wastewater and total phosphorous removal during wastewater treatment process at a local beverage company in Phnom Penh were investigated followed by the determination of the optimum application of aluminium sulfate and Klaraid for phosphorous flocculation. Aluminium sulfate versus total phosphorous at different ratios of 20:1, 21:1, 22:1, 23:1, and 24:1 were studied whereas Klaraid was studied at the concentration of 9 ppm, 11 ppm, 13 ppm, 15 ppm, and 17 ppm. Physico-chemical characteristics of wastewater viz pH, color, dissolved oxygen, total phosphorous, ammonia, and chemical oxygen demand (COD) before and after treatment were analyzed. Aluminium sulfate versus total phosphorous at ratio of 22:1 was the most effective in removing total phosphorous whereas the optimum value was at 13 ppm for the application of Klaraid. At these values, observed physico-chemical characteristics of the effluents were complied with the guideline limit of Ministry of Environment of Cambodia (MoE). By comparing the effectiveness of the two flocculants, application of aluminium sulfate was most effective in phosphorous removal while that of Klaraid was better in terms of color and ammonia removal.