Abstract
The aim of this study was to investigate the current situations of wastewater from milking center at dairy farms in order to propose the low-cost treatment systems for purifying wastewater. From the investigation on handlings, treatment processes and conditions of the effl uent from milk house or milking parlor at all dairy farms (199 farms) in H town, the treatment processes of wastewater have been classified into five groups according to the manure contamination into drain water and the settling tanks installing. As this classifi cation, 18 samples of wastewater obtained from 15 milking centers were chemically analyzed. From these analytical results, the effective measures of wastewater treatment for dairy farms in H town need to be considered.
Drain water from milking parlor at 20 % of free stall dairy barns were seriously polluted by manure. On the other hand, in almost all milk houses at tie stall dairy barns, drain water was not contaminated by manure, and some drain water passed through the settling tanks conformed to the effl uent standards. The factors determining the degree of water pollution were revealed as the mixing rates of manure to drain water of milking center.
From the result mentioned above, the wastewater without manure contamination in milking center would not be polluted seriously and could be treated by simple pulifi ed systems. To reduce the pollution caused by wastewater from milking center in H town, separation of manure from drain water and using low-cost treatment systems such as overfl ow type some settling tanks or artifi cial wetland seems to be more practical compared with using some costly purifi cation systems such as membrane based biological treatment processes.
