The Capability of Tulis River to Receive Liquid Waste from Production Test of Geothermal Wells and Relationship by Irrigation in Dieng Central Jawa

Abstract

The research on Tulis River water mainly known to serve irrigational purposes is set to examine the quality and quantity as well as the capability to receive liquid waste from production test of geothermal wells. The physical and chemical properties of the Tulis River water and the liquid waste were analyzed. The capability of the Tulis River to receive the liquid waste was determined by using the mass balance equation to each parameter that represents water quality standards, extending up to a maximum sustainable limit level at which the liquid can hold. The quality parameter to be analyzed were total dissolved solids (TDS), conductivity, Sodium Absorption Ratio (SAR), Chloride (Cl), Sulphate (SO4) and Boron (B). By using simulation and regression method the maximum discharge of the save liquid waste of each parameter to be flowed to the Tulis River can be determined. The results of this research showed the quality of the liquid waste of the production test geothermal wells that directly or after treatment plant flow to the Tulis River belongs to group IV of liquid waste. During the dry season the Tulis River water at the upstream of the production test geothermal wells contained 1,5 mg/l higher Boron than the maximum Boron content level limit of the irrigation water / group D (Boron 1 mg/l). In the rainy season, the quality of the Tulis River water ñ seemed to be suitable for irrigation water. Boron material had been found to originate from young volcanoes activity, which eventually produced Borate acid. The quantity of Boron is the main limitation for the discharge of the liquid waste permitted to flow to the Tulis River. The discharge capability of the Tulis River to receive liquid waste is 0,067 up to 0,90 liters / minute during dry season and 33,5 up to 62,5 liters / minute during rainy season.