The Estimation of Water Demand and Alternative Water Resources in Patra Jasa Building Year 2020-2025

The development of the capital city is very rapidly this will cause water demand will continue to increase along with the rate of population growth, all fulfillment of food needs, and activity of the population closely related to the needs of water. This research aims to determine the total number of water needs required by the Patra Jasa building in the years 2020-2025 and to conserve water use and costs with the presence of alternative water sources. This study used the research method of case study approaches with the accumulation of primary data and secondary data, subsequent analysis of the availability and water needs, and replaced with alternative water sources. From the results of this study, the consumption of clean water 63838.5 m3, non-consumptive water per year 46681 M3 with details of flushing needs 36500 m3, watering 6351 m3, and cooling tower 3650 M3. The potential of source researchalternative water sources as in this is a source of rainwater that can be used to meet the daily needs of the building of 879.38 m3/day so that it can cover all the needs of non-consumptive water. FRP tank design used is FRP tank 1200 m3 with a method of rain supply that can be harvested from the roof of Patra Jasa building is 320973.7 m3/year and the average requirement is 174.9 m3/day, 5274 m3/month, 63838.5 m3/year. Annual water uses savings of 57835.71 m3/year or Rp. 725,880,160.00.


Introduction
The development of the region in the capital is very rapid, this will cause water demand will continue to increase as the rate of population growth. All fulfillment of food needs and activities of residents are always closely related to the needs of water. These needs are inevitable, but must be predicted and planned to be well-utilization. The most common thing is the imbalance between availability and water needs. To achieve the balance between the needs and the availability of future water, it is necessary to analyze water needs and efficiency of water use.
According to the [22] Based on Jakarta data in figures 2018 and 2019, which is collected through survey data and data of several units of Jakarta provincial government is obtained information of water that is channeled to the customers. Most of the water was channeled to companies, stores, and industries with a total of 117,089 subscribers in 2016, in 2017 as many as 119,788 subscribers, and in 2018 as many as 122,070 customers. This amount increases annually with a percentage of the value (in million rupiah) that varies in 2016 by 30.22 percent. 2017 of 30.33 percent and 2018 30.17 percent, the nominal percentage did decline annually but the number of subscribers and their own nominating rate increased.
Identification of the problem is the availability of clean water is not met well due to the increasing number of population, the need for water needed at the Patra Jasa Tahnun Building 2020-2025, an alternative water source as an efficient way to meet Water needs.
The purpose of this research is to determine the projection of water availability for the fulfillment of nonconsumptive water needs at the Patra Jasa Year building 2020 -2025, to conserve water and cost with an alternative source of water.

Methodelogy
This research uses a study method with a case study approach, where the method used is a quantitative and analytical descriptive that aims to evaluate the conditions of a certain period as the basis of planning for the Based on the data that has been collected, based on theoretical and empirical analysis, which is then concluded by the results of the analysis.

Results and Discussion
The calculation below is the discharge of rainwater for 2 years as follows:  Coefficient (C) of the Streaming The flow coefficient is a coefficient whose magnitude depends on the surface condition, slope and material type in the area of rain, it is the roof with concrete material type, which means the coefficient of addressing (C) is 0.95. Can be seen in table II.  = Q x t = 0.061069 x (4 x 3600) = 879,3865 m 3 /days Thus, the volume of rainwater for 2 years that is accommodated on the reservoir tank to be in a non consumptive clean water is 879.3865 m3/day. According to the [16] Based on the comparison between rainwater supply and the demand of Vsuplay raw water < Vdemand so that rainwater supply is insufficient for the overall needs of the average raw water of the building occupants. So calculation of tank Volume based on the supply of securities in January, February, July, September, October, November that tends to supply high rainwater as in  Here is a chart of water balance Comparison of rainwater availability with water needs at Patra Jasa Monthly building (m3/month) Kebutuhan (m3) VOLUME 2 │ NUMBER 2 │ MARCH 2020 Available online at http://proceedings.worldconference.id. ISSN: 2656-1174 (online) According to the [23] In the first year at the end of December FRP tank still leave water as much as 833.8 m3 of rain water. So that the remaining water is used for the next year with the same calculations. The first year there is excess of rainwater because the tank capacity is insufficient to accommodate the discharge of rainwater in the tank because it is only able to fulfill a small need. The excess water rain occurs in September, October, November with a magnitude of 355.9 m3, 886.6 m3, 987.7 m3. Rainwater while the vacuum tank water occurs in May and June.
From the water balance  These savings do not include electrical financing, pipeline maintenance and maintenance of water pumps.

Conclusion
1) The potential of this research on the availability of water from alternative water sources such as in this case is a source of rain water that can be used to meet the daily needs of development of 879.38 m3/day so it can cover all the needs of non consumptive water. 2) Based on the analysis of the research needs of consumptive and non-consumptive water is: a. Consumptive Clean water Year 63838.5 m 3 . b. Non Consumptive clean water years 46681 m 3 with details needs flushing 36500 m 3 , Watering 6351 m 3 , and Cooling Tower 3650 m 3 . 3) FRP tank design that used is FRP tank 1200 m3 with a method of rain supply that can be harvested from the roof of Patra Jasa building is 320973.7 m3/year and the average requirement is 174.9 m3/day, 5274 m3/month, 63838.5 m3/year. Annual water use savings of 57,835.71 m3/year or Rp. 725,880,160.00.