Universitas Pertamina promotes responsible water management by assessing opportunities to reduce freshwater demand and recover water from campus operations. Quantitative assessments conducted through research and prototype development examine air-conditioning condensate, treated wastewater effluent, and drainage water as potential sources for reuse. Rainwater harvesting is assessed as a complementary source for suitable campus applications. These assessments estimate recoverable water volumes and identify treatment processes, storage requirements, and potential uses.
Rainwater Harvesting Potential for Toilet Flushing
Universitas Pertamina has assessed rainwater harvesting opportunities at GOR I, a building accommodating classrooms, faculty offices, laboratories, and a canteen. Approximately 3,120 m² of roof area is available as a potential rainwater catchment. Based on rainfall and runoff calculations, approximately 195.27 m³ of rainwater per month could potentially be collected.
The proposed system would convey rooftop runoff through pipes equipped with mesh screens into a storage tank. Collected rainwater would subsequently be supplied for toilet flushing, subject to appropriate water-quality and operational requirements. This application could reduce freshwater demand for toilet flushing.
Recovery of Air-Conditioning Condensate
Universitas Pertamina has assessed air-conditioning condensate recovery at the Griya Legita Building. Air-conditioning systems generate condensate during cooling and dehumidification, providing a potential water source that could be recovered instead of discharged.
Measurements and calculations involving eight air-conditioning units indicate an estimated condensate generation potential of approximately 178.84 litres per day. The assessment considers zeolite and activated-carbon filtration as treatment components, with handwashing at washbasins identified as a potential application.
Suitability for handwashing would need to be confirmed through treated-water quality testing and any additional treatment required for the intended use.
Further Treatment of Wastewater Effluent
Universitas Pertamina has also evaluated opportunities for further treatment and reuse of wastewater treatment plant effluent. Wastewater from buildings within the university area is collected and treated centrally through physical and biological processes.
The assessment examines additional treatment to improve effluent quality for potential subsequent use. The proposed process incorporates equalisation, slow sand filtration, microfiltration, and membrane filtration.
Following treatment, the recovered water would be stored in a 5,000-litre reservoir before use, subject to confirmation of its suitability for the intended application. This figure represents proposed storage capacity, rather than treatment throughput or the volume of effluent actually reused during a reporting period.
Drainage Water Recovery for Landscape Irrigation
A further assessment examines the treatment and recovery of drainage water containing greywater and other wastewater streams from urinals, washbasins, dishwashing, showers, ablution facilities, and laundry activities.
The assessment considered a flow of approximately 6.28 m³ per day, equivalent to 6,280 litres per day, as the basis for treatment system design. The proposed treatment objective is to achieve water quality suitable for landscape irrigation, described in the assessment as Class IV water quality. This represents a design objective rather than verified treated-water performance.
The proposed system consists of a collection tank, a horizontal roughing filter, rapid sand filtration, a reservoir, and a disinfection unit. A 400 m³ reservoir is included in the design to store treated water before its proposed use for irrigation.
Quantitative Basis for Water Reuse Development
The assessments provide reference values for evaluating potential water availability and infrastructure requirements across several campus sources.
| Water source | Quantified estimate or design parameter | Proposed application |
| Rooftop rainwater at GOR I | Potential collection of approximately 195.27 m³/month from 3,120 m² of roof area | Toilet flushing |
| Air-conditioning condensate at Griya Legita | Potential generation of approximately 178.84 litres/day from eight units | Handwashing, subject to verification of treated-water suitability |
| Treated wastewater effluent | Proposed 5,000-litre storage reservoir following additional treatment | Subsequent uses determined by treated-water quality |
| Drainage water | Assessment flow of approximately 6.28 m³/day and proposed 400 m³ storage reservoir | Landscape irrigation, subject to treatment performance and water-quality verification |