Seminar from ITB professor (11 Apr.) Wetland potential for recycling of wastewater treatment plant effluent (湿地、排水処理)



Open seminar
by Prof. Prayatni Soewondo, Environmental Engineering, Faculty of Civil Engineering and Environmental, Institut Teknologi Bandung (ITB), Indonesia.


11 APRIL 2013, 11:00-12:00, Venue: BASE 1st Floor meeting room.

Wetland Potential as alternative solution for recycling of domestic WWTP (wastewater treatment plant) Effluent. Case Study : Bojongsoang WWTP, Bandung.



The need for water tends to rise along with the increasing population and improving living standards. Most of water used as rinse water, for example water used for bathing, for washing hands, to wash clothes, and more, approximately 70-80% of water consumption will turn into domestic wastewater. Along with the increasing water demand, the raw water needs to be processed is increasing as well. However, the increasing need for raw water is not followed by an increase in raw water, both in quality and quantity. These conditions encourage efforts to find alternative sources of raw water which more secure than others in terms of quality and quantity. One of its efforts is by making use again (reuse) effluent from wastewater treatment. The technology will be used to process must be cheap, effective, and not difficult in treatment. Technology used in this study is constructed wetland. The purpose of this research is measuring the treatment efficiency and determining the optimum operating conditions.

Bojongsoang (in Indonesia) wastewater treatment handles domestic wastewater and produces effluent that can be utilized as recycled water. There are several available treatments in order to recycle water; one way is by using a constructed wetland. This research operated constructed wetland reactors, along with several variations: different aeration process, different layers of medium inside the reactor (50 cm and 40 cm thick), different HRT, and different plantation. Within these different variations, the most efficient total COD removal (91%) was found in the reactor that used aeration with 40 cm thick medium layer, 2 days HRT, and Typha latifolia plantation. The ratio for BOD/COD in this particular reactor was 0.7. It was also discovered that the longer the wastewater is being treated, the better the results of COD removal. For aerated reactor, the BOD/COD ratio was 0.25, while BOD/COD ratio for the non-aerated reactor was 0.42. From the BOD/COD ratio, it was discovered that aeration affected a constructed wetland by increasing the degradation of organic materials. The most efficient ammonium, TKN, and total phosphate removal was found in an aerated reactor that utilized 50 cm layer of medium, 2 days HRT and used Scirpus grossus. The KT value in this research was 0.6-2.5/day. The wetland area needs to increase if the KT decreases. On the other hand, the KS value in this research was 24.62 m3/m2/day and 12.1 m3/m2/day. The significant value of KS confirmed the short-time contact between the wastewater and the reactor medium, which resulted low pollutants removal. When using the chi square test, the result from both CSTR and PFR model simulation showed close values between k value in the field and the model one. The PFR model had smaller chi square result than the CSTR one, which meant the PFR model was more similar to the reality in the field instead of CSTR.