Notice of Intent to Make a Determination – Start of Public Comment Period

The International Development Research Centre (IDRC) must determine whether the proposed construction of a Wastewater Treatment Plant (WWTP), located in Wringinputih Village, Muncar Sub-district, Banyuwangi Regency, Indonesia, is likely to cause significant adverse environmental effects. 

To help inform this determination, IDRC is inviting comments from the public respecting that determination. All comments received will be considered public and may be posted online. 

Written comments must be submitted by August 16th, 2026 to: 

Renee Larocque  
Program Leader, Animal Health 
International Development Research Centre 
Email: rlarocque@idrc.ca  

Project Description  

This project, funded by IDRC and the Government of Canada, aims to improve the sustainability and social inclusiveness of shrimp farming in Indonesia. Indonesia is the world's third biggest producer of farmed shrimp. Shrimp aquaculture is economically important but has historically contributed to mangrove ecosystem destruction and water contamination. The project seeks to identify the most cost-effective, gender-responsive and nature-friendly climate-smart strategies for increasing production of small-scale shrimp aquaculture while simultaneously restoring the critical mangrove ecosystems. The research activities are taking place in Banyuwangi and Indramayu, Indonesia, two key coastal regions for shrimp farming in Java. The project is being implemented in collaboration with shrimp farmers, coastal communities, government, supply chain companies, the private sector and other stakeholders. 

 In Wringinputih Village, Banyuwangi Regency, the project is piloting a "climate-smart shrimp aquaculture" system (CSSA) which integrates mangrove restoration with improved wastewater treatment and other sustainability measures. Researchers are using real-time environmental monitoring and a project-designed greenhouse gas emissions calculator to assess the environmental performance of CSSA compared with conventional farming. Researchers are also identifying and supporting mangrove-based livelihood activities, particularly for women, and working with policymakers to support the adoption of climate-smart practices.  

Description of Physical Activities 

The proposed construction takes place in the shrimp farming area of Wringinputih which is located near a river area and coastal estuary, with a mangrove area separating ponds from the river. Ponds in Wringinputih Village have historically operated without a centralized wastewater treatment system and discharged aquaculture waste directly into the environment. This has resulted in the progressive degradation of coastal water quality, an increase in disease prevalence among shrimp stocks, and consequent pressure on mangrove ecosystems. Based on water quality measurements conducted in the coastal waters of Wringinputih Village, several parameters were found to exceed quality standards, particularly nutrient parameters such as ammonia (NH₃) and phosphate (PO₄), as well as certain pH values falling outside the optimal range.  

To address this, the project proposes to construct a communal Wastewater Treatment Plant (WWTP) which would serve approximately 21 hectares of shrimp pond land or 14 pond blocks. The physical construction consists of:  

• Shrimp pond embankment equalization (raising approx. 50-60cm with soil)   

• Two channels to convey treated effluent to discharge (782m long, 13m wide; 768m long, 7.81m wide)  

• Weir gate operational system (3m, 12cm thickness)  

• Sedimentation plots with zigzag construction (91m x 47m x 36m x 81m, surface area 4,227m2, height 2.5m) 

• Aeration pond (44m x 36m x 44m x 38m, surface area 1,296m2, height 2.5m)  

• Wetland pond (46m x 38m x 48m x 44m, surface area 1,692m2, height 2.5m) 

• Concrete treatment pond embankments 

Treatment ponds and their embankments will be constructed from concrete grade K-175 with bamboo piles as a ground reinforcement solution.  

System description: The WWTP system is designed with two inlet points sourced from two main rivers. Both rivers function as outlet channels from the targeted beneficiary ponds, meaning the water entering the WWTP system constitutes wastewater generated from aquaculture activities. 

Given that the pond system operates by utilizing tidal movements, each river is equipped with a weir structure fitted with an openable and closeable gate system. The operational mechanism of these water gates is designed in a coordinated manner as follows: 

• Water intake phase: When the ponds require a water supply, the weir gates are opened to allow seawater to flow into the pond system, while the WWTP gates are closed to prevent wastewater from mixing with the incoming water. 

• Harvest discharge phase: When the ponds enter the harvest period and require drainage, the weir gates are closed to stop the inflow, while the WWTP gates are opened to allow pond wastewater to flow into the treatment system for processing before being discharged into the receiving water body. 

This bidirectional operational mechanism ensures that wastewater from aquaculture  

pond activities can be collected and treated in a controlled manner, while simultaneously maintaining a clean water supply for the ponds throughout the aquaculture production cycle.  

The discharged waste will enter the Wastewater Treatment Plant (WWTP) system which is designed with sedimentation plots with a zigzag flow pattern, an aeration pond, and a wetland pond. The zigzag system in the sedimentation plots functions to increase hydraulic retention time and improve the mixing process of wastewater from various ponds, thereby enabling sedimentation of suspended particles and reduction of the initial pollutant load before the water enters the next treatment unit. This increased retention time is known to play an important role in enhancing the efficiency of aquaculture wastewater treatment processes. 

The aeration pond subsequently functions to increase dissolved oxygen concentration and accelerate the oxidation of organic matter and nitrification, thereby helping to reduce ammonia concentration and stabilize water pH conditions. The aeration process also supports the activity of microorganisms involved in the transformation of nitrogen from ammonia into nitrate, which is relatively less toxic to aquatic organisms. This aeration-based and biological process wastewater treatment system is commonly applied in aquaculture waste management to improve water quality prior to discharge into receiving water bodies. 

The final treatment stage is carried out through a constructed wetland pond, which utilizes the interaction between plants, microorganisms, and substrate to remove pollutants through physical, chemical, and biological processes. Constructed wetlands have been widely used as an environmentally friendly and low-cost technology for aquaculture wastewater treatment, as they are capable of effectively reducing concentrations of nitrogen, phosphorus, organic matter, and suspended solids. Furthermore, the use of photosynthetic organisms such as seaweed in wastewater treatment systems has also been proven effective in absorbing nutrients such as nitrogen and phosphorus from the water, thereby reducing the potential for eutrophication in the ecosystem.  

Rationale for design: The WWTP design was developed by considering the physical conditions of the area and the operational characteristics of the extensive-intensive aquaculture system, which utilizes tidal dynamics as its primary water intake and discharge mechanism. The identified tidal flooding threat in the area formed the basis for establishing a uniform embankment elevation referencing the southern embankment as the minimum design standard, as validated through LiDAR data. Furthermore, the gate operational system was designed in a coordinated manner with two inlet points sourced from two main rivers, enabling a clear separation between the clean water intake phase and the harvest discharge phase, thereby ensuring that only wastewater generated from aquaculture activities enters the treatment system. 

The sequential arrangement of treatment units in the WWTP scheme reflects a tiered and complementary ecotechnology approach. The zigzag pattern in the sedimentation plots was designed to extend hydraulic retention time and facilitate the settling of suspended particles before water advances to the subsequent treatment unit. The aeration pond then functions to elevate dissolved oxygen concentration and support the nitrification process, thereby reducing ammonia levels in the wastewater. In the final stage, the wetland pond harnesses the interaction between plants, microorganisms, and substrate — including photosynthetic organisms such as seaweed — to absorb residual nutrients including nitrogen and phosphorus, ensuring that the effluent discharged into the receiving water body complies with the established quality standards.