Revolutionizing Urban Sanitation: Engineering Resilience and Equity, 3 Cities (Pontianak, Semarang, and Mataram) in Indonesia

         Transforming lives through clean, resilient, and inclusive sanitation! The Citywide Inclusive Sanitation Project (CISP) aims to provide 2.5 million people in Pontianak, Semarang, and Mataram with safe, climate-resilient sanitation. Join us in bridging disparities, strengthening governance, and building sustainable systems to safeguard public health and promote national development goals. The project focuses on enhancing sanitation infrastructure, strengthening regulations, and improving institutional governance. In 3 Cities, Pontianak, Semarang and Mataram, a Project Implementation and Supervision Consultant (PISC) will :

(1)Assist in Design: Provide expertise in designing wastewater treatment plants (WWTP) and related infrastructure. (2) Supervise Construction: Oversee civil works and monitor WWTP performance during the operational testing phase. (3) Manage Procurement: Support tendering, procurement, and contract administration processes. (4) Ensure Safeguards: Monitor adherence to environmental and social safeguards per ADB guidelines. (5) Build Sustainability: Promote public awareness, engage communities, set tariffs, and build operator capacity for sustainable wastewater management.

The project addresses local needs through these targeted actions while aligning with national development goals for equitable sanitation access.

1. Introduction

The Citywide Inclusive Sanitation Project (CISP) transforms Pontianak, Semarang, and Mataram urban sanitation. By constructing advanced wastewater treatment plants and extensive sewer networks, CISP aims to provide safe, climate-resilient sanitation services to millions. This initiative enhances public health and fosters sustainable urban development, ensuring a cleaner, healthier future for all.

 The attachment Table 1 Citywide Inclusive Sanitation Project (CISP) Overview:  Pontianak, Semarang, and Mataram provide a concise comparison of the wastewater treatment project details for three cities: Pontianak, Semarang, and Mataram. This matrix highlights critical elements such as target outputs, WWTP locations, and project components, offering a structured view of the Citywide Inclusive Sanitation Project (CISP). By examining each city's system's unique features and capabilities, stakeholders can better understand the project's design philosophy focused on sustainability, efficiency, and community engagement. This table serves as a reference for decision-makers and engineers, emphasizing the commitment to sustainable urban sanitation solutions tailored to regional needs.

Table 1 Citywide Inclusive Sanitation Project (CISP) Overview:  Pontianak, Semarang, and Mataram

2. WWTP: Citywide Inclusive Sanitation Project (CISP)

2.1 Design Philosophy: Sustainability, Efficiency, and Community Impact

The wastewater treatment plants (WWTPs) designed for the Citywide Inclusive Sanitation Project (CISP) in Pontianak, Semarang, and Mataram embody a comprehensive design philosophy focused on achieving environmental sustainability, operational efficiency, and significant community impact. These systems are tailored to meet the unique requirements of urban sanitation, ensuring public health protection and environmental preservation.

2.1.1 Sustainability in Design

Sustainability is at the forefront of the design philosophy, prioritizing strategies that minimize energy consumption, chemical dependency, and greenhouse gas emissions. The WWTPs promote water reuse and resource recovery through renewable energy integration, such as biogas production from sludge digestion. For example:

• Pontianak: WWTPs at Nipah Kuning and Martapura, with capacities of 12,000 m³/day each, integrate co-treatment processes (100 m³/day) to optimize resource efficiency and facilitate potential resource recovery.
• Semarang: The Banjardowo WWTP incorporates a scalable biogas production system with an expandable co-treatment capacity (150 m³/day, expandable to 250 m³/day), supporting renewable energy goals.
• Mataram: The Tanjung Karang Sekarbela WWTP emphasizes low-energy designs for its 8,000 m³/day treatment capacity, aligning with the city's focus on sustainable development.

2.1.2 Efficiency and Flexibility

Operational efficiency is achieved through advanced treatment processes, robust pre-treatment, and reliable equipment, ensuring cost-effectiveness over the WWTP lifecycle. Key design elements include:

• Optimized sewer networks (e.g., 55 km in Pontianak, 111.6 km in Semarang, and 72.32 km in Mataram) to minimize maintenance and reduce inflow variability.
• Pilothouse connection programs in each city (1,500 in Pontianak, 4,352 in Semarang, and 4,000 in Mataram) ensure efficient initial implementation and provide scalability for broader coverage.
• Automation and monitoring systems, such as SCADA, improve operational reliability, allowing real-time flow rate adjustments and influencing quality variations

2.1.3 Community-Centered Approach

Understanding each location's socio-economic and geographical context is integral to the design process. The following considerations ensure that systems align with local needs:

• Regionally Appropriate Technologies: Materials and technologies are selected to match each city's climatic and geographic conditions, ensuring resilience and compatibility.
• Stakeholder Engagement: Regular consultations with local communities address concerns such as aesthetics, noise, and odours, fostering public support and acceptance of the projects.
• Economic Accessibility: Subsidized house connections funded by local budgets (e.g., 6,000 in Pontianak, 10,000 in Semarang, and 9,500 in Mataram) reduce financial barriers for low-income households.

2.1.4 Advanced Sludge Management

Effective sludge management is a cornerstone of the design philosophy, focusing on safe disposal or beneficial reuse. It includes:

• Composting to support local agriculture.
• Energy recovery is achieved through anaerobic digestion, which produces biogas for power operations or contributes to the local energy grid.
• Coordinated disposal strategies to prevent environmental contamination.

2.1.5 Integration with Sustainable Development Goals (SDGs)

The WWTP designs align with global SDGs, specifically goals related to clean water and sanitation (SDG 6), affordable and clean energy (SDG 7), and climate action (SDG 13). Combining innovative engineering, stakeholder engagement, and sustainability principles, the CISP WWTPs ensure long-term resource stewardship and contribute to healthier, more resilient urban environments.

The design philosophy ensures regulatory compliance and environmental protection, fosters community well-being, and supports sustainable urban development across Pontianak, Semarang, and Mataram.

2.2 Methodology Review: Design-Build Approach for WWTP

The design-build review methodology for wastewater treatment plants (WWTPs) emphasizes sustainability, efficiency, and community impact, which are critical for ensuring that projects meet regulatory requirements and enhance public health and environmental protection. The Conventional Activated Sludge (CAS) process has been selected for the WWTP in 3 Cities  (Pontianak, Semarang, and Mataram) due to its established effectiveness in treating municipal wastewater and its ability to meet environmental standards. This choice aligns with the overarching goals of the project, which include providing safe and sustainable sanitation services to the local community while minimizing environmental impacts (Lazar et al., 2021; Romero et al., 2016). The review Design and building are :

1. The project overview for the WWTP design-build review highlights the importance of constructing climate-resilient facilities and sewer networks. The Comprehensive Integrated Sanitation Plan (CISP) aims to deliver sustainable and inclusive sanitation services to improve the project cities' public health and environmental quality. By ensuring that the design-build review approach adheres to technical, environmental, and operational standards, the project can effectively contribute to these goals (Lazar et al., 2021). The methodology employed in the design and construction phases is crucial for achieving the desired outcomes, as it ensures that all components of the WWTP are designed and built to the highest quality standards (Lazar et al., 2021; Semblante et al., 2014).
2. The preliminary assessment conducted for the WWTP project in 3 Cities  (Pontianak, Semarang, and Mataram) indicates that the initiative is technically, economically, and environmentally feasible. This assessment considers various factors, including geographical, environmental, and socio-economic considerations, vital for understanding the project's context. The feasibility evaluation confirms that the project aligns with regulatory requirements and sustainability goals, making it a valuable investment for the region's future (Lazar et al., 2021). Such comprehensive assessments ensure that the project can deliver long-term benefits to the community while minimizing adverse environmental impacts (Lazar et al., 2021).
3. In the design development phase, the project follows a structured approach that includes conceptual and detailed engineering designs. The conceptual design phase outlines the basic layout and components of the WWTP and sewer network, ensuring that they align with project objectives and environmental considerations. The detailed engineering design phase provides comprehensive specifications for all technical components, ensuring the project is ready for construction and meets all necessary regulatory requirements (Lazar et al., 2021; Semblante et al., 2014). This phased approach is critical for ensuring the project is systematically developed and implemented, leading to successful outcomes (Lazar et al., 2021).
4. The Environmental and Social Impact Assessment (ESIA) is a vital component of the WWTP project in 3 Cities  (Pontianak, Semarang, and Mataram), as it helps to identify potential environmental and social impacts associated with the project. The project can minimize adverse effects by developing comprehensive mitigation measures while enhancing positive outcomes for the local community. Engaging stakeholders throughout the project lifecycle fosters transparency and builds trust, ensuring that the project meets the needs and expectations of the community (Lazar et al., 2021). This stakeholder engagement is crucial for achieving community acceptance and support for the project, which is essential for its long-term success (Lazar et al., 2021).
5. Construction planning for the 3 Cities  (Pontianak, Semarang, and Mataram) WWTP project involves developing a detailed project schedule and resource allocation plan. The project schedule outlines each phase's timeline, including design, procurement, construction, and commissioning. This systematic approach implements the project efficiently and effectively, while the resource allocation plan ensures that labour, materials, and equipment are managed effectively to meet project requirements (Lazar et al., 2021). This comprehensive plan allows the project to achieve its objectives within the specified timeline and budget while minimizing environmental and social impacts (Lazar et al., 2021).
6. The construction phase of the WWTP project is divided into distinct phases to ensure systematic and efficient implementation. Each phase includes specific activities and milestones, from planning and design to site preparation, construction, commissioning, and monitoring. This phased approach allows for careful management and oversight of all aspects of the project, ensuring that it is completed successfully and operates effectively (Lazar et al., 2021). Engineers closely monitor the construction phase to identify and resolve potential issues before they escalate(Lazar et al., 2021).
7. The commissioning and handover process for the WWTP project in 3 Cities  (Pontianak, Semarang, and Mataram) involves thorough testing and verification of all systems and comprehensive training for local operators. It ensures that the WWTP operates efficiently and meets all design and regulatory requirements, providing sustainable and reliable sanitation services to the community (Lazar et al., 2021). The formal handover to relevant authorities is a critical step in ensuring that the project is integrated into the local sanitation infrastructure and continues to operate effectively (Lazar et al., 2021).
8. The WWTP's operational plan and maintenance schedule In 3 Cities  (Pontianak, Semarang, and Mataram), the design ensures the efficient and reliable operation of the plant and sewer networks. By following these guidelines, the WWTP will meet regulatory standards, minimize downtime, and extend the lifespan of its assets, thereby providing sustainable and adequate sanitation services to the community (Lazar et al., 2021). We must emphasize the importance of ongoing maintenance and operational efficiency as these factors directly impact the long-term success of the WWTP and its ability to serve the community effectively (Lazar et al., 2021).

The design-build review methodology for the WWTP project in 3 Cities  (Pontianak, Semarang, and Mataram) is a comprehensive approach emphasizing sustainability, efficiency, and community impact. By carefully considering all aspects of the project, from preliminary assessments to design development, environmental and social impact assessments, construction planning, and operational strategies, the project can effectively meet its goals of providing safe and sustainable sanitation services to the local community while minimizing environmental impacts. The successful implementation of this methodology will contribute to improved public health and environmental protection in 3 Cities  (Pontianak, Semarang, and Mataram) and the surrounding areas (Lazar et al., 2021).

Below (Table.2) is a comprehensive matrix based on the methodology for reviewing the design and building of the Wastewater Treatment Plant (WWTP) in 3 Cities  (Pontianak, Semarang, and Mataram). It includes stages, key criteria, process requirements, and essential actions.

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