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LCA Case Study: Sachet vs PET Bottled Water (Lagos)

Designing a cradle-to-grave comparative lifecycle model to inform packaging policy and urban sustainability decisions.

Project Type: Sustainability Research & Systems Modelling
Year: 2026
Institution: Susbridge

Single-use water packaging dominates urban consumption in Lagos, with sachet water and PET bottles serving millions daily. Despite widespread use, limited transparent, locally contextualized lifecycle evidence exists to guide policymakers, producers, and sustainability advocates.

This project developed a cradle-to-grave Life Cycle Assessment (LCA) comparing sachet water and PET bottled water using a functional unit of 1 litre consumed. The study combined deterministic modelling, sensitivity analysis, and Monte Carlo-style uncertainty assessment to evaluate climate impact, water depletion, and cumulative energy demand. Beyond technical modelling, the project translated findings into policy-ready insights and interactive decision tools.

1. Develop a Transparent Cradle-to-Grave LCA Model

Constructed a full system boundary covering raw material extraction, packaging production, filling operations, transport, consumption, and end-of-life under Lagos-specific assumptions. The model quantified GWP, water depletion, and cumulative energy per 1 L delivered.

2. Integrate Sensitivity & Uncertainty Analysis

Implemented scenario testing and Monte Carlo-style uncertainty ranges to evaluate robustness across recycling rates, packaging mass changes, and mismanaged waste shares.

3. Identify Impact Hotspots

Disaggregated lifecycle contributions to determine which stages—packaging production, filling energy, transport, or end-of-life—drive environmental burden.

4. Translate Results into Policy & Strategy Outputs

Converted technical outputs into policy memos, visual dashboards, and scenario tools to support decision-makers, NGOs, and sustainability communicators.

1. Climate Impact (GWP)

 Sachet baseline: 0.0425 kg CO₂-eq/L
 PET baseline: 0.0897 kg CO₂-eq/L
Sachet water currently demonstrates lower climate impact per litre consumed under Lagos default assumptions.

2. Water & Energy Intensity

 Water depletion: 12.4 L (sachet) vs 82.6 L (PET)
 Cumulative energy demand: 0.592 MJ/L (sachet) vs 1.912 MJ/L (PET)
Sachet systems show significantly lower resource burden.

3. Hotspot Drivers

 Packaging production is the dominant driver in both systems (38–56% of GWP).
 End-of-life mismanagement significantly affects outcomes.
 Transport contributes minimally under current assumptions.

4. Policy Levers Identified

 Lightweighting packaging offers the strongest cross-system impact reduction
 Increasing PET recycling to 50% substantially lowers its GWP.
 Reducing sachet open-burning rates improves performance margins.

Overall Insight

This study provides one of the few localized, reproducible lifecycle comparisons of sachet and PET water in Lagos. By combining technical rigor with communication design, the project bridges the gap between lifecycle modelling and actionable sustainability policy.

It demonstrates how urban packaging debates can move from opinion-driven narratives to quantified, scenario-tested environmental evidence.

The project includes a Scenario Studio dashboard, enabling live adjustment of:

 PET recycling rates
 Packaging mass multipliers
 Sachet mismanaged/open-burn shares

This transforms the LCA from a static academic output into a decision-support tool.

Life Cycle Assessment (LCA)
Life Cycle Inventory (LCI) development
LCIA modelling
Monte Carlo uncertainty analysis
Sensitivity modelling
Policy translation & science communication
Data visualization & interactive dashboard design