Waste to wealth: The use of plastic waste to produce cheaper and better interlocking paving blocks

Nigeria is the largest waste generator in Africa, generating about 2.5million-tons/annum, with Lagos, the major culprit of the 36 states. 70% of plastic waste that ends up in landfill gets burnt to reduce volume for increased landfill capacity. 60% of Lagos' 18million population live in slums and below $1/day. Waste-pickers collecting plastics (sort/wash/pack) to sell to recyclers is a common sight in landfills. Lagos state supports the picking due to its desire to increase recycling. However, with few recyclers and too many pickers, supply is outpacing demand leading to ridiculously low prices of around 15naira/kg (i.e. 3-pence) of sorted/washed/packed waste plastics.

Popularly used for community-roads, driveways, parking areas, airports, etc., interlocking paving blocks market in Nigeria is worth over 3-millions dollars (Market Publishers 2018). They are cement based and mostly only affordable to rich people/communities or governments due to high costs. Production also consumes natural resources with high cost and embodied carbon (lime through cement, and sand). This project seeks to develop more affordable interlocking paving blocks, produced from recycling 'unwashed' plastic and little sand with u.v. stabilisers to prevent degradation. This will lead to higher prices for 'unwashed' plastics and support better/safer/healthier/more-estimable means of plastics aggregation.