Objectives

The primary objective is to establish a safe and efficient landfill gas extraction network at the Buffelsdraai Landfill. The project mitigates environmental and safety hazards posed by methane accumulation while ensuring regulatory compliance through the installation of durable pipeline infrastructure, monitoring systems, and proper waste gas management.

Scope of Work

The successful contractor will deliver the following:

• Site clearance, vegetation removal, and disposal of debris and obstructions.
• Excavation, shoring, and backfilling of trenches for underground pipelines.
• Installation of 450 mm HDPE pipework, including bends, couplings, valves, and sampling points.
• Construction and commissioning of biogas horizontal wells (underground drainage networks within landfill cells to collect gas and leachate).
• Connection to existing gas infrastructure and header stations.
• Reinstatement of access roads, subbase layers, and all disturbed surfaces to original or better condition.
• Implementation of odour control, dewatering, stormwater management, and temporary traffic control.

Technical Requirements

Tenderers must adhere to the following specifications:

• CIDB Grading: Minimum Grade 3 CE, a South African contractor classification denoting capacity for medium-scale civil engineering works.
• Pipeline & Materials: HDPE PE100 SDR 11 PN 16 pipes with gas-tight butt fusion or electrofusion joints. Systems must maintain 3–5% gradients to prevent liquid buildup and accommodate landfill settlement over a minimum 10-year lifespan.
• Valves & Fittings: Chemical-duty thermoplastic butterfly valves (10 bar rating, FPM seals, glass-reinforced vinyl ester, 316SS shaft) designed to resist corrosion from leachate and gas condensate.
• Testing & Quality Assurance: Air testing at 1.5× maximum suction pressure for 15 minutes. All acceptance control testing must be performed by an approved commercial laboratory. Mandatory as-built surveys upon completion.
• Safety & Environmental Controls: Strict compliance with the Occupational Health and Safety Act (Construction Regulations 2014). Prohibition of naked flames/smoking in operational zones due to methane risks. Leachate containment, daily trench closure, and dust/noise mitigation are mandatory.
• Procurement & Evaluation: 80/20 preference point system (80 points for price, 20 points for socio-economic goals like ownership and local presence). Minimum functionality score of 60 points required. Performance guarantees (5–10%) and 10% retention apply. Tender validity is 120 days.

Skills and Experience Requirements

Bidders must demonstrate verified capability and qualified resources:

• Corporate Experience: At least one successfully completed comparable project within the past decade. Comparable works involve buried pipeline installation, trench excavation, bedding, backfilling, and road reinstatement, valued at ≥70% of this tender’s estimate.
• Key Personnel: Detailed organisational chart and CVs required. Site Agent and Foreman must each hold a minimum of three years’ relevant experience, including similar projects. Evaluation rewards up to ten years of specialised track records.
• Planning & Methodology: Submission of a preliminary programme (bar chart), site-specific construction methodology, quality control plan, and plant/equipment inventory. Methodologies must address landfill-specific risks, including ground instability, leachate ingress, and rapid spoil disposal.
• Health & Safety Competence: Appointment of OHSA-compliant competent persons, including a Construction Supervisor, Safety Officer, and health & safety representatives. A site-specific Health and Safety Plan must be approved before work commences.
• Administrative & Financial Compliance: Active CSD registration, valid CIDB status, SARS Tax Compliance PIN, B-BBEE certificate, and cleared municipal rates. Audited financial statements required for tenders exceeding R10 million.