Sanitation Water Filtration Project in Zuarinagar, Goa: A Case Study

Project overview

Ocean Non Wovens supplied and installed 1000 SQM of Ocean HDPE Liner 2000 Micron for a sanitation water filtration project in Zuarinagar, Goa. The liner covers the base and walls of the filtration system so that contaminated water inside it cannot seep into the surrounding soil and groundwater.

• Location: Zuarinagar, Goa
• Product: Ocean HDPE Liner 2000 Micron (2 mm)
• Quantity: 1000 SQM, supplied and installed
• Application: Impermeable lining for a sanitation water filtration system

Why a sanitation system needs a liner

Wastewater in a treatment or filtration unit carries bacteria, organic matter and, near industry, chemicals and heavy metals. If the basin leaks, those contaminants move into the soil and groundwater. A welded HDPE geosynthetic liner is a continuous, practically impermeable barrier that keeps the water where the treatment process can deal with it. The liner itself does not filter anything; it contains the water so the filtration stage can work.

Objectives

• Stop contaminated water infiltrating the surrounding soil and groundwater.
• Give the filtration system a durable, impermeable lining.
• Keep maintenance low over the long term.

Site conditions

1. Industrial surroundings: Zuarinagar, near Vasco in South Goa, has several industries that add to the pollution load in local water.
2. Heavy rain and humidity: Goa gets a heavy south-west monsoon, and exposed parts of the liner face strong sun the rest of the year, so it needed good UV and weather resistance.
3. Loose soil: The ground had loose soil and erosion risk, so the liner needed good puncture resistance.

Why the 2000 micron HDPE liner

• Chemical resistance: HDPE resists a wide range of acids, alkalis, salts and organic contaminants found in wastewater.
• Durability: Carbon black in the resin gives HDPE good UV resistance, and at 2 mm the sheet stands up well to mechanical stress during installation and service.
• Very low permeability: Intact, welded HDPE lets practically no water through, so the system’s only losses are at defects, which is why seam quality matters.
• Thickness: 2 mm is at the heavy end of the common range (0.5 to 2.5 mm). The extra thickness adds puncture resistance on loose or stony ground, though it makes the sheet stiffer to handle than thinner grades.

For large lining jobs, HDPE geomembranes are commonly specified to GRI-GM13, which sets minimum values for density (at least 0.940 g/cc), tensile properties, tear and puncture resistance, carbon black content and stress-crack resistance.

Installation

Site preparation. The site was cleaned and the ground levelled so that stones and sharp edges could not puncture the liner.

Liner deployment. The 1000 SQM of Ocean HDPE Liner 2000 Micron was laid across the base and walls of the filtration system to form a complete barrier.

Welding and testing. Seams were joined by thermal fusion welding. HDPE seams are normally checked non-destructively: dual-track fusion welds by air-pressure testing of the channel between the two tracks (ASTM D5820), and extrusion welds and patches by vacuum box (ASTM D5641).

Results

• Groundwater protection: The liner stopped contaminants seeping into the surrounding ground.
• Low maintenance: A thick HDPE liner has a long service life, so the system should not need frequent repair or relining.
• Room to grow: The system can be extended or modified if treatment needs change.

Choosing a liner for wastewater

Thin or low-grade liners cost less up front but are more likely to fail early, leak and need replacing. Installation matters as much as the material: poor subgrade preparation, bad welds or a liner left under tension can all cause leaks.

• PVC liners: More flexible, but plasticisers leach out over time and exposed PVC degrades faster under UV.
• EPDM liners: Flexible and suited to smaller jobs, but they do not handle oils and many hydrocarbons well.
• HDPE liners: Strong chemical and UV resistance at low cost per square metre, which is why they are the usual choice for large sanitation and containment projects.

When comparing HDPE quotes for a job like this, our article on geomembrane cost per sq ft explains how sq ft, sq m and per kg rates relate and what each one includes.

Working with Ocean Non Wovens

Ocean Non Wovens supplies and installs HDPE liners and other geosynthetics for sanitation and water filtration projects such as this one in Zuarinagar. For a consultation or quote, contact us, or see related work on the case studies page.