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Wastewater treatment plant for the surgical gloves industry

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Year 2021

Project location Ansell Portugal - Industrial Gloves, Sociedade Unipessoal, Lda, Portugal. 

Objectives

  • Full wastewater treatment for WATER REUSE. · 
  • Adaptation to possible future modifications of the manufacturing facilities. · 
  • Treatment of the generated sludge.

Installed technologies Drum screen for coarse solids removal. Preparation tanks for pH adjustment, coagulant preparation and polyelectrolyte preparation. Coagulation-flocculation system SIGMA PFL. Dissolved air flotation clarifier SIGMA DAF- FPAC. Compact membrane bio-reactor SIGMA SMBR with ULTRAFILTRATION membranes. Sludge treatment with filter press.

Reactives Physical chemical process is based on the addition of a coagulant agent to aggregate the solid matter and separate it from the liquid phase plus a flocculant agent (polyelectrolyte) to form larger flocs that are easily separated in a dissolved air flotation system. pH adjustment is done with the addition of NaOH to pH around 7.0.

Coagulant synthetic coagulants are recommended, specially poly-aluminium-chloride or similar.

Flocculant anionic polyelectrolyte is recommended, with medium to high molecular weight.

Background

ANSELL is a leading company in the surgical gloves manufacturing sector. It has facilities for its gloves manufacturing that requires a complete treatment for wastewater. The main objective is obtaining WATER WITH HIGH QUALITY FOR REUTILIZATION. The wastewater is characterized by high content in total suspended solids with blue colour that, when not treated properly, brings clogging and other problems related with environmental pollution. The wastewater also has a high COD associated to these solids, a physical-chemical separation of the solids is the most efficient solution. Soluble COD is highly biodegradable and is removed with a biological treatment.

The pre-treatment consists of large solids removal with drum screen, a homogenization tank specially configured to maintain the wastewater in constant movement so the blue solids do not settle, all followed by a SIGMA PFL coagulation-flocculation system. SIGMA PFL is an in-line system that allows to effectively aggregate the solid matter. The aggregated matter is forming flocs that will be 

removed from the water in a dissolved air flotation system SIGMA DAF model FPAC. The clarified water from the SIGMA DAF-FPAC has a high quality almost completely free of suspended solids, turbidity and COD. The clarified water is pumped into the biological treatment for polishing. 

The SIGMA SMBR process (‘membrane bio-reactor system’) consists of a compact and high efficient biological treatment, the process takes place in a compact reactor when an anoxic zone, aeration chamber and ultrafiltration chamber are built-up in the same equipment. Applying ultrafiltration membranes as clarification allows to achieve very high biomass concentration inside the reactor, between 6000 – 12000 mg/L MLSS. The SIGMA SMBR is a modular plant that can be upgraded by adding additional ultrafiltration modules. The effluent from the treatment has a high and constant quality, making the water suitable for REUSE. 

The sludge generated is treated with a filter press. 

        Wastewater characteristics
CODTSS
22000 mg/L 20000 mg/L 


 

Physical-chemical removal efficiency (Sigma PFL + Sigma DAF-FPAC)
CODTSS
90%  99.5% 

 

Full treatment removal efficiency 
CODTSS
99.3%99.9%


Process diagram 

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