Challenge

Gadot Petrochemical Industries on the Kishon River in northern Israel needed to clean up wastewater discharge to meet new government standards and help protect the river, a stream the Israeli government had targeted for restoration. The wastewater was complex organically, containing organic acids and hydrocarbons, and exhibited wide variations in concentration and composition. COD ranged as high as 3,600 mg/l, and BOD topped 1,500 mg/l. Oil and grease were present, also. Previous treatment included an API separator for oil and grease removal, and a pond for pH control.

Solution

Siemens Water Technologies successfully pilot-tested a PACT system at the site for six months in 1990, in conjunction with Y. Lebel Consulting Engineers of Tel Aviv; Raveh Ecology, Haifa; and Invirotreat International of London. The test indicated high quality results in all reactors, including:

• 95 percent removal of COD, and
• 98 percent removal of BOD.

The full-scale system consists of  oil-water separation, equalization in the pond, then treatment in two single-stage aerobic PACT systems, operated in parallel. Flow is 75,000 to 100,000 gallons per day. 

In the PACT system, powdered activated carbon and activated sludge work together to achieve a high degree of treatment. Biodegradable and non-biodegradable contaminants are treated simultaneously and the biomass is protected from upsets. Following clarification, the treated water is discharged to the Kishon River.

Results

As a result of the new PACT system, effluent from Gadot meets the new requirements and protects the river: 

• 95 percent COD, BOD removal
• Waste solids thicken and dewater to 40-50 percent solids concentration
• 10 percent less in capital cost than conventional biological treatment
• Smaller footprint than activated sludge
• Significant savings in operational costs, including personnel time and costs.