Over the years 1960-1975, a derelict sand mining pit was used as a landfill for hazardous waste, mainly phenolic pitch residues, “Rezokol” glue containing post-phenolic sodium sulphite, dye production waste and dye intermediates. Today, it constitutes the central section of the “Zielona” landfill complex. An estimated 82,000 tonnes of waste have been deposited on a site approximately 4 hectares in size. Coupled with disorderly waste depositing, the lack of any kind of landfill structuring plan made it difficult to identify separate occurrence areas for different waste types. Archival data allowed the presence of tarry residues, mazut and production residue tar to be identified on the bottom of the landfill. The north-western section of the former pit is filled with dyes, post-phenolic sulphite, rags and waste paper, construction debris filling the central and east sections.

The derelict pit continued to be filled until the day the hazardous waste landfill on Lisia street was opened for use, and the post-phenolic sodium sulphite utilising technology introduced.

Over the years 1984-1994, the former hazardous waste landfill was converted into an incineration yard for non-hazardous waste and special-purpose production hazardous waste (such as waste nitro compounds), and a burn site for rubber-coated appliances and fittings. The yard was duly liquidated for reasons of missing substrate insulation and leachate drainage, and – primarily – the lack of air pollution preventive measures.

The overall thickness of the waste layer deposited at the “Zielona” landfill on the former pit site has been estimated at approximately 15 m. Waste deposited on-site included hazardous waste, non-hazardous waste and inert waste. After the landfill had been formally shut down, non-hazardous waste was deposited in peripheral site sections in a disorganised manner, all matter backfilled with debris.

On-site studies of the soil-and-aquatic environment suggest that the central section of the “Zielona” waste landfill complex, substrate included, is indeed the most heavily contaminated area.

Location sketch for the “Zielona” waste landfill complex (to a drawing by Pietrucin, 2015)

Over the years 1987-1991, an Isolated Sludge Landfill was developed west of the incineration area, partly on site of the former sand pit (for a detailed description, see Point of Interest No. 2 of the Educational Virtual Tour).

Works to build a general-purpose non-hazardous waste dump east of the incineration yard began in 1989. The area between Zielona and Wypaleniska streets (1.3 hectares in size) was adapted for new purposes by developing a drainage basin beneath the landfill bottom, at an elevation of 58 m ASL.

Archival data suggests that the new non-hazardous waste landfill with a capacity of 65,000 m³ was overfilled by the year 2000, waste deposits reaching 3 m AGL.

Given the dump overfill condition, a decision was made to recultivate it. In all probability, all production waste other than non-hazardous deposited at the site was mixed with less voluminous waste from semi-technical production, and from two waste incineration stations. Chemical analysis results for on-site soil and groundwater point to trace presence of substances associated with waste generated in fungicidal compound (chlorophenol) production, and by heat exchangers and/or raw material (glycol) residue. Under another potential scenario, some of the waste stored at the landfill could have been owned by entities other than the “ZACHEM” S.A. Chemical Plant or its legal predecessors.

According to a due diligence* report commissioned for the “Ciech” S.A. Group in 2006, the majority of all waste – post-phenolic sodium sulphite, dye production waste, dye intermediates and limestone grit – had been transported off the landfill as part of an effort to recultivate the central section of the “Zielona” waste landfill complex and its former incineration yard.

WASTE INVENTORY FOR THE “ZIELONA” LANDFILL according to the DUE DILIGENCE REPORT (2006)

Type of waste		Waste volume [Mg]
1.	Post-phenolic sodium sulphite	51,400
2.	Post-phenolic pitch	2,300
3.	Dye production waste and dye intermediates	19,600
4.	Limestone grit	3,200
TOTAL:		76,500

*A due diligence audit is a comprehensive examination of the condition of an enterprise, generally commissioned by a third-party investor interested in purchasing a business and thus in checking whether the offer is truly favourable. The audit extends to the whole enterprise with a view to provide a holistic picture of the same. It is carried out by external specialists.

Having purchased a part of the “ZACHEM” S.A. Chemical Plant site, the “Ciech” S.A. Group proceeded to liquidate heavily contaminated land, and eliminate 19,000 Mg of chlorophenols in the vicinity of the “Zielona” waste landfill complex. Ex situ remediation was duly carried out along the south-western section of the “Zielona” waste landfill complex, the exercise involving treatment of all soil excavated outside the waste area.