Development and optimization of a waste management model for selected Sappi Saiccor laboratories

Abstract

The purpose of the study was to formulate a model that can improve waste minimisation, management, and remediation; with the goal of minimising risk to health of staff working in the targeted facilities and the environment of the Sappi Saiccor Laboratories. This model was based on waste generated by the chemical laboratories of a chemicals manufacturing company, namely, Sappi Saiccor Laboratories. The study employed both quantitative and qualitative (pragmatic) methods within a case study design. The quantitative aspects of the study involved both the solid and liquid waste streams generated in the laboratories. Sampling was conducted using a simple random method, which is part of probability methods. Eleven laboratory staff (50 percent of the total laboratory staff) participated in the laboratory analysis of the waste stream at the Sappi Saiccor laboratories. For the qualitative aspects of the study, the same eleven laboratory staff members participated via completion of preand post- assessment questionnaires regarding the development of a new model for waste management at Sappi Saiccor Laboratories. Probability methods of sampling were used to ensure the generated results were representative of the entire population. A pre-risk assessment questionnaire was designed, implemented and assessed to identify all gaps and areas of improvement of the current waste management system. The types of waste generated, and their current disposal or treatment methods were described in the questionnaire. The use of a piloted questionnaire before and after the implementation of the new waste management model showed an increased awareness in waste handling, treatment, and disposal on the part of the laboratory staff involved throughout the study. The results provide evidence that the creation and implementation of a waste management model at the Sappi Saiccor laboratories improved environmental awareness and personal safety of laboratory staff which lead to reduced risk on the people and the environment. Waste characterisation was possible through perusal of documented laboratory analysis methods, highlighting the major components of hazardous waste, alkaline waste, and toxic inorganic materials with corrosive characteristics. The largest quantities of generated solid hazardous waste comprised pieces of glass, used paper towels, and nitrile gloves impregnated with toxic hazardous substances. A labelling system was introduced and implemented, in addition to the use of colour codes to classify/categorise the generated waste. The staff from the Sappi Saiccor laboratories generating the waste recommended the treatment and recovery of chemical substances such as copper sulphate anhydrous (CuSO4) and potassium chromate (K2CrO4), using physicochemical techniques as opposed to the current practice of discarding into effluent channels without any form of pre-treatment. These are regarded as green alternatives designed to prevent damage to human health and the environment, as opposed to discarding the substances down the sink drain, situated under a fume hood. An integrated model for minimisation, management and treatment of waste was developed and the in-depth analysis concerning prediction of daily total laboratory waste generation at the Sappi Saiccor laboratories was performed to generate a multi-variable linear regression model for prediction of total waste. A multi-variable predictive model, which is a function of three independent parameters; number of people working per laboratory (Tp), number of laboratory tests performed per laboratory (Tt) and quantity of consumed chemical solutions per day (kg) (Tc) was developed. The main outcome of the predictive model suggested that the quantity of chemicals consumed per laboratory has the greatest effect or impact on the quantity of total waste produced. . The waste prediction methodology applied in this case study can be adapted in any other laboratory unit within Sappi Sulphite Mills or allied industries which use acid bisulfite process for the manufacture of 92-94% alpha cellulose. Indicator and/or parameter adjustments may be required to adapt this methodology prior to the organisation of waste management plans in other laboratories belonging to different companies.