Determining pollution levels using material balance methods.
At present, the Department of Environment in Bangladesh has limited financial and human capacity to carry out regular water analysis to monitor industrial pollution. Such analysis can be very expensive and complicated and there is lack of expertise and equipment facilities to conduct such water analysis. This research aims to assess the feasibility of using a material balance approach to try to determine pollution load generated by factories. This approach involves gaining a detailed understanding of production process and identifies where, and how much, pollution is generated in terms of inputs and outputs of those production processes.
The work was undertaken with factories undertaking winch dyeing in the project area, and tried to generate rough estimates of pollution loads generated by these firms and then to compare them to the results from detailed water analysis. The protocol for conducting material balance in the dyeing industry included collection of data from factory staff and management team. This was done through interviews, dialogues and questionnaires sent to seven factories. All these data were used to generate a profile on the inputs and outputs from the dyeing production process. Sampling was undertaken at various stages of the production process and composite sampling was done at the final discharge point. Water analysis was conducted for different parameters such as biological oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved solids (TDS), sulphate and various heavy metals. The values were then used to estimate total amount of wastewater generated and also pollution loads both in terms of concentration and weight.
The results show that there is great variation in terms of pollution loads depending on age of machinery, whether they are manual or automatic, and different shades of colour dyed. Dark colours and whites generate very different pollution loads.
Data were collected on the number and size of winch dyeing factories in the project area. Using a material balance approach it was possible to assimilate all this data and provide best guesstimate of the pollution load flowing into the local water body.
Final Research Report Section 3. 23 pp.