Data Collection and Audit Preparation. Lecture 10

Transcription

1 Data Collection and Audit Preparation Lecture 10

2 Operations personnel should be asked for input as they are close to how processes actually run (not necessarily how they can and should run) and can provide valuable and pertinent information. Specialists and staff from different areas should be consulted or co opted as and when necessary. The second important pre audit step is for the team to access, assemble and review site information in order to gain a good understanding of the processing operations of waste generation. Information should be obtained on the processes, raw materials, production schedules, wastes streams, operating costs, environmental reports, permits and company policies.

3 Table shows the area of expertise required for input or inclusion in the assessment team depending on the objectives of the assessment.

4 Waste Audit The audit phase of the waste minimization involves going into the plant to confirm information, collect additional data and develop a detailed and practical understanding of how and where the waste streams are generated. This is accomplished in following four steps: 1. Site investigation 2. Construction of process flow diagrams 3. Definition of process inputs and outputs 4. Material balance Firstly, the unit operations in the plant are investigated and process flow diagrams checked or developed as necessary. Once all the unit operations are designated and interconnections established the next step is to account for material flows into and out of these units.

5 Inputs can include raw materials, chemical, reused material, process water, steam and power, while outputs can include primary products, co products, waste to be reused, waste requiring disposal and emissions. The inputs and outputs need to be quantified and if sufficient information were not available from the pre audit data collection then in plant measurements and characterization would be required. A wastewater sampling program should be planned carefully and cover the full range of plant operating conditions, e.g. startup, changeover and shutdown. Wastewater flows can be easily determined if water meters are installed, otherwise pump curves/ times and manual measurements can be used. Overall, waste quantities are recorded in waste manifests but additional measurement may be required in plant to establish the amounts and characteristics of wastes generated in specific areas. Once the material inputs and outputs around a process have been established it is useful to try and construct a material balance to confirm data and highlight information gaps and inaccuracies.

6 Table shows assessment and information that can be used in the waste audit and assessment. It is unlikely that the plant data will be complete and information gaps will need to be identified and filled during the audit stage.

7 Identification of Waste Minimization Alternatives From the information accumulated in the waste audit, and the observations made by the assessment team while examining the plant in detail, a number of waste minimization alternatives may be identified. These can range from obvious and easily implemented measures to longer range and more sophisticated alternatives. Furthermore, problem waste streams can also be identified. These can include, for example, waste that are particularly expensive to dispose of and wastes that affect treatment plant efficiency.

8 It is the responsibility of the assessment team to evaluate and screen the waste minimization alternatives identified from the audit and priorities in relation to the assessment objectives and other selected criteria such as cost and ease of implementation. The waste minimization options should then be allocated into priority grouping in order to guide the effort for the subsequent feasibility analysis. Source reduction is a good operation practice as it avoids or minimizes the generation of waste. These options therefore generally have a high priority. Recycling allows waste materials to be put to beneficial use but involves significant effort or high cost and therefore receives low priority.

9 Feasibility Analysis The number of waste minimization alternatives taken to the feasibility analysis stage will be dependent on the time and resources available for the program. Waste minimization alternatives should be evaluated in terms of technical and economic feasibility. As discussed earlier, procedural or housekeeping changes can often be implemented directly at minimal cost after appropriate review and training. Options that involve process and/ or equipment changes are likely to be more expensive and may affect production rate and quality. These options therefore require a more detailed analysis and may need field testing.

10 Technical criteria that need to be considered for the purpose of feasibility include: 1. Safety 2. Product quality 3. Compatibility with existing production 4. Labour requirements 5. Environmental effects The economic evaluation of waste minimization alternatives should be carried out using the company's preferred methods but generally involves a cost/benefit analysis. Payback periods are commonly used to assess economic feasibility of waste minimization projects.

11 WASTE ASSESSMENT REPORT To complete the waste minimization assessment it is necessary to document the information and conclusions of the study in an assessment report. This should include: 1. A summary of background information 2. Results of the waste audit 3. Results of the waste minimization assessment 4. Technical and economic analysis of the waste minimization alternatives 5. Recommendations and priorities for implementation of waste minimization measures

12 MONITORING AND RE-EVALUATION That the waste minimization effort does not finish with the issuing of the assessment report. It will be necessary to monitor the success of the measures taken, give feedback to the assessment team and employees, and maintain general awareness and enthusiasm for the programme. Finally, the waste minimization program should be dynamic. It will need to be reviewed and reevaluated in response to changing circumstances such as changes in production, new regulations and dvances in technology. Thus the team leader should continue to champion waste minimization to meet these changing needs.