CHAPTER 4 REVISION OF GUIDELINES VOL.1 PARTS B & C The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report CHAPTER 4 REVISION OF GUIDELINES VOL. 1 PARTS B & C 4.1 Discrepancies in the Current Catchment Strategy Reports The following discrepancies were identified for correction upon revision of the existing catchment strategy reports. (1) Outline of Catchment Study Report This issue relates to the format of a catchment study report. While the current catchment reports contain a summary checklist of the catchment strategy reports, it does not include basic information such as catchment name and present connection PE. (2) No Link between Sewerage Development Effects and Catchment Strategies This issue relates to the content of the report. Current reports focus on the location of new STP sites, routes of new sewers, and the development of the sewerage system, but the effects of sewerage development on effluent-receiving rivers are neither mentioned nor examined. Therefore, the objectives for the sewerage system and its implementation are unclear. (3) Current Analytical Approach for Catchment Strategies This issue relates to the analytical approach of catchment plans. The current Guidelines show the general procedural scheme for developing sewerage catchment plans, but this scheme combines or blends what to do and what to consider. Since different developers use different approaches for catchment plans, comparing and evaluating these catchment strategies becomes complex. (4) No Consideration for Local Water Conservation This issue relates to constraints in identifying catchment strategies. The concept of local water conservation does not exist in the current Guidelines. (5) No Quantitative Analysis on Sludge Management This issue relates to financial analysis. Current catchment reports do not perform quantitative analysis on sludge management. Therefore, the evaluation of sludge management with the selected catchment strategy has no quantitative basis. (6) Revenue is not considered in the NPV calculation, and O&M costs are calculated using a percentage of capital costs These issues relate to financial analysis. Developers are currently requested (based on the Guidelines) to calculate NPVs of options only for capital and O&M costs. O&M costs are 4-1 The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report often set as a certain % of capital costs. Therefore, in the event that an option is prioritised based on NPV, the option with the lowest capital costs tends to be assigned a higher priority. This is a reason for construction of more smaller-sized STPs in the catchment area. 4.2 Revisions Introduced into Guidelines Vol. 1 The following items have been proposed to address current discrepancies. (1) Outline of Catchment Study Report Inclusion of a summary sheet containing the outline of the study report in Part B Section 3 The Structure of a Catchment Strategy Report is recommended. Anticipated content is as follows: • Catchment name • Catchment area • Water use conditions • Population • Number of water borne disease cases • PE projection • Connected PE • No of water intake points • Number of STPs without project and with project • First STP commission year • Number of upstream STP without project and with project • Discharge pollution load per unit of area without project and with project • Quality of received water without project and with project • Reduced pollution load without project and with project • Capital cost • Total O&M cost • Project net present value • B/C value In the summary sheet, results with the projects or without the projects are presented in order to compare the effect of sewerage catchment strategies. Since this summary sheet is used not only for the catchment report but also for prioritisation of the catchment’s projects, a re-evaluation of content will be conducted to reconcile the required data with the prioritisation after trial application of the manual for prioritisation. (2) Link the Effect of Sewerage Development to Catchment Strategies Use of BOD5 pollution load as a major factor in considering sewerage development is 4-2 The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report proposed. In formulating catchment strategies, current and future discharged BOD5 pollution loads are calculated to show the effects of sewerage development. Figure 4.2.1 shows an example usage of BOD5 pollution load. The effect of sewerage development is expressed as a decrease in the BOD5 pollution load. 350 300 250 Pourflush 200 IST 150 Private STP Public STP 100 50 BOD Discharge Pollution Load, kg/d 0 Present Future Figure 4.2.1 Example Usage of Pollution Load The alternatives are evaluated by utilizing metrics measuring modified pollution load, such as pollution production load per unit of area, reduction of pollution load per unit of area, and cost per unit of reduced load. Table 4.2.1 shows the example of alternatives described in Appendix E. Table 4.2.1 Example Evaluation of Sewerage Alternatives Pollution Reduction in Reduction cost Zone production load pollution load Alternative Kg as BOD5/ha Kg as BOD5/ha RM/kg as BOD5 A High High High Decentralization Decentralization or B High Low Medium - Low connection to another STP C Low Low High On-site D High High Low Connection to another STP E Low Low Low Connection to another STP (3) Analytical Approach for Catchment Strategies The following scheme or steps are proposed to better analyse catchment strategies. See Figure 4.2.2. 4-3 The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report Identify planning area Define catchment boundaries Identify land use and development profiles PE forecasts Identify alternative sewerage strategies Technical, financial, and environmental evaluation Select and optimize sewerage system Staged implementation scheme The first four steps are involved in collecting (and calculating) background information on the catchment study area. Alternative sewerage strategies are then formulated in this step by using background information. In the next two steps, technical, financial and environmental evaluations of each strategy (option) are conducted. Finally, the preferred option is implemented in phases. Figure 4.2.2 Analytical Approach for Identification of Appropriate Sewerage and Sludge Management Schemes 4-4 The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report (4) Local Water Conservation When river flow is low, the risk of river dry-out exists due to the change in the discharge point after sewage is collected at a single large STP. Therefore, introducing local water conservation efforts is recommended to prevent dry-out of the river due to the change in the discharge point of treated water in Section 6 Issues and Constraints. Figure 4.2.3 shows an example of local water conservation. Multi-Point Discharge System Centralized Discharge System A multi-point discharge system favors a river with A centralized discharge system favors a river with flow mostly composed of domestic sewage effluent. flow that does not rely primarily on domestic sewage effluent. Figure 4.2.3 Example of Local Water Conservation (5) Sludge Management For purposes of quantitative analysis of sludge management, typical sludge production data and an example of sludge management alternatives are presented. Sludge production is calculated based on the sludge generation rate as shown in Guidelines Vo l . 4 . Table 4.2.2 presents the typical sludge production for mechanized plants included in Section 5.6 Sewage Sludge Quantification. An example of sludge management alternatives is presented in Section 7 Identification and Assessment of Optional Sewerage Management Strategies to show how to analyse the sludge management. Onsite and centralized strategies are explained using schematic diagrams and financial considerations are presented (Figure 4.2.4). 4-5 The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report Table 4.2.2 Typical Sludge Production for Mechanized Plant Dewatered Dewatered PE Produced sludge PE Produced sludge sludge sludge (m3/day) (m3/day) (m3/day) (m3/day) 2,000 8.1 0.41 31,000 125.6 6.28 2,500 10.1 0.51 32,000 129.6 6.48 3,000 12.2 0.61 33,000 133.7 6.68 3,500 14.2 0.71 34,000 137.7 6.89 4,000 16.2 0.81 35,000 141.8 7.09 4,500 18.2 0.91 36,000 145.8 7.29 5,000 20.3 1.01 37,000 149.9 7.49 5,500 22.3 1.11 38,000 153.9 7.70 6,000 24.3 1.22 39,000 158.0 7.90 6,500 26.3 1.32 40,000 162.0 8.10 7,000 28.4 1.42 41,000 166.1 8.30 7,500 30.4 1.52 42,000 170.1 8.51 8,000 32.4 1.62 43,000 174.2 8.71 9,000 36.5 1.82 44,000 178.2 8.91 9,500 38.5 1.92 45,000 182.3 9.11 10,000 40.5 2.03 46,000 186.3 9.32 11,000 44.6 2.23 47,000 190.4 9.52 12,000 48.6 2.43 48,000 194.4 9.72 13,000 52.7 2.63 49,000 198.5 9.92 14,000 56.7 2.84 50,000 202.5 10.13 15,000 60.8 3.04 16,000 64.8 3.24 17,000 68.9 3.44 18,000 72.9 3.65 19,000 77.0 3.85 20,000 81.0 4.05 21,000 85.1 4.25 22,000 89.1 4.46 23,000 93.2 4.66 24,000 97.2 4.86 25,000 101.3 5.06 26,000 105.3 5.27 27,000 109.4 5.47 28,000 113.4 5.67 29,000 117.5 5.87 30,000 121.5 6.08 4-6 The Study on Improvement of Planning Capability in Sewerage Sector in Malaysia Final Report Onsite Strategy Centralized Strategy Figure 4.2.4 Example of Sludge Management Alternatives (6) Financial Analysis To improve financial analysis, the following tactics are recommended: 1) Introduction of tariff revenue in addition to costs for financial analysis 2) Proper setting of O&M costs for each treatment system By introducing revenue and by estimating the O&M costs properly, the option of a larger STP may have a greater chance of selection as a priority project.