Neni Sintawardani

Sustainable design of sanitation system based on material and value flow analysis for urban slum in Indonesia

Material flow analysis (MFA) and value flow analysis (VFA) were applied to the sanitation system in an urban slum in Indonesia. Based on the results of the MFA and VFA, garbage and excreta disposal costs were evaluated to be 0.7% and 1.1%, respectively, of per capita income. Such value flows seem reasonable in light of the recognized affordability to pay (ATP) standard. However, current excreta disposal methods create negative impacts on downstream populations. Because such disadvantages do not go back to disposers, but passed to downstream, the current value flow structure does not motivate individual toilet users to install treatment facility. Based on current material and value flow structures, a resource recycling sanitation system scenario was examined. Based on VFA, an affordable initial cost for such a system was calculated; this was found to be comparable in price to a cheaper composting toilet that is currently available in the market.

The organic agricultural waste as a basic source of biohydrogen production

Biohydrogen production research was carried out using raw materials of agricultural organic waste that was obtained from markets around the Bandung city. The organic part, which consisted of agricultural waste material, mainly fruit and vegetable waste, was crushed and milled using blender. The sludge that produced from milling process was then used as a substrate for mixed culture microorganism as a raw material to produce biohydrogen. As much as 1.2 kg.day−1 of sludge (4% of total solid) was fed into bioreactor that had a capacity of 30L. Experiment was done under anaerobic fermentation using bacteria mixture culture that maintained at pH in the range of 5.6-6.5 and temperature of 25-30oC on semi-continuous mode. Parameters of analysis include pH, temperature, total solid (TS), organic total solid (OTS), total gas production, and hydrogen gas production. The results showed that from 4% of substrate resulted 897.86 L of total gas, which contained 660.74 L (73.59%) of hydrogen gas. The rate of hydrogen production in this study was 11,063 mol.L−1.h−1.

The Concept of Resources Oriented Agro-Sanitation System and Its Business Model

This chapter proposes concept of the sanitation business model, based on the discussions; what is necessary to solve current world’s sanitation issue and what is the limitation of current sanitation concept. Proposed policy was on the basis of the Postmodern Sanitation concept; (1) discuss a sanitation value chain which create and add a value to human excreta and its products, and build a sanitation business model to drive this sanitation value chain, (2) design the sanitation business model focusing on incentive for individual toilet users, (3) analyze current user’s value chain to find available potential resources, (4) connect these potential sanitation resources to next value chain, (5) make a financial plan based on market analysis of sanitation product, (6) find and organize facilitating organization to support individual toilet users’ business. This concept was applied for the case of rural area in Burkina Faso, and reasonable agro-sanitation business model was designed based on material flow analysis and value flow analysis.

Experiment of a Resource-Oriented Agro-Sanitation System for Urban Slum Area: Case of Indonesia

This chapter describes case study of applicability assessment for resource-oriented agro-sanitation business for urban slum in Indonesia, based on interdisciplinary field survey, (1) economic feasibility assessment, (2) demand potential assessment, and (3) social acceptability. The value flow analysis evaluated garbage disposal cost and excreta disposal cost at 0.7 and 1.1%, respectively, of household income, which represents a reasonable cost to disposers. However, under the current disposal scheme, negative value due to excreta disposal to river appears to be passed on to downstream populations. The structure of this value flow indicates that little attention is paid to the negative externalities, indicating that a solution in this case may be difficult to obtain. The affordable initial cost of a new resource recycling system was evaluated and compared with the costs of a currently available compost toilet by evaluating equipment lifetimes and potential income streams available from the sale of human excrement fertilizers. To estimate a value for the human excrement fertilizer, real-world case study in Indonesia, in which money was paid in exchange for human urine, was referred to. The evaluated affordable initial cost derived was sufficiently comparable to the price of a cheaper composting toilet currently available in the market. This implies that such a resource recycling system is feasible even in an urban slum. Results of demand and supply assessment showed that if resource-oriented sanitation system was diffused, supply would excess demands in the circle of 32 km radius, therefore cost discussion should assume more than 32 km transportation. According to the results of case estimation of tea plantation, total cost for fertilizer provided by resource-oriented sanitation system is possibly competitive to the normal price of synthetic fertilizer. However, if compared to subsidized price for low-income farmers, it seems difficult to compete. Regarding social aspect, the context of Islamic law is important. Islamic authorities regarded the resource-oriented sanitation system as no problematic concept and acceptable in the context of Islamic law.

Strength analysis of 157 BQTN-EX materials for biogas reactor tanks

Anaerobic reactor tanks to process wastewater tofu factories to produce biogas fuel as a substitution fuel to cook were constructed. Wastewater from tofu factories is acid with pH of 5-6, therefore reactor was built by acid proof materials and reactor tanks must be coated by UV proof materials. The reactor tanks must resist to mechanical load due to either hydrostatic or gas pressure. The material that fulfill those requirements for reactor tank was 157 BQTN-EX and as the reinforce structure were C-Glass Woven Roving and ceramic fiber. The reactor tank has 250 cm in diameter, 400 cm in height, 60 cm dome height and 0.7 thicknesses. Reactor tanks were reinforced by rings and fins made by the same materials as the reactors tanks. Tensile strength of 157 BQTN-EX was 1,430 kg/cm2 and permissible strength was 170.2 kg/cm2. Reactor tanks contain 20 m3 of wastewater, 3,800 of cut bamboos and 3 m3 of biogas. Analysis of the strength at longitudinal direction was 153.7 kg/cm2, transversal direction was 91.82 kg/cm2 and dome strength was 66.96 kg/cm2. Therefore longitudinal, transversal and dome stress occurred were lower than permissible stress of 157 BQTN-EX materials. Hydrostatic test result at longitudinal was 2×10 -4% and transversal strain were 15×10 -5 %, the both strains are lower than 0.05% therefore the reactor structure will be strong and safe during operation.