Innovative technologies for decentralised water-, wastewater and biowaste management in urban and peri-urban areas

Abstract

Avoiding the comingling of water flows coming from different sources and thus obtaining flows with a very low dilution factor is the first and major step key to technical solutions for adequate treatment of household wastewaters. Through their decentral structure and effective recovery of water, energy and fertiliser these systems can be highly cost efficient. Fresh water consumption can be reduced by up to 80% while nutrients can be recovered to a large extent. Source control is also advantageous for hygienic reasons: low volumes are far easier to sanitise. Source separation technology in municipal waste water treatment does often lead decentralised or semicentral systems. The first essential step is the separate collection and treatment of toilet waste in households, which contains almost all pathogens and nutrients. New toilet systems with very low dilution factors, ranging from vacuum- through urine sorting to dry toilets, have been introduced in several projects and proven feasible. New ideas such as the black- and greywater cycle systems are presently under research at the Technical University Hamburg Harburg. Such modular, integrated and small scale systems are only possible through recent advances in membrane technology and, due to their small scale, do have the potential to be installed in densely populated regions. These technologies are options for following the principles of ecological sanitation, to contain, to sanitise and to reuse also in urban areas (EcoSanRes, 2003).

Effect of Hydraulic Retention Time and Recycle Ratio on Anoxic/Oxic Bioreactor and Artificial Wetland Performance for Domestic Wastewater Treatment

“…+ -N and NO 3 --N removal The overall removal of NH 4 + -N by the reactor was 85% quite similar to that obtained by [8] . The average concentrations of NH 4 + -N in the influent, anoxic oxic and artificial wetland during the experimental operations were 11, 2.4, 1.1 and 1.5mg/L respectively.…”

“…The average concentrations of NH 4 + -N in the influent, anoxic oxic and artificial wetland during the experimental operations were 11, 2.4, 1.1 and 1.5mg/L respectively. The average removal of NH 4 + -N were 78, 85, 85, 88 and 89 % with effluent concentration of 1.9, 1.2, 1.3, 2.1 and 1.2mg/l operated with HRT of 5, 3, 2, 4 and 1hr respectively ( fig.…”

Integrated, Decentralized Wastewater Management for Resource Recovery in Rural and Peri-Urban Areas

“…This not only implies a higher cost of treating diluted wastewater (due to its larger volumes, and thus larger facilities needed), low energy-efficiency (bigger pumping and conveying facilities, implying increased operational costs for users) and less efficient energy recovery from wastewater (due to technological and process limitations); it also uses large volumes of treated, mostly drinking-quality water merely as a transport means for primary waste and system flushing. Otterpohl and co-workers estimated that by enacting source control and differential water use, new decentralized technologies could manage wastewater systems with just around 20% of the current water demand [54], which is usually drinking grade. Traditional systems are strongly dependent on electrical energy supplies for pumping, potentially making the system poorly resilient during exceptional events and power failures [55,56].…”

Policy Transformations and Translations: Lessons for Sustainable Water Management in Peri-Urban Delhi, India

“…Studies focusing specifically on wastewater reuse and management in peri-urban situations have argued that decentralised approaches may offer opportunities for wastewater reuse and resource recovery, as well as improvements in local environmental health conditions (Otterphol et al, 2002;Parkinson and Taylor, 2003).…”