Urban net-zero water treatment and mineralization: Experiments,modeling and design

Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb. The purpose of this work was to identify a first design of a denitrifying urban NZW treatment process, operating at ambient temperature and pressure and circum-neutral pH, and providing mineralization of pharmaceuticals (not easily regulated in terms of environmental half-life), based on laboratory tests and mass balance and kinetic modeling. The proposed treatment process is comprised of membrane bioreactor, iron-mediated aeration (IMA, reported previously), vacuum ultrafiltration, and peroxone advanced oxidation, with minor rainwater make-up and H₂O₂ disinfection residual. Similar to biological systems, minerals accumulate subject to precipitative removal by IMA, salt-free treatment, and minor dilution. Based on laboratory and modeling results, the system can produce potable water with moderate mineral content from commingled domestic wastewater and 10–20% rainwater make-up, under ambient conditions at individual buildings, while denitrifying and reducing chemical oxygen demand to below detection (<3 mg/L). While economics appear competitive, further development and study of steady-state concentrations and sludge management options are needed.     

Developing a procurement path determination chart SEM-based approach

The choice of an appropriate procurement system is crucial to construction project success. Procurement selection is largely based on path determination charts, with at least eight key criteria needing to be weighted by decision-makers. Including certain criteria whilst ignoring client-borne transaction costs (TCs) resulting from environmental uncertainties simplifies this process. TCs are ‘unseen’ costs associated with pre- and post-contract work. The effects of uncertainties in the transaction environment and procurement systems on TCs are investigated, comparing the traditional and design-build procurement systems. A cross-sectional sample approach was deployed, involving survey questionnaire and results verification through ‘real-world’ cases. Data was sought from construction professionals in management, design and operation of construction projects. The research participants evaluate their time spent on procurement activities using a five-point Likert scale. Hypotheses of the relations between environmental uncertainties, procurement systems, and pre- and post-contract TCs are tested using a structural equation modelling (SEM) approach. The study found that TCs account for about 46.75% and 42.88% of the daily time spent by project managers in traditional and design-build procurement systems in New Zealand respectively. The study concludes that the TC concept is a useful framework for determining objective instead of subjective opinions for procurement decisions.     

Strategies for overlapping dependent design activities

Overlapping activities that are traditionally performed in a sequential manner can significantly reduce project delivery times. Overlapping, however, should be approached in a systematic manner to reduce the costs and risks. Information gathered from sector‐based case studies and from the manufacturing domain suggest a formalised framework for identifying overlapping opportunities and strategies can be successfully implemented for infrastructure projects. This framework considers activity characteristics, such as evolution of upstream information and sensitivity of downstream activities to changes in upstream information, to identify appropriate overlapping strategies. Overlapping strategies, such as early freezing of design criteria, overdesign, and early release of preliminary information, are selected based on activity characteristics. These strategies operate either by speeding up the evolution of upstream information or by reducing the sensitivity of downstream activities. By aligning overlapping strategies with activity characteristics, project managers can make better decisions on when and how much to overlap sequential activities to reduce overall project delivery time.     

A Review of “The Urban Wisdom of Jane Jacobs”

A large proportion of the urban population in developing countries lives in informal settlements due largely to rapid population growth and widespread poverty. Traditional regulatory measures—price control, minimum physical standards, eradication of squatter settlements, and urban growth control have failed to improve the housing conditions among the poor. More recently, international donor agencies have encouraged new policies based on affordability for consumers, and many developing countries are shifting their priorities to upgrading existing informal settlements and to sites and services projects for low-income settlements. Both traditional and recent government policies are guided by three key norms—unique occupancy, minimum physical standards, and one-step regularization—which are not in line with the individuals' behavior in the housing market. Therefore, governments and donor agencies need to critically examine the impacts of these norms and to consider alternative strategies such as multiple occupancy, adaptable shared housing, and multistep housing development.     

“They have good intentions”. Young People's Experiences of Living in Melbourne's Peri-Urban Areas

While contemporary urban theories suggest that individuals have transcended their geographical community, evidence suggests that urban residents still feel ‘attached’ to place. In the literature, several socio-demographic characteristics are associated with place attachment. Scholars suggest physical features, such as community ‘greenspace’, may also influence place attachment. Yet research does not consider the relationship between one's objective proximity to greenspace or the objective availability of community greenspace on residents' place attachment. This study employs multi-level models and draws on police incident data, census data, two spatial data sets and survey data from over 4000 residents living across 148 state suburbs in Australia to assess the relationship between greenspace proximity and greenspace availability on place attachment. Our findings indicate that greater proportions and more accessible greenspace may not improve residents' attachment to their local community.     

The Case of The Case Study in City Planning and Municipal Management

Abstract

PLAN FOR REZONING THE CITY OF NEW YORK. A Report by Harrison, Ballard &; Allen. City Planning Commission. New York. 1950. 290 pp. maps, illustrations. $2.00.

CONTROLLED ACCESS EXPRESSWAYS IN URBAN AREAS—A symposium. Highway Research Board Bulletin No. 25. Washington, D. C., 1950. 45 pages, illustrated. 60 cents.

SOCIAL PRESSURES IN INFORMAL GROUPS. By Leon Festinger, Stanley Schachter and Kurt Back. Harper Bros., New York, 1950. x-930 pp. $3.00.

PRODUCTION OF NEW HOUSING. A Research Monograph on Efficiency in Production. By Leo Grebler. Social Science Research Council. New York 1950. ix+ 186 pp. $1.75.     

Frustrations of National Planning: Reality and Theory in Colombia

Realities of national planning in Colombia are used as background for an examination of theory and models of national planning. Colombia is a democratic and relatively prosperous developing country of Latin America which has had a few periods of violent crises. National planning is highly centralized in Colombia along the lines suggested by several theorists in the United States. Yet the national planning function has been rife with frustrations and dubious successes. Such conditions merit examination of the theory of national planning in general.     

Critical Reasoning for an Enlightened Architectural Practice

The capitalist political economy plays a crucial role in shaping the built environment and how architects practice. Capitalist aims are often antagonistic to principles of good architectural practice and, as a result, the desires of practitioners to provide good architecture are colonized and politically debilitated. Architects who use social processes embedded with critical reasoning are more able to empower themselves politically. They are in a better position to design buildings that respond to human needs rather than being antagonistic to such needs. To prepare architects for such practice, more attention is needed in preparing students to think critically during their architectural education.     

Teaching Hazards Mitigation

Abstract

This article examines the formation, activities, and significance of a group dubbed the “London Conceptualists” by Peter Cook that were students of Bernard Tschumi at the Architectural Association School of Architecture during the mid-1970s. Through RoseLee Goldberg, director of the Royal College of Art, the students were introduced to theories of performance along with radical experiments in performance art. Goldberg's conception of space as an arena for the realization of theory goaded the London Conceptualists away from writing and drawing toward installations and performance in disused buildings. This article situates their activities in London in the late 1970s and analyzes their relationship to other performance art practices and to conceptual architecture.