Реагентная очистка различных видов сточных вод трехкомпонентной композицией

Представлены результаты экспериментальных исследований реагентной очистки сточных вод трехкомпонентной композицией (коагулянт, флокулянт, щелочной реагент), которые проводились в ООО «ДальВОДГЕО». Экспериментально подобрано соотношение реагентов в композиции, причем флокулянт растворяется в кальцинированной соде и вводится после коагулянта. Испытания на стоках от пищевых производств (с высоким содержанием органических и минеральных взвешенных веществ) при недостаточном щелочном резерве подтверждают большую эффективность очистки и меньший объем осадка в случае применения композиции по сравнению с раздельным вводом реагентов. Ключевые слова: сточные воды, интенсификация реагентной очистки, коагулят, флокулянт, подщелачивающий реагент, коагулирующая-флоккулирующая щелочная композиция The results of experimental studies of reagent wastewater treatment with a three-component composition (coagulant, flocculant, alkaline reagent), which were carried out at DalVODGEO LLC (from 2015 to 2018, when one of the authors, S.B. Kundenok, worked as a chief project engineer in this organizations), then jointly with the Far Eastern Federal University (2017–2020). The ratio of reagents in the composition was experimentally selected, and the flocculant is dissolved in soda ash and introduced after the coagulant. Tests on effluents from food production (with a high content of organic and mineral suspended substances), with an insufficient alkaline reserve, confirm the greater efficiency of purification and a smaller volume of sediment in the case of using the composition in comparison, with the separate injection of reagents. Keywords: waste water, intensification of reagent treatment, coagulum, flocculant, alkalizing reagent, coagulating-flocculating alkaline composition Contribution of the authors: the authors contributed equally to this article. The authors declare no conflicts of interests.

On the variability of squeezing behaviour in tunnelling

The magnitude of squeezing deformations in tunnelling often varies over short distances, even if there is no obvious change in the construction method, in the depth of cover, in the lithology or rock structure. As long as the reasons for the variability are not known, the tunnelling-induced convergences cannot be predicted with sufficient reliability. Reliable predictions, however, are important for determining the temporary support or the excavation diameter. Otherwise, large-scale tunnel repairs may be necessary, which can cause delay and additional costs due to remedial actions as well as due to the enforced interruption of other operations in progress at the same time. The analysis of different case studies concerning the AlpTransit project shows that the squeezing variability can be traced back to the heterogeneities in the rock mass at different scales as well as the variation of the orientation of the planes of anisotropy (bedding or schistosity) to the tunnel axis. In order to improve safety and economy of tunnel construction in squeezing ground, the influence of these factors on the convergences was determined quantitatively (by means of analytical solutions or numerical modelling), so that they can be used as indicators during construction for the timely identification and prediction of the squeezing behaviour. Particular attention was paid on factors, whose variation, even if small, may affect the convergences sensitively . Based on these quantitative investigations, design aids were developed, which should help the project engineer to estimate and better understand the variability of the squeezing intensity. The squeezing variability also concerns TBM tunnelling: In contrast to conventional tunnelling, shielded TBMs are particularly vulnerable to squeezing due to the very limited space available. Therefore, in order to better deal with the squeezing variability in TBM tunnelling, different (stiff as well as deformable) lining options were discussed.

STUDY ON FACTORS INFLUENCING LABOUR PRODUCTIVITY IN RESIDENTIAL BUILDINGS IN INDIAN SCENARIO

The construction sector is diverse as it contains contractors, consultants, designers, owners and others. Poor productivity of construction workers is one of the causes of cost and time overruns in construction projects. As construction is a labour-intensive industry, this paper focuses on labour productivity in the construction industry and to identify factors affecting labour productivity at building construction project. The performance of labour is affected by many factors and is usually linked to the performance of time, cost, work pressure, safety measures and quality. The questionnaires were distributed to supervisors, project Engineer, labourers, the top 35 factors were identified, categorized into 3 different groups, using SPSS tool, which is analytical software, the factors were analyzed and ranked considering relative importance index were calculated. And also calculated actual productivity for Brick Masonry is taken from sites. The result shows the factors considered which most affects the labour productivity loss in residential buildings and actual productivity versus expected productivity the brick masonry work were calculated.

Contractual liability of a project engineer

The paper focuses on the contractual liability of a project engineer and the consulting engineer, which means that misdemeanour and criminal liability will be neglected, as well as the moral duties that these persons have as members of an autonomous organization (in Serbia, it is the Serbian Chamber of Engineers). Non-contractual (tort) liability also remained outside the scope of the paper. The project engineer and consulting engineer are professionals - an architectural engineer, so a high degree of attention is required of them, expressed through the legal standard of a good expert. The requirement is that the project engineer acts independently, which means that he is not an employee and that he does not perform his work for the employer. There is no employment contract between the project engineer and the client. He assumes his obligation arbitrarily, by concluding a contract with the client. As neither the contract for the design of the building nor the contract for the supervision of the performing of works are regulated by the Law on Obligations, the content of the contract is left to the contracting parties. The aim of this paper is to determine the basis of contractual liability for the main obligations that project engineer and consulting engineer assume. The paper also focuses on trying to define the origin and basis of liability for the soundness of the building.

Framework for Assessing Resilience in the Communication Networks of AEC Teams

Architecture, engineering and construction (AEC) teams experience frequent changes in membership when delivering a project. While some of these changes are planned (e.g. phased involvement, role reassignment), others are unexpected (e.g. career change, sudden downsizing). Poorly planned or unexpected changes in membership can bring communication to a standstill and impair a team’s ability to deliver a successful project. By examining literature from civil engineering, as well as recent studies on network and team science, we propose a conceptual framework that places the formation, disruption and recovery cycle of communication networks in the context of a construction project. The purpose of this framework is to gain a better understanding of resilient communication networks at the project-level. To demonstrate the potential of this framework, email data was collected from the construction manager on an in-progress project that experienced an unexpected departure of their onsite project engineer. A week-byweek content and network analysis was performed for a period of one month to examine the impact of this change in team membership. The results suggest that the disruption in their communication network, measured as between a 40 to 50% loss in density, average degree and centralization following the departure of the Project Engineer, closely resembled the pattern of loss and recovery illustrated by the resilience triangle. Through discussion, the implications of these results at the project- and firm-level impacts are explored. Specifically, the framework demonstrated potential in forecasting vulnerability in a communication network by examining structural properties, such as high betweenness centrality relative to other members. However, we further that additional studies are needed to fully understand the dynamics and long-term benefits of more resilient communication networks, particularly as they relate to demographics and skillset of team members and the role of integrated delivery methods in promoting more robust networks.

Causes of delay on highway construction projects in Thailand

Delay in construction project is an important issue in construction management. This is because delay will cause negative impacts on both the owner and the contractor. For owner, it will lead to the late opening of new road. For contractor, it will cause extra operating cost. In this paper, therefore, the causes of delay in road construction projects are researched. This paper studied a list of road construction delay causes gathered from literature having different countries. Internationally, twenty-six factors that might cause delays of road construction projects are identified in this research. Among 26 factors, considering in Thailand, eight key factors are typically found as the cause of delays in road construction projects. These 8 factors are then prioritized to identify the most important causes of delays in road construction projects in Thailand. A questionnaire and personal interviews through project engineer have formed the basis of this paper. The study indicates that the 5 top factors affecting road construction delays are: incomplete drawings, lack of equipment efficiency or financial status of contractors, delay in relocating existing infrastructure structures, less of project engineer experiences, and delay in relieving environmental impact, respectively

Requirements and Solution of Barrier-Free Measures upon Architectonic – Construction Solution of Kitchen and Bathroom in a Flat of Special Determination

Healthy person does not often realize its certainty when he moves around in the flat and makes activities related to running of the household. Persons on wheelchairs, moving with crooks or walking stick, or otherwise handicapped, are in more difficult situation. Therefore barrier-free environment in flats defined for persons with limited ability of movement and orientation is very important. This group of people faces the biggest problem with barrier-free transfer when working in the kitchen, as well as when moving around in the bathroom or WC. In order to better understand the wheelchair person we have to take into consideration how this person moves around in the kitchen, how he gets from and on the wheelchair in the bathroom and WC. He movers either alone or with his assistant, therefore the project engineer shall also consider the handling space for another person when designing the size of floor area. Persons with handicap must deal with safe movement around their flat on everyday basis.

Proposal of Architectonic – Construction Solution of Barrier-Free Measures of Entry Premises in Non-Residential Buildings Specified for Use by the Public

Barrier-free environment should be an obvious part of our life. The reality is but different. In non-residential buildings specified for use by the public one can uselessly look for information useful for persons with limited ability of movement and orientation. The question of information boards is very disregarded and often non-dealt with at all. Upon entry into most of the buildings you will not find any optical system for deaf people, acoustic system (voice light) for blind people or information related to barrier-free access for people with movement handicap. Project engineer, upon performing his work has to take into consideration the fact that building being designed shall be used by all groups of citizens. Try to look around with eyes of a person who moves on wheelchair or through a walking stick. You will find missing information and orientation system on possibilities of barrier-free movement inside the building on each and every building.