Sanitary Sewer

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HIJ provides consultancy services for engineering and management of sanitary sewer collection and treatment in Asia and the USA. Our experience includes planning, feasibility study, design, as well as project preparation technical assistance and project implementation management in the field ofsanitary sewer.

Stormwater and sewage separated system: Sewage treatment is less effective when sanitary waste is diluted with stormwater, and combined sewer overflows occur when runoff from heavy rainfall or snowmelt exceeds hydraulic capacity of sewage treatment plants. To overcome these disadvantages, most modern cities built separate sanitary sewers to collect only municipal wastewater and exclude stormwater runoff collected in separate storm drains. The decision between a combined sewer system or separate systems is mainly based on need for sewage treatment and cost of providing treatment during heavy rain events. Many cities with combined sewer systems built prior to sewage treatment have not replaced those sewer systems.

HJI has extensive experience in following areas:


Biological nutrient removal, including modelling, and are skilled in advanced aspects of sludge processing including anaerobic digestion, associated heat recovery and energy generation.

HJI can manage all aspects of odor control, from initial optimization of processes to minimizeodor generated, to the installation of appropriate technology for the removal of odor. Our expertise covers both the development of new sites, and optimizing and extending the life of existing sites.Our expertise includes:

Feasibility studies

Conceptual and detailed designs

Operating and capital cost evaluation

Tender/contract preparation and analysis

Contract supervision

Site supervision and QA/QC

Facilities commissioning technical support

Environmental Impacts Assessment

Due diligence

Sewage treatment process optimization

HJI’s designs incorporate all conventional treatment processes, primary, secondary and tertiary treatment. Environmental issues such as odorminimization, containment, abatement, noise and visual aspects of treatment plant. Where appropriate, advanced treatment techniques and innovative design approaches are considered.

HJI’s aim is to provide solutions which are appropriate to our clients' needs. We consider projects on an individual basis to provide solutions that are consistent with discharge requirements and determine the most appropriate and cost-effective solution.

HJI’s approach to wastewater problems put emphasis on understanding the site specific mechanisms which affect process performance, before determining the most appropriate solution. Benefits to customers