IAM clears and maintains sewers continuously before typhoon and rainy season with over 400 tonnes of waste cleared in first quarter

Publish Date: 29/04/2022

With the upcoming typhoon and rainy season, the Municipal Affairs Bureau (IAM) clears and maintains sewers in various districts continuously with a focus on stepping up inspection in areas susceptible to floods. The silt clearing work in multiple low-lying areas has been completed, and over 400 tonnes of waste was cleared from public drains between January and March this year. Moreover, IAM continues to step up inspections of construction sites and food establishments and initiates prosecutions against violations of regulations. IAM appeals to the society to jointly protect the drainage network to safeguard the normal functioning of the drains.

IAM is responsible for the maintenance and clearance of about 500 kilometres of sewers, over 42,000 manholes, 73 municipal pumping stations and 186 marine outfalls throughout Macao. About 75% of sewers in Macao has implemented diversion of clear water and wastewater, while the old-fashioned combined sewers are mainly distributed in San Kio, Inner Harbour, S. Lourenço and other old districts. IAM handles the areas susceptible to floods with priority. From January to March this year, IAM has cleared more than 57,000 metres of sewers and catch basins for 5,500 times, in addition to completion of records and analysis of CCTV footage of about 7,500 metres of sewers. A total of over 400 tonnes of waste has been removed from public drains, an over 80% increase compared to the same period last year.

Solidified grease and cement grout block drains

During regular inspections and clearance of sewerage networks, solidified grease and cement grout are often found to obstruct the operation of sewers. This mainly involves food establishments which have not installed proper grease interceptors or have not cleared them regularly, causing the solidified grease to block the sewers, and illegal discharge of wastewater of construction sites, discharging untreated wastewater or construction waste to the public sewerage network. IAM continuously carries out operations with relevant departments and has inspected the grease interceptors of food and beverage establishments of 259 establishments/times in total. During the inspections, 28 written records were issued due to failure of the grease interceptors to perform the proper operational efficiency, and two establishments were ordered to close due to violations of the regulations and failure to make improvement as required. Meanwhile, inspections of the construction sites in various districts have been carried out for 152 times. 12 cases of illegal discharge of wastewater were uncovered, for instance, discharging wastewater containing sands and mud to drains in public streets without effective filtration process. Written records or accusation letters have been issued accordingly.

Regular focus on desilting and establishment of rainstorm emergency response mechanism

Every year before the approach of typhoon and rainy season, IAM carries out inspections and clearance of sewers, municipal pumping stations, rainwater catch pits, open channels and other facilities in low-lying areas susceptible to floods in advance. In addition, the locations where flooding occurred in the previous year have been followed up continuously, including Rotunda Flor de Lótus, Avenida Panorâmica do Lago Sai Van, the underground road tunnel at Oriental Arch, etc. The relevant departments have been contacted to handle and increase the frequency of clearance work at the locations concerned.

Upon the approach of a typhoon or rainstorm to Macao, the priority is given to inspection and clearance in low-lying areas susceptible to floods. If the yellow rainstorm warning signal or above is issued by the Macao Meteorological and Geophysical Bureau, IAM will activate the rainstorm emergency response team mechanism. Pumps will be turned on remotely for drainage of rainwater according to the real-time height of sea tides; staff will be sent to inspect the operation of rainwater pumping stations; pumps will be adjusted and controlled for speedy flood relief depending on the situations. When tropical cyclone signal no. 8 or a rainstorm warning signal is issued, IAM will send staff to be stationed at major drainage pumping stations. The outsourced emergency drain clearance personnel will be increased to 8 teams with a total of 24 persons, who will assist in the inspection and emergency clearance work in various districts throughout Macao. In addition, IAM has issued letters to the regulatory departments of construction licenses to assist in requesting large construction sites to send staff to be stationed at the sites during the typhoon and rainy season so as to cope with drainage emergencies.

Technology monitoring introduced to step up inspection and law enforcement

In view of the growing increase in the maintenance and management work of sewerage networks, along with the issue of aging of the frontline drain clearance personnel, IAM will strengthen outsourced services and management of information system (App) with the aim of elevating the speed and frequency of desilting work, continuously improving the inspections, desilting, tracing and recording of drains, and strengthening random inspections and regulatory mechanism. In addition, through the continuous introduction of advanced technology on the market, such as drain clearance robots for clearing box culvert drains, and utilisation of surveillance cameras (CCTV) in drains, IAM actively monitors the conditions of drains and steps up regular inspections each year to increase the efficiency in desilting and repair works.

IAM continuously optimises its inspection mechanism, including strengthening and increasing the frequency of inspections and carrying out joint operations with relevant departments. Follow-up, re-inspections, guidance on improvement and penalty are initiated against violations of regulations. IAM appeals to the public or businesses to refrain from pouring waste, grease and other substances to public drains in the streets. The sector is required to step up clearing of grease interceptors and wastewater filtration equipment in construction sites. Cement grout and other construction waste or grease must not be discharged to the public sewers. IAM has formulated the guidelines concerned for the sector’s reference. The information has been uploaded to the IAM website https://www.iam.gov.mo/e/resource/. The sector is welcome to visit the website and protect the drainage networks with joint efforts, so as to avoid affecting the normal operation of catch basins and drains.