Oceans are a common heritage of mankind and rich source of food and energy, cheapest means of transportation and a great blessing of Almighty Allah. Over millennia, oceans have facilitated trade and supported economies globally, resulting in rapid population growth in coastal cities. This population influx into coastal cities had in turn caused a detrimental effect on coastal waters andneighbouring seas. Moreover, industrial growth and modern urban lifestyle has resulted in production of non-biodegradable waste, chemicals and effluents, which are discharged without suitable treatment, primarily into the nearest water bodies, e.g. lakes, rivers, streams and ultimately their influx into seas.
Environmental problems like global warming, acid rain, air pollution, urban sprawl, waste disposal, ozone layer depletion, water pollution and climate changes are the phenomena, which have caused an imbalance in nature causing severe implications for human life as well as other creatures. Marine pollution has become a global concern due to its adverse effects on environment, marine life, marine infrastructure/ vessels, navigational safety, economy and human health.
Karachi, being the premier port cityand economic hub of Pakistan, is host to thousands of small and large industrial setups and ever growing population. The city generates approximately 500million gallons andover 16000 tons of liquid and solid waste respectively daily, of which only a small portion is treated and disposed of properly. Most of the effluent is discharged into various small rivers/ steams and eventually into the sea. This effluent also carries tons of solid waste with it and contributes heavily to the marine debris in Karachi harbour.
Marine debris in Karachi harbour has adverse effects on the shipping and fishing industry as floating garbage disrupts smooth operation of marine systems and contributes towards decrease in marine aquatic life. In order to control marine debris in sea, a number of techniques are being utilized worldwide, which include physically collecting debris using boom containment, nets and mechanized means through use of debris collection vessels.
Under auspices of national vision for Clean & Green Pakistan and Chief of the Naval Staff’s Initiative to promote Blue Economy, Pakistan Navy has taken various field level initiatives for preservation and protection of marine environment. These measures include installation of liquid waste treatment plants at various locations in PN areas, tree plantation in coastal areas, holding of seminars/ conferences on marine pollution and organising beach cleaning campaigns. In order to overcome the problem of marine debris in Karachi Harbour, Pakistan Navy has designed and built 02 x Marine Debris Collection Barges as per modern trends as a pilot project. After successful technology demonstration on a barge using mechanised conveyor belt technology, work commenced on design of Marine Debris Collection Barges. After an extensive review of existing marine debris removal systems/ technologies design of 8.7 m Marine Debris Collections Barge (MDCB) was completed. Based on this design, constructions of 02 x MDCBs have been completed followed by extensive trials in Karachi Harbour. MDCBs operate on the principle of utilizing a mechanised conveyor system to collect marine debris and transfer it to an onboard Debris Collection Basket. The barge can thus cover a reasonable area of the harbour and mechanically, collect floating solid debris with minimal human efforts. The collected debris can be offloaded at the designated jetty for further disposal. MDCBs have also been offered to other maritime agencies e.g. PMSA, KPT and KS&EW for removal of marine debris in their respective AoR.
Indigenous design and construction of the said barge was undertaken keeping in view the local marine environment, sea conditions in the harbour, debris classification and types and finally disposal. In order to address the requirements the barge is based on a twin hull catamaran design,which affords stability even in slightly choppy seas experienced within the harbour during monsoon season (April-September). Furthermore, the hull is constructed withmarine grade aluminium, which is less prone to corrosion and thus facilitates towards a longer hull life. For floating debris collection from the sea, amechanised conveyor system was designed by Ship Construction Departmentof PN Dockyard and the item was sourced locally and modified to ensure that debris collection is effective through use of grabbers on the conveyor. Marine debris collected by the barge is stored onboard in an open top removable container. Once the barge is alongside jetty this container is lifted over a garbage vehicle/ truck and its split bottom opened to deposit debris directly into the vehicle. The empty container is returned onboard and the barge can continue its debris collection operation. The barge can thus be operated with a minimal crew with mechanical means performing most of the tasks.An additional feature is installation of a solar panel on top of the control cabin for battery charging thus further contributing to ‘green’ energy.
Construction and utilization of mechanical means for collection and disposal of floating marine debris is an interim solution, which has been implemented by Pakistan Navy in the best interest of protecting the marine environment at Karachi Harbour. However, the key solution to preventing solid and liquid waste pollution lies in effective implementation of relevant regulations,adopting correct ways and means of handling solid and liquid waste being generated primarily on land by industries and municipalities.Until and unless strict implementation of relevant environment pollution control is not ensured, solid waste will eventually find its way back into the sea and create furthertoxic environment for marine life and shipping. Being one of the prime users of the sea, Pakistan Navy is concerned and proactively in search of ways and means to control marine pollution all along Pakistan’s coastline.