KWAME NKRUMAH UNIVERSITY OF SCIENCE AND TECHNOLOGY

NAME: KPODO FREDERICK.

INDEX NUMBER: 9985113.

PROGRAMME OF STUDY: BSC ENVIRONMENTAL SCIENCE.

SOLID WASTE MANAGEMENT REPORT

REPORT ON A VISIT TO THE OTI LANDFILL SITE ON 23RD

NOVEMBER 2015.

OBJECTIVE

To understand the principles of solid and liquid waste management at the landfill site.

The processes that occur at the landfill site.

INTRODUCTION

A landfill site is a final disposal site where municipal solid waste is dumped, compacted or

flattened, covered with sand, and left to decompose or break down. It is also called ‘waste dumps’

or ‘rubbish dumps’.

In Ashanti region, the landfill which has been operational since 2004 consists of 4 cells and sits

on 100 acres of land It is scheduled to receive waste through 2020 and then close. By then, it is

projected to have 4,500,000 tons of waste .It has waste management facilities that would help

reduce the stench from the site and is capable of containing some of the solid and liquid waste

generated in the Kumasi metropolis. The Oti landfill was designed for a period of 15 years with

three phases and has been used for 11 years. (2004-2015)

At the entrance is a checkpoint; where people are checked before entering the site and a control

room; which has a weighbridge to measure the exact tonnage of waste materials generated every

day. It also helps them to know the weight of waste produced from the individual collection

stations. At the control room, every company’s name, where the waste is coming from and tonnage

are recorded and the source of the waste.

The landfill site is operated by the Kumasi Metropolitan Assembly (KMA) and contractors. There

are three methods of waste collection. One is the door-to-door collection; where vehicles collect it

from individual houses. Landlords pay for this. Secondly is the communal collection; where waste

is collected at the transfer station (temporal place of gathering waste) and the heap collection or

leftover collection. For every one (1) tonne of waste collected by a contractor, he is paid GHS

15.00. 1500 metric tons of wastes are generated in the Kumasi Metropolis but only 1300 metric

tons are collected. The remaining 200 tons may go to water bodies, animal feeding, into drains or

burnt.

SOLID WASTE MANAGEMENT AT OTI LANDFILL MANAGEMENT

According the guide, solid waste is managed by spreading first, compacting and covering. The

waste is deposited on an escavated ground after weighing. Bulldozer spreads the waste after the

trucks have brought them from the collection stations. Compacting machine is used to compress

waste into small bundles or volume treatment and should be covered. Due to financial constraints

a lot of the waste are not covered causing harm. The landfill has cells in which solid waste are put

and they have base areas of 1800m2 and 20000m2. The cells are in a form of a plastic bowl. The

waste is compacted to 25 meters before it is covered with clay. Underneath the compacted waste

are Geo-membranes, perforated PVC pipes with Geo textile covering, and stone chippings. When

it rains, the leachate drips through the profile into the pipes, then flows into the pond for treatment.

The pipes are in the form of a bone of a fish which are interconnected. The chippings sieve coarse

materials from the leachate. There are also gas outlets with the help of air vents and also Gibeons

(large rocks) to make the system stable and they use it to produce a little bit of biogas. The clay

separates the sub base water from the leachate. The Geomembrane which consolidates the clay

liner and prevents contamination of groundwater. Geomembrane lining is protected by the

Geotextile layer. Two new cells were under construction to increase waste intake. According to

the guide, hazardous waste is treated by EPA and hospital wastes are not brought there. When the

landfill is exhausted, the area can be used for a recreational site.

LIQUID WASTE MANAGEMENT AT OTI LANDFILL MANAGEMENT

The treatment of liquid waste is natural with no anthropogenic activities. The leachate with faucal

sludge are brought to the land fill site. There are nine waste stabilization ponds at the site. Six are

anaerobic ponds. Among the six, two receive the faecal matter and four support it so that the

retainsive time would be longer. There is also one facultative pond and two aerobic or maturation

pond. In the anaerobic ponds which is 3m deep, the solid components move down into the pond

and undergo anaerobic decomposition due less oxygen in low portions of the pond. The anaerobic

ponds are linked to each other and when liquid waste is put there it has to stay for about sixty days

(60 days) before it’s discharged. The two facultative ponds are shallow and allows UV rays to

enter, killing some microorganism. The maturation pond has life in them like alligator, snakes and

when they start dying, it means, there’s a need to check the system and companies also take

samples to test if it’s safe to discharge. After the faucal waste has been treated, its treated waste

and leachate are collected in another pond called steel basin for some time before it is channeled

into a nearby river body (Oda River). There are also bore holes to check if there are ground water

contamination from the ponds.

CONTRIBUTION OF THE SITE TO THE ENVIRONMENT

Noise pollution from the operation of compactors, excavators, dozers and other related machines.

Contamination of the nearby river which is a source of drinking water to the inhabitants

downstream.

CONCLUSION

Although landfilling is the most preferred method of waste management in Ghana, it also has

challenges which include unsustainable financial support, poor maintenance and the like. I

therefore recommend that, there should be enough financial support from both private and public

agencies of concern to help engineer the system up to the set standards. Proper maintenance

approaches must be employed to prolong the lifespan of the equipment(s) used and the site as a

whole. There should be other alternatives such as waste reduction and recycling strategies so that

there will be no pressure on the site.

REFERENCES

Mr. Wiafe, Deputy Manager at Landfill Site

Dr.B.Fei-Baffour (Solid Waste Management Lecture Notes.)