A number of issues can arise from incineration plant due to some factors like design of the plant, location and condition of waste supply.

1. depending on your design, air pollution could be prevalent. An incinerator could emit dioxins, and when such is above allowable limit, it is a serious public health concern.

2. When your waste supply is highly commingled without room for sorting, the plant could generate more toxic substances.

3. If the incinerator is not located away from residential area, fly-ash could cause problems to surrounding infrastructures, especially concrete houses, and could impact aesthetic value.

4.If the waste water generated from the facility is not managed with respect to cooling and treatment, there could be thermal and toxicity impact on biodiversity.

There are other disadvantages that depend on your interest - whether you meant disadvantage to the investor, other waste stream businesses, land use and others.

Waste to energy plants need a steady supply of feedstock like biomass. The unintended consequences of burning trash for power generation can be:

- Closing of recycling facilities to ensure that there is enough fuel for the W2E plant. If the plant is not sized to receive just residual waste, then the facility must receive all kinds of trash, including recyclable ones.

- Importation of waste for fuel. This was in the news in 2016 when Sweden imported garbage because it doesn't have enough to feed its W2E facilities. It might look good for some countries but it could be politically unacceptable for some (such as Canada exporting garbage to the Philippines which the latter then returned after a public uproar, and points scored by politicians who took advantage, although the garbage isn't for W2E).

- Encouraging a waste(ful) mindset. Instead of repairing broken items, designing products to last longer, recycling, composting--businesses and people would be encouraged to generate more waste, especially if the W2E facility incentivizes waste generation.

In addition to the difficulties already mentionned:

1) First of all, please check carefully if burning the available waste can reach a positive energy balance at all! Here, in Europe, the combustible fraction of municipal solid wastes has an average moisture content above 50 %. This causes a net energy deficit: drying it consumes more energy than the burning could produce. Therefore, incineration always needs a co-combustible, usually natural gas here. With selective waste collection and increasing plastic recycling, the situation is getting even worse for incinerators.

2) Air pollution is really difficult to control when the fuel is municipal solid waste. If the burning temperature is too low, you emit PAH and dioxine. If it is too high, you emit NxO. The usable margin between the two is really narrow.

3) The combustible fraction of municipal solid wastes has a high ash content, it may easily reach 10 %. In Europe, incinerator ash is under the hazardous waste regulation, due to its high concentration of toxic metals. Then, large-scale operators often have difficulties to pay the fee of disposing such a huge amount of hazardous waste.

Despite all these draw-backs, incineration is still widely used because it is often the least bad choice. Especially in large cities like Paris, for instance.